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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Audionote Japan (Kondo) Ongaku... Can I Clone to DIY!

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#81
hi Kmtang,


No, several month before I was suffer for colonic cancer treatment.

2008-05-28 need back to hospital too.

All posting photos was before I admitted in hospital & pending in home without test!


I continous for testing project only.

I also prepare the Cobalt base nano-amorphous MC stepup with riaa & will comapre to kondo M7 phone later. I was using this set up with clear audio champion reference & gold finger head.

will test both them.


thx

thomas
 
#85
Heres one I made earlier! Project started in 1994 using Audionote UK transformers and basic components. The only plan was the picture of an Ongaku on the front of positive feedback magazine and a schematic supplied by AudionoteUK. I didnt know the top was copper from the picture! As built it was OK but the mains transformer ran too hot and there was a distinct lack of high frequencies. Later schematics include a 7n cap on the cathode of the 6072. This corrects the frequency response. The polarity of the bias cap is also corrected on later schematics. The components have gradually been changed to include shinkoh tantalum resistors, black gate caps, silver foil caps, NOS valves and silver wire everywhere except the OPTs. I think it is now quite good. The remote controled ALPS pot works beautifully. I'll post some pictures of the works next time I have it apart. There are still a few things to improve yet. Recently the mains transformer burnt out so I rewound it without the 211 heater coils which are now supplied by a different transformer. It now runs at a reasonable temperature. Its still work in progress. I must get round to making transformer covers. There is a direct in bypass around all the remote control junk for ultimate performance but I can't hear the difference.

Thomas. I hope you are recovering well.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
 
#87
Hi Erik,

Yes, The Ongaku clone pictured above is still in regular use.

I now have a Genelec system for studio use which is no doubt cleaner but it doesn't touch the emotions like the Ongaku can.

It is pretty much as it was except the 211 heaters are now supplied by switch mode power supplies. I know it's heresy but it works, and there is now no 50hz hum even at high volumes with no signal.
Something I never achieved with conventional transformers. If switch mode noise is there, I cant hear it.

Good luck with yours. Post some pictures when it's done.
 
#89
PhilPrice said:
Hi Erik,

It is pretty much as it was except the 211 heaters are now supplied by switch mode power supplies. I know it's heresy but it works, and there is now no 50hz hum even at high volumes with no signal.
.
Click to expand...

SMPS switch mode power supply can work extremely well....so it is no surprise (for me).

"Audio Consulting" of which I think highly implements it with succes in their reference 300B amp....a wooden box out of proportion but they are not into looks 😀
 
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