Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Toxophilite on February 29, 2016, 03:38:47 pm
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Hi All
Thought I'd ask those in the know a question
I have a deluxe reverb build(with bias vary trem) That I built with the help of the generous folks on this board.
It works great, but I really want to use it in this cab I built a while back with a JBLD130F in it
It sounds good with the D123 in the smaller cab it currently lives in but the D130 is much bigger and louder
This is partly the slightly bigger deeper cab, heavier baffle and the efficiency of the D130
Anyway to use it in that cab as is, I would need to move the tube sockets from a blackface style orientation to a more tweed one. So that I can orient the chassis on edge at the back of the cab, like a tweed amp)The picture mostly depicts the amps as is. I've looked at it and if I'm careful and plan it well there's room to make the move. The sockets would be moved to the bottom edge(the same edge as the switches)
I would obviously need to lengthen many wires and be careful as to their lead dress
My question is: Would re-orientating the AC filament windings prove a problem noise-wise? (I wouldn't need to remove them unless it seemed like it would be a problem)
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If your BF Deluxe amp is quiet and sounds sweet--don't mess with it. The BF style chassis is shallow--there would not be enough air circulating around the tubes. You would need to strip the chassis because filings and debris would be everywhere. Its not easy to do. Instead consider building a head cab for it and use it piggyback with you JBL speaker cab. Maybe I'm lazy....Jim
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My question is: Would re-orientating the AC filament windings prove a problem noise-wise? (I wouldn't need to remove them unless it seemed like it would be a problem)
Look at your picture; the edge of the back apron (where the sockets will go) is closest to the camera. If you moved the sockets, I'd lay the heater wires essentially along that edge, and just bring them inward to the sockets once the wiring string gets to a socket. In other words, like a tweed amp was originally wired.
I don't think that will present a noise issue on its own.
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You'd have to pay me more than it would cost to buy a new cabinet to take a good working amp and rework the chassis, at least to the extent I understand what you're proposing, which is not complete. I'm lazy too.
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Thanks for the input
In case I wasn't clear this isn't an actual BF reverb chassis. It's actually a Hammond A0-43 chassis that i built the amp inside. The amp is working well, but if I'd thought about orientating it the other way before I started the build. I would of. I've done a fair amount of altering my build as I try new ideas so I'm aware of the problems inherent. Heck on this one I added a reverb circuit in a separate piggyback chassis and it works great (it's just not in this picture. I'll add a picture as it's kind of funny looking, but works. (it'll end up facing inwards with the transformers) (in the picture I think I was trying 6L6GCs in the amp for kicks)
Hot Blue Plates, to clarify, were you suggesting tucking the heater wires into the corner of the chassis, underneath where the sockets would end up ( I did that on my vibrolux build with a 'tweed style' layout) or along the top edge, essentially closest to the camera and 'above' the new socket placement?
Out of curiousity for a reverb tank(in the bottom of the cabinet is it better to have the transformers hanging upside down (ala blackface) or horizontal, (like some tweeds)
re-orientating the tube sockets would also allow me to separate the power tubes a little more (they're a little close)and or try a vibrolux OT as I would have the room
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A JBL D130 is a fearsome transducer.
I would seriously consider NOT putting it in the same box with a tube amp. Build a head cabinet. Even rubber-mount the chassis to reduce the shake.
Yes, I know Fender and Mesa sold D130 combos. But we did lots of dubious things back in the day. Mexican weed and leaded-gasoline. 2-pin wall outlets.
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++ what PRR eloquently said. The Marshall style head with tubes up is easy to do with a Hammond chassis--this affords maximum heat dissipation and minimized vibration problems (tubes shaking out of their sockets). Jim
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... Hot Blue Plates, to clarify, were you suggesting tucking the heater wires into the corner of the chassis, underneath where the sockets would end up ( I did that on my vibrolux build with a 'tweed style' layout) or along the top edge, essentially closest to the camera and 'above' the new socket placement? ...
"Above" the sockets correlates to how the tweed amps had their heaters run, as there was a lip at that open edge of the chassis. The wires were tucked right into the corner formed at that lip. My instinct is to route heater wiring as far away from preamp components as possible/practical. However, where you suggested "below" the sockets would probably be just as good.
... Out of curiousity for a reverb tank(in the bottom of the cabinet is it better to have the transformers hanging upside down (ala blackface) or horizontal, (like some tweeds) ...
If you're going to place this chassis at the top of the cabinet (but in the new orientation), I don't think it would matter one bit to the reverb pan either way.
But I think PRR has a very good point. And a head/cab arrangement let's you easily use that D130 with any other future amp build (just swap heads, or run a cable to the other amp's speaker out)...