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Digest of miscellaneous electronics and effects articles
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Newsgroups: alt.guitar
From: bk233@cleveland.Freenet.Edu (Jack W. Weinmann)
Subject: Theremin and Voice Effects Board information
Organization: Case Western Reserve University, Cleveland, OH (USA)
Date: Sun, 30 Aug 92 11:46:57 GMT
There is a good article about the theremin (including an original circuit
diagram) in the July 1991 edition of Popular Electronics magazine on page
66 in a column called "Antique Radio."
There is also and article on a Digital Voice Effects Board in the September
1992 edition of Radio Electronics magazine on page 37.
I have not tried the Voice Effects board and I cannot verify whether it
works or not. I simply mentioned this for anyone who is interested in
reading about these two effects.
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Newsgroups: alt.guitar
From: mwang@sedona.intel.com (Michael Wang)
Subject: Re: Building effects units for guitars
Organization: Intel Corporation
Date: Tue, 8 Sep 1992 17:10:45 GMT
In article <1992Sep8.080946.15963@fel.tno.nl>, jsgn3@fel.tno.nl (Jos Groot) writes:
>
> I wondered whether readers have DSP algorithms (or pointers to them) to get
> well-known guitar effects, like flanging, phasing, chorus or distortion.
>
> --
> Jos Groot (jos.groot@fel.tno.nl)
> Physics and Electronics Laboratory TNO-FEL
> P.O.box 96864
> 2509 JG The Hague, The Netherlands
I'm not up on my DSP algorithms, but I might be able to give you a start.
Chorusing is essentially taking the "straight" signal, delaying it by a
small amount (or several different small amounts) and mixing all the
resulting signals back together. Some chorus effects also allow the delay
times to be modulated back and forth, giving kind of a wavering effect to
the sound.
Phasing is, I believe, taking the straight signal, delaying it by a time
interval that is swept back and forth ( i.e. delay by 0, then delay by 1,
then delay by 2, then delay by 1, then back to delay by 0), and mixing the
two signals back together. This gives the sound kind of a "sweeping" effect
as the delayed signal goes between adding and cancelling the original.
Distortion is changing the shape of the waveform itself. Exactly how the
shape changes gives the different types of distorted sounds. You might
start with simply clipping the peaks and squaring them off. I'm not sure
what that would sound like, but that is "classical" distortion in electronic
circuit design.
Hope this helps.
Mike Wang
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Newsgroups: sci.electronics,alt.guitar
From: grey@bnr.ca (Bryan Miller)
Subject: Re: Building effects units for guitars
Organization: Bell-Northern Research Ltd.
Date: Wed, 9 Sep 1992 13:39:21 GMT
In article <1992Sep8.080946.15963@fel.tno.nl>, jsgn3@fel.tno.nl (Jos Groot) writes:
|> I wondered whether readers have DSP algorithms (or pointers to them) to get
|> well-known guitar effects, like flanging, phasing, chorus or distortion.
|>
|> Thanks in advance, Jos Groot
|>
|> --
|> Jos Groot (jos.groot@fel.tno.nl)
|> Physics and Electronics Laboratory TNO-FEL
|> P.O.box 96864
|> 2509 JG The Hague, The Netherlands
Sorry Jos,
I had code to do some of those, but abandoned it when I came to work here.
I wrote some myself and just twiddled the parameters. Mike Wang's suggestions
should give you a good start there. (btw, band limiting gives a pretty good
distortion effect). I can say, though, that you need to write the code VERY
efficiently. If your sampling rate drops below ~30kHz, you'll lose the treble,
and it sounds pretty bad.
I know for a fact that there is some code out there, so try archie to look
for it (I can't do that from here). Or post a question to comp.dsp
Good Luck. Keep us posted if you find some good quality effects. I'll post
mine if I can get them from my old accounts.
Grey
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Newsgroups: alt.guitar
From: META000 <META@UNB.CA>
Subject: Re: In search of the ultimate Chorus effect (for guitar)
Organization: The University of New Brunswick
Date: Tue, 22 Sep 1992 14:13:16 GMT
The best chorus I ever got was sending my guitar through a splitter to
two amps, one driving a little Leslie speaker at slow speed, and the
other with tremolo set for a slow speed and moderate depth. Put these
two babies at either side of you, and get ready to forget the words to
every song you know. It's a terrific effect, but VERY distracting.I
suppose an equivalent might be to use two independent phasers set for
slightly different parameters, going to two different amps, or two
separate flangers or chorusses doing the same dance.
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Newsgroups: sci.electronics,alt.guitar
From: bonobo@Ingres.COM (David Victor)
Subject: Re: Increasing pickup gain
Reply-To: bonobo@Ingres.COM (David Victor)
Organization: Ask Computer Systems Inc., Ingres Division, Alameda CA 94501
Date: 29 Oct 92 20:35:46 GMT
In article <1992Oct29.015948.28552@samba.oit.unc.edu> Richard.Banks@bbs.oit.unc.edu (Richard Banks) writes:
>
>So, can someone send me an ascii schematic of a compressor,
>give step by step instructions on how to build one, or direct me
>to references and articles that have either of the two former
>contained in them.
>
>Thanks.
> - Rich
Check out the latest edition of Electronic Musician (I think it's them).
They have an article on how to build a stereo compressor...
-David Victor
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Newsgroups: alt.guitar
From: META000 <META@UNB.CA>
Subject: analog flanger mods
Organization: The University of New Brunswick
Date: Thu, 12 Nov 1992 23:21:06 GMT
Several people had e-mailed me to ask for the flanger mods I had
hinted at in an earlier epistle. Here they are.
Most analog delay devices (this includes delay lines a la DM-3, as
well as chorusses, and flangers) have two insertion points where a
few simple component changes, coupledwith a toggle switch or two can
yield a whole new palette of sounds.
