New Solid State FX loop source - $20

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sonicmojo
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Re: New Solid State FX loop source - $20

Post by sonicmojo »

Thanks for the tips. I already ordered the IRF830s but don't plan to try again in this particular amp. My guess is my incoming signal was too hot and for some reason killed them. Don't know why exactly..... I'll fix and try these for a tamer amp in the future.
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frankdrebin
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Re: New Solid State FX loop source - $20

Post by frankdrebin »

It's always better to attenuate before the buffer,I use a 220k/10k divider for that and the signal will be fine for pedals and racks.
The bias on this loop is too high,I go for 50v (see KOC)so I can use a bigger cap on output with less problems.

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dorrisant
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Re: New Solid State FX loop source - $20

Post by dorrisant »

Here is a spacing diagram... Print at 1:1 or 100%. Use the lines to fold over edge of chassis to keep 'er straight... Strike the two dots. Drill to 7/16". Enjoy!
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dorrisant
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Re: New Solid State FX loop source - $20

Post by dorrisant »

Ten Over wrote: Wed Aug 30, 2017 12:34 am The only way I have ever damaged a MOSFET was when I exceeded the gate to source voltage. If you are going to order new MOSFET's, you might want to consider STF7N60M2. It has internal zeners from gate to source, same pin-out as IRF830 and same price.

If you are ordering parts, you also might consider changing the 10M resistor to a 4.7M and changing the 47K to a 2-watt variety. The 4.7M will allow a much larger signal swing for the send before clipping. A 2-watt 47K resistor will allow the use of higher B+ voltages.
So, with these changes, what kind of B+ can we use? I will try the STF7N60M2 as well if it will give some more wiggle room.
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dorrisant
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Re: New Solid State FX loop source - $20

Post by dorrisant »

So I put this loop in a JCM800-ish project... http://ampgarage.com/forum/viewtopic.php?f=9&t=30633

I have about 280vdc feeding it from the final filter node. I put it on a bypass switch so I could hear any differences. As is, the loop adds some gain to the signal. I have installed send and return trims to mine. I had to turn the trims to about 3:00 to get unity between bypass and engaged. With the way it is right now, I can't really tell a difference between bypass and engaged as far as any coloration... a bit more time may reveal the difference though. I ran a Strymon El Capisatan in the loop with glorious results. I also tried a Moer Shakey Jimi in there and instantly found myself playing Bridge of Sighs... I think the truth is in the fact that I kept forgetting that the effect was in the loop and I was just leaning on the natural character of the pedal to do its job.

Btw... I did a small mod to the loop. I replaced R7 with a 47k 3w instead of the 1w that was in there. This was one of the mods that Ten Over suggested. I may try changing the 10M to 4M7 later, but I'm pretty happy with this baseline so far. I really like the loop.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
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