My friend has told me recently for a SRPP preamplifier that has 2 x 6SN7 per channel, normally a 1 x 6SN7 is enough in SRPP circuit, how come having 2?
He has the actual preamplifier and he has sent me a description: "The audio circuit has two dual-triode 6SN7 tubes per channel. The lower tube is set up as a long-tailed differential pair. one of the grids is grounded, the other is the input grid from the volume control. Input signals are amplified by this stage and converted to differential (push-pull, or balanced ) outputs by this circuit. One half of the second dual triode is the follower for the one half of the lower tube, and the second half of the upper tube is the follower for the other half of the lower tube.
Refer to HeadWize - Project: An OTL Tube Headphone Amplifier by Kurt Strain for an example of a single-ended mu follower stage. Imagine that the lower tube is a differential pair and there is a second follower above the other half of the differential pair. Two tubes, single-ended input, balance d outs."
Can anyone explain to me what is it about? I'm really curious how a SRPP with 2 tubes (4 triodes)?
Thanks!
He has the actual preamplifier and he has sent me a description: "The audio circuit has two dual-triode 6SN7 tubes per channel. The lower tube is set up as a long-tailed differential pair. one of the grids is grounded, the other is the input grid from the volume control. Input signals are amplified by this stage and converted to differential (push-pull, or balanced ) outputs by this circuit. One half of the second dual triode is the follower for the one half of the lower tube, and the second half of the upper tube is the follower for the other half of the lower tube.
Refer to HeadWize - Project: An OTL Tube Headphone Amplifier by Kurt Strain for an example of a single-ended mu follower stage. Imagine that the lower tube is a differential pair and there is a second follower above the other half of the differential pair. Two tubes, single-ended input, balance d outs."
Can anyone explain to me what is it about? I'm really curious how a SRPP with 2 tubes (4 triodes)?
Thanks!
I found the link of my friend's unit:
SA-11 Upgrades
And start under the section Basic Upgrade (3rd paragraph of the website).
Hmmm... How long do you think elecrolytic capacitors in such close proximity with radiating heat tubes will live before asking for one more $5,000 upgrade?
An externally hosted image should be here but it was not working when we last tested it.
The 'basic upgrade' section says that the original circuit is cathode-coupled and the modified circuit uses an SRPP. Is your unit original or 'upgraded'. By the way, this is not an upgrade but a redesign.
I note with amusement that after the 'upgrade' the unit can achieve astonishing performance: distortion less than 1% at 1V out! This is only an order of magnitude worse than a much simpler circuit can achieve - truly 'high end'.
I note with amusement that after the 'upgrade' the unit can achieve astonishing performance: distortion less than 1% at 1V out! This is only an order of magnitude worse than a much simpler circuit can achieve - truly 'high end'.
I think I am wondering why you seem to want to do a tour around possible preamp architectures, without saying what you want this preamp to do. It was cathode-coupled, possibly modded to SRPP, now you want to look at Aikido. Throw cathode follower, low-mu grounded cathode, and ring-of-three with NFB into the ring and you have covered all the common possibilities.
Because someone I know who has stock Counterpoint SA-11 but Alta Vista no longer offer the mod. And he is seeking comment but couldn't write English by himself. So if you are in my position, will you give him a hand???
I know a person recently has the SA-11 refurbish his "modded" unit but sounds like he didn't want to give out the circuit.
I know a person recently has the SA-11 refurbish his "modded" unit but sounds like he didn't want to give out the circuit.
Yes, you are right for "concept" in certain way. We group of friends has tried that, with no dynamics!! Gain is not an issue when dealing with CD player but what about impedance?? Impedance mismatch ruins everything.
Many mfg has built their CD player with direct output with volume pot, never success. The most important part is my friend is a vinyl guy. And he has the Counterpoint SA-9.
Many mfg has built their CD player with direct output with volume pot, never success. The most important part is my friend is a vinyl guy. And he has the Counterpoint SA-9.
Almost all audio systems are intended to operate with severe impedance mismatch. Low source impedance, high load impedance is the correct way. The last thing you want in an audio system is impedance matching!
As long as you don't have long interconnects (high capacitance), high value volume pots (high and varying source impedance) or amps with low and non-linear input impedance it should be fine. The perceived lack of "dynamics" might simply be due to a lack of low-order distortion and a reduction in noise.
As long as you don't have long interconnects (high capacitance), high value volume pots (high and varying source impedance) or amps with low and non-linear input impedance it should be fine. The perceived lack of "dynamics" might simply be due to a lack of low-order distortion and a reduction in noise.
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