The principle is simple. Recirculation (aka regeneration or
resonance or repeat), and mixing (aka depth, intensity, etc.)
controls simply introduce different proportions of the delayed
signal back into the delay loop (with recirculation) or into the mix
(with the intensity or depth control). One needn't be restricted to
simply AMOUNT of delay signal. By use of different filtering
capacitors, one can also adjust WHAT gets recirculated or mixed.
For instance, ifyou trace the input to the recirculation control
(i.e., the one at left, looking from the back, with the lugs at 7to
5 o'clock) it should lead back to a capacitor anywhere from 0.1uf to
10uf in value.If you replace that cap with one half that value, the
lower frequency cutoff will be raised by one octave; if you replace
with a cap 1/4 the original value, the low end rolloff goes up two
octaves, and so on. Do this and there will be disproportionately
more high end recirculating, which should lead to a sharper flanging
or chorus sound, and to a kind of "dub" echo sound for delay
lineswhere each iteration gets thinner and thinner. If you perform
a similar replacement on the mix/intensity depth control, what you
get is that the bassier side of the flanged/chorussed/delayed signal
is less prominent in the mix. Incidentally, I did this to the
reverb control on an old Gibson amp I used to have, and the reverb
went from annoying and boingy to bright and airy. I recommend it.
Ideally, one would be wise to replace the original blocking
capacitor with one 1/10 the original value, andthen, using a 3-way
mini-toggle, switch in other capacitors inparallel to get something
around 1/4, and something roughly equal to the original value.
Depending on the space available, this may be hard to do, but need
notbe impossible in your basic floor box, as long as you're willing
to be creativeabout where the switch gets mounted.
A second, almost inverse, mod involves filtering outnot the LOW end
of the recirculated or delayed signal, but filtering out the HIGH
end. There are two ways. One involves soldering a capacitor (about
1000 - 2200pf should usually be enough) between the input to the
control(the leftmost lug again) and ground (usually the chassis of
the control). The second involves connecting the same cap between the
wiper (centre lug) and ground. The first one gives a fixed filter,
while the second one decreases the filtering effect as you turn the
control up.
I highly recommend this latter mod for delay lines (echo type). I
find it really cleans up the grit from sound that has recirculated
through a long delay. You'll find that the sounds produced by
combinations of high-cut and low-cut of recirculated and delay
signal can make more natural sounding ambiences, and help to make
the delay and straight sounds distinct from each other, rather than
one being a slightly distorted copy of the other.
I'm not alone in these recommendations or design features. PAiA
electronics' "hyperflange" employs a variable bass-cut circuit in
the recirculation path of its' premier flanger/chorus in order to
tame recirculation so that it doesn't oscillate into a squeal or
howl when you crank the resonance up.
Overall, this should cost you no more than $10 at RadioShack prices,
and should rejuvenate your analog delay devices. I think you'll be
pleasantly surprised with the new palette that's available.
The only constraint or caveat I needto mention here is that you
should make sure any polarized caps you use or replace are oriented
at the same polarity (+/-), and that you perform such mods only on
clearly analog boxes whose mix and recirculation controls have one
lug (the rightmost) connected to ground, acting in attenuator mode.
Lastly, any ofthese mods will obviously void your warranty.
Mark Hammer
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Newsgroups: alt.guitar
From: irc_ss@vax.clarku.edu
Subject: Soldano Hot Mod II
Organization: Clark University
Date: 2 DEC 92 05:18:36 GMT
I was just reading a review of the new Soldano Hot Mod in the latest
Guitar Player magazine and was wondering if anybody has had any
experiences with it. I've been thinking of getting a distortion pedal
but the more I think about it, the better an option the HM sounds. I
promise to post a summary of all replies I get.
I have a Marshall Artist head (also recommended by Guitar Player!).
For those who haven't read the new GP, the HM is a replacement for the
second tube in your amps. It gives the effect of modifying your amp to
give "over the top" gain and sustain. It retails for list $150.
Shyaa.(see you in drunk)
/)
/ \
\_/ ********** Life is what happens to you ***********
|_| ****** while you're busy making other plans ******
|_| J.Lennon
|_| _____ _ _ _ __ _ _______ _____ _
|_| / ___ \ | | | | (_) | \ | ||__ __|/ ___| | |
/{-|_|_)\ | / |_| | | | | _ | \| | | | | (___ | |
\+|=== +/ | | _ | |__| | | | | |\ | | | _\___ \ |_|
)|=== ( | \___| | | __ | | | | | \ | | | | \___) | _
/+\=== o\ \_____/ |_| |_| |_| |_| \_| |_| \_____/ (_)
\+ ###\o/ Box 571,Clark U,950 Main,Worcester,MA 01610 (508)755-6544
`-----\
`=
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Newsgroups: rec.music.makers.bass,rec.music.makers.guitar
From: till@acid-rain.lucid.com (Don Tillman)
Subject: Re: what exactly is a "small stone"?
In-Reply-To: tom@cpac.washington.edu's message of 24 Jan 93 10:59:53 GMT
Organization: Lucid, Inc.
Date: 24 Jan 93 11:05:32
From: tom@cpac.washington.edu (Tom May)
Date: 24 Jan 93 10:59:53 GMT
Phase shifters are not part of the flanger/chorus/echo family. A
phase shifter also delays the signal, mixes it back in, uses feedback,
and has a modulated delay, BUT the delay is achieved with an opamp
unity-gain phase-shift circuit which produces a DIFFERENT amount of
delay for different frequency components (actually, there are usually
six of these circuits in series). This produces a much different
sound from chorus/flange, although both flange and phase are comb
filters, it's just that the comb looks different.
Right. A phase shifter comb will have 4, 6, or 8 notches distributed
evenly over a few octaves. A flanger comb will have a large number of
notches distributed evenly per Hz (so the first octave will have 1 notch,
the second 2 notches, the third 4 notches, the fourth 8, and so on).
