Tycho Brahe Iron and output, and the Fuzz Face front end ?

[petemoore]

  Starting with Tycho, Q1..[GGG NpN Tychobrahe schematic]
  http://www.generalguitargadgets.com/pdf/ggg_toct_sc_improved.pdf
  The Tychobrahe looks complicated.
  Q1 is an upside down gain stage with a feedback loop between Q3c and Q1e ?
  Q2 & Q3 buffer into gain stage, looks similar to darlington a bit.
  Anyway, splicing a Fuzz Face or..fitting it to the transformer and diodes [with perhaps a little bit of help] seems like it might be easier than working with the Tycho transistors [only] as Fuzz sound then kick in the diodes & transformer for octave. Or harder.
  Transformer and diodes that could accept other fuzzes or distortions to produce octave or octave-ish sounds, that's what I'd like.
  Any suggestions as to what might make a good interface [such as another darlington say, in front of the transformer and diodes?].
  Or just what might be the reasons that the Tycho has the relationship between Q3c and Q1e, complex bias arrangement on Q1B.
  Any other ideas or trials involving Fuzz Face interfaced to transformer and diodes to produce heavy fuzz and octave welcomed.
  Just one switch to go from Fuzz to Octave, all at around unity.
 

[azrael]

lifting one of the diodes from the circuit results in just fuzz. No need to add another circuit...

[petemoore]

  First part correct, as shown it is easy to get around the 'octave' section and make a Fuzz from a Tycho fragment.
  Second part is opinion which the above post isn't in complete agreement with.
  Where there's a will there's a need so to speak.
  It's not your basic fuzz, and the topology is like 'dream'...odd, in the way the routing and whatnot [I called it feedback, I guessed].
  Dissecting it beyond 'its a fuzz' with a rectifier section after it is rather difficult because it looks like and interactive-dynamic thing going...mystery to me about the how/why of the upside down/reversed Q1...all tied in with the collector/output section on the emitter side, the collector of Q1 would be a boosted replica of the base signal...plus some kinda wierdness due to bias or if there is some kinda feedback thing going on.
  Hopefully I've confused things enough, and there is no need for more vague references about misnomered glimpses of the happenings within.
  Perhaps understanding and modifying it is also out of the frame of relevant reference, at this point it is, for me at least, that was the reason for starting the thread....
  what's going on in there?, what does the transformer/diode section expect to see amplitude and impedance wise?, why is Q1 oriented like a chocolate dream ?, Q2 and Q3...are they contrary to an altered darlington or is saying darlington-derived a complete misnomer?
  Say...anyone tack a FF where the Tycho transistors 'were' ?
 

[Zedmin_fx]

lifting one of the diodes from the circuit results in just fuzz. No need to add another circuit...

does that mean if i put a spst toggle in with the diodes then I will get just fuzz from this beast?

[petemoore]

  I've never actually tried it.
  People who have claim it is a heavy fuzz, cool sound.
 

[Zedmin_fx]

yea the fuzz kicks ass in this thin I think I will try it.

[Zedmin_fx]

well yea it workes this pedal is so cool, I love how now I have an octave up fuzz and just a  sick ass fuzz

[earthtonesaudio]

  what's going on in there?, what does the transformer/diode section expect to see amplitude and impedance wise?, why is Q1 oriented like a chocolate dream ?, Q2 and Q3...are they contrary to an altered darlington or is saying darlington-derived a complete misnomer?
  Say...anyone tack a FF where the Tycho transistors 'were' ? 

Break it up into smaller parts...
Think of Q1 as a common emitter amplifier stage, with the intensity control as it's gain control.

Q2 is just a buffer.  Probably helps prevent motorboating.

Q3 gets its drive from Q2 which is basically just following Q1's collector.  The intensity control is a gain control for Q3 also, because there's negative feedback from Q3's collector, through that RC network, through Q1's emitter, back into Q3's base.

The AC signal at the top of C4 is in phase with the signal coming from the collector of Q3, so very little current travels through R9, making it appear larger to the collector of Q3, which should increase gain again.


Stick a Fuzz Face gain stage in there, and it should work just fine, provided you have enough output current to drive the transformer and diodes.  But it won't sound exactly like this circuit.
Try this variation for a somewhat closer approximation to the Tycho topology:
http://www.geocities.com/tpe123/folkurban/fuzz/morefaces.gif  (lower left circuit)

[azrael]

Glad to hear it works! i have an Octavia PCB sitting around, myself. i was going to do it, but realized I already have a fuzz, and would never being using it for anything other than the octave up effect.

