Guyatone - PS-021 Guitar Exciter  [schematic]

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Guyatone - PS-021 Guitar Exciter

Postby Tham » 30 Sep 2016, 01:19

Many did not realize that Guyatone's PS-021 Guitar Exciter
was one of the most versatile and unique pedals of the
mid-80s.


This ''PS'' range of effects was also rebranded under Nady.


http://www.qsic.jp/?pid=104385586

http://item.rakuten.co.jp/yasukukaeru/y1989071/



I found the circuit some time ago, downloaded it, deleted it
and am still trying to locate the website again.

It's based on the LM324 quad op-amp.

Turning the ''Exciter'' knob to the left generates even harmonics
- simulating a valve amp/distortion, and turning it to the right
gives out odd harmonics, that of a transistor amp/distortion.

No other pedal has the capability of doing this to this day.

It's unfortunate Guyatone has long discontinued this PS range
of effects. Their current ''Micro'' range is a shadow of their
former range's design and versatility.
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Re: Guyatone's PS-021 Guitar Exciter

Postby Warpeggio » 01 Oct 2016, 00:03

Direct control of the harmonics sounds pretty interesting - would love more info.
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Re: Guyatone's PS-021 Guitar Exciter

Postby Tham » 20 Oct 2016, 04:37

This guy describes exactly what I was trying to tell you people
about this effect.


'' My friend used one on his setup around 1986, in line after the
distortion unit, such as Boss’s Heavy Metal. You could get
virtually any kind of distortion sound with it, because the “Color”
control, you can vary the harmonics from even to odd.

The “Exciter” adds a brilliance to the sound, similar to the
Aphex Aural Exciter, so it can even be used for vocals. ''

'' With the “Color” turned to the left, around 9 o’clock, you
would get even harmonics, close sounding towards a
tube amp’s distortion.
Placed after the distortion, you
could step on it when you wanted to do a solo, as it would
boost your sound level up as well. This was a versatile,
superb and underrated effect, and none of the
other effects manufacturers made an equivalent unit.
''

'' The closest I could find at that time was Dod’s Harmonic
Enhancer, and this had no “Color” or compressor built in.
Boss had no such effect in their immense armamentarium.
Most guitarists were ignorant of the existence of this effect.
''


http://www.guitarandpedal.com/guyatone- ... 80s-japan/




However, I think he a mistake when he said the ''Color'' control
varies the sound from even to odd harmonics. It's rather the
''Exciter'' control, as you may note from the tiny waveform icons
at the left and right corners of the knob.

The ''Color'' was more like a tone, brilliance or ''enhancer'' control.


I too ordered Dod's Harmonic Enhancer from the US at that time, and
it was a pale design compared to Guyatone.
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Re: Guyatone's PS-021 Guitar Exciter

Postby Tham » 07 Dec 2016, 04:42

After making a similar post on this great effect in the DIY Stompbox
forum, one of the members there actually ordered one.

Here's his video in it.


Link




The main part of the circuit is built around Sanyo's LA6324
quad op-amp, of which replacements are the LM324, uPC324
and HA17324.

The sustainer/compressor part of the circuit is built around
the envelope shaper IC, the LM3080 transconductance amplifier.
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Re: Guyatone's PS-021 Guitar Exciter

Postby Tham » 02 Feb 2017, 04:22

Here's another exciter circuit.

I think the "Phase Shift" switches between odd and even harmonics,
and couldbe replaced by a variable resistor like that of the Guyatone's.

http://www.guitarelectric.eu/schematy/E ... ml#schemat
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Re: Guyatone's PS-021 Guitar Exciter

Postby Dirk_Hendrik » 02 Feb 2017, 08:12

Odd circuit . Seems like a treble booster where the signal is phase shifted, then the top end is filtered out, amplified a little and mixed to taste to the original signal. My best (whichj is not extensive) idea of Exciters was they add harmonics to the signal
Sorry. Plain out of planes.

http://www.dirk-hendrik.com
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Re: Guyatone's PS-021 Guitar Exciter

Postby Tham » 16 Feb 2017, 03:32

The Guyatone exciter was used and popularized by Tomoyatsu Hotei,
the lead guitarist of the Japanese pop band, Boowy, in the 1980s.

That is why when you search for the Guyatone PS-021 on the net,
especially in those Japanese auction sites, you will see the name "Boowy"
listed along with the Japanese description of it.


Link
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Re: Guyatone's PS-021 Guitar Exciter

Postby Tham » 16 Feb 2017, 03:36

Strange, this forum seems to have no button to edit the post.

Here's the Tomoyatsu Hotei video again, in case the earlier link
does not work.


[youtube]https://www.youtube.com/watch?v=4zHRkkVxVwY[/youtube]
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Re: Guyatone's PS-021 Guitar Exciter

Postby Tham » 25 Feb 2017, 00:01

Another exciter by the Lell, the Russian company.

LELL EX-9 EXCITER.


http://www.lell.ru/php/template.php-btn=1&m_id=10.htm


Note that it also enhances even harmonics.

Translated :

" Exciter enriches signal higher even harmonics (overtones) in
the midrange and high-frequency areas, the number of harmonics
is proportional to the amplitude of the signal.

The effect is obtained by means of exciter can not be created any other way. "

https://translate.googleusercontent.com ... UahgSV3r6w
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Re: Guyatone's PS-021 Guitar Exciter  [schematic]

Postby aionios » 30 Oct 2017, 20:53

(Cross-post from DIYSB: http://www.diystompboxes.com/smfforum/i ... c=115148.0)

PNG: https://aionelectronics.com/schem/guyatone_ps-021.png
PDF: https://aionelectronics.com/schem/guyatone_ps-021.pdf

Let me know if anything looks wrong and I can double-check.

The compressor half is nearly part-for-part identical to a Dynacomp, with the exception of the Sustain knob (and yeah, I triple-checked the R10 resistor value: green-blue-yellow... that and the value of the Sustain knob itself are the only components that are different).

The exciter portion looks pretty familiar too:
http://experimentalistsanonymous.com/di ... xciter.gif

The bass version uses the same PCB, so I assume it's just a matter of swapping out a few capacitors here and there. I've got the bass version as well (the PS-020), so I'll get that one cracked open before too long and post the changes for that version.

I'm planning on putting together a DIY PCB project for this which will probably be available shortly after the new year. But in the mean time, I thought I'd make the schematic available for anyone who wants to have a stab at putting one together on their own, or just studying it.
Aion Electronics - DIY PCB projects for classic and obscure circuits

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Re: Guyatone's PS-021 Guitar Exciter

Postby albru80 » 31 Oct 2017, 15:52

Thank you for the schematic!
I want to draw a layout but I'm not sure about something:
to completely eliminate the flip flop switching from the schematic would you get rid of Q9, Q10, Q11, R15, R16, R20, R40, R41, R69 and C10?
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Re: Guyatone's PS-021 Guitar Exciter

Postby mirosol » 01 Nov 2017, 08:09

aionios wrote:(Cross-post from DIYSB: http://www.diystompboxes.com/smfforum/i ... c=115148.0)
I'm planning on putting together a DIY PCB project for this which will probably be available shortly after the new year..


Please do! I'd be interested in purchasing a PCB.

Way i see this, it's like dyna comp to simplified bbe stinger to BMP tone stack :) A friend collects Guyatones and from experience i can say this is one hell of a pedal.
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