SE 45 tube amp and tubes available

[zwuttoo]

I did try some boutique coupling caps, ( A-08S )Jupiter & Audio Note ,but preferred the "original Yamamotos" so they went back in,It is part of the matter that I used
Yamamotos CA-03L phono pre-amp ( with 6AK5 pentodes)and the two together in stock form pleased my ears best.

 

[tubelectron]

Yes, I would be interested to build a Single-Ended 45 tube amp...

But relying only on old stock tubes often in questionable condition, or paying the huge price tag for the rare 45 reissues dissuades me from going any further...

T

 

[gadget73]

Maybe consider something like a 6BX7 instead. Its a twin triode, but if you parallel the sections its good for 12 watts of plate dissipation total. Its nice and linear, and not direct heat so that part becomes easier. Also not dumb money, though you are limited to old production.

6AS7 would also make a worthy output tube. Another twin triode but fairly beefy.

 

[Ken Boyd]

Maybe consider something like a 6BX7 instead. Its a twin triode, but if you parallel the sections its good for 12 watts of plate dissipation total. Its nice and linear, and not direct heat so that part becomes easier. Also not dumb money, though you are limited to old production.

6AS7 would also make a worthy output tube. Another twin triode but fairly beefy.

Do you have any drawings of a good amp that uses the 6AS7 tube for outputs.

 

[Ken Boyd]

How about this one looks doable.

6AS7G Triode Push-Pull Amp Design | PDF | Electromagnetism | Electric Power

Scribd is the world's largest social reading and publishing site.

www.scribd.com

 

[gadget73]

seems needlessly complex but I've never built anything around that tube. Just seems like something worthy of building around and i have a couple in the "one of these days" pile.

6080 is another option, basically the same as a 6AS7 but in a less-cool looking bottle.

 

[Selmerdave]

6V6 in triode is reputed to be sonically similar to a 45...

 

[CohibaJoe]

Yes, I would be interested to build a Single-Ended 45 tube amp...

But relying only on old stock tubes often in questionable condition, or paying the huge price tag for the rare 45 reissues dissuades me from going any further...

T

Check out the ELEKIT/Sunvalley support site. Seems a ELEKIT will be coming out TU-4523 (45 Tube + 2A3 Tube).

recent visit to ELEKIT and Sparkler Audio

 

[tubelectron]

Thank you Guys !

6BX7 - something like this, @gadget73 ?



Yes, I have a bunch of 6080WA tubes, but I use them for my DIY U-OTL :

6V6 in triode is reputed to be sonically similar to a 45...

Interesting information ... I was thinking about that for my DIY U-6V6 - to be finished - that were intended for pentode operation :

Check out the ELEKIT/Sunvalley support site. Seems a ELEKIT will be coming out TU-4523 (45 Tube + 2A3 Tube).

recent visit to ELEKIT and Sparkler Audio

Thanks for the tip ! It seems that there's nothing yet... Already finding 45 RI at an affordable cost would be enough, but no way...

T

 

[gadget73]

6BX7 - something like this, @gadget73 ?

yeah that would do it. I might go with just a single section triode as a driver, maybe a 6J5. Either way it would be a pretty simple amplifier. Depending on the particulars, maybe tickle in a little feedback, either plate to plate or global as you prefer.

 

[tubelectron]

6V6 in triode is reputed to be sonically similar to a 45...

@Selmerdave : do you have some schematics in mind ? Or operating point ? During SE tests with 10Y/VT-25 triodes, I experimented for comparison with a 6V6GTA in triode and it could reach 2WRMS pure clean sine wave, but like an idiot, I noted nothing !

I think that the plate voltage was fairly high, near 380-400V, and the bias at -30VDC. It was operating in fixed bias. The plate dissipation was close to the maximum allowable. That's all I can remember !

T

 

[Selmerdave]

@Selmerdave : do you have some schematics in mind ? Or operating point ? During SE tests with 10Y/VT-25 triodes, I experimented for comparison with a 6V6GTA in triode and it could reach 2WRMS pure clean sine wave, but like an idiot, I noted nothing !

I think that the plate voltage was fairly high, near 380-400V, and the bias at -30VDC. It was operating in fixed bias. The plate dissipation was close to the maximum allowable. That's all I can remember !

T

I don't have any direct experience, though I would like to check it out someday. I know that the Poinz Musical Machine, PP 6V6 triode, was very widely and highly regarded. JELabs has a SE build, always worth checking out I think:

Hi-Fi for the Deck: Rpi3B >TDA1543x4 DAC > Simple Triode SE6V6 amp > EV Sonocaster

jelabs.blogspot.com

 

[tubelectron]

Thanks @Selmerdave !

T

 

[gadget73]

quick internet poke leads me to this datasheet, which is for a tube thats the same as a 6V6GT other than packaging. Decent number of 6V6 family members out there in various packages, this is one I wasn't aware of but that doesn't say much.

https://frank.pocnet.net/sheets/184/6/6BW6.pdf

it has triode data in it.

6K6 is another that actually has pretty good looking triode curves and has some operating data in that mode. I've actually wanted to try those as a sub for a 6V6 in some console amp that has transformers wound for 4 ohms. In pentode mode they want a higher plate to plate load than a 6V6, so in theory they should be slightly happier about the mismatch caused by running 8 ohm speakers.

6F6 has triode data too.

 

[buglegirl]

6BX7 - something like this, @gadget73 ?

Interesting. Also uses the 6J6 as a driver which is another cheapy tube.

Frannie

 

[buglegirl]

yeah that would do it. I might go with just a single section triode as a driver, maybe a 6J5. Either way it would be a pretty simple amplifier. Depending on the particulars, maybe tickle in a little feedback, either plate to plate or global as you prefer.

Yah a 6J5 might be a better choice than the 6J6 its another cheapy easy to find tube.

Frannie

 

[gadget73]

more linear too, 6J6 is a bit funky on the curves but probably makes a perfectly good long tail pair if you're stuck with a 7 pin socket.

actually that makes me have ideas for something, but this is off track enough at this point LOL

 

[tubelectron]

I retrieved my SE 6V6GTA Triode Connection tests...
Finally, I had drawn a schematic and noted all the values, I forgot that !

* Operating conditions :

AT IDLE : No signal
Vplate = 372V
Vscreen (via Rs 1K) = 371V
Vg1 (via Rg 270K) = -30V fixed bias
Vk = 0V no cathode resistor
RL = 5K
Vsupply = 395V
Ik = 34mA
Total dissipation = 12.5W

AT MAX PWR : 4.12VRMS/8R/400Hz sine wave before clipping = 2.2WRMS
Vplate = 370V
Vscreen (via Rs 1K) = 367V
Vg1 (via Rg 270K) = -30V fixed bias
Vk = 0V no cathode resistor
RL = 5K
Vsupply = 394V
Ik = 37mA
Total dissipation = 13.7W

Waveforms @400Hz / 2.2WRMS :



* Without changing the bias (-30V), I also installed a 6L6GC and an EL34 in triode connection to see their behavior :

6L6GC = 2.6WRMS out.
EL34 = 3.2WRMS out.

T

 

[tubelectron]

OK : Back to the type 45 tube Reissues...



T

 

[gadget73]

EL tubes are interesting, they make modern stuff that is quite different from the old, but they just come right out and tell you its not the same and even have charts showing various differences. I appreciate that at least you know what you're getting. IMO its better than "here is tube X" with a sheet thats a dead match for one from decades ago, but in-circuit it doesn't behave the same at all.

never used any of their products but I have poked around the website a few times.