Hi Johnsonwu, I may be misunderstanding your intent. If you are not planning on changing the circuit that is inherent in the amp, then there are no real risks that I can see.
BTW, I agree with you that the circuit is superior to the Classic 120's and the VT series..... this has been borne out in the listening tests that I and my a'phile group have conducted vs. the VT series and the Classic 60 that we also AB'ed against. ( presumably the Classic 120 is the same basic circuit).
I have yet to hear a better ARC amp in the mids than the ARC D70mk2, even in the ARC VS series of today. |
I pulled the trigger on an ARC D70mk2 about a year ago..here are my thoughts on it: http://forum.audiogon.com/cgi-bin/frr.pl?ramps&1277362082&&&/Audio-Research-D-70-mkII-Tube-amp-
Agree with Tubegroover, I do not think one can buy a better tube amp on the market for anything near the price. Don't agree that the amp lacks ultimate detail, air or bass control of more expensive tube amplifiers. In an 'AB' with a BAT VK75 amp of recent vintage, all preferred the ARC and by no small margin. I do think that everything else in the system has to be up to what the D70 can bring to the table. |
Johnsonwu, I will be very interested in your outcome after you have modded your D115Mk2. WZ Johnson got the circuit very right, IMHO. Changing what he designed could be a risky business, OTOH I applaud your experimentation. |
Johnsonwu, sorry to hear of your travails. I would say that there must be something still wrong with your D115M2 if it sounds foggy and a bit slow.
Did you replace all of the tubes and check the caps? |
'Foggy', certainly isn't a term that comes to mind when I listen to my ARC!
Not sure what you are hearing, but if 'Foggy' is a factor, then I would suggest you look elsewhere in the chain for the offender. |
Sbrown, Thanks for sharing that info on the KT120's. I was wondering about this and was going to call Arc about it. You just saved me the call, LOL.
Too bad, as the KT120 is a very good tube. With decent 6550's getting a little hard to find, I'm glad I just re-tubed with SED's. |
JohnsonWu, you say that every time you have used vintage ARC amps, even after replacing the caps, that they still exhibit smear and glare but at higher headroom.
In my system and with the original caps in the ARC, I am not exhibiting this symptom. As I asked before, could it be something else in your system that is the cause of what you are hearing? How sensitive are your speakers and what tap are you using on the amps to connect them to? I have a small dedicated room, so I am not driving the amp that hard ( which could be why I am not hearing your symptom ;))), what size is your room? |
I was reading the new Absolute Sound today and noticed that Dick Olsher just acquired a D70Mk2.. He comments that the D70mk2 has "glorious midrange" in a review of the CJ mono amps. I totally agree with him in this statement. |
JohnsonWu, I just don't agree with your assessment of the sound that the older ARC amps exhibit. My D70Mk2 has wowed all of the a'phile group that has heard it in my system. So much so, that one of the group traded a BAT VK75SE for a pair of M100's ( with the same wonder caps) and never looked back after he heard my ARC/CAT set up.
I'm sure you are aware that ceramic tweeters will exhibit glare and hardness with aplomb. The same can be said, to a slightly lesser extent, for the beryllium tweeters in your Utopia's. A hard dome can be bright and exhibit glare IF any of the upstream components are at all bright...speaker cables, preamp, front end, amp etc.
I believe and i think many others are beginning to believe also, that a silk dome or a ribbon is far less likely to exhibit this behavior than a hard ceramic or metal dome. Which, if I'm not mistaken is one of the reasons that Dave Wilson chose a silk dome for his top of the line speaker, the Alexandria XLF. I guess when it comes to this discussion, YMMV. |
Hifikeek1 and Johnsonwu, IF you had an unlimited budget for cap replacement, which caps would you use in the D70 or the D115? and why? |
Johnsonwu, good to see that you like your modded D115.
I feel this way about my D70Mk2 and IMHO it's one of the best sounding
ARC amps. I have a feeling that this is why Dick Olsher bought one too!
A stone cold classic! |
Johnsonwu, I actually have not owned the D70mk2 for more than about 18 months. However, I am pretty enamored of this amp and would recommend it to anyone thinking of a great mid powered tube amp. BTW, I have a feeling that Dick Olsher is into good sound like the rest of us, and if it comes from triode or pentode isn't the main issue. Just so long as the gear can portray music. That is my way of looking at gear, I'm not attached to triode or pentode or tubes vs. ss or whatever, IF the piece under question sounds great, that's what I'm looking for. Isn't that what we are all seeking? |