Since a phase
shifter is not just a tweak on the flanger theme, I don't have the
foggiest idea how they simulate it in digital multi-effects boxes, and
Trivial actually; just implement the z-transform equivalent of:
s-1
F(s) = ( ---- ) ^ N
s+1
(where N is 4, 6, or 8)
, and mix with the original signal. Any text on digital filters covers
this. For some reason though no digital noise box seems to have as good a
phase shift sound as the analog phase shifters. Since the digital boxes
are all closed up it's impossible to tell what the problem is; could be the
DAC, the ADC, the accuracy of the DSP chip, a goofy algorithm, anything.
-- Don
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Newsgroups: rec.music.makers.guitar,alt.guitar
From: dnj@kauai.verity.com (Dave Johansen)
Subject: Re: Wha + distortion (was Re: Adding master volumes)
Organization: Verity, Inc. 1550 Plymouth Ave, Mt. View, CA 94043
Date: Mon, 25 Jan 93 18:01:54 GMT
This is an interesting thread that has been around for quite a while..
The general consensus has been to wha before distortion boxes as this
give the "most dynamic range" according to the wha manufacturers.. The only
other seeming valid reason I've heard for wha --> distortion was from
Eric Johnson in the GP article on distortion... His feeling was that
to run high gain pedals before "tone" type devices had a tendancy to OVER-drive
the wha, chorus, etc, etc devices giving them a harder edge... I tried
this and found distinct differences between the two... I stuck with
the wha-distortion as this appeals to my taste.. I found that wha after
distortion gave a really dramatic sweep, but gave me the impression
of sweeping the distortion and not the sound of the guitar.. before
the distortion gave me a sweep of the tonal characteristics of the guitar..
This may seem blatantly obvious, but it gets more extrinsic as you start
worrying about choruses, reverb and the like and which order these go into..
The rule of thumb I've always heard was tone devices, then distortion/gain
and then time domain devices (echo,chorus,flange,reblurb,etc....), But rules
are meant to be broken.... Thank <insert favorite deity>, or none of us would
be having these or any other discussions....
-dnj
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Newsgroups: rec.music.makers.guitar
From: fdvlba@zia.aoc.nrao.edu (Fort Davis VLBA site)
Subject: Re: Electronic projects for musicians
Organization: National Radio Astronomy Observatory, Socorro NM
Date: Mon, 1 Feb 93 22:04:29 GMT
>P.S. And here is another related electronics question - does anyone
>have a pointer to a decent solid state schematic for a tone control
>suitable for guitar applications having most of the following
>features (especially the mid control):
>Bass control
>Midrange control
>Treble control
>Presence control
>Loudness switch
If you roll off or on both tone controls, you can effectively get midrange
boost and cut (if your tone responses are set up properly, i.e. with a gap
between ranges affected). All I had room for was volume, treble, bass in
my Strat. I got my circuits from the Coughlin-Driscoll Op amp textbook I
used at school (the blue and yellow one). They have a tone circuit that
uses only one op amp with treble and bass in the feedback loop. I used
the other amp in the package (TL081? the ratshack bifet 8-pin) for 3x
voltage boost.
Both tones cranked up act like a loudness control, with a bathtub-shaped
frequency response. A presence control is found in the final amp circuit
of some tube amplifiers, and has no application for onboard guitar that I
know of.
__
Steve Cowell, tube amp freak...
scowell@vlbacc.aoc.nrao.edu
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Newsgroups: alt.guitar
From: META000 <META@UNB.CA>
Subject: Re: BOSS EH-2
Organization: The University of New Brunswick
Date: Sun, 4 Apr 1993 21:57:07 GMT
In article <93092.092631KLH110@psuvm.psu.edu> Karl Houseknecht <KLH110@psuvm.psu.edu> writes:
>Na: it's just a glorified bright switch. Don't even bother to waste your $20.
>.
>.
I can't speak to the BOSS EH-2 in particular but I will say that
"enhancers" need special conditions to work well, unless they happen
to be top-of-the-line (and even then, some conditions need to be
met).
1) The general design is that the midrange and up is distorted
(which adds higher harmonics but very little of those - i.e., 2nd,
3rd, etc. - which are added by fuzz-boxes) and then recombined to
add extra harmonic content to the original untampered signal.
2) Three conditions must be met: a) the signal must have some high
end to begin with [basses don't fare so well here in most cases], b)
the signal must be of sufficient amplitude to BE distorted by the
circuit or else there can be no harmonic content added, c) the
sound reproduction system must be capable of reproducing those extra
harmonics [this includes both amplfier and speaker bandwidth]; many
popular amp speakers won't do terribly well at producing that slick
Nile Rodgers rhythm sound, and most systems set up for a distorted
sound probably won't sound very different with such a gadget
engaged.
3) I built the "Harmonic Sweetener" that appeared in EM a few years
ago (a Jules Rykebusch design). It was super-cheap (about $8 Cdn
worth of parts), and, within limits, worked reasonably well. One
thing became apparent though. If you don't start with a noise-free
signal going into the box, these things sound like your tuner
drifted between stations. Consequently, one should see these things
either as something earlier in the signal chain, or at least AFTER
a noise gate.
4) Not for the metal-head. These are for folks who like a
shimmering rhythm sound, full of finger glisses and such, or for
folks who want their Les Paul to sound like Les Paul's (now THAT's
clarity!)
Mark Hammer
P.S> I think I'll phone about this one!
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From: dam@dcs.glasgow.ac.uk (David Morning)
Newsgroups: alt.guitar
Subject: Dave's Wah Pedal From Hell (Was: Wah-Wah
Date: 15 Apr 93 10:55:41 GMT
Organization: Glasgow University Computing Science Dept.
wohlbier@cae.wisc.edu (John Greaton Wohlbier) writes:
>when you (can't recall who wrote the article) said that a wah wah is a variable
>bandpass...do you mean that the band width is variable or that the
>band just shifts across the frequency range?
In the cheap early ones, the bandwidth is constant and the centre frequency
just shifts.
Fancier one using state variable filters use constant Q, they sound different as
the bandwidth varies with frequency.
Look up a state variable filter in an active filter book for these.
You should find the simple constant bandwidth one there too...oh here! Try this
You'll need to tweak it for your desired range, current values give 300 ~2K2 Hz
sweep..
