Traynor Darkhorse 2W output

[bbbing]

I'm reading up on the Traynor Darkhorse and it sounds like a really interesting amp. You can switch from a 6v6 push pull output section to a 12au7 push pull output section. Does anybody know how this switch works? I can't imagine Traynor putting 2 OT's to handle the different tube impedances.

[teemuk]

- Go to Traynor's website.
- Download schematic.
- Profit.

It's an extremely simple setup, not worth explaining here since schematics are easily and quickly accessible.

[rdjones]

Just a single OT.

With such highly attenuated output compared to the full output design, impedance matching isn't really a criterion when in the 'triode' mode.

The most complex part of the switch is the LED indicators.

rd

[bbbing]

Thanks for the response. I had no idea the schematic was up on the website. Cheers

[jdpas29]

i have a traynor darkhorse amp and am wondering if i couls sub the 12au7 with a 12bh7 due to the fizzy nature of the 12au7 during any distortion or drive.

i have been told that the heater current is the only difference that could be a potential problem and i don't know how to read schematics in detail.

the 12au7 requires .3 heater current where the 12bh7 requires .6

would it be a problem running a 12bh7 in this amp?

[Colossal]

i have a traynor darkhorse amp and am wondering if i couls sub the 12au7 with a 12bh7 due to the fizzy nature of the 12au7 during any distortion or drive.

i have been told that the heater current is the only difference that could be a potential problem and i don't know how to read schematics in detail.

the 12au7 requires .3 heater current where the 12bh7 requires .6

would it be a problem running a 12bh7 in this amp?

I don't know what the PT in your Darkhouse can handle but if the amp was built to fit a price point, you might run into some problems powering that 12BH7. Many production amps are built to provide exactly what they require and no more, so extra heater filament capacity might be an issue and it's prudent to be thinking about it as you have.

Second, if you are getting a fuzzy tone with a 12AU7, you might not do any better with a 12BH7. My guess is that the output transformer is probably not the greatest and is not doing the tone any favors. Some of the fuzz may be just be the quality of triode distortion and the way the amp is set up. I would find out about the PT and then a 12BH7 is an easy swap. If it still is fizzy, look at the OT and then the circuit to tweak. Depends on what you are going for too. Find the schematic and investigate that PT! Post a photo of the OT if you would. Don't take this wrong but if that OT is the size of a butter pat and made in China, no tube you can put in it is going to sort that out.

Tone starts with your iron, then the tubes, then the circuit and component choices. Cheap iron with Chinese steel = and you are about your tone.

[rdjones]

i have a traynor darkhorse amp and am wondering if i couls sub the 12au7 with a 12bh7 due to the fizzy nature of the 12au7 during any distortion or drive.

i have been told that the heater current is the only difference that could be a potential problem and i don't know how to read schematics in detail.

the 12au7 requires .3 heater current where the 12bh7 requires .6

would it be a problem running a 12bh7 in this amp?

You should be able to plug in any of the 12V 9A based tubes without causing damage. The difference in filament current between 2x6V6 + 2x12AX7 + 12AU7 and that with the 12BH7 should be tolerable.
Traynor was well known to way overspec their transformers in the old days, hopefully that is still the case.
As a precaution I'd monitor the power transformer temperature before and after the swap.

http://www.nj7p.org/Common/Tube/SQL/Tub ... hp?base=9A

I expect the 12BH7 to put out more power and as a result have a different tone, if it's better will be up to your ears. ;->

reddog Steve

[roseblood11]

Does anybody know the specs of the output transformer, especially the primary impedance?
I'm planning a similar power amp with switchable tubes, and I'm not sure which transformer to use. I've got a Heyboer with 6k6, an upgrade part for a Fender Blues Jr.
Perfect for the two 6V6, but maybe too low for a 12au7?