#26 pre amp

[coolzero]

Thinking of testing different tubes with this same circuit instead of 26 tube. Any suggestion for matching and fine sounding alternate tube for 26?

[eboz]

Originally Posted by coolzero

Thinking of testing different tubes with this same circuit instead of 26 tube. Any suggestion for matching and fine sounding alternate tube for 26?

You are going to have to change the filament voltage for just about any other tube. If you can vary this voltage, then I would try the following tubes in the same circuit: 10, 56, 112. The 56 and the 10 can handle higher plate voltage, and make sure to check the plate load. The 56 is indirect heated and also different socket, but it shouldn't take too much modification to get there. I wonder if for the 56, you could tie the heater to the cathode and run it like a DHT? I hope you have a variable filament supply!!

[coolzero]

Originally Posted by eboz

You are going to have to change the filament voltage for just about any other tube. If you can vary this voltage, then I would try the following tubes in the same circuit: 10, 56, 112. The 56 and the 10 can handle higher plate voltage, and make sure to check the plate load. The 56 is indirect heated and also different socket, but it shouldn't take too much modification to get there. I wonder if for the 56, you could tie the heater to the cathode and run it like a DHT? I hope you have a variable filament supply!!

Thanks Eboz. Changing filament voltage is not a problem for me. But which of the tube has the most superior sonic advantage out of all these?

[eboz]

Originally Posted by coolzero

Thanks Eboz. Changing filament voltage is not a problem for me. But which of the tube has the most superior sonic advantage out of all these?

I think you should try all of them, really. But if you have to choose one, I guess the 112 as it is similar and possibly exceeding that of the 26. Try it and let us know!

[nicoch58]

10Y
Firefly

[andyjevans]

Alternatives to 26 are 10Y and 01A for good sound. I've tried a bunch and that's what I'd recommend for a line stage. I actually like 1G4G but it's too microphonic for general use. VT-67 is a good sound but 10Y and 01A are better. Haven't tried 46 in a line stage - may be interesting.

Andy

[quanghao]

Originally Posted by coolzero

Thinking of testing different tubes with this same circuit instead of 26 tube. Any suggestion for matching and fine sounding alternate tube for 26?

i use one cricuit for tube 26, 45, 6c4c. it is very exelent, no hum no noise.
you see:
HQ-DHT (All tube DHT amli) 26-45-2A3

[mach1]

Thinking of testing different tubes with this same circuit instead of 26 tube. Any suggestion for matching and fine sounding alternate tube for 26?

You could also try filament starving (ie reducing the voltage) to reduce THD.

[quanghao]

Originally Posted by Rod Coleman

Quanghao, thanks for sharing! looking good!

You have Fans on the filament circuit heatsink?

Please post the filament circuit, if you changed anything.

I post in this link:
HQ-DHT (All tube DHT amli) 26-45-2A3

[coolzero]

Originally Posted by eboz

I think you should try all of them, really. But if you have to choose one, I guess the 112 as it is similar and possibly exceeding that of the 26. Try it and let us know!

Originally Posted by nicoch46

10Y
Firefly

Originally Posted by andyjevans

Alternatives to 26 are 10Y and 01A for good sound. I've tried a bunch and that's what I'd recommend for a line stage. I actually like 1G4G but it's too microphonic for general use. VT-67 is a good sound but 10Y and 01A are better. Haven't tried 46 in a line stage - may be interesting.

Andy

Originally Posted by quanghao

i use one cricuit for tube 26, 45, 6c4c. it is very exelent, no hum no noise.
you see:
HQ-DHT (All tube DHT amli) 26-45-2A3

Thanks guys for all your suggesstions. I will try whaever possible and post the results eventually.