Is it worth replacing output resistors or just the caps???

[budx3385]

Great call, Chris, that is indeed what I'm looking at. And I've cut off the muting xstrs in the 965, as recommended (super worthwhile), but the 971 has a relay. So I have ordered one pair of each of those resistors from michael percy - the Caddock TF020 and the new Vishay TX2352. I'm looking forward to replacing the carbon dust pillboxes.

I take it you have tried this already?

 

[Pars]

No, I don't buy $6 resistors. Wife is already pissed at what I do spend

I did remove the muting transistors, and have implemented a muting relay on the discrete I/V stage I am (still) working on. I would have to go back and A/B it, but I don't recall hearing much from their removal (other than don't power the thing up or down with the preamp on and unmuted).

 

[budx3385]

well, removing the muting xstrs in the 965 was a noticeable improvement in clarity, even more than replacing the RCA output connectors was. Same result in the $25 Denon 615 that I use as a test board. Instant effect - no burn-in required

My $6 resistors arrived. I plan to install them this weekend and see (hear) what difference this makes for myself.

Fortunately, my wife only smiles when I exude about a worthwhile upgrade!

Before I go replacing every cap, I want to see what this does.

 

[budx3385]

well, I received the new film resistors from michael percy. In short, this tweak was WAY worthwhile.

I put the Vishays in the Rotel 971 I have modded and the Caddocks in a Rotel 965 I have made similar mods to. The effect was the same in both. Clarity and balance up the wazoo. No overemphasis anywhere. Really no burn-in. Just super clear - a remarkable improvement. Almost as impressive as swapping out opamps or output caps. BTW, I tried simply shorting one to the RCAs, in the unit that has its muting xstrs removed, and that sounded somehow raw and unrefined. The output series RC does a job (if a guru could tell us how or why, that would be really helpful), and using "boutique" ingredients made a whopping difference for me.

my two cents, and the point of this thread, after all

so, comments please, gurus???

 

[Pars]

Interesting... these were the 100 ohm series resistor(s) on the output (my 855 has two per channel)? Were these generic metal film (what mine are, probably Philips)? You had mentioned carbon in yours? I wonder what a good quality metal film (Dale RN55/60, Roederstein, etc.) would do here? Probably not as good as either the Caddock or Vishay bulk foil, but possibly worth it?

Thanks,

Chris

Quote:

Originally Posted by budx3385 /img/forum/go_quote.gif well, I received the new film resistors from michael percy. In short, this tweak was WAY worthwhile. I put the Vishays in the Rotel 971 I have modded and the Caddocks in a Rotel 965 I have made similar mods to. The effect was the same in both. Clarity and balance up the wazoo. No overemphasis anywhere. Really no burn-in. Just super clear - a remarkable improvement. Almost as impressive as swapping out opamps or output caps. BTW, I tried simply shorting one to the RCAs, in the unit that has its muting xstrs removed, and that sounded somehow raw and unrefined. The output series RC does a job (if a guru could tell us how or why, that would be really helpful), and using "boutique" ingredients made a whopping difference for me. my two cents, and the point of this thread, after all so, comments please, gurus???

 

[budx3385]

Sorry for the response lag - getting ready for the big annual meeting. Yes, Chris, there were two series 100 ohm resistors per channel in the 965, and I replaced both with a single 100 ohm Caddock on each channel. I did a similar replacement in the 971 with the naked Vishays. I really don't know what the stock pieces were, I just assumed they were standard carbon. Both swaps made a huge difference. If you try it, please let me know what you experience.

I sure would like to hear from another "headphoneus supremus" or maybe a "member of the trade" why this is so effective and yet so underemphasized.
It's SO simple. And having done this in conjunction with replacing output caps and opamps, removing muting xstrs, replacing output RCAs, etc, I can jump up and down with delight - my modded CD player sounds WAY better on my headphone amp than two very expensive stock units.

 

[Pars]

Quote:

Originally Posted by budx3385 /img/forum/go_quote.gif I sure would like to hear from another "headphoneus supremus" or maybe a "member of the trade" why this is so effective and yet so underemphasized.

Well I know Mike Elliot (ex. Counterpoint prez and designer, currently AltaVistaAudio) uses the Caddocks in his "upgrades" of Counterpoint stuff. And I'm sure only on series resistors in the signal path. I've gotten a bit jaded regarding hi-dollar "upgrades" which consist of swapping out parts with boutique ones, but don't really address the circuit shortcomings (of which his have several). Perhaps this one has some real merit to it. I'll have to try it, probably on my preamp, and maybe on one of the discrete I/Vs which are ready to go once I get around to putting it in

Regards,

Chris