# AC128 sub in fuzz foundry



## mywmyw (Oct 24, 2019)

AC128s appear to be impossible to source with any certainty. I'm a little over my head looking for a replacement... Can anyone suggest:

1. A reasonable silicon or other sub, and associated circuit mods to make it work properly ( I have some of bugg's trimmit pads)
2. A link to a decent straightforward guide to testing the relevant aspects of the pnp transistors, so I can buy a bulk bag and sort myself
3. A reliable source for the actual ac128. 

Thanks!


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## K Pedals (Oct 24, 2019)

mywmyw said:


> AC128s appear to be impossible to source with any certainty. I'm a little over my head looking for a replacement... Can anyone suggest:
> 
> 1. A reasonable silicon or other sub, and associated circuit mods to make it work properly ( I have some of bugg's trimmit pads)
> 2. A link to a decent straightforward guide to testing the relevant aspects of the pnp transistors, so I can buy a bulk bag and sort myself
> ...


I’d go with a 2N3906


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## Nostradoomus (Oct 24, 2019)

I don’t remember specifically but I think I just threw random GT402b’s in there and it fired up. Probably 70Hfe for Q1 and 100hfe for Q2 should do it.

You don’t need to use AC128, any PnP GE within those parameters will work. I use a cheapo component tester I got on eBay for 12 bucks.


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## Mir9 (Oct 24, 2019)

A lot of things will work, and even the real ones used things other than the AC128. They have some recent  Russian germanium and all silicon versions. 

I have a real Vexter one and have made clones that sound  just like it with AC125's and  Russian MP16B's. I also tried silicon (2n3906, 2n2907), which sounded a little more agressive, but the controls work the same.


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