Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JGk on January 09, 2022, 01:47:10 pm
-
Hi all I am currently in the process of building a quad 6v6 tweed twin looking for suggestions for an OP tyranny 40 watts, 4000 to 6000K ohms have been suggested. I plan on running a 8ohm 15 inch speaker with it. any suggestions would help since I find out put impedance a world of black magic and such.
Thanks JGK
-
Edcor or Hammond are my favorites. others are out there based largely on wallet size and guitarist hype
the better question;
do you want the OT to be part of your Tone?
if so, get one undersized by a smidge so it saturates more
I like the OT to simply pass on what I feed it, so I oversize a smidge
-
Hi all I am currently in the process of building a quad 6v6 tweed twin looking for suggestions for an OP tyranny 40 watts, .....
Which tweed Twin? The low power 5E5a 40w or the 5F5a which is 80w?
Why 4 x 6V6 instead of 2 x 6L6GB/GC?
If you want only 40w, 2 x 6L6GB/GC will do it easy. The 2 x 6L6 will save room also.
-
... quad 6v6 ... looking for suggestions for an OP tyranny 40 watts, 4000 to 6000K ...
Why 4 x 6V6 instead of 2 x 6L6GB/GC?
If you want only 40w, 2 x 6L6GB/GC will do it easy. ...
I'll set aside questions of "Why?" to say that you can simply use any output transformer that was intended for 2x 6L6 into your desired speaker load. Same power output, same primary impedance.
-
Doing the HP tweed with Quad 6v6s just because, I like the sound of 6v6s and tweed era Fenders will probably do a PPIM and a bit of a PLEXI mod on 1 channel. I'm hoping that with a quad of 6v6s and a 15 inch speaker I'll sound big sound necessarily loud. I do like slightly smaller OP transformers looking at a heyboyer bandmaster op 4k with 4 and 8ohm taps thye alos have one at 6.6k also. Got 6L6 amps tpp just need a Winter project
-
Doing the HP tweed with Quad 6v6s just because, I like the sound of 6v6s and tweed era Fenders will probably do a PPIM and a bit of a PLEXI mod on 1 channel.
That's fine, but know it will cost you some more chassis space and more wiring. Watch your layout and lead dress.
-
Watch you screen and plate voltage too! Unless your using JJ 6v6’s
I’d go with the 4 k primary from heybor with the 4 and 8 ohm tap.
Put those taps on a switch connected to your speaker Jack.
If your using the 8 ohm speaker and have the switch on 4ohms, your primary will double from 4K to 8k
Which means you can pull two tubes, the outside pair and run the amp at half power and still have the correct impedance on the two output valves.
So you can run all 4 tubes with 8ohm tap on 8 ohm speaker or use the 4ohm tap and two tubes and the 8 ohm speaker.
A nifty half power switch.
It’s called reflected load impedance and it works great.
If you try this with a 6600 ohm transformer you’ll have 13.2k primary using the 4 ohm tap with a 8 ohm speaker, which would be better suited for the 6F6 rather than 6V6.
So 4K is your best bet, and that is the perfect transformer for the job. In my opinion.
Let us know how it goes!
-
You could potentially go the other way with it too!!
Fender used 6.6k on the deluxe with two 6v6’s
Now if you wanted that tone, get a 4ohm speaker instead.
With the 4ohm speaker connected to the 8ohm tap, your primary impedance will now be 3.3k.
Which is good for 4 6v6’s or a pair of EL34’s
Then switch to 4 ohm tap with the 4 ohm speaker and you back to 6.6k
For the two 6v6 half power arrangement.
Lots of options with reflected load impedance in mind.
If you choose this way though, you’ll need to remember to not accidentally run two 6v6’s with the 3.3k impedance (I.E.- the 4 ohm speaker on the 8 ohm tap) because!! It will sound harsh, you may get ghost notes, and you will be in danger of damaging the tubes, and output transformer.
The other way with the 4K transformer and 8 ohm speaker will make this impossible to happen as long as you are only using 6v6 tubes.