Need help picking a OT

[iknowjohnny]

For two 6V6. I can of course just grab anything made for a deluxe, but i want something that will give me the most power. I now have a 30w heyboer custom made to use in a classic 30 but it's primary is 3800. I believe 6V6 want about 6k, yes? so what would be a good pick to match a pair of 6V6 and is 30w ? Something cheap would be good, as this is just an old build that rather junky but it sounds decent so i want to get the load right w/o spending much. The PT is a 18 watt is thats a concern. I don't know the specs but I imagine most of them are in the same ballpark. I think i got it from reading the 18 watt forum years ago, so whatever they tend to use there.

[martin manning]

6V6 usually use 6k6 to 8k. What plate voltage do you have? An option would be to miss-match the Heyboer to get 7k6.

[iknowjohnny]

400vDC plates. But it has only 8 and 16 ohm taps

[chordball]

Can anyone see any reason not to use the following for a pair of 6V6's?

http://www.classictone.net/40-18039.html

It's a JTM45 OT but at 8k into 4, 8, and 16 ohms it seems like a good candidate for a nice, beefy OT.

I was looking at the DeArmond R15 OT from Mercury but this seemed like a good alternative.

[iknowjohnny]

Can anyone see any reason not to use the following for a pair of 6V6's?

http://www.classictone.net/40-18039.html

It's a JTM45 OT but at 8k into 4, 8, and 16 ohms it seems like a good candidate for a nice, beefy OT.

I was looking at the DeArmond R15 OT from Mercury but this seemed like a good alternative.

Well, yes, fenders do use 6.6k OT's whick isn't that far off from 8k, but what i read is that the optimal impedance for a pair of 6V6 is 5.7k. So while fenders is fairly close 8k i would think it's getting too far off to consider it a good pick. But i'm certainly not knowledgeable enough. I'm just looking at numbers and it just seems even that it's no doubt perfectly usable why pick one that far off when there ae others to be had that aren't.

[martin manning]

The optimum load depends upon the plate voltage. Fender's DR uses 6k6, but that is a little too low for the 400V on the plates IMO, 8k would be better. 5k4 is definitely too low and would probably result in red plating.

[chordball]

I should have clarified that it's for cathode bias 6V6, same as a 5E3 which does spec an 8K primary. I assumed 5E3 when I saw deluxe but were you referring to the deluxe reverb? That one calls for the 6.6K. I'm still learning so the more info the better.

[Bombacaototal]

I actually have a similar question. I got the 40Watt Classic Tone output tranny for the Vibroverb with 4, 8 and 16 ohm taps (attached). I will use it on my DRRI with 6V6 and stock PT.

Is it correct that the 4 ohm tap connected to the 8 ohm speaker the primary impedance is a perfect 8K match for JJ 6V6S output tubes? That meaning I should use the OT on the 4ohm Tap given my cabinet is 8ohm?

[martin manning]

Yes if you put double the specified impedance on any secondary tap the reflected impedance on the primary will be doubled. It may not be an optimum configuration given that the transformer has been designed for the specified impedances, but it will surely work.

[Bombacaototal]

Yes if you put double the specified impedance on any secondary tap the reflected impedance on the primary will be doubled. It may not be an optimum configuration given that the transformer has been designed for the specified impedances, but it will surely work.

Thanks Martin. Do you see any drawbacks of this configuration sound-wise (given it is not optimum)

The alternative would be to find an OT with 8K primary, correct?

I would also probably not be able to use this OT in any other tap configuration (8ohm or 16ohm), correct? If that is the case then probably no point in adding to my amp an impedance selection for this OT

[martin manning]

The 4, 8, 16 becomes 8, 16, and 32. The 16 might be useful, but I'd just use the 4 ohm tap and call it 8, leaving the others unconnected. For a guitar amp I doubt there would be any detrimental effect using it that way, but it's easy enough to hook it up and listen.

[Bombacaototal]

The 4, 8, 16 becomes 8, 16, and 32. The 16 might be useful, but I'd just use the 4 ohm tap and call it 8, leaving the others unconnected. For a guitar amp I doubt there would be any detrimental effect using it that way, but it's easy enough to hook it up and listen.

Thanks for the advice. I am thinking about the same, just call it 8 and notnise the others.

[Bombacaototal]

Just a couple more questions
1) the nfb of my amp is 4.7k (4ohm) which will be equivalent tp 5.6k (8ohm). Given this will be a 4ohm OT which will work like a 8ohm should I keep the 5.6k
2) will this OT work with a 2 output like the fender amps (internal and external)?

[martin manning]

Yes, and yes.

[Bombacaototal]

Yes, and yes.

Perfect! Thanks again