0.022uF
-----------||-------------
| |
| --/\/\/\/-----------|
| | 220k |
| | |
| | |\ |
| | | \ |
In o---/\/\/\-----||-----|- \
10k | 0.022uF | \ |
| | \ |
\ | >--------------------o Out
56ohms / | /
\ ---|+ / TLO 71/72
| | | /
\ | | /
/ | |/
2k \<- |
/ | |
| | |
o------------------------------------------------o Gnd
The 2k pot is the sweep range. It'll probably need an input buffer before it
as its input impedance is low, so maybe a dual op-amp like the TLO72 would be
better.
Bandwidth is around 150 Hz.
Dave
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Newsgroups: alt.guitar
From: META000 <META@UNB.CA>
Subject: EQ/Guitar-Mimicry/PAiA
Organization: The University of New Brunswick
Date: Fri, 14 May 1993 21:03:55 GMT
In response to several requests, this is a kind of omnibus posting.
1) PAiA Electronics makes a number of different tone-altering
gadgets, including a 4-band parametric equalizer. They can be
located at: 3200 Teakwood Lane, Edmond, OK 73013, (405) 340-6300,
fax (405) 430-6378. A drum machine kit of theirs is currently on
display in the June 1993 issue of Electronics Now (formerly Radio
Electronics). I've been dealing with them since 1978 and highly
recommend them. Get hold of their catalog. There are plenty of
goodies for the electronic guitarist, and they are generally about
60% of the cost of buying the commercial equivalent (IF you can find
it; their kits are generally highly unique and highly flexible in
their design). If you are a solder-phobe, have no fear. Their kits
come with copious documentation and will up your level of knowledge
of how to build and modify things.
2) I posted an item recently about a schematic in Electronic
Musician magazine for a tone-altering device that would mimic
different pickups. I located my copy of the schematic, and much to
my dismay, there are a few things different than what I cited in my
posting. First, I couldn't find the exact issue number, but since
it refers to a recent article in a December 1986 issue of EM, I can
only assume that it would have been printed sometime in early 1987.
Second, Craig Anderton states at the outset of the article that the
circuit is for simulating different **wiring** combinations of
pickups (e.g., series, out-of-phase, etc.). This is not the same as
a Gibson-to-Fender converter but has some merit on its' own. The
circuit consist of a buffer section that feeds 5 bandpass filters (tuned
to 115, 230, 670, 1040, and 2240 hz respectively), plus a highpass
filter (set for around 7khz), plus an all-pass section that lets one
combine an in-phase or inverted version of the original signal, to a
final mixer stage. This latter feature allows one to have the
original with notches or peaks at different resonant frequencies
(although not both), or have several select resonant bands. The
highpass section is for adding "sheen" to the original sound (it
boosts the high end a bit).
3) On the topic of guitar-mimicry, there has been some discussion of
"why don't you just get another guitar?" Some writers have responded
that they would rather just swap guitars when they want to change
their soundrather than futz around with controls and programming.
Good points, but there are times when you want a wholly different
sound for different bars in the same song. It would be nice to step
on a button and do that, without a Rick Neilsen 7-neck behemoth, or
a cotterie of roadies tossingyou guitar 5b. On my own guitar (a
rather bastardized early 60's Epiphone Coronet), I have a 3-pickup
configuration of Strat-style pickups (don't ask, I wound them
myself), and have replaced a variable tone control with a 3 position
toggle switch. The switch selects between bypassing the tone
roll-off ( nice feature), and one of two high-cut capacitors. I
forget the exact values, but one is probably about .015uf and the
other about .0047uf or thereabouts. The .015uf is just shy of the
usual tone control value (typically .02), and gives the usual mute
sound of a fully backed-off tone control, but the other cap gives a
completely different voicing, due to the resonant circuit created by
the inductanceof the pickups, the resistance of the volume control,
and the capacitance of the tone cap. The only thing I can liken it
to is a Fender-to-Gibson converter. Personally, I'm partial to
"sparkly" settings like the neck+bridge settings on Telecasters and
ES-335's. I find the small-value tone cap takes off the "sheen" of
the single-coil pickups and gives me a bit more bite in the upper
midrange/lower treble. Obviously, the full meat of a humbucker is
unobtainable in this situation, but the high end really changes
character substantially. You can have the same pickups selected,
flick the tone switch (it's passive), and it sounds like you've
engaged some kind of sophisticated EQ-ing. A bit of an oversell, I
suppose, but surprisingly effective for the minimal amount of
technology involved. So, how do you do it?
Most tone controls consist of a 250-500k pot wired up to the input
of the volume control. Either a wire will go from the volume
control to the tone control (and a capacitor is wired from the one
of the tone-control lugs to the tone-control casing) or a capacitor
is wired from the volume-control input to the tone control, and the
tone-control case is wired directly to one of the tone-control lugs.
Either way, you have a variable resistor in series with a capacitor,
going to ground. Remove the existing capacitor, and replace it with
a smaller value. Experiment until you find a value that gives you a
fair degree of bite, but removes the real high end. Those of you
withtwin volume/tone controls can try replacing the tone-control cap
for the*rear* tone control and leave the front one intact. This way
you can switch between varying degrees of mellowness with the front
pickup, and use the rear for varying degrees of bite. I emphasize
that this tone control trick is for taming a sizzlingly crisp
single-coil into something vaguely resembling a side-by-side
humbucker. It will *not* turn the latter into the former. For that
I recommend one of the cheesy Aphex clones (and a lot of EQ-ing).
Mark Hammer
---------------------------------------------------------------------------
From: khe@hpfcso.FC.HP.COM (Keith Erskine)
Date: Tue, 15 Jun 1993 21:28:00 GMT
Subject: Re: Speaker emulator circuit
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: rec.music.makers.guitar
In rec.music.makers.guitar, you@where.ever.you.are writes:
> The Mesa Tri-axis simulator uses a simple TLO72 connected as a semi
> integrator
> - a small cap in the feedback loop shunting a resistor - to give a
> constant
> rate rolloff and it drives that into an RLC circuit to give a resonant
> peak
> around 4kHz. LF cut off is around 50Hz. This is the closed back system.
