Started this and found a few errors so far. Here's my suggestions: Bass 3 needs to go to ground as per schematic so it can be moved to J1. The presence controls are little screwy. I think this may fix it: Presence 3 should move down to R21, then C9 (22nf cap) should have the bottom leg moved down one to line up to Presence 2. I still haven't got it working but I think that's a start. Hopefully those suggestions are correct.
Built it and it works. Not quite sure if I'd say it's 100% verified yet as I have odd things happening. First, it squeals with gain at about 75% up when the presence and treble are also up. This may be a cap issue but I'm not sure. I've tried numerous JFETS and it still happens. Second, I am having problems biasing Q4 (maybe this causes the issue with the squeal). I can not bias to ~4.5V using a J201 or a 2N5457 if Q3 is in place. If Q3 is off the board, then I can bias it fine. Once I bias Q4 I put in Q3 and can bias it to ~4.5V. Once this is done and I keep gain under 75% is sounds great but I think it still messes with the voltage of Q4. Any ideas of what could be happening there?
I tried out both J201s and 2N5457s and various combinations and just decided to stick with the 2N5457s. It's less gainy but more usable overall and gave me better note decay.
I first used it into a Fryette PS2A power station, essentially using the Fryette as a power amp and this as a preamp. It's a little muffled with humbuckers but is killer with my single coils on my tele and acts as a great preamp. It became way more usable with humbuckers when I put it into the front of an amp and sounds like a good overdrive--still need to watch the bass though.
That's odd. My presence seems to work. I'll have to double check that. Are you having any issues with biasing Q4 by chance? For some reason I am (check out my prior comment).
This ones being a pain for me. Voltage on all transistors perfect, presence working, but whisper quiet output. I'm wondering if I've got the transformer the wrong way round. Would that do it?
Started this and found a few errors so far. Here's my suggestions: Bass 3 needs to go to ground as per schematic so it can be moved to J1. The presence controls are little screwy. I think this may fix it: Presence 3 should move down to R21, then C9 (22nf cap) should have the bottom leg moved down one to line up to Presence 2. I still haven't got it working but I think that's a start. Hopefully those suggestions are correct.
ReplyDeleteThanks for the corrections. The layout is updated. You also need to add a cut at P-8.
DeleteIs this one verified yet?
ReplyDeleteBuilt it and it works. Not quite sure if I'd say it's 100% verified yet as I have odd things happening. First, it squeals with gain at about 75% up when the presence and treble are also up. This may be a cap issue but I'm not sure. I've tried numerous JFETS and it still happens. Second, I am having problems biasing Q4 (maybe this causes the issue with the squeal). I can not bias to ~4.5V using a J201 or a 2N5457 if Q3 is in place. If Q3 is off the board, then I can bias it fine. Once I bias Q4 I put in Q3 and can bias it to ~4.5V. Once this is done and I keep gain under 75% is sounds great but I think it still messes with the voltage of Q4. Any ideas of what could be happening there?
ReplyDeleteI tried out both J201s and 2N5457s and various combinations and just decided to stick with the 2N5457s. It's less gainy but more usable overall and gave me better note decay.
I first used it into a Fryette PS2A power station, essentially using the Fryette as a power amp and this as a preamp. It's a little muffled with humbuckers but is killer with my single coils on my tele and acts as a great preamp. It became way more usable with humbuckers when I put it into the front of an amp and sounds like a good overdrive--still need to watch the bass though.
Verified sounds very good but presence doesnt work
ReplyDeleteThat's odd. My presence seems to work. I'll have to double check that. Are you having any issues with biasing Q4 by chance? For some reason I am (check out my prior comment).
DeleteHas this one been verified?
ReplyDeleteThis ones being a pain for me. Voltage on all transistors perfect, presence working, but whisper quiet output. I'm wondering if I've got the transformer the wrong way round. Would that do it?
ReplyDeleteYou can use this transformer either way round Ben, its 10K / 10K, so must be something else
DeleteOh of course! I’ll put that down to a Homer Simpson moment 🤣
DeleteI've always fancied making this but it seems most have struggled to get it going properly. Good luck mate!!
Delete