O/T with 6K6?

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Ampman5150
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O/T with 6K6?

Post by Ampman5150 »

Hello all...
I have 3 Hammond 1760H Output transformers with a 6600 impedance. These work well with the 6V6 'Deluxe' style amps I currently build but it appears the 6BQ5's prefer something around the 8K area..
Any thoughts on using the 6K6?
Thanks
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Re: O/T with 6K6?

Post by Daviedawg »

You could use that OT with 6K6s but it would be best to juggle the output impedance you use to balance the higher input impedance looked for by the 6K6s. I think they like 12 to 16k. But you should probably check that as I am working from memory.

I am not sure I have seen anyone use 6K6s with the 18 watt circuits. So that will be interesting.

Dd

Edit. On the PPWatt forum you will find a circuit "Classic 10" under the Universal pcb list which is a push pull circuit with an LTP PI and 6K6s. It is not an 18 watt circuit but will give you values in the power stage for 6K6s as a starting point if you go that route. As implied in the name it targets 10 watts out.
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Re: O/T with 6K6?

Post by crgfrench »

I think 6K6 in the OP refers to the OT primary, not a tube type ...

He's asking "can I run EL84s with a 6600 ohm ["6K6"] output transformer?".

And the answer is yes you can. But it will sound different than if you used an 8K OT.
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Re: O/T with 6K6?

Post by Ampman5150 »

Thanks for the responses..
The 1760H is a 20 watt transformer that has an input impedance of 6K6 that is correct. 6V6's love it and is the basis for the 5E3 deluxe.
I know that 6BQ5's prefer a bit higher of an input impedance such as 8K or so in a push pull design.
Just wondering if anyone out there had any experience with it.
Cheers
RJ
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JMPGuitars
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Re: O/T with 6K6?

Post by JMPGuitars »

Ampman5150 wrote:
Mon 09/09/19 12:50 pm
Thanks for the responses..
The 1760H is a 20 watt transformer that has an input impedance of 6K6 that is correct. 6V6's love it and is the basis for the 5E3 deluxe.
I know that 6BQ5's prefer a bit higher of an input impedance such as 8K or so in a push pull design.
Just wondering if anyone out there had any experience with it.
Cheers
RJ
You can build an 18 watt amp with 6V6s if you'd be interested in that. Plenty of people have done it.
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Re: O/T with 6K6?

Post by Ampman5150 »

You can build an 18 watt amp with 6V6s if you'd be interested in that. Plenty of people have done it.
I have as well.. As to why I have a bunch of 20 watt transformers with a 6K6 input impedance.

I was more wondering if any of you have built an EL84 amp with a lower impedance tranx.
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Re: O/T with 6K6?

Post by crgfrench »

I'm just starting a 22W 6V6 Plexi(ish) build with a 7k primary OT, so we are in similar boats. Good luck with yours!
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Re: O/T with 6K6?

Post by Ampman5150 »

crgfrench wrote:
Mon 09/16/19 3:29 pm
I'm just starting a 22W 6V6 Plexi(ish) build with a 7k primary OT, so we are in similar boats. Good luck with yours!
I've built plexi amps with 6V6's and had great success.
The basis of my question was using a 6,600 ohm impedance OT (a perfectly matched transformer for 6V6's) but using EL84's instead!
Thanks and good luck
R
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Re: O/T with 6K6?

Post by Ampman5150 »

JMPGuitars wrote:
Mon 09/09/19 12:52 pm
Ampman5150 wrote:
Mon 09/09/19 12:50 pm
Thanks for the responses..
The 1760H is a 20 watt transformer that has an input impedance of 6K6 that is correct. 6V6's love it and is the basis for the 5E3 deluxe.
I know that 6BQ5's prefer a bit higher of an input impedance such as 8K or so in a push pull design.
Just wondering if anyone out there had any experience with it.
Cheers
RJ
You can build an 18 watt amp with 6V6s if you'd be interested in that. Plenty of people have done it.
Thanks again for your response... I believe the basis of my question has been missed by the masses.
I was wondering if anyone has built an el84 amp using a 6,600 OT (usually used for 6V6 amps)
Cheers
R
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Re: O/T with 6K6?

Post by JMPGuitars »

Ampman5150 wrote:
Thu 09/26/19 9:16 am
Thanks again for your response... I believe the basis of my question has been missed by the masses.
I was wondering if anyone has built an el84 amp using a 6,600 OT (usually used for 6V6 amps)
Cheers
R
Sorry, I didn't respond to the question once you made it clearer because I haven't done that, nor do I know anybody that has either. Generally 8K is considered important for the 18 watt sound with EL84s.

You can always try it out and adjust component values to accommodate the 6.6K OT. If it doesn't sound great, go back to standard specs with an 8K OT. Maybe drill your chassis for both OTs?

Thanks,
Josh
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