> In the open backed system, the cap is removed giving a flat (read
> brighter)
> sound, the LF roll-off goes up to around 200Hz and the resonant peak moves
> down to around 3.3kHz.
>
> I ran the schematic to the Mesa Tri-axis simulator through a shareware
> simulator, PC-ECAP, to get those results. I then matched the curve with a
> reverse engineered home brew using a quad op-amp - TLO74.
>
> Dave
Good info on the Mesa Tri-axis simulator, thanks!
Where did you get the schematics, from Mesa?
I want to get stereo outs from the speaker simulator output, do
the schematics indicate how difficult/easy it would be to do that?
Thanks mucho,
Keith Erskine
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Newsgroups: rec.audio,alt.guitar
From: jayceem@macs.ee.mcgill.ca (Jean-Charles Maillet)
Subject: Trading Guitar Pedal Circuits
Organization: McGill University - MACS Laboratory, Montreal, CANADA.
Date: Tue, 29 Jun 1993 02:05:16 GMT
I'm looking for an ibanez tube screamer (ts-5 or 9) schematic. I'm
not even sure if it's got a custom chip in it. Anyhow, I've got schematics
for MXR's Dyna Comp, Distortion +, Electro Harminx Small stone and Big muff,
The Univibe, Roger Mayer's cry baby upgrade plus a cool Marshall JCM800 mod
for strat players.
---------------------------------------------------------------------------
Newsgroups: alt.guitar
From: META000 <META@UNB.CA>
Subject: chorus <--> flanger mods
Organization: The University of New Brunswick
Date: Fri, 2 Jul 1993 17:31:59 GMT
Those of you who have to decide between buying a flanger OR chorus
for budgetary reasons, or who have one of each and want to try what
it sounds like to have two of each, consider the following:
The basic difference between a flanger and chorus (other than the
kinds of controls they usually come with) is the delay range they
cover. In most cases, the delay chip they rely on to achieve that
difference in time delay is exactly the same chip, made to perform
differently on the basis of a few external components.
One of the most popular chips used for analog flangers and chorusses
is the MN3207, made by Matsushita/Panasonic (it is a cousin of the
MN3007). The time delay range it covers is determined by its'
associated clock-driver chip, the MN3102 (or MN3101). If you take
your flanger/chorus apart and find these babies inside, you will
likely find a small value capacitor beside the 3101/3102 (somewhere
between 5pf and 100pf, depending on the model/function). Decreasing
the value of this capacitor REDUCES the time delay, while increasing
it LENGTHENS the time delay. You'll likely find something in the
range of 5-20pf for flangers and 20-47pf for chorusses.
By replacing the existing cap with a small value one (e.g.,
6.8-10pf) and installing a 3-position toggle switch to either add in
one of two other capacitors in parallel, or use the replacement
value alone, you can switch between flanger, short chorus, and long
chorus. Not unlike the "range" switches found on some pricier units.
I bought a cheesy chorus for $20 from a pawn shop and modified it in
this manner and it works great. Obviously a two-knob chorus (rate,
depth) does not make a full-fledged flanger, but within those
limitations I've got a very flexible chorus for the price of a toggle
switch and two caps (about $3.00). If you have a 4 or 5-knob
flanger, upping the delay range can create some really interesting
sounds.
You can probably bank on a value of 6.8-10pf getting you standard
flanger sounds, a combined value of 20-25pf (e.g., 10pf + 15pf in
parallel) getting you those sounds that don't sound like the
standard boxy flanger tone, and a combined value of double that
(e.g., 10pf + 39pf in parallel) getting you the standard spacy
chorus sounds. Feel free to fart around from there, although you
probably shouldn't go lower than 5pf or higher than 100pf without a
noticeable deterioration of sound.
A word of caution: this will void your warranty (if you still have
one).
Mark Hammer
P.S.: This is for analog only, not for digital.
---------------------------------------------------------------------------
Newsgroups: rec.music.makers.guitar
From: dam@dcs.glasgow.ac.uk (David Morning)
Subject: Re: HELP:Real tremolo desired
Organization: Glasgow University Computing Science Dept.
Date: Mon, 20 Sep 1993 09:54:00 GMT
Hyram Ballard <GLGYHRB@OTAGO.AC.NZ> writes:
>G!day,
>Does anyone know of a schematic or effect unit that produces real
>tremolo, not that weird chorused stuff found on most. I!d like an actual
>amplitude modulation device with variable depth and speed. All the old
>valve amps used to have these almost as standard! What do the C&W folks
>use to produce this sound??
What? The old amplitude modulated thingey? It's quite straight forward.
Simplest is just a resistor and a photo-resistor forming a potential divider.
Shine a LED on the photo-resistor and the volume goes down, turn the led off
and the volume comes back up. Now drive the LED with a sine wave at around
2Hz and instant tremelo.
Vary the amplitude of the sine wave and it varies the depth of tremelo, vary
the frequency of the sine wave and it varies the frequency of the tremelo.
You might get away with a triangle rather than a sine wave at a pinch.
Check out the Nat Semi Linear Data book for stuff. For a photo-resistor, you
should be able to get a hold of an ORP-12 down there in NZ.
Dave
---------------------------------------------------------------------------
Newsgroups: rec.music.makers.guitar
From: till@acid-rain.lucid.com (Don Tillman)
Subject: Re: Reverb circuit
In-Reply-To: npstewar@eos.ncsu.edu's message of Mon, 29 Nov 1993 14:44:19 GMT
Organization: Lucid, Inc.
Date: 30 Nov 93 00:46:42
From: npstewar@eos.ncsu.edu (NATHAN PHILLIP STEWART)
Organization: North Carolina State University, Project Eos
Does anybody have a good source for reverb tanks?
