Identify coupling caps

[Adamo]

I'm gonna play around with my recently acquired Ibanez FZ5 and I want to swap out the 'coupling' caps. Can any of you identify which ones they are based on this (crappy) schematic?



I'm also open to any other suggestions to try and help the sound of this thing. It's supposedly a slight variation on an OD850 but is very 'thin'.

Thx

[GibsonGM]

.047 at the input looks a bit small....I spose you could play with the 470p feedback cap off the 3rd transistor.   One way of doing this may be to open it, and use an audio probe...listen to each section, see if it can be improved by piggy-backing a cap in parallel with one already there (they'll add!)....see if you note any good changes.

Upping caps makes you run the risk of 'mud' when clipping, so doing it on the fly might work better than saying "hey, try changing this cap".  At least you know right away before you do any permanent changes! 

[thelonious]

+1 to everything Mike said.

I'm wondering about this area, too. What is the value of that pot connected to the 820 ohm R?

[R.G.]

Forgive me if this seems simplistic, but if you don't know what coupling caps are well enough to pick them out on a schematic, why should they be changed?   

[Adamo]

Forgive me if this seems simplistic, but if you don't know what coupling caps are well enough to pick them out on a schematic, why should they be changed?  

Good question. I found this from an old thread here at DIY referencing modding an FZ5:

'....one place to focus on is coupling caps. In the FZ5 and OD-9, they are .1 uf. In the 850, they are 1 uf. You may find that the larger value is too woolly. Or you may find that the smaller value is too thin. You might try .47 as a compromise, or a combination may work.'

[antonis]

Any idea for the reason of 2 different Vr (with same Voltage value), except perhaps for preventing overloading of PS when not bypassed..??

[anotherjim]

If it's built as per that scheme, then leave the cap right after the input alone unless you want it to change the bypassed sound. If you have built it true bypass (deleted the switch fets at input and output), then you can change that cap.

But, it looks like a Big Muff Pi clone built  between a buffered bypass, and all the published tweaks for the BMP should apply.

That said, it differs in the final stage where a FET buffer is placed right after the tone stack. That 0.0022uF (why can't people write it as 2n2?)
and 510k before the FET is a high pass filter cutting everything below 140Hz (assuming the FET buffer impedance is so high that I can ignore it). Maybe increasing that cap (4n7 gives about 70Hz) might lift the bottom end enough.

[Adamo]

.047 at the input looks a bit small....I spose you could play with the 470p feedback cap off the 3rd transistor.

I'm definitely going to do this, but just to clarify, you're talking about the cap that comes after the third transistor adjacent to the two diodes (in the bottom left the schem, correct?

[Adamo]

I'm wondering about this area, too. What is the value of that pot connected to the 820 ohm R?

I'll open it up tonight and get the value of that pot. Is that the 'distortion' pot?

[antonis]

Is that the 'distortion' pot?

More likely the Level or Saturation pot...
(if there is such a label on your pefdal..)

[antonis]

That 0.0022uF (why can't people write it as 2n2?)

Because they like the hard way...
(and keep us scratching the paper for fly crap..)

[anotherjim]

This might help...

[Adamo]

Anotherjim, That's a fantastic diagram!I I now have all the tools and information to permanently screw this pedal up, Ha ha!

[ubersam]

The input cap (47nF) actually looks big enough to me, it cuts off around 6.6Hz which is very low. The rest of the coupling caps look large enough, most will cut around 15Hz, except for the 2n2 cap that anotherjim mentioned:

...That said, it differs in the final stage where a FET buffer is placed right after the tone stack. That 0.0022uF (why can't people write it as 2n2?) and 510k before the FET is a high pass filter cutting everything below 140Hz (assuming the FET buffer impedance is so high that I can ignore it). Maybe increasing that cap (4n7 gives about 70Hz) might lift the bottom end enough.

I'd swap that out for a 4n7 first, even a 10nF. If you do not have those cap values, you could just replace the JFET's bias resistor (510k) with a larger one, a 1M or a 2.2M. That would also lower the cutoff down to 72.4Hz or 32.9, respectively.

[Adamo]

Very interesting plot twist----I was noticing that the schematic that I posted wasn't really matching up with the pcb for this pedal. Then it finally dawned on me........the label on the pcb says 'PCB - TM5 ....'. A little more searching unveiled that this pedal is actually an Ibanez TM5 'Thrashmetal' pedal. I found images and schematics that match my pedal exactly. The pedal has the 'FZ5 60's Fuzz' label on it but the pcb is the TM5. This is crazy! Has anyone ever come across this before? I'm wondering if this happened at the company or if someone pulled the old switcheroo. I bought a russian big muff off a guy from craigslist a few months back and he threw this pedal in for nothing, he said he didn't like it.

[lead2203]

Is that schematic right? ....(the first one on here)....is the tone stack like that? If it is ....... I would swap  the .0047 and the .01. .....I would also try a .047 in place of the .01.

[tubegeek]

I bought a russian big muff off a guy from craigslist a few months back and he threw this pedal in for nothing, he said he didn't like it.

He lied to you. He probably bought it from Guitar Center, tried to switch the boards and then return it, or something, and then decided to be a nice guy and pawn it off on you.

Is my guess.