Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mresistor on August 21, 2011, 12:43:06 pm
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guys - I built a 65DR clone a couple years back and it's been stored, basically because I use the my Hoffman boarded PR head all the time. Anyway, I have been checking out the DR and noticed that I have to turn the volume up to around 2 on either channel to get any sound.
I'm wondering if this is a problem with the pots or if there is another problem. Has anyone ever experienced this with their amp?
Mine has Heyboer PT and OT and JJ 6V6s. I swapped 12at7s and nothing changed. The normal channel has been recently "marshalized" but it didn't affect this problem.
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The dial doesn't mean anything.The pots may be dirty or just the way you installed them.It's a common thing.
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Have you tried to change the first preamp tube?
/Leevi
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Pots are essentially brand new. CTS vol pots Installed per Fender 65 Deluxe Reverb schematic. Push-back cloth wire. Yes, I just swapped out V4 with a new EH and have the same symptom. I'm also wondering if an amp is biased on the cold side if it would exhibit this? I might pull out the chassis and take the readings on the tubes.. phsyco. I'd like to believe you are correct and it's normal: still there's this nagging suspicion........
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Nearly all vintage Deluxe Reverbs do the same thing.It's because the have real nice audio taper pots.You have CTS pots that have the same taper as the originals.
You are just fine.Play the amp or move the knob until it makes you happy.
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I had no idea people played amps on "2" :icon_biggrin:
Is that possible?
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All the CTS 1Mohms volt pots I used showed the same symptom (no sound before 2). Bourns or Alpha are acting differently; none of these have the same taper progression, though.
I bought a set of 250K Bourns the other day; they measure between 230K and 265K.
All these things are not really bad, in fact; amps components are often 10% or 20% tolerant and heat is another factor of variation.
... Fuzzy electronics! :icon_biggrin:
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I had no idea people played amps on "2" :icon_biggrin:
Is that possible?
LOL - well not on mine, that's for sure...
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I checked my rebuilt AB763 DR (with Doug's Alpha pots) and found that volume starts about "1.8" and increases more or less evenly from there. All the vintage BF Fender amps we used to play (when they were new) exhibited the same characteristic. Now if Fender knobs started at "0" instead of "1" I think you wouldn't even notice it...
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I had no idea people played amps on "2" :icon_biggrin:
Is that possible?
Haha, we actually quit gigging at one bar (where we would have to turn it down to like 2" on my tweed deluxe, talk about no sweet spot, that amp if it isn't over half way has no balls at all). Anyway, the bartender (woman) who I might add is NOT the manager of the bar, would have us turn down until she could chat on her cell phone in the bar. I kid you not, the money was on the low side to begin with, and if you have to turn down where the amp's are just barely making noise, it takes any sort of 'energy' the band might have had away to a point where its like, why are you even hiring us? We finally turned down they're offer of gigs there. I know for some its like, hey whatever I'll play at any volume, but on a 5 piece where your barely making beer and gas money you soon tire of hauling your gear across town only to tell you to turn down to a whisper.. haha. It was actually comical at one point, I mean I'm like dude I'm using about 13 watt amp with a inefficient speaker and I'm still to loud? Oh well, sorry to side track things, but yeah some people actually DO have to play at 2... (even in my apt I'm at 5 or so on the Tweed fortunately the neighbors like my playing).
Regards,
Don
PS: VVR is a wonderful thing and future amps under 50 watts (all mine will be) will probably have it from here on out, the extra 30-40 bucks is cheap for attenuation that kinda works, just an opinion of course.