BYOC Octave Fuzz compression issue.

PurpleStrat · July 07, 2008, 03:07:26 PM

I read a few post at BYOC about others having this issue but no one has answers as to why. The issue I have is that with the Octave on the note compresses if you hit it hard and fades in out then back in. If you palm mute a note then hit it open after the palm muted not will be louder. Any ideas?

DougH · July 07, 2008, 03:27:26 PM

So the BYOC support people don't have an answer? That is where I would try first.

Hard to tell without a schematic. And if it is a generic problem with the design, do you think BYOC will pay us for fixing it for them?

Dragonfly · July 07, 2008, 03:36:42 PM

quick guess... Q1 has too high an hfe, and its over saturating the other transistors.... you might try swapping the transistors around and see if that helps...or try a 2n3906 instead of the 5087.

PurpleStrat · July 07, 2008, 03:40:26 PM

Quote from: DougH on July 07, 2008, 03:27:26 PM
So the BYOC support people don't have an answer? That is where I would try first.

Hard to tell without a schematic. And if it is a generic problem with the design, do you think BYOC will pay us for fixing it for them?

I guess not. I saw two threads and three people with this issue and no replys by anyone in support.

Here is a link to the PDF. It's on the last page.
http://buildyourownclone.com/octavefuzzinstructions.pdf

And no I don't think they will pay!

DougH · July 07, 2008, 04:11:56 PM

You might try 1n914's in place of the 1n34a diodes.

Gus · July 07, 2008, 04:12:11 PM

What does a "real" one act like?

Dragonfly · July 07, 2008, 04:24:18 PM

Quote from: Gus on July 07, 2008, 04:12:11 PM
What does a "real" one act like?

Look close at Q1 is that a mistake or is that by DESIGN?

You're right...I hadn't really looked at the schemo closely....

a collector - base resistor on Q1 would probably be of great assistance in keeping this thing biased...

In fact the whole biasing of this design seems a bit "questionable"....

PurpleStrat · July 07, 2008, 08:03:58 PM

Quote from: Dragonfly on July 07, 2008, 04:24:18 PM
Quote from: Gus on July 07, 2008, 04:12:11 PM
What does a "real" one act like?

Look close at Q1 is that a mistake or is that by DESIGN?

You're right...I hadn't really looked at the schemo closely....

a collector - base resistor on Q1 would probably be of great assistance in keeping this thing biased...

In fact the whole biasing of this design seems a bit "questionable"....

Yeah the bias does sound off. I'll stick a 3906 in and see what happens.

PurpleStrat · July 07, 2008, 09:28:04 PM

Stuck a 3906 in and it helped but the compression was still their. Stuck in an OC44 and MUCH BETTER!! Put in 3904's for Q2 and Q3 and it sounds like the biasing is better but now it's pretty noisy. I'll have to try some 2n2222's next.

Dragonfly · July 07, 2008, 10:03:44 PM

Quote from: PurpleStrat on July 07, 2008, 09:28:04 PM
Stuck a 3906 in and it helped but the compression was still their. Stuck in an OC44 and MUCH BETTER!! Put in 3904's for Q2 and Q3 and it sounds like the biasing is better but now it's pretty noisy. I'll have to try some 2n2222's next.

Heres why the OC44 sounded better...

it doesnt "need" a collector-base resistor to bias...it can be biased by the "leakage", much like a Tonebender, so it will work better as Q1

any SILICONS you want to try, you should use a 470k (or so) collector-base resistor, and that should help the issue.

DougH · July 08, 2008, 07:14:05 AM

I don't see a problem with the topology of the circuit around Q1- but R2 looks too big at first glance. I suspect the base is getting starved of current. R5 and R8 look very big for a bjt circuit as well. It's a goofy looking circuit for sure (R11/Vcc stuck out on the end of R7 & R8, why? etc). It looks like it is vulnerable to all sorts of interactions and tough to bias if the transistor choices are not "just right". There certainly are more straightforward ways to build octave fuzzes, which would be more appropriate for a kit I would think...

Gus · July 08, 2008, 07:53:00 AM

Nothing wrong with the bias of the first transistor it a real "design".

