The Amp Garage

yes, in practice I noticed the gain on ~7 (on the "other" channel vol pot) yields the most gain. But again, I am trying to understand why . I see the mixer (voltage divider) goes through the other channel's vol pot before going to ground; ie, as I understand the vol pot adds some (variable) resistan...

But again, wouldn't the amount of signal attenuation and/or treble bleed through the mixer (with or without the cap) depend on the "other channel"´s vol pot setting ? Apart from the main question (cap on vol pot, thanks for the answer), that´s basically what I am trying to understand.

Hi everyone, this weekend I was playing with my 1987 clone normal channel. I changed the cathode from 820/220uf to 1k5/220uf, and added a 500pf bright cap to the normal channel volume pot. This gave me a JTM45-ish tone which worked very well with a strat. Loved the result! However, I was a bit conce...

drew wrote: ↑Fri Aug 10, 2018 6:59 am Comparing the photo of the completed amp to the layout diagram, do you have the wire from V2, pin 8 connected to the wrong end of the 33K resistor?

I will double check that tonight, thanks for the observation!

(though I seriously suspect the wire is simply tucked beneath the board)

ok my friends, good news! Here´s what I did tonight: 1. checked the solder joint as noted by tubeswell, but it didn´t help. 2. tightened the PT and OT bolts, input jacks. No noticeable difference. 3. replaced the main filter cap and redid the 'star' ground. Didn´t help either. 4. grounded the 32-32 ...

You have a good eye, thanks!

I had already fixed the presence pot while doing a round of checking - and was beating myself enough for letting it pass..... now on to the treble.

martin manning wrote: ↑Thu Aug 09, 2018 11:48 am Does the bright volume affect the hum?

Not really. It adds a touch of hiss when past 7 (which I think is fairly normal), but the fundamental hum remains unchanged.

This morning I tested removing the preamp tubes (nothing connected to the amp). With v1 (only) removed, the hum continues. With v2 (only) removed, the hum stops. I tested 5 different spare preamp tubes I had (Mullards, chinese, sovtek...) and the hum continues, so I pretty positive it's not the tube.

It seems quite a buzzy hum, does the presence setting affect it? Just tested it and yes, turning presence all the way to zero seems to improve things. What does it mean?? So in the 1st instance, it may be a good idea to re-establish all the chassis 0V connections, ie slacken the fasteners off, rota...

Thanks for the replies! I am trying to recall any modifications I made to the amp since I built it (assuming the hum was not there when I built the amp). AFAIR I only replaced the bright channel coupling cap (0.022 TAD ->0.0022 Sozo) and the mains filter cap (32/32 -> 50/50). Is it possible that the...

Hi, about an year ago I completed my first build, a plexi 50w clone (Ceriatone kit). Since then, I have been using it almost exclusively (99% of the time) plugged to my Suhr Reactive load (SRL), for bedroom use. Last weekend, after several months, I plugged into a real cabinet - probably for the thi...

Sure, I am familiar with the WU splice.

I was mostly concerned with possible noise and such (as you can see I am a novice builder).

Thanks!

Hi everyone, I want to reuse a set OT/PT/choke from a previous build, but I am pretty sure I'll have problems with the length of the leads. I need some advice on how to proceed. As replacing them completely sounds a bit outside my current ability.... what would be the best approach in this case (if ...

I would explain it this way: The volume pot is a voltage divider with R1 being the resistance from the input to the wiper and R2 being the resistance from the wiper to ground. The output voltage (ignoring source and load impedances) is Vin * R2/(R1+R2). The bright cap is across R1. At high frequenc...

Hi everyone, here´s a beginner question. I added a resistor in series with my Plexi´s 500pf bright cap on the gain pot in order to 'reduce' a bit the ammount of boost. I seems to work the way I intended, but I just want to make sure I really understand how it works. Here´s is how I see it: say R1 is...