I am once again feeling the need for tubes... I've heard some pretty expensive (and good sounding) monoblocks, an amazing SET, and very nice preamp... Tested a push-pull 6L6 amp in my room once and was shocked at the sound that came from my old speakers. I've since upgraded to larger, more powerful (and more sensitive) speakers. My current amplification is just not cutting it. My new mains are 102dB 1W/m sensitive, so low power isn't a huge deal as long as the bass remains clean.
I fell in love with the 6AS7 a while back and really cannot quite understand why. I am looking for an amp that will match the sound of that $2000 SET, which I absolutely loved. But, I cannot spend anywhere near $2000. I don't have a whole lot of spare money right now, but can fund the project slowly (though I'd really rather have a simple, quick and easy solution as I am getting quite lazy lately). I am going to limit it more to $200 or so.
I have seen the Lilliput amp circuit and a couple of other 6AS7 circuits and had a thought... The Lilliput produces about 2.5W as shown in the circuit, using one half of the dual triode per channel. If I used both halves of the dual triode (so two 6AS7's total for stereo), this would halve Ra and Rk, causing the tube to draw twice the current. Correct so far? So, would this cause my power output to basically double? I am looking to use a Hammond 270HX transformer, which is something like 275-0-275V at 200mA (and I am guessing that means each 275V wire carries 200mA, so 400mA total if full-wave rectified). The 275V when rectified is quite a bit too high, so I figured I'd use a tube rectifier and LCRC filter to smooth the power. Would this all work?
Now... the other part... Like I mentioned above, I'm getting lazy. I haven't really felt like building amps or anything at all lately. I don't know that I can stick through the project. It's been one of those years so far... just kind of sucks. Would it yielf better results (and cost about the same) if I went ahead and sprung for a SE 2A3 or similar amp? I apologize in advance for this question, but any good sounding amps out there that use a PCB? The S-5 kit is really not an option. I doubt it will give me what I am looking for sound-wise. I always sound so disorganized...
Thanks for any suggestions
I fell in love with the 6AS7 a while back and really cannot quite understand why. I am looking for an amp that will match the sound of that $2000 SET, which I absolutely loved. But, I cannot spend anywhere near $2000. I don't have a whole lot of spare money right now, but can fund the project slowly (though I'd really rather have a simple, quick and easy solution as I am getting quite lazy lately). I am going to limit it more to $200 or so.
I have seen the Lilliput amp circuit and a couple of other 6AS7 circuits and had a thought... The Lilliput produces about 2.5W as shown in the circuit, using one half of the dual triode per channel. If I used both halves of the dual triode (so two 6AS7's total for stereo), this would halve Ra and Rk, causing the tube to draw twice the current. Correct so far? So, would this cause my power output to basically double? I am looking to use a Hammond 270HX transformer, which is something like 275-0-275V at 200mA (and I am guessing that means each 275V wire carries 200mA, so 400mA total if full-wave rectified). The 275V when rectified is quite a bit too high, so I figured I'd use a tube rectifier and LCRC filter to smooth the power. Would this all work?
Now... the other part... Like I mentioned above, I'm getting lazy. I haven't really felt like building amps or anything at all lately. I don't know that I can stick through the project. It's been one of those years so far... just kind of sucks. Would it yielf better results (and cost about the same) if I went ahead and sprung for a SE 2A3 or similar amp? I apologize in advance for this question, but any good sounding amps out there that use a PCB? The S-5 kit is really not an option. I doubt it will give me what I am looking for sound-wise. I always sound so disorganized...
Thanks for any suggestions
needtubes said:
You will need to halve the primary impedance of the output transformer as well to double output power.
SRPP designs by Flemming R. Madsen - electronics teacher and audio hobbyist from Islandthe mA rating on transformers is usually given as DC current after rectification, not current per leg of the secondary. while its more of a guideline than an absolute maximum, i would not expect 400mA out of that unit.
Quite right, I had missed that earlier.
You would expect 200mA DC out of it with FW rectification, and even then it would probably be quite warm.
Another thing, you said you enjoyed the sound of a PP 6L6 amp, yet intend to build a single ended amp. No matter what the hype says, PP amps need not always be sonically inferior to SE amps. With the availability of cheap Hammond transformers in the US, why not try a small PP amp with dissimilar dual triodes (like 6EM7 or 6DR7 etc) for around 4W. It should be very cheap to build, and by all accounts should sound very nice 😉
Another option is a SE 6EM7 as posted on Gary Kaufman's site if you are emotionally allergic to PP for whatever reason.
You would expect 200mA DC out of it with FW rectification, and even then it would probably be quite warm.
Another thing, you said you enjoyed the sound of a PP 6L6 amp, yet intend to build a single ended amp. No matter what the hype says, PP amps need not always be sonically inferior to SE amps. With the availability of cheap Hammond transformers in the US, why not try a small PP amp with dissimilar dual triodes (like 6EM7 or 6DR7 etc) for around 4W. It should be very cheap to build, and by all accounts should sound very nice 😉
Another option is a SE 6EM7 as posted on Gary Kaufman's site if you are emotionally allergic to PP for whatever reason.
That's about half of what you'll need to make any kind of decent sounding amp. I would recommend using a 5998 or 7236 instead of the 6AS7G. They have a higher mu and can put out adequate power with a more commonly available 2.5K - 3K OPT.
John
I think I hit the wrong key for the budget... I meant more along the lines of $300, which is still not quite enough, I know.
Thanks for clearing up the current rating on the transformers... that always threw me a little. If I have to cut the primary of the transformer in half to use the two triodes in parallel, then that makes it darn near impossible. As it was I needed about 1k already.
Those SEP and SRPP circuits are somewhat interesting... But I think I may have to give up hope of using the 6AS7 and look elsewhere... I really want something that glows quite well, though.
I did enjoy the sound of the PP 6L6, yes, but also qnjoyed the sound of the SE KT88. It was quite lovely... I suppose either would do, really... I am just dying for more detail, warmer bass, and less shrill highs. My current amp does not deliver at all...
I was looking at the 6EM7 a while back... I may have to go back to it. I'll do some more looking around I suppose...
What would you recommend as VERY nice SE iron that doesn't cost a ton (easily available in US, preferred)? Nice PP iron?
Thanks
Thanks for clearing up the current rating on the transformers... that always threw me a little. If I have to cut the primary of the transformer in half to use the two triodes in parallel, then that makes it darn near impossible. As it was I needed about 1k already.
Those SEP and SRPP circuits are somewhat interesting... But I think I may have to give up hope of using the 6AS7 and look elsewhere... I really want something that glows quite well, though.
I did enjoy the sound of the PP 6L6, yes, but also qnjoyed the sound of the SE KT88. It was quite lovely... I suppose either would do, really... I am just dying for more detail, warmer bass, and less shrill highs. My current amp does not deliver at all...
I was looking at the 6EM7 a while back... I may have to go back to it. I'll do some more looking around I suppose...
What would you recommend as VERY nice SE iron that doesn't cost a ton (easily available in US, preferred)? Nice PP iron?
Thanks
- Status
- Not open for further replies.