• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Hi-end 845 with only two stage

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#163

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#164
audiodesign said:
This evening the first test using the GM70 Graphite like diode in the configuration of the attached image.

1000v without the GM70

940v with the GM70 like diode

Until now I don't see problems.

I remember this:
http://www.audiodesignguide.com/Claudio845/VTPS_solutions.png
Click to expand...


Here we go again. :xeye: :whazzat:

Did you know that if you takle a bar of gold bullion, mill it out and install an axe handle, you can actually use it to pound in fenceposts?!!!!! :smash:

Nuff said.
 
#165
The idea of this evening.

845 driver by 2A3 direct coupled to the input tube.

This allow to skip the strange 6HV5A TV vacuum tube but it mantain high performances with a very short signal path.

This is not a final schematic!
 

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#171
Power Supply sonic perfomance test, 1 is the best

1) dual 6D22S after the solid state diodes bridge

2) no vacuum tube diode after the solid state diodes bridge

3) single GM70 after to the solid state diodes bridge

with the GM70 the sound is too smooth, with 2 x 6D22S the sound since to be more natural

In dual mono configuration will be necessary only one 6D22S per each channel
 
#172
audiodesign said:
Power Supply sonic perfomance test, 1 is the best

1) dual 6D22S after the solid state diodes bridge

In dual mono configuration will be necessary only one 6D22S per each channel
Click to expand...

That recalls me an amp made by a good guy in Russia, Shalin, and built by a couple of friends on his specs including the transformers

here the full circuit

I never ever understood why one should use a vacuum diode after a full SS bridge. Would a mixed bridge (SS+tube) be "better"?
 
#173
The mixed configuration can give the same sound with less tubes
http://www.audiodesignguide.com/Claudio845/VTPS_solutions.png

I cannot understand in the schematic sent the meaning of the 10MK after the solid state bridge and before the 6d22s.

---

One note: the difference on sound of combination 1 and 2 are very little and probably it is possible get the same result with the 1 adding a resistor before the first cap
 
#179
Tango vs Bartolucci

Yesterday evening with two my friends with a lot of experience in music reproduction has been started the first section of a sonic performances to compare the Tango to Bartolucci.

Using the same interstage INT8C (second release) I have changed the output transformer Tango X10S with Bartolucci 115BN.

Test evironment:
- Rega Planar 3
- Cartridge SUMIKO BLUE POINT EVO III
- My Pre Phono End
- SYNCHESTRA Reference interconnect cables
- SYNCHESTRA SIGNATURE Speaker Cable
- Martin Logan AERIUS modified

The 845 two stage amp. was with the solid stade rectifier and 1100V 70mA bias.

It is very difficult decide which is the best of this two reference transformens but the Bartolucci seen to be more neutral.
The Tango is a little bit smooth.

In a previuos test with all Tango transf. (NC-20 and X10S) the sound was completely too smooth so unacceptable.
 
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