SRS Exciter EQ

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
Post Reply
User avatar
agoldoor
Breadboard Brother
Information
Posts: 112
Joined: 26 May 2011, 04:37
Has thanked: 39 times
Been thanked: 20 times

Post by agoldoor »

70's-ish Fuzz that was traced by Brad of Creepy Fingers, and traced/dissected over at the DAM forums.
Anyone want to take a shot at making up a vero layout? Mods, I posted this over at the Requests folder, so if this is out of order, please feel free to delete this thread.
SRSEQEXCITERSCHEM.png

User avatar
mictester
Old Solderhand
Information
Posts: 2869
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 33 times
Been thanked: 758 times
Contact:

Post by mictester »

Try this!
Unverified!!
Unverified!!
"Why is it humming?" "Because it doesn't know the words!"

User avatar
Nocentelli
Tube Twister
Information
Posts: 2142
Joined: 09 Apr 2009, 07:06
Location: Leeds, UK
Has thanked: 925 times
Been thanked: 827 times

Post by Nocentelli »

Is it any good? and what other trannies might work instead of the 2N3565? They don't seem that easy to find.
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote:Sorry,but u r not the only member here
I'm not? Well fuck this site then. I only want meaningful conversations with myself.

User avatar
mictester
Old Solderhand
Information
Posts: 2869
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 33 times
Been thanked: 758 times
Contact:

Post by mictester »

Nocentelli wrote:Is it any good? and what other trannies might work instead of the 2N3565? They don't seem that easy to find.
It's a fairly ordinary silicon fuzz face with an output buffer and a tone control. It sounds pretty good, but has to be the first effect in a chain of effects because of the interaction between the circuitry of the guitar and the effect.

If you can't get the 2N3565 (which is a fairly low gain, low voltage silicon switching transistor), the 2N2222 would be a great replacement with almost identical properties. If you wanted to get silly and annoy a Texan redneck, you could use three of the transistors in a CA3046 array, sand the top off the device and claim that it's a special "proprietary fuzz chip"....
"Why is it humming?" "Because it doesn't know the words!"

User avatar
mictester
Old Solderhand
Information
Posts: 2869
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 33 times
Been thanked: 758 times
Contact:

Post by mictester »

By the way - a 10k pot for the tone control has much more range!
"Why is it humming?" "Because it doesn't know the words!"

User avatar
Solidhex
Resistor Ronker
Information
Posts: 261
Joined: 02 Apr 2008, 04:43
Has thanked: 10 times
Been thanked: 15 times

Post by Solidhex »

mictester wrote:By the way - a 10k pot for the tone control has much more range!
You'll get more mids (less scoop) out of the circuit when the EQ knob is turned fully clockwise with a 10K but the "action" only really exists in the first 2K's of the tone control. A 5K audio could be good possibly but a linear 10K will bunch all the action in the beginning of the pot rotation. I've tried it.
Lowering the value of C2 might provide a little more treble and give a different response to the EQ control. Its there to rid the Fuzz face section of high end oscillation and fizz. Depending on the gain of the transistors it can be selected to taste.

User avatar
Dr Tony Balls
Diode Debunker
Information
Posts: 813
Joined: 07 May 2009, 14:29
my favorite amplifier: Sunn Model T
Location: Brooklyn, NY
Has thanked: 2 times
Been thanked: 153 times

Post by Dr Tony Balls »

mictester wrote:If you can't get the 2N3565 (which is a fairly low gain, low voltage silicon switching transistor), the 2N2222 would be a great replacement with almost identical properties.
I dont know if that's exactly right to say. The 2N3565 is spec'd with a pretty broad gain range (100-600) so i'd suspect that like a Foxx Tone Machine, these SRS circuits vary from unit to unit. 2N2222 are spec'd at a lower gain range (~40-300) so you might want to experiment with socketed transistors and see how the 2N2222s compare to some other higher gain transistors.

User avatar
edkoppel
Information
Posts: 25
Joined: 15 Jun 2011, 17:32
Been thanked: 26 times

Post by edkoppel »

hey dudes.
yeah the pedal sounds insanely huge.
Brad/Creepyfingers just posted a clip of his clone, with an added gain control (which seems to bring in quite a bit more dynamics than the OG), but for some reason the squelching high end is gone on his version? It actually sounds way more smooth now.
http://soundcloud.com/creepyfingerseffe ... eq-exciter

And I sent the original to Jerms a few weeks ago, so he has it to dissect.

here's the thread I posted on the dam forum right after the pedal came in:
http://stompboxes.co.uk/forum/viewtopic.php?f=6&t=10951

Image
Tone Machines: vintage effects blog:
http://tonemachines.blogspot.com/

User avatar
OnTheTundra
Information
Posts: 41
Joined: 19 Sep 2010, 15:47
Has thanked: 1 time
Been thanked: 10 times

Post by OnTheTundra »

mictester wrote:Try this!
SRS_EQ_Exciter.gif

You need a cut at E9 then its verified.

User avatar
mictester
Old Solderhand
Information
Posts: 2869
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 33 times
Been thanked: 758 times
Contact:

Post by mictester »

Fixed!
Corrected
Corrected
Great sounding pedal. I've built it with 2N2222s, three transistors in a CA3086, BC107s and ME520s (best of all). The original devices would tend to have Hfe in the 80 - 150 range, so modern lower gain devices are best.
"Why is it humming?" "Because it doesn't know the words!"

User avatar
chicago_mike
Tube Twister
Information
Posts: 1755
Joined: 03 Jul 2008, 04:38
Has thanked: 23 times
Been thanked: 297 times

Post by chicago_mike »

I just wanna know who the redneck is...

I can make a road trip and annoy his ass for you! :mrgreen:
Skyline FX 2013

User avatar
OnTheTundra
Information
Posts: 41
Joined: 19 Sep 2010, 15:47
Has thanked: 1 time
Been thanked: 10 times

Post by OnTheTundra »

This pedal is the shit. I love the sweep of the EQ. Extreme to extreme. Sounds Awesome.

User avatar
Nocentelli
Tube Twister
Information
Posts: 2142
Joined: 09 Apr 2009, 07:06
Location: Leeds, UK
Has thanked: 925 times
Been thanked: 827 times

Post by Nocentelli »

OnTheTundra wrote:This pedal is the shit. I love the sweep of the EQ. Extreme to extreme. Sounds Awesome.
Great. Another addition to the ever-expanding "to build" list.
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote:Sorry,but u r not the only member here
I'm not? Well fuck this site then. I only want meaningful conversations with myself.

User avatar
agoldoor
Breadboard Brother
Information
Posts: 112
Joined: 26 May 2011, 04:37
Has thanked: 39 times
Been thanked: 20 times

Post by agoldoor »

Wow! Thank you SO much for finding and verifying that! I had built this when mictester graciously provided the vero, but then it never quite worked so I never debugged it! Just pulled this one off the shelf to fix it!

Post Reply