There have been posts about the schematic and Q1 here IIRC. Time to search

Does BYOC have a real tyco to compare against to give you an answer? How do you know the effect is broken, have you heard a real one?

This has been on the web for years

http://www.geofex.com/FX_images/tyoct.gif

DougH · July 08, 2008, 08:01:40 AM

Haha, the joke's on me...

I didn't even recognize that, it's been so long since I built mine (which works great btw). The bypassed 820k should have been the clue (I thought that looked familiar.) RM's 24v design.

Edit: And yes, it does compress with the "intensity" cranked. Check out Tobias's excellent cllp at GGG for an example. I like it that way btw, sounds "wild".

Gus I'll hand it to you- you spotted this one right from the beginning. I need to start drinking coffee before I get on here...

Dragonfly · July 08, 2008, 09:55:18 AM

Quote from: DougH on July 08, 2008, 08:01:40 AM
Haha, the joke's on me...

I didn't even recognize that, it's been so long since I built mine (which works great btw). The bypassed 820k should have been the clue (I thought that looked familiar.) RM's 24v design.

Edit: And yes, it does compress with the "intensity" cranked. Check out Tobias's excellent cllp at GGG for an example. I like it that way btw, sounds "wild".

Gus I'll hand it to you- you spotted this one right from the beginning. I need to start drinking coffee before I get on here...

Jokes on BOTH of us... I didnt even think of the Tycho either !

Ditto on the coffee!

Dragonfly · July 08, 2008, 10:16:33 AM

PurpleStrat · July 09, 2008, 02:39:44 PM

Quote from: Gus on July 08, 2008, 07:53:00 AM
Nothing wrong with the bias of the first transistor it a real "design".

There have been posts about the schematic and Q1 here IIRC. Time to search

Does BYOC have a real tyco to compare against to give you an answer? How do you know the effect is broken, have you heard a real one?

This has been on the web for years

http://www.geofex.com/FX_images/tyoct.gif

Whhoops I did'nt know it was an Octavia! I thought it wa original! Well from the schematic you linked it looks like I should try putting the 3906 back in and just lower the others to taste. My way still sonuds cool though!

warioblast · July 14, 2008, 10:16:04 AM

I built the GGG tycobrahe octavia and it has compression too. I think it's just the nature of the pedal.
You may try to add a pre-gain pot (see GGG schematic). It's a nice add-on, you'll find more sweet spots. IMHO.
You can also find target voltages at page 3 => http://www.generalguitargadgets.com/pdf/ggg_toct_instruct.pdf

Mark Hammer · July 14, 2008, 01:04:31 PM

I was just rummaging through the BYOC website and looking at the build instructions for the "Armstrong Twin" - an Orange Squeezer / Green Ringer combination pedal. I noticed that they appear to use a dual LED which is orange when connected one way, green in another way, and blue when connected another way. BYOC use the orange setting to indicate the Orange Squeezer section only, green for the Green Ringer, and blue for both.

First, I have to say that is a simply adorable coinciding of LED and pedal characteristics; a bit like the way that some country songs start with a title that demands a song be written to accompany it, that LED demands such an effect combination. Second, has anyone seen such LEDs, and do they clearly correspond to those colours? If so, that may be a very useful component to have on hand since the 3 colours produced are easily distinguishable from each other, and three different colours in one little LED slot makes a very efficient way of differentiating status.

PurpleStrat · July 15, 2008, 12:26:38 AM

Quote from: warioblast on July 14, 2008, 10:16:04 AM
I built the GGG tycobrahe octavia and it has compression too. I think it's just the nature of the pedal.
You may try to add a pre-gain pot (see GGG schematic). It's a nice add-on, you'll find more sweet spots. IMHO.
You can also find target voltages at page 3 => http://www.generalguitargadgets.com/pdf/ggg_toct_instruct.pdf

That definitly seems like something I should try. I have a gernaium in for Q1 now and it's better but I just think I don't like the circuit. I'm so used to Foxx Tone Machine clones.

News:

BYOC Octave Fuzz compression issue.