Accutronics are the folks who made all the classic reverb tanks that we
know and love. They're still around, though nowadays they're called Sound
Enhancements, Inc. (Perhaps they were taken over by another company?)
Anyway, you can get hold of them thusly:
Sound Enhancements, Inc.
185 Detroit Street
Cary, IL 60013 USA
708 639-4646 (humans)
708 639-4723 (fax)
They'll be happy to send you a brochure, pricelist, and an application
note.
-- Don
J. Donald Tillman, Consultant
Software Engineering, Analog Electronics
Palo Alto, California 415 327-6234
Internet: Till@Lucid.com
[Not affiliated with Lucid, Inc.; as a favor they allow me use of their
network connection.]
---------------------------------------------------------------------------
From: bnorris@ece (Bill Norris 7-0108)
Newsgroups: alt.guitar,alt.emusic
Subject: Re: Algorithm Search - Chorus, Reverb, etc...
Followup-To: alt.guitar,dc.music,alt.emusic
Date: 10 Sep 1994 05:54:32 GMT
Organization: Oakland University, Rochester, Michigan, U.S.A.
References available on request.
For starters there are periodicals like the Computer Music Journal
or the Journal of the Audio Engineering Society. These are naturally
rather technical, but hey, so are we, right? They are also rather
expensive, so just find a good library where you can waste afternoons
reading back issues.
Or you can buy a book like "Foundations of Computer Music" edited by
Curtis Roads and John Strawn. (MIT Press) This collects articles from
the above journals as well as others. And then each article has a
bibliography of other articles, so you can do more research than you
really want to.
A more all-in-one approach is offered by F Richard Moore in Elements of
Computer Music (1990 Prentice-Hall), ISBN 0-13-252552-6. He has plenty
of algorhythms (sic) but they are written in "c music", something I have
never used and I got tired of reading about it.
So there ya have it. Drop me a line some time.
William Norris
bill@mugwump.eng.wayne.edu
---------------------------------------------------------------------------
From: ljh@teleport.com (Larry Huntley)
Newsgroups: alt.guitar,dc.music,alt.emusic
Subject: Re: Algorithm Search - Chorus, Reverb, etc...
Date: 11 Sep 1994 03:07:37 -0700
Organization: Teleport - Portland's Public Access (503) 220-1016
In <34rhmo$6pi@oak.oakland.edu> bnorris@ece (Bill Norris 7-0108) writes:
>References available on request.
See the July 1994 Dr. Dobb's Journal for an introduction to all these
algorithms written by our own Dennis Cronin.
- L
--
Larry Huntley Portland, Oregon Guitars/Organs/Electronics/Computers
"Look at _this_. Ever seen one of _these_before_? I built _this_ for you.
What do you mean, 'What the fuck is it?' It's a goddamn ETUDE, asshole."
Frank Zappa, "The Real Frank Zappa Book"
---------------------------------------------------------------------------
From: rgonzal@gandalf.rutgers.edu (Ralph Gonzalez)
Newsgroups: rec.music.makers,rec.music.makers.guitar,rec.music.makers.bass,rec.audio.pro
Subject: Re: Hi-Fi tube amp as bass amp
Date: 9 Dec 92 20:09:27 GMT
Organization: Rutgers Univ., New Brunswick, N.J.
fredh@cv.hp.com (Fred Handloser) writes:
>Awhile back there was a discussion of using an old Hi-Fi tube amp
>as a guitar or bass amp. I can't find that thread. If anyone has
>the thread I would appreciate it if they could mail it to me.
>I have an old Sherwood Model S-1000II 36 watt tube amp that I'd
>like to use as a practice amp for my bass. It seems to work
>for that purpose. I'm using a speaker cabinet that is suited to
>bass. Will using this old amp with a guitar or bass harm the
>amp? The guy I got the amp from said he tried to play his guitar
>through it and it started to smoke so he stopped. I used this amp
>tonight for about 1/2 hour and it did not smoke.
I've used a Dynaco Mark III 60w tube mono amp for my bass. It is
intended as a hi-fi amp. Seemed to work fine. I used a Dyanaco
preamp with it as well, modified to take a 1/4" plug.
I don't think it would be too easy to blow out a tube hi-fi amp,
but I wouldn't use a transistor hi-fi amp unless it's pretty
hefty. If you put too much signal through a tube amp it will
distort a lot but in most cases this won't make it run a lot
hotter than it's already running on idle. On the other hand,
you can blow a transistor pretty easily by putting too much
current through it...
Probably the main advantage of a public-address tube amp is that
it is built rugged and has handles, 1/4" input jacks, mixing
pots, etc.
By the way, mono tube hi-fi and PA amps are pretty cheap. In the
ads in the back of The Audio Amateur or Speaker Builder (for hi-fi
enthusiasts) I often see 30-60w mono tube amps for under $50. The
reason is that someone has only one mono amp which isn't much use
for a stereo hi-fi...
-Ralph
PS: you can get info on Audio Amateur and Speaker Builder magazines
at 617-924-9464, or write to PO Box 243, Peterborough, NH 03458.
--
Ralph Gonzalez, Computer Science, Rutgers Univ., Camden, NJ
Phone: (609) 757-6122; Internet: rgonzal@elbereth.rutgers.edu
---------------------------------------------------------------------------
Newsgroups: rec.music.makers.guitar
From: scowell@Mr-Hyde.aoc.nrao.edu (Steve Cowell)
Subject: Re: talkboxes
Organization: National Radio Astronomy Observatory, Socorro NM
Date: Fri, 10 Jun 94 17:25:18 GMT
Here is the proper homemade talkbox:
Materials:
6' of 3/8 or 1/2" Tygon hose
1 full-range horn driver, screw-on type... University preferred
A/B switch
small champish amp
PVC adaptors driver to hose
First find the driver. Don't get caught climbing the pole at your
local ballfield late at night... order one of the drivers from
MCM Electronics.... about $45 new, midrange titanium is OK.
