I have now looked a little more at the schematic and it is NOT just a Gainclonebut rather a sort of current dumping topologi, so maybe it has potential afterall...
Hi Koldby,
exactly, the My_Ref is Mauro Penasa's (successful) attempt to implement Tim DeParavicini's Musical Fidelity A-370 with a chip amplifiers.
The LM3886 is used as an Howland current pump driven by the LM318 (also part of the A-370).
My variation is partly inspired by Penasa goals for his next work, the My_Evo (a My_Ref evolution).
You'll be welcome to the second run, it will start the first week of May.
He-he
Quanghao´s thread was closed here @ DIY forum, probably because it was too close to the actual Goldmund Telos. He made some very fine PCB´s that he sold, but as far as I know, they are not awailable anymore.
My amp is putting out > 250Wats pr.channel and still has the refinement of small class A amps like F5. It was the only amp that could challenge the OTL tube amp in musicality, transparency and delicaty and that from a big bold solid state feedback amp...
Actually that is why I will try the FE ´cause aparently you can´t tell from the topology directly if it is gold or glitter
Koldby
You're the designer of the Audio Mirror? Did I read that right?
That is the best implementation of the topology, inspired by the Hitachi topology for their magnificent To3 lateral mosfet. Why not special
I found that the dedicated driver per mosfet improve performance at low SPL (which is probably the more common listening level). At higher SPL, better one driver for all mosfet.
Actually that is why I will try the FE ´cause aparently you can´t tell from the topology directly if it is gold or glitter
Oh? I would like to hear your opinion. It is not going to sound like tube amp at all
Thanks. It does look like an interesting amp. Do you have an opinion on other Golmund clones that might be available?
He-he
Quanghao´s thread was closed here @ DIY forum, probably because it was too close to the actual Goldmund Telos. He made some very fine PCB´s that he sold, but as far as I know, they are not awailable anymore.
My amp is putting out > 250Wats pr.channel and still has the refinement of small class A amps like F5. It was the only amp that could challenge the OTL tube amp in musicality, transparency and delicaty and that from a big bold solid state feedback amp...
Actually that is why I will try the FE ´cause aparently you can´t tell from the topology directly if it is gold or glitter
Koldby
hello
red cards??
do you use pre telos?
what railvoltage you have?
and what caps did you use ? C8-10
output 1058? 10n20? how many
Regards
Stig
Amp seems to be working now! I followed what Olphy posted on 2295 (except for thermal contact T7 to T10 that I yet have to figure out) and the DC offset oscillations have disappeared. There is still some drift in the offset until the amp warms up ( from roughly 100mV down to +-5mV) but the protection circuit operates fine now at least as far as tested. I work some more to stabilize it.
I can't believe this fine circuit, debated in hundred of pages of posting on several treads, is so sensitive that a few "pF' capacitors are all that is needed to stabilize it...
Thanks for your inputs.
I can't believe this fine circuit, debated in hundred of pages of posting on several treads, is so sensitive that a few "pF' capacitors are all that is needed to stabilize it...
Thanks for your inputs.
Yes of the ORIGINAL Audio Mirror brand made in Denmark in the mid 1980´s, not the current American tube amplifiers made under the same brand! Tube preamplifiers TPA4 and TPA4a and Tube/mosfet hybrid power amp TFA3 was manufactured.You're the designer of the Audio Mirror? Did I read that right?
That is the best implementation of the topology, inspired by the Hitachi topology for their magnificent To3 lateral mosfet. Why not special
Well a lot of amplifiers with diff. fet input, bjt vas and lateral output has been made, and non has been very outstanding, as the Telos is IMHO.
koldby
I dont know about that, but maybee...
pre Telos? Do you mean in the opamp preamp. stage in the power amp? No! Or do you mean a Telos preamplifier clone? N0. I use an Aikido tube preamp with relay volumen control.
10p silvered mica
+/- 80 volts rail
12 per side (6 p and 6 n) 10N20
Koldby
Hello Quanghao and thank you for the wonderfull pcb´s.
Too small? You really think so? They are 600VA each...
Well anyway my loudspeakers are VERY efficient and presents an easy load with no seriuos dips in impedance.
Very good indeed. As you can see in my previous post here, it has bettered all of the amps I have made prior to it. The only amp that can challenge it is the 25 Watt 6C33 otl, but it needs a remake with better components and better chraftmanship and a little improvement here and there to match the Telos or surpass it. IMHO.
Thanks again Quanghao
Koldby
Thanks Tommy,
Yes and in the critical positions Vishay Bulk (feedback)and AMC as power resistors.
Koldby
New layout?
Is this implemented in your new PCB offerings?
And is it better sounding?
Koldby
No, it was closed because he was stealing the Goldmund trademark to try to sell his parts. Anyone is free to copy any nonpatented circuit. Stealing trademarks is illegal and highly unethical.