I would like to build a tube based line amp, nothing too fancy but
with a great sound, an extended frequency responce, will match a ss amp input and not a kit. I have on hand a number of ecc81's.But I am willing to look at circuits using any other tubes/valves.
I have had a quick look at a number of sites but cannot find anything suitable.
Can anyone with experience of building such a project please point me in the right direction.
Many thanks
Phil.
with a great sound, an extended frequency responce, will match a ss amp input and not a kit. I have on hand a number of ecc81's.But I am willing to look at circuits using any other tubes/valves.
I have had a quick look at a number of sites but cannot find anything suitable.
Can anyone with experience of building such a project please point me in the right direction.
Many thanks
Phil.
12AX7?
From someone who's a green horn on tubes (but likes that sexy glow, and hates the output transformers on the tube power amps), what about a design based on the 12AX7 (or equivalent) series?
This may seem to be the solution for a tube sound but with the grunt of solid state for the power amp! Correct me if I'm wrong........
From someone who's a green horn on tubes (but likes that sexy glow, and hates the output transformers on the tube power amps), what about a design based on the 12AX7 (or equivalent) series?
This may seem to be the solution for a tube sound but with the grunt of solid state for the power amp! Correct me if I'm wrong........
Hello phil
I have a great page to recomend you. This article discribes a simple circuit with 12 different tubes suggested, and power supply. I think this is JUST what you are looking for. Figure 2 in the article would be my choise of circuit, but it inverts the signal. This is really no problem because you can compensate by switching the + and - on the speakers. All the tubes on the list ar well known and used by many.
http://www.users.globalnet.co.uk/~valveamp/
Your 81's can easily be used, check out
http://members.tripod.com/~gabevee/mytubamp.html
to learn how you can set up your own circuit from the ecc81.
-stig
I have a great page to recomend you. This article discribes a simple circuit with 12 different tubes suggested, and power supply. I think this is JUST what you are looking for. Figure 2 in the article would be my choise of circuit, but it inverts the signal. This is really no problem because you can compensate by switching the + and - on the speakers. All the tubes on the list ar well known and used by many.
http://www.users.globalnet.co.uk/~valveamp/
Your 81's can easily be used, check out
http://members.tripod.com/~gabevee/mytubamp.html
to learn how you can set up your own circuit from the ecc81.
-stig
Hello Phil and Stig,
when I read that Phil is intending to use the ECC81, I was tempted to disrecommend it as I had many occasions to listen to amps using this tube and none of them was sounding particularly pleasant or musical.
But as I had no tried schematic to contribute, I stood mute.
I followed the link and the 1st coming to attention was Simon Shilton's name. I know him as a transformer designer and he certainly is not sitting on his ears. I would follow his recommendations w/o hesitating.
I observed he does NOT have the ECC81 in his list of recommended tubes. But he has the 6CG7 (noval/miniature9 socket version of the 6SN7), the 6SN7, the ECC82 and the 5687 in his list, and I know all these tubes make gorgeous music. The 5687 also fits for this but is a lil'bit high transconductant and I would rather use it with an output transformer. This is running at my place at the moment, just magic.
Phil, my hint, keep the ECC81 as a deterioating example to try it out yourself but I would be surprised if you or anyone else prefers the ECC81 to one of the tubes I mentioned; this is not an audio tube and was never designed for that and has been tried out manytimes not to sound that well. (yeah, I know, the 5687 also was not deisgned for audio and was widely used in tube computers, but it has been tried out to sound gorgeous.)
when I read that Phil is intending to use the ECC81, I was tempted to disrecommend it as I had many occasions to listen to amps using this tube and none of them was sounding particularly pleasant or musical.
But as I had no tried schematic to contribute, I stood mute.
I followed the link and the 1st coming to attention was Simon Shilton's name. I know him as a transformer designer and he certainly is not sitting on his ears. I would follow his recommendations w/o hesitating.
I observed he does NOT have the ECC81 in his list of recommended tubes. But he has the 6CG7 (noval/miniature9 socket version of the 6SN7), the 6SN7, the ECC82 and the 5687 in his list, and I know all these tubes make gorgeous music. The 5687 also fits for this but is a lil'bit high transconductant and I would rather use it with an output transformer. This is running at my place at the moment, just magic.
Phil, my hint, keep the ECC81 as a deterioating example to try it out yourself but I would be surprised if you or anyone else prefers the ECC81 to one of the tubes I mentioned; this is not an audio tube and was never designed for that and has been tried out manytimes not to sound that well. (yeah, I know, the 5687 also was not deisgned for audio and was widely used in tube computers, but it has been tried out to sound gorgeous.)
Phil,
the preamp i am currently using is a borrowed one, but as i know meanwhile, it is on AudioNote level or better; my friend Manfred lend it to me until my own differential PP preamp gets ready. So i had to ask him for specifics.
Manfred's preamp has an input selsector and a 50kOhm ladder attenuator at the input. From that the 5687's grid is fed. The tube runs at 25 mA quiescent current. The used trannie is a Simon Shilton / SJS model PA102; it has a turns ratio of 5:1 and an impedance ratio of 15kOhm to 600 Ohm.
Warning, the trannie is slightly uncheap, but AFA i can tell, it is worth it.
At the moment, SJS has one pair of them on sale for UK-Pounds 85 a piece with chrome-plated shrouds. The normal retail price is at UKP 115, TMK. Recently, a British line preamp was reviewed in a German high-end audio magazine, Manfred reported, and the unit had a retail price of about US$ 9000.
With this simple structure, you are launched directly to orbit
Run and order as long as the sale trannies are available.
the preamp i am currently using is a borrowed one, but as i know meanwhile, it is on AudioNote level or better; my friend Manfred lend it to me until my own differential PP preamp gets ready. So i had to ask him for specifics.
Manfred's preamp has an input selsector and a 50kOhm ladder attenuator at the input. From that the 5687's grid is fed. The tube runs at 25 mA quiescent current. The used trannie is a Simon Shilton / SJS model PA102; it has a turns ratio of 5:1 and an impedance ratio of 15kOhm to 600 Ohm.
Warning, the trannie is slightly uncheap, but AFA i can tell, it is worth it.
At the moment, SJS has one pair of them on sale for UK-Pounds 85 a piece with chrome-plated shrouds. The normal retail price is at UKP 115, TMK. Recently, a British line preamp was reviewed in a German high-end audio magazine, Manfred reported, and the unit had a retail price of about US$ 9000.
With this simple structure, you are launched directly to orbit
Run and order as long as the sale trannies are available.
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