Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on March 07, 2014, 05:49:54 am
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I know some of you enjoy EL84 tone. So this could be a way to convert a 6V6 amp to use EL84's.
Just use a mini-toggle SPDT to switch between 270ohm/10w (6V6) to 130ohm/10w (EL84).
Note I used an unused pin to make the heater connection easier.
This is a very quick and easy project that is inexpensive using Hoffman's parts.
Check for errors and note the orientation of the pins between the 8 pin to 9 pin.
With respect, Tubenit
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You mean use a pair of 8pin bases-(like used in bias checker) with 9pin tube sockets mounted in them?
sorta like Yellowjacket/Substi-tube thingies? If yes, great idea, & great timing, as I'm in middle of build
to shut my Buddy up about his Cornford-Harlequin, & Carrera, best things since sliced bread yappings,&
was thinking about how to pull that off.
Funny, but I've had 3 questions answered, without having to ask a thing. I just logged on, and seems
topics I had quandaries about are being discussed already. Thanks for all the great input/time it must take up, very much appreciated.
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I may be wrong, but my understanding is that yellow jackets have some "extra parts" in them that may change the tone more then what I am suggesting.
With respect, Tubenit
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I highly recommend you do not connect anything to pin 1 on that el84 socket. Some (not all) el84s have pin 1 internally connected to pin 2. I personally have a pair with this internal connection. Merlin has some too. We had a discussion about this sometime last year.
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OK, great information.
Revised drawing.
Thanks, Tubenit
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If pin 1 of your 6V6 socket was grounded adding a parallel 250-270 ohm resistor from pin 8 to pin 1 of the adapter will save you from needing a switch.
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adding a parallel 250-270 ohm resistor from pin 8 to pin 1 of the adapter will save you from needing a switch.
Show me how to fit a 10watt resistor into that into the 8 pin socket base? :dontknow: :icon_biggrin:
Tubenit
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Would you not only need a 5W?
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It is VERY cramped in there when you put it together. I don't have any 5 watt or even 3 watt resistors that will fit into what I am doing.
Tubenit
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No big deal. Glad you posted the idea, I was going to make an amp with two sets of sockets to accept both types of tube now I'll just make some adapters.
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Just an idea
this kind of retainer isn't much loved
(http://i.ebayimg.com/00/s/NzUwWDc1MA==/z/qDIAAOxy4dNSxJg7/$_12.JPG)
but if you use the adapters in top down solution, may be it will be better to
think about the use of those retainer as to keep the adapter in place
K
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but if you use the adapters in top down solution, may be it will be better to think about the use of those retainer as to keep the adapter in place
You mean something like this? :icon_biggrin:
With respect, Tubenit
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Exactly :thumbsup:
Franco