Take the driver to your local True Value or other hardware store
and find the PVC fitting that will screw on the the threads with
minimal forcing. I think this is 1 1/4" double female. Piece
together the reducers to get down to 1/2" ID. In the same store
you should find the Tygon hose... you can go inside or outside
the adaptor. My best sounding talkboxes used copper up to the
mic, then a short piece of hose. Experiment...
Attach the driver as the speaker of the small amp... you can actually
place the driver in the back of the amp if you like. Run the hose up
the mic stand (you do have a mic/stand, don't you?) with a little
poking past the front of the mic... experiment here too.
Put the A/B switch between your guitar and the two amps. Switch it
when you want to talk.
Things to watch for...
Dont use much bass through the driver.
Place a slobber loop in the plastic hose.
Ground both amps to the same place.
A little distortion makes the effect better.
Experiment with open/closed throat.
If your main amp is near 20w, you can switch the speaker instead of
A/B'ing the input. Dont do this with a 100w amp... solid state amps
don't like their loads being switched while in use.
Horn drivers are much superior to speakers for this, imo...
--
Steve.....scowell@aoc.nrao.edu
---------------------------------------------------------------------------
From: circuitdes@aol.com (CircuitDes)
Newsgroups: rec.music.makers.guitar
Subject: Re: Talkbox plans wanted, please...
Date: 13 Jun 1994 12:38:03 -0400
Organization: America Online, Inc. (1-800-827-6364)
In article <CrBBFy.JB6@murdoch.acc.Virginia.EDU>,
sha3u@fermi.clas.Virginia.EDU (Scott H. Andrews) writes:
In response to the talk box plans, I would definitely NOT follow the
Craig Anderton plans. The reason? If you are going to make your own
custom talk box, why not make it a real effects unit? You don't have
to be limited to using two amps. You can build your power amp circuit
into the box along with a switching circuit and have two outputs so
you can adjust mic and guitar separately. I recently built a custom
unit such as this for one of the musicians who contacted me through
aol.com
This unit was comparable to the price of the Heil unit which is just
simply a box with a speaker in it and a tube.
Mike Putnam
CircuitDes@aol.com
Circuit Design Music Electronics
PO Box 5415
Central Point, OR 97502
(503) 664-7904
---------------------------------------------------------------------------
From: ceh1@acpub.duke.edu (Charles Eric Horowitz)
Newsgroups: rec.music.makers.guitar
Subject: HOW TO MAKE YOUR OWN PEDAL/EFFECTS
Date: 19 Jun 1994 23:15:30 GMT
Organization: Duke University; Durham, NC; USA
On the subject of making your own pedal,
which is something I am about to do, here is what I am
planning to do and hopefully shouldnt encounter much difficulty.
MAKE SURE YOU READ THIS WHOLE ARTICLE THROUGH IF YOU ARE
PLANNING ON DOING THIS FOR THE FIRST TIME. IT CONTAINS
THE BASIC PROCEDURES AS WELL AS A COUPLE GOOD HINTS AND
SUGGESTIONS.
First, while looking for a project for my Integrated Circuits course,
I was paging through a Popular Electronics magazine from 1967-1983
in out Engineering Library. After that year, there were no more,
but I later found it had changed names to (I think) Electronics Now.
Anyways, I came across circuits for a Wah Wah, Fuzz Box, something called
a UniMod which has several tone controls, tremelo, and a couple other
things, and an envelope follower(or something close to that).
To build a pedal, first find a circuit like I did. Xerox the whole article
out of the source and read it thouroughly. See if what they say
is within your realm of knowledge. If it is, then figure out
what parts you need to get.
Youll probably want to do this on a PC Board because its cheaper and
smaller than a breadboard. There are PC Boards Kits
available at Radio Shack, but they arent very good. To make a PC
Board, first buy a PC Board. Make sure by checking with the diagram
in the magazine that its big enough. Get a drill bit that
is 1/16" or smaller. Buy a resist-ink pen.(look for that specifically
in Radio Shack as its a fantastic pen, it should be in its own
package with that name.) If you cant find one, buy an Extra-Fine Sharpie
felt tip pen. Get some very-fine steel wool. Buy a bottle of PCB Etchant
>from Radio Scrap, and if you can, buy a bottle of Resist Ink Remover.
If you cant find the remover, then you may have to buy the kit, which
comes with a bottle of it, but ask around first.
Now youve got the materials for your board. Make several copies of the
board diagram. (Thats the black and white picture with all the connections
between holes on it, but nothing else drawn in). Now, tape the picture
onto a PC Board on the shiny side if you have single-sided PCB, or either
side if you have double-sided. Cover the whole diagram with tape to keep
it on the board. Now using the tiny drill bit, drill all the holes into
the board. After you have done that, take your extra-fine steel wool and
clean the shiny side of the board very good. After doing this, try to
be careful when handling the board. Any dirt or fingerprints can ruin the
outcome of this project. Now that its clean, you have to draw all the
connections using your resist-ink pen. You have two options here.
One, you can just sit down and try to draw it, but this takes a lot
of time and a lot of foresight so you dont draw to big and end up ruining it.
Or you can get some carbon paper, and tape it to the board, and with a ball
point pen, go over the entire circuit diagram, so you have it ready and
all you have to do is go over the image with the resist-ink pen, but in
my experience, this doesnt help that much and it does take a while.
Either way, you will end up drawing your circuit on the PCB shiny side,
with the resist-ink pen. If you dont get a very good pen, you may
have to double over all you drawing, and thats a real pain, so you
may want to test this whole process on a small board first. Now your
circuit is drawn. Pour some Etchant
*****WARNING*****
This stuff can stain almost anything if nopt removed within
a few minutes, so be careful with it and dont let it sit in the
sink or anywhere you spill some, for too long(including your hands!)
(the stuff that looks like iodine into a non-metal container, preferable large
enough to contain the board and allow some volume to shake it around a little.
Put your board(make sure it is clean and that the ink on it is solid)
into the etchant.
