Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on March 09, 2024, 07:46:00 am
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The amp is affectionately called "Bonnie" because I listened to alot of Bonnie Raitt working on this for my friend.
He wanted a "clean" amp for a pedal board that sounded warm at low volumes. So that was the criteria. He owns 2 VibroChamps and a vintage blackface Deluxe Reverb. The DR sounds very sterile and thin at super low volumes and to get the sound he likes, and it's too loud for his taste.
So, this one is a "sort of - kinda - psuedo" Deluxe Reverb (topology) that is cathode biased, using lower voltages, a Dumblish inspired tone stack, reverb prior to LTPI and a PPIMV.
Tube line up is 12AY7, 12DW7, 12AT7 and 12AU7 with 6V6's. With 5751, 5751, 12AT7 and 12AX7 ..... the amp has some superb grind at low volumes and I would never need an OD pedal with it.
It sounds fantastic to me! Very warm clean tone at remarkably low volumes. The Warehouse G10C is a perfect speaker for this amp design, IMO.
I'm guessing with the tube lineup used, that the amp sounds like maybe 10 watts at the volume I play at? The only other push/pull amp that I've been able to achieve the warm rich tones at low volumes with uses 6BM8 power tubes.
While the wiring looks rather unkempt, the amp is the quietest amp I've ever built. The difference between idle volume and playing volume without adjust any volumes is really sweet. It would be easy to walk off and accidentally leave this one on.
With respect, Tubenit
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Schematic and layout if anyone is interested.
IF you're looking for something at low volumes that sounds warm and has nice mids available, this may be worth considering. I feel like it gets a great done like a Princeton Reverb or Deluxe Reverb that's cranked, but it does it at conversational volume levels.
It only has 340v on the 6V6 plates which I think may be a factor in the warm tone at lower volumes?
with respect, Tubenit
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Nice amp.. So you have used it with both tube lineups Which lineup does your friend prefer?
I think this amp could work with a Hammond 290AX too. Are you using a DR OT ?
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Looks great. You seem to have quite the stash of perfect curly maple.
If you were going to make one of the switches foot switchable, which would you do?
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Schematic and layout if anyone is interested.
IF you're looking for something at low volumes that sounds warm and has nice mids available, this may be worth considering. I feel like it gets a great done like a Princeton Reverb or Deluxe Reverb that's cranked, but it does it at conversational volume levels.
It only has 340v on the 6V6 plates which I think may be a factor in the warm tone at lower volumes?
with respect, Tubenit
Thanks for posting the design. Lower volume is definitely more of a thing these days.
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Question, does your reverb return volume affect the volume of the amp when you turn up the reverb?
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Tubes used by my friend are 12AY7, 12DW7, 12AT7 & 12AU7. Yes, the OT is a Hammond DR replacement.
It's actually a veneer of flamed anigre instead of maple. The sides and bottom are plain pine without knots. The cab is very light weight which was also a request of the owner.
I would footswitch either the PAB (if not using an OD pedal) or the hi/low not the midboost. The midboost is on with single coils and off with humbuckers.
The reverb pot and the reverb dwell do not interact with or change the volume.
My friend has 4 vintage Fender tube amps and a PCB board Vibrolux. He believes this amp has the best tone of all of his at lower volumes for jamming and at a volume that one might use at an open mic.
With respect, Tubenit
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Tubenit - did you consider making this amp with 6K6 power tubes? Seems like they would be a good pairing. Thoughts?
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did you consider making this amp with 6K6 power tubes?
I did not. 6K6 tubes break up quicker than 6V6 in my experience & since he wanted a "clean" pedal board platform they would not have been a good "fit" for that objective.
And he already had 4 Fender amps that were using 6V6's so he could "borrow" tubes from other amps if ever needed.
With respect, Tubenit
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Fine work there tubenit!!! You keep getting gooder and gooder :thumbsup: