Gold mine of DI¥ audio tubes schematics from Japan

[Soundhappy]

That loftin white is certainly interesting with a half wave rectifier.

Amplifiers schematics show is a direct coupled amp's.
Easy to build with PSU full wave or other of Your choice

 

[Soundhappy]

DIY tube articles updates HOME

 

[Soundhappy]

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[astouffer]

That last one with the OPA602 looks very interesting.

 

[Kay Pirinha]

I think it is more confusing. Look at the 6CA7's: Plate supply is 373 V, potential at both cathode resistors is 244 V. How do these tubes work with just 129 V plate voltage?
Best regards!

 

[Kay Pirinha]

More than that, where ist this 244 V "E" bus referenced to ground? I only recognize two resistors of 56k in series and a single one of 110k in parallel with them to ground.
Best regards!

 

[Sorento]

The outputs work on a floating ps, whose negative terminal is the E and the positive is the B1. So the 6ca7s get the full 370.
Only the biasing of the outputs is refereced to gnd, which puts the negative of the floating B1 at 244 relative to gnd.

 

[Kay Pirinha]

In this case the voltage readings in the schematic are misleading, at least. Isn't there a convention that all voltage readings are referenced to ground, if not specified otherwise?

Best regards!

 

[PCL200]

At the top righthand corner of the schematic there seems to be a definition of what a 'boxed' voltage means. I don't know any Japanese though, but I see a 'circled' E, so in line with Sorento, it probably says that the 'boxed' voltages have E as reference.

 

[astouffer]

Everything is direct coupled so the opamp sets the bias for the output via the input stage?

 

[PCL200]

My knowledge of solid state circuits is very poor, so with that in mind...

Yes, I think you're right. But since the OPA602 (which 'senses' the difference over the two 1 Ohm cathode resistors of the EL34S's) feeds its 'bias corrrection' to the lower EF86, it doesn't garantee that also the first and second stage will work perfectly balanced. They could be a little off balance as long as the two EL34S's draw the same current.

I also think that connections A en B at the cathodes of the EL34S's connect to a safety circuit (too much current, than the B+ to the EL34S's shuts down by a relais).

 

[Soundhappy]

遠い昔のラジオ少年 HOME

 

[Soundhappy]

MJ^9312_(03)DC-amp(131)6C33C-B-power-amp_KanedaA.pdf - Google Drive

 

[Soundhappy]

MJ^9312_(04)OTL-amp(10)_7242-SEPP-OTL-amp_MiyazakiY.pdf - Google Drive

 

[Soundhappy]

http://green.zero.jp/kirifuri1993/radio-boy/index.html#gsc.tab=0

 

[Soundhappy]

 

[Soundhappy]

Updates 遠い昔のラジオ少年 HOME

 

[Soundhappy]

遠い昔のラジオ少年 HOME

 

[gideon1990]

Someone here built a 3 * 6080 OTL a few weeks ago, he'll probably enjoy this one

 

[Soundhappy]

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