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[rollo]

 OK its official its in the shop. The power supply cap in one blew up. Sooo why not change a few parts. Starting with the metal oxide resistors [ yuck]. Takman carbon film or Riken. Mundorf MRE non inductive as required. Hexfred rectifiers and Diodes.
  New Audio Note silver over copper female RCAs and AN speaker terminals. Internal wiring to be shielded copper litz by Audio Note.
  The power caps will be Elma Cerafine or Audio Note. Only 8 caps and 16 resistors per amp. Parts expense reasonable. Labor not sure yet being evaluated as we speak.
  Any thoughts or suggestions ? Power caps ?


charles

[richidoo]

It's gonna come back sounding like Halcro and you're gonna want all those dirty cheap parts back in there! Just kidding, Charles. You know it's gonna rock! I'm glad you're finally getting them fixed. My heart sank when you reported their untimely demise. How long till lift off?

[mgalusha]

You might be surprised at the difference. I have the Cyber 845's and one of the resistors failed, taking out one of the PS caps. I did much the same thing, hexfreds, high ripple/low ESR (panasonic TS ED) caps, vishay high voltage resistors in the PS and added bypass caps to all the PS sections. I replace all the PS caps, not just the B+ ones. More clarity and definition.

[Mike L]

Had a tube fail in my cyber 800's that took something with it.  I never thought of upgrading parts, nor am I really sure what can be done.  May have to investigate further.

Thanks,
Mike

[rollo]

You might be surprised at the difference. I have the Cyber 845's and one of the resistors failed, taking out one of the PS caps. I did much the same thing, hexfreds, high ripple/low ESR (Panasonic TS ED) caps, vishay high voltage resistors in the PS and added bypass caps to all the PS sections. I replace all the PS caps, not just the B+ ones. More clarity and definition.

 Thanks for the response. my concern about part selection is I do not know the sonic character of such. Since I do not mod and have no experience in part selection I'm puzzled. The Panasonic's are well regarded Caps and probably good enough. but what about another choice say Elma Refine, Audio Note, Mundorf etc. Is there much of a sonic difference to be concerned about ? Since IMO the power supply is the amp in essence I would like to make the ultimate one. Since the design will remain the same part selection is all I have to go with.
  Since metal oxide resistors were used should I use Vishay metal film or carbon. Can the Vishays be bright or thin compared to their carbon film counterparts ? Or are they just neutral ?
  Thanks for your advice.


charles
   I do not want to loose the rich aand full character.  
  So I have been looking at amps that I like the sound of to see what they use.

[mgalusha]

The only resistors I replaced are the ones in the PS. These are to equalize the voltage between the caps. The key with these is they have to be able to handle the high voltage without failing. I used 3 watt vishay metal film as they were rated for 750V each. The reason one of the original caps failed is because the equalizing resistor failed allowing one of the caps to see more than it's rated voltage. Because of the very high voltages in these amps, the B+ caps are wired in series to accommodate this. These resistors were chosen mostly for their voltage rating and the fact that they were not metal oxide. Mills wire wound would have worked well except they don't offer them in a high enough resistance to suit me and the 12Watt size is really too big for the space.

As for the esoteric stuff like Mundorf/Audio Note/Etc, if you can find some that will fit they should work fine. I could not find any Mundorf that would work. I chose the Panasonic based on their ESR and lifetime ratings in addition to the needed voltage/capacitance ratings. Of course they also had to fit the board. I didn't find any of the high end Nichicon Muse of the correct values either.

So far I have not changed anything other than the power supply parts. I am sure better coupling caps would make a difference but I've been unwilling thus far to spend the $$$ on the V-Caps, which are what I want.

[rollo]

Thanks. Very informative. I have settled on Panasonic caps. Vishays as well for the power supply. I installed V-caps [ .1 and .47 ] to date with marvelous results. The resistors in the signal path will be either Takman or Riedon. Hexfreds as well. That 22K semi conductor must go as well.
  Consonance mentioned that the RCA and speaker terminals are generic copies of WBT. They recco changing them . The results were not subtle according to them. Same for internal wire. They recco shielding the existing or going for the wire of the day { they like silver}. I like copper.
  Your help and time is very much appreciated.  Waiting for the Tech to get back to me with his findings of what blew up. Then we can decide on what and how to proceed.


charles

[Triode Pete]

The quality of build (mod updates / repair) is more important than the quality of parts.

Make sure your "Russian" tech knows what he is doing and is "trained" in the art of soldering and the layout of components (caps / resistors / wires, etc.)

If not, you're wasting your money...

My $0.02,
Pete

[rollo]

The quality of build (mod updates / repair) is more important than the quality of parts.

Make sure your "Russian" tech knows what he is doing and is "trained" in the art of soldering and the layout of components (caps / resistors / wires, etc.)

If not, you're wasting your money...

My $0.02,
Pete

 Agreed. Scott Gramlich of SG custom sound will be doing part replacement only. The design is sound basically an Audio Note design. The Amp itself is also a clone of the audio note circuit which was borrowed from Westinghouse. We do not ant to ruin a good thing just part swapping. Getting rid of just the metal oxideresistors will make a nice difference.  The last thing I want is to change the full rich character of the design. Tubes are for that.


charles

[rollo]

Thanks again Mgalusha. Kiwame 5w resistors in the power supply, Panasonic caps[ thank you], V-caps at coupling positions [ .1] and [.47]  International Hexfreds, Takman 1% carbon films in signal path.. Internal wiring Audio Note shielded copper litz. Audio Note RCAs and binding posts. Tubes: GE 211s, RCA 211s, TJ Meshplate 211s to play with.


charles

[richidoo]

Sounds like a winner. When will you hear it all done?

[rollo]

Sounds like a winner. When will you hear it all done?

  In couple of weeks. Parts still coming in. Vendors suck.


charles

[rollo]

Its done.    /  In a word . World class sound. With only 8 hrs I cannot believe the improvement. Full, rich with clarity and detail. The Holy Grail combo.
  Basically the resistors Kiwame and Takam are responsible for the improvement. The caps [ V-cap] were previously installed. The Caps for the power supply were changed to Edcor in lieu of Panasonic [ lower ESR ]. No circuit changes just a parts swap.
  I expected a change for the good but was not prepared for this result. We held off on the internal wire for signal and power for now. I felt that the changes implemented were enough for now and that too much done would not enable me to discern any the difference. When fully broken in the signal wire will be Audio Note Lexus, the speaker wire Audio Note copper. Power wiring Neotech.
  However it sounds so good now the wire change may not be required. Time will tell but you now the Nervosa thing. A little research a qualified tech and life is wonderfull. Next up the Preamp.


charles

[Triode Pete]

When am I coming over for a listen?

[rollo]

When am I coming over for a listen?

  Actually we need to get together to square up on the power cords. I owes yous some mulla. Are you going to the Audio Syndrome meeting Friday ? Next up is to defrankenswartch the Loesch preamp. He put Axion caps in lieu of the MIT. A bad boy he is. He also eliminated the passive pre option. Bad boy.
  what we will be looking at is to turn the loesch into a phono stage only and replace the Elma volume pots with Lightspeed attenuators. Replace those sandstone resistors with Kiwame. Diodes to International oversized Hexfreds. Really no need to go any further than that as we know what this preamp is capable of. Haven't bought the Israeli batteries yet but a new pair of Duracell copper top Lithium's made a nice difference in control and noise level. Thanks for the tip Braveheart.


charles