[petemoore]

  There it is...IMO.
  Workin' 'bout perfect now...I figured there was room for more mileage toward where I wanted to go [guided by listening to records and developing preconcieved notions].

[Gus]

Things to read up on.  Chapter 5.3 of the big red book and other stuff you can find on the web.  GEOFEX transformer splitter article

Also look for the thread started by Mark H on the gain control of the tyco.

Transformers and circuit output resistance.  Low output R and higher output R what happens?

Whats the output R of a FF and whats the output R of the tyco?

Also
http://www.diystompboxes.com/pedals/SOU2.GIF
note the 1K
For more controlled gain increase the 100 ohm and/or decrease the feedback adjust pot. 

[petemoore]

  The only related thing I found at GEO so far is this schematic:
  http://www.geofex.com/schemata.htm
  Other than the opamp is being used differently than as a buffer [11k feedback R] and 18v supply I don't see anything immediate which would help me produce octave.
  Here's what I have: FF->Clipping Diodes->2n5088-Booster->TL082-Buffer
->1k->47uf->TM022->diodes->volume control.
  I have staging caps up to and including the transformer input, I figure after that it is all AC anyway, but iron is heating and I'm gonna throw in an output cap too.
    Mark H. thread on the tycho and it's gain control is a good read.
  I think I understand the gain control on the Tycho, and it's role in the Tycho circuit producing octave, and that I'm not motivated at this time in re-replicating or improving the Tycho, I've put the Tycho transistor circuit to the back burner for a time or two, a replacement 'front end' circuit is the goal at this time.
  I like the Tycho transformer octa-fuzz sound, but I'm not impressed with the front end necessarily, and suspect that an improved front end is possible if not happening already.
  As I understand it the transformer is low R across the secondary, which has a ground connections, thus requires a low impedance to drive it, I chose a TL082 buffer>1k>47uf  for that, the 1k just seemed like a good idea, and it has nice easy to work with solid core leads, the 47uf is what was handy.
  Output R of the Fuzzface: I'm not really sure, I thought I could dig that out of the GEO FF article...
  http://www.geofex.com/Article_Folders/fuzzface/fffram.htm
  But didn't find any ballpark output impedance figures or discussion of calculating it.
  Whats the output R of a FF and whats the output R of the tyco?
  Output R of the tycho looks like the 1k2..the last collector resistor.
  Output R of the FF...not sure..it has about 10k collector resistor.
  I go with "High" as a guess, high impedance output which would have troubles driving the low impedance of the small resistance of the transformer secondary which has a ground connection.
That guess led to the TL082 buffer stage being spliced bewteen the FF output and the tranny input.
  I see and have built the SOU, which produces a good octave, and have a 1k at the transformer's secondary/input.
  I thought I'd do some recommended reads this morning and be able to ferret somethings of useful information.
  Anyway, I put a volume control [500k] and some RF shunting capacitors at the FF input [2x little caps marked '10'] in an attempt to supress RF, the radio reciever still works, tunes itself out as I play guitar through it for a minute.
  And I put a cap marked 151 across the symmetric clipping diodes at the end of the FF, which tamed the high octave, and something I did when adding taming caps and an end volume control made lower octave appear in bits and spurts.
  The circuit is also ~noisy.

[petemoore]

http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS008357.PDF
  Data Sheet for the TL082
  And the Data for the TM022:
  http://www.mouser.com/Search/Refine.aspx?Ntt=TM022
  States the secondary impedance as '600ohms', But I though it would need to be a reflected impedance.
  So as it turns out, my ability to analyze what I've built is rather limited.
  And I was 1/2 focused on reducing the Opamp's output impedance in some way, even though I think the transformer only reflects impedance as I got that far.
 

[Celadine]

Thought I'd throw this in - I use just the transformer + diodes + volume out and put different effects in front to drive it - instant _____tavia.  Adds that cruel fizz to whatever flavor of drive used.   

[petemoore]

Thought I'd throw this in - I use just the transformer + diodes + volume out and put different effects in front to drive it - instant _____tavia.  Adds that cruel fizz to whatever flavor of drive used.
  I just wanted a different front end that I could mess with with the MO22 and Diodes.
  Nothing groundbreaking particularly expected but hoped for, perhaps the stock 3 transistor circuit is 'it'...I know that isn't true, there are many other transformer/diode FWR driver options and schematics.