It sould cover the board. It works best is you gently rock the etchent back
and forth over the board(maybe not best, but quickest). The copper
covered side of the board will begin to turn a pinkish color, but it is not
near from done. When the whole board is the color of the uncoppered side,
which for you double-sided people is a light yellow, then its probably done.
Pull it out with a pair of pliers(gently!) or some plastic so not to stain
your hands, and hold it under a cold faucet for 2 minutes. All the copper
should have dissolved away, except for the resist-ink. Now dry the board,
and spill a little resist-ink remover on the board and gently scrub
with a sponge until all the ink is gone, and lo and behold your PC board
is done, almost! Use the steel wool to clean the remaining copper and
if on the other side some "shrapnel" is left over from the drilling,
use a file to remove it as this side can be abused without consequences.
Now your board is done.
Now go buy all elements(resistors, capacitors, chips, etc.) for the board.
If Radio Shack doesnt have things you need, you may have to order them.
Call 1-800-DIGIKEY for a catalog of parts.
Buy jumper wire, and pc-board rosin core solder. Now just solder parts
on as called for.
Two Notes,
1) When dealing with potentiometers, if the circuit says that it is used
to control something(volume, gain, etc.) be sure to leave enough length
on the leads to reach to the outside of whatever housing you will mount it
on. If the circuit says it is a fixed pot(You set it once, and leave it
alone) Then there are PCB pots which a really small and more convienient.
2) Be sure to test your connections periodically with a Ohm-meter. Make
sure what should be connecting read an ohm or two, and parts that dont,
read zero ohms. If there is even the slightest problem, go back an fix it.
For those of you who have never soldered before, honestly, you pick
it up real quick. Remember, anything you try for the first time, do it
on a test board. Dont risk your whole project. Try soldering a resistor
or two on a test board, and do it real close together to see how to keep
them from connecting.
Now, everything should be close to done. First thing to do is test your
board with an oscilloscope,etc. Make sure no ridiculous outputs are
coming out that could damage you circuit, amp or guitar.
Final words, this could take quite a bit of time (24 hours of work.),
so take it slow and think every part through before doing it. One mistake
and you may have to start over. Another suggestion is to ask an Electical
Engineer for help in the technical side of things. Any EE whose a sophmore
or higher in college should eb able to help you read diagrams, and get access
to a soldering iron and oscilloscopes, power sources, etc and help you
test your circuit.
Good Luck, and if there are any questions concerning this article,
dont hesitate to e-mail me.
CHUCK
ceh1@acpub.duke.edu
---------------------------------------------------------------------------From dave@tyrell.net Sun Feb 12 12:16:56 1995
Newsgroups: alt.guitar.amps
Path: zip.eecs.umich.edu!panix!bloom-beacon.mit.edu!world!uunet!news.sprintlink.net!news.tyrell.net!tyrell.net!dave
From: dave@tyrell.net (Dave Bales)
Subject: Re: Op-Amps for Preamp Use
X-Nntp-Posting-Host: tyrell.net
Message-ID: <D3uLqx.8DH@tyrell.net>
Sender: news@tyrell.net (*)
Organization: Tyrell Corporation - 800-TYRELL-1 - POP's in 504/816/913/316
X-Newsreader: TIN [version 1.2 PL2]
References: <3hesms$cvm@newsbf02.news.aol.com>
Date: Sat, 11 Feb 1995 18:23:20 GMT
Lines: 13
Although they haven't been state-of-the-art for some time, I've used 5532's
for a lot of stuff (compressors, pre-amps, analog drums, etc). They're not
4136 pin-compatible, but they're quiet and cheap.
Just an opinion.
Dave in KCMO
JERRYCORK (jerrycork@aol.com) wrote:
: Does anyone have any favorite op-amps they have had success with in
: instrument pre-amps? I would very much like to find a pin-compatible
: replacement for a Ratheon 4136 if anyone knows of one.
: Jerry Cork
: Moscow, ID
From jmurphy@mercury.sfsu.edu Sun Feb 12 12:17:11 1995
Path: zip.eecs.umich.edu!panix!bloom-beacon.mit.edu!world!uunet!news.sprintlink.net!howland.reston.ans.net!agate!news.ucdavis.edu!csus.edu!mercury!jmurphy
From: jmurphy@mercury.sfsu.edu (James Murphy)
Newsgroups: alt.guitar.amps
Subject: Re: Op-Amps for Preamp Use
Date: 11 Feb 1995 22:28:22 GMT
Organization: San Francisco State University
Lines: 13
Message-ID: <3hjdm6$ia6@news.csus.edu>
References: <3hesms$cvm@newsbf02.news.aol.com>
NNTP-Posting-Host: jmurphy%@mercury.sfsu.edu
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JERRYCORK (jerrycork@aol.com) wrote:
: Does anyone have any favorite op-amps they have had success with in
: instrument pre-amps? I would very much like to find a pin-compatible
: replacement for a Ratheon 4136 if anyone knows of one.
: Jerry Cork
Use something with a fet input, like a TLO62.
James
: Moscow, ID
From stout@tardis.et.tudelft.nl Wed Feb 15 13:12:28 1995
Path: zip.eecs.umich.edu!caen!usenet.cis.ufl.edu!usenet.eel.ufl.edu!news.bluesky.net!udel!news.sprintlink.net!EU.net!sun4nl!news.nic.surfnet.nl!tudelft.nl!liberator.et.tudelft.nl!tardis.et.tudelft.nl!stout
From: stout@tardis.et.tudelft.nl (Rob Stout)
Newsgroups: alt.guitar.amps
Subject: Re: Op-Amps for Preamp Use
Date: 15 Feb 1995 13:48:25 GMT
Organization: Delft University of Technology, Dept. of Electrical Engineering
Lines: 8
Message-ID: <3ht0n9$kft@liberator.et.tudelft.nl>
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> Use something with a fet input, like a TLO62.
I guess TL072 and TL082 are less noisy.
Rob.
--
Email: stout@tardis.et.tudelft.nl -- Tel: +31 15 783643 (TU) or +31 15 625214
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