Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: texwest on October 06, 2019, 10:07:36 am
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Hi all, I'm new to the forum but have been working on my amps for a long time and have built a 5e3 and princeton reverb this year.
My new PR is made with no vibrato but used the extra holes for a mid knob and dwell.
I've searched all the web extensively but wondering about the reverb and dwell pots.
Would the dwell work better with a linear pot rather than audio. It seems like a lot of the action is between 10-5 on the dial.
I see a lot of people say to change the reverb pot to audio.
So I'm wondering if any of you have a preferred set up reverb audio/dwell audio or reverb linear/dwell audio or reverb audio/dwell linear, etc.????
I may end up just trying for myself but I have the buss wire on the back of the pots so want to check in first.
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BTW here's a pic of my build. It works great and is Quiet.
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I use audio taper for both.
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How does a linear taper react on the Dwell control?
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I'm thinking Drive can be Linear, because you generally want to hit the tank pretty good. If you do small reverb sometimes, "Reverb" (return) can be Audio.
Making both Audio gives a HUGE range of reverb, and I would expect half the dial to be inaudible except inside a padded cell.
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I'm thinking Drive can be Linear, because you generally want to hit the tank pretty good. If you do small reverb sometimes, "Reverb" (return) can be Audio.
Making both Audio gives a HUGE range of reverb, and I would expect half the dial to be inaudible except inside a padded cell.
What you say makes sense based on my observations with the audio dwell pot. It's only really useable in the upper ranges with the audio pot. And if you made both audio you would have very little reverb with any setting where both were set under 4.
I looked up the 6g15 schematic and both of the pots are linear.
I'm thinking the best setup would be either - both linear or Rev audio/Dwell linear.
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My Princeton Reverb clone has a 1 meg linear Dwell pot and a 100k linear Reverb pot. I was about to suggest doing something to limit the range of the Dwell pot because I never turn it below half way. However, noodling around a bit I discovered that even with the Dwell pot near zero there’s some unexplored territory. Just a touch of reverb with a short decay. Also, the Dwell control is very useful at the top of its range (IOW 7-10 if it were on the faceplate) so you would lose some of that with an audio taper pot.
I think an audio taper Reverb pot might be an improvement. I rarely turn the reverb above 3 and find it very “touchy” in terms of getting it just where I want it. Keep in mind though that every reverb tank is different and I forget which reverb tank is in this build but do remember that it is surprisingly lush compared to an earlier PR build.
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My Princeton Reverb clone has a 1 meg linear Dwell pot and a 100k linear Reverb pot. I was about to suggest doing something to limit the range of the Dwell pot because I never turn it below half way. However, noodling around a bit I discovered that even with the Dwell pot near zero there’s some unexplored territory. Just a touch of reverb with a short decay. Also, the Dwell control is very useful at the top of its range (IOW 7-10 if it were on the faceplate) so you would lose some of that with an audio taper pot.
I think an audio taper Reverb pot might be an improvement. I rarely turn the reverb above 3 and find it very “touchy” in terms of getting it just where I want it. Keep in mind though that every reverb tank is different and I forget which reverb tank is in this build but do remember that it is surprisingly lush compared to an earlier PR build.
I think you are spot on! I believe the dwell pot should be linear. But the reverb pot could be either linear or audio. If you think it is too touchy I would change it to audio.
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Agree. Tank is a box of loss. You want to hit it near design level. Weak drive and cranked recovery brings up hiss.
There IS a lot of scope for "small" reverb. Even 25dB below Topanga Canyon, not obvious, will put the sweet into many sounds. But most of that should be on the recovery side (after recovery amp) for minimum hiss. Drive *might* logically be a 2- (or 4- or 6-) way switch: "good" and "WOW!"; a Lin pot is probably simpler.
All this assumes you (or someone) "designed" the signal path. Random experiments will give too much or too little and then you may start with Audio taper just to get in a zone. If you find you never get above 5 on Audio taper, you should probably add a fixed cut-down to 20% and then see if most of the pot is useful, and if you truly like wee drive with hissy recovery.
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Thanks for your response.
No I was saying that I'm never really getting below 5 on the dwell. That's why I think linear would work better. Most of the useful stuff with the dwell knob is between 10 going down to 7. So I thought linear would make more of the dial useful. The way I'm using the dwell knob is to dial out the super far away sound you get when you start to turn up the mix knob. So kind of like a guitar tone knob start at 10 and then turn it down to taste.
I was just playing with the amp with a guitar student and we cranked the reverb mix knob and turned down the dwell and we didn't get much hiss at all.