Guyatone's PS-021 Guitar Exciter/Compressor

[Tham]

I'm no guitarist, but know a little about electronics, and built a
couple of distortion boxes based on projects in electronic magazines
for a guitar friend during the 80s.

Guyatone's PS-021 Guitar Exciter/Compressor, was one of
the most versatile effects of the 80s, and is one that should
definitely be built.

Their range of effects was also made by Nady, presumably under licence.


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

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


I found the circuit diagram some time ago, but can't locate the
website anymore.


Placing a distortion pedal before it and turning the ''Exciter'' control
to the left gave out even harmonics, essentially that of valve distortion.

[Mark Hammer]

Interesting pedal.  Was not aware of that one.  Thanks for drawing it to our attention.

In some respects, it is a predecessor of later attempts to re-introduce the treble bite that seems to frequently be removed by compression.  I wonder how they did it.

[Tham]

I made a post about the exciter in this local guitarists' forum
years ago.

It's based on the LM324 quad op amp.

https://forum.lowyat.net/index.php?showtopic=1559773&view=findpost&p=36338118



Revised link of the local supplier.

Very low cost. RM 1.50 = US 35 cents.

http://synacorp.my/v2/en/amplifier-comparator/270-lm324.html

[Tham]

Interesting pedal.  Was not aware of that one.  Thanks for drawing it to our attention.

In some respects, it is a predecessor of later attempts to re-introduce the treble bite that seems to frequently be removed by compression.  I wonder how they did it.

You are welcome.

It doesn't really retain the treble bite.

It radically changes the output waveform.

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

No other effect pedal on the market can do that
to this day.

There were other ''exciter'' pedals like Dod's FX-85
Harmonic Enhancer, but they enhance the harmonics
of the original sound, mostly odd ones. giving more
presence.

http://www.americaspedal.net/fx85/

[Tham]

Here's an ''exciter'' circuit using the TL072.

http://www.guitarelectric.eu/schematy/Efekty/Inne/Exciter.gif.html#schemat

[StephenGiles]

The there is this exciter circuit:

http://groupdiy.com/index.php?topic=889.0


and my goodness - this one!!!

https://www.dropbox.com/s/x66sbryzdt3i7ar/104e_sch.jpg?dl=0

[Mark Hammer]

Virtually all exciter circuits require extended bandwidth from both the pickups and amplifier speakers.  People have a tendency to come into music stores, plug a humbucker-equipped guitar into an amp with four twelves (that roll off above 5khz) and ask "Is this thing even on?".  That's one of the reasons why many name-brand attempts (DOD, Boss, Aphex, et al.) at exciter pedals never really took off - because many consumers didn't understand the contexts in which they would be useful or even audible.

This demo video seems to present the PS-021 to good effect:

[Tham]

The video doesn't really demonstrate the PS-021's potential,
as he just played it clean.


Way back in 1986, I bought one and let Hillary Ang, one of
the top rock guitarists here at that time, try it. Intially he just
played it clean into his practice Peavey amp and it didn't
sound anything special.

When I met him again a few days later however, he begged
me to let him use it at his performance at this local rock cafe
for the next few weeks, because it was ''really good''.

I then went to the cafe to check him out.

When he soloed, he stepped on both the exciter, connected
after his Boss DS-1, and a DD-2 digital delay after it.

His sound suddenly became much more dynamic, punchy
and fatter with presence.

He used a Fender Strat with a Seymour Duncan jazz neck
humbucker in the bridge, and a single coil in the neck, with
a Marshall JCM 800.

I took a look at the PS-021 on his stage and he had turned
the''Exciter'' control all the way to the left, giving out even
harmonics.

I think the ''Color'' control was at the 9 to 10 o'clock position,
with ''Sustain'' at 2 o'clock.

[digi2t]

Just found one at a reasonable price. What the heck, I'll pick it up and open it up. Should have it in a couple of weeks.

This intrigues me.

I do have one of these monsters...



Never used it much, let alone trace it. Probably has nothing in common with the Guyatone, but might be interesting to investigate.

[Tham]

Just found one at a reasonable price. What the heck, I'll pick it up and open it up. Should have it in a couple of weeks.

You got one at a bargain price ?

Good for you.

It is being sold at some of these Japanese auction sites
at really high prices, some over 12,000 yen.

[Tham]

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-ps-021-compressor-and-exciter-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 symbols 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 the Guyatone.

[bluebunny]

I do have one of these monsters...

When are you gonna put the wheels back on that pickup truck, Dino?   

[digi2t]

When are you gonna put the wheels back on that pickup truck, Dino?   

Dunno... but I did find a picture of them casting the pedal...

[Tham]

Administrators :

The ''Bold'' function in the text window does not work.

And it would be good to include a button to upload files and images.

Virtually all major forums have this facility, including that at
Free Stomp Boxes.

[bluebunny]

This is really the wrong place to raise this, but anyway...  Aron provides space in the Gallery to upload pictures in case you don't want to host them elsewhere (e.g. imgur.com).  Take a look in the "READ THIS BEFORE..." thread.

[duck_arse]

when you say

The ''Bold'' function in the text window does not work.

are you meaning this button?

when I type "it seems to work", then highlight "it seems to work" and press the B for bold, it seems to work fine.

[Ben Lyman]

I think it may not work on all computers because it doesn't work on mine either. Not a big deal to me.
I suppose one could find OTHER ways TO ACCENTUATE THEIR TYPE   

[bluebunny]

GOOD IDEA BEN; YOU FORGOT COLOURS   

[PRR]

> upload files and images.

The forum has no funding. Free to use and essentially zero ads. Image space costs real money. There are many fine free hosting services. I like PostImg.org

> The ''Bold'' function in the text window does not work.

Works for some people (browsers), not for others.

when I type "it seems to work", then highlight "it seems to work" and press the B for bold, it seems to work fine.

I see:


Page source: (brackets replaced)
{br /}when I type "it seems to work", then highlight "it seems to work" and press the B for bold, {strong}it seems to work{/strong} fine.{/div}

I believe different renderer engines, zooms, and font settings interpret "strong" differently.

[digi2t]

Came in today. Here are some pictures;









I had a few minutes tonight to play with it, just guitar in and out to my small practice amp. I'm really rather impressed! It's a really cool tone shaper. There's really no bad settings on this puppy. You can go with settings that brighten up your sound, but not overly so, to settings that help enhance the lower frequencies. For instance, I can kill coil on my bridge humbucker, but that tends to induce a bit of buzziness to plucked open D, B, and E strings. Adjusting the Color and Exciter pots smooth's that right out, resulting in a nice full, buzz free sound, but still retaining that single coil feel. On the neck humbucker, again, Exciter allows you to fill out the lower frequency spectrum, and Color can add some beautiful top end sparkle.

It's a subtle pedal. It makes an immediate impact, yet after a few minutes of playing, my ears believe that my tone was always that great. Then, when I turn it off, my brain goes "WOAH!... what happened?". Tomorrow I'm going to try this with some dirt. Pretty sure it's going to shine.

One of the best buys I've made in a long time. Have to get through the Funk-a-Duck trace right now, but I'll be moving on to this one next. Everybody should have this baby on their board.