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DIY Stompboxes => Building your own stompbox => Topic started by: Snufkinoob on June 05, 2022, 02:59:35 PM

Title: Boss FZ-2 Hyper Fuzz tone controls into stock FY-6 circuit...?
Post by: Snufkinoob on June 05, 2022, 02:59:35 PM
I've been trying to get back into fuzz building after a very long hiatus so I'm very rusty, and am not sure if this would work, so any advice is much appreciated.

The standard Fy-6 "super" fuzz contains 6 transistors. I love that circuit, and it's a relatively simple build. The Boss uses 3 IC's in addition to 4 transistors. Too much for me building from scratch. I won't need the buffer/flip-flop part of the circuit, and don't want the boost, just the bass and treble controls, so could it be a simple case of building the FZ-2 IC tone section and drop it between the FY-6 mode/tone toggle and the volume/output?

Here's the Hyped Fuzz schematic: https://www.pedalpcb.com/docs/HypedFuzz.pdf (https://www.pedalpcb.com/docs/HypedFuzz.pdf)
And here's an FY-6: http://3.bp.blogspot.com/-cBIzyse_wes/T0EHt4QmTvI/AAAAAAAAA88/Y1fbps_nMsQ/s1600/univox_superfuzz_schematic.gif (http://3.bp.blogspot.com/-cBIzyse_wes/T0EHt4QmTvI/AAAAAAAAA88/Y1fbps_nMsQ/s1600/univox_superfuzz_schematic.gif)

Is there any interaction between the IC's that would cause just using this single one not to work? (I'm very naive when it comes to these things, clearly.) I'm assuming that simple, passive tone circuits wouldn't achieve the same tonality, and that you would at least need a couple of additional transistors?

Any advice or noob-based insults welcome.

Ta!

Title: Re: Boss FZ-2 Hyper Fuzz tone controls into stock FY-6 circuit...?
Post by: antonis on June 05, 2022, 03:42:09 PM
Quote from: Snufkinoob on June 05, 2022, 02:59:35 PM
don't want the boost,

Just to have a coordination basis.. :icon_wink:

On which stage you refer on as "boost"..??
Title: Re: Boss FZ-2 Hyper Fuzz tone controls into stock FY-6 circuit...?
Post by: Snufkinoob on June 06, 2022, 11:30:38 AM
The Hyper fuzz has a "Boost" mode that bypasses the fuzz. (But the treble and bass controls are still active) useful, but not necessary if I can get away with cutting down as many components as possible.
Title: Re: Boss FZ-2 Hyper Fuzz tone controls into stock FY-6 circuit...?
Post by: antonis on June 06, 2022, 03:03:16 PM
You can get away of anything you like.. :icon_wink:

But you'll result into something like below:

(https://i.imgur.com/wFJtJB8.png)
Title: Re: Boss FZ-2 Hyper Fuzz tone controls into stock FY-6 circuit...?
Post by: idy on June 06, 2022, 03:40:10 PM
So you like the active B and T from FZ-2 and want to try them after mode toggle of FY-6. The only caution would be to add a large cap between, because there is a voltage divider on the FY (47k series and 10k to ground) which will/may load the bias to the FZ tone section.

Spitballing, this is the kind of place people put a 1uf. If you are losing bass you would have to go to a larger (electrolytic) but this armchair solder jockey says try and see.

You might better off using the output section also from the FZ: the FY uses a booster stage after the (fixed) tone section because you are loosing a lot of level: the voltage divider cuts the volume for the tone bypass path to about 1/6th to match level out of the little filter. So big boost after is a help. The FY is active B and T and has no loss, so buffer is appropriate. Mixing these up, putting the boost after the active B and T will/may introduce an unwanted distortion stage after all this precision tone shaping.


Since you are taking your output after the filter/voltager divider you are still OK with the FY booster after. But you might consider taking the input from before the tone section, the output of the 10uf, and using the FZ tone section with it's buffer to replace the entire tone/output section of the FY. I would experiment and try both. They will probably sound different.