The OP is correct, the D115 Mk 2 is a nightmare to bias. I used to own, and love, a D70Mk2...which is what I think the Classic 60 is based on, the D70mk2 is a stupendous sounding amp, BUT the biasing scheme was best left to a tech and really could be considered as criminal! Same goes for the D115...and I'm sure it sounds just as great!
Replacement Amp For Audio Research Classic 60
Very pleased with my System which is Turntable based and consists of the following;
Audio Research Classic 60 Tube Amp.
Audio Research LS5 MKIII Pre-Amp.
Herron VTPH-2A Phono Stage.
ProAc Response 2.5 Speakers.
I have owned the ARC Classic 60 Tube Amp since New it has been that long. Scott Frankland formerly of MFA has changed all of the important Caps.
Fearful due to Age that I need to research a Replacement Amp in either Solid State or Tube form but here is the catch; It needs to fit in a Rack so the Dimensions should be 19" Wide Max X 8" (Give or take High) X 16" Deep.
ARC LS5 MKIII has Balanced Outputs but I can go to Single Ended since there is a Switch on the MK III for Balanced or SE. I am running it SE at present to the ARC Classic 60.
My musical tastes are Classic Rock and Folk with some Classical.
In my research the one that has caught my eye is the Pass XA25 but I am truly not sure how this would be with the ProAc’s. I would hate to buy this Blind. I also liked the Luxman 509X very much but I really do not need an Integrated. These two Models are mentioned to give an idea of Price Range also.
Any suggestions would be appreciated.
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@sturgus You have hit the nail on the head since after much research this is what I have decided to do; 1) Classic 60 is in Scott Frankland’s Shop at present. Years ago he was unable to source the 4 Filter Caps and these can be seen if you look at Images on the net (In the middle of the Amp with Red Plastic Caps). This was a concern for me due to the age rightfully or wrongly. Scott has recently rebuilt an ARC M-300 and the Filter Caps that he changed in that Amp will fit in the Classic 60. He is also going to change out the 6 Infini Caps that he installed previously to V-Caps Copper Foil types. A full Spa treatment essentially. 2) I agree with the other posters that an ARC Reference 75SE will be the replacement if it comes to me replacing this Amp after this work. Keeping my eye out for a NM One Owner unit at present. I really appreciated all suggestions to my question. |
I looked up the ARC D115 MKII and it appears to be a nightmare to Bias so I need to pass on this recommendation but it was appreciated. The tube biasing is no more complicated than any other push pull tube amp, 65mA each output tube, done by the user with a meter. Yes there are other once in a "blue moon" adjustments, AC and DC balance (not super critical AR's words) if you want to get into those too, that's what makes this amp one of the push pull tube legends. http://www.audioresearch.com/ContentsFiles/D115_Manual_Schem.pdf Cheers George |
In my research the one that has caught my eye is the Pass XA25 but I am truly not sure how this would be with the ProAc’s. I would hate to buy this Blind. As you may be aware, Reno Hi-Fi, which is apparently the leading Pass dealership in the USA and is wonderful to deal with, offers 14 day return privileges less only two-way shipping. Although they can’t sell a new unit (as opposed to a demo model or trade-in) to anyone who is within 100 miles of a different authorized Pass dealer. I purchased an XA25 from them last year. It replaced the very well regarded 300B-based VAC Renaissance 70/70 MkIII I had been using for several years, and I haven’t regretted the change for one instant. Among the various published reviews of the XA25, I found that the one by Terry London (A’gon member Teajay), at hometheaterreview.com, characterized its sonics especially well. That said, John Atkinson’s measurements of your speaker show it to have a sensitivity of only 83 db/2.83 volts/1 meter, which for its 8 ohm nominal impedance means 83 db/1 watt/1 meter. JA also measured the XA25 as being capable of providing 80 watts into 8 ohms (presumably after leaving class A at a significantly lower power level, given its 25 watt/8 ohm published rating). And I wouldn’t count on it quite being able to deliver 80 watts into your speakers, because their impedance is well above 8 ohms at a lot of frequencies. The bottom line is that I would expect the amp to reach its limits when producing SPLs in the mid-90s at a listening distance of say 10 feet in a medium sized room. That will be more than enough for many listeners with most or all of their recordings. But if your listening includes recordings having particularly wide dynamic range, such as many well engineered minimally compressed classical symphonic recordings, I would have my doubts. I listen to a lot of those kinds of recordings, btw, but my speakers (Daedalus Ulysses) are rated at 97.5 db/1 watt/1 meter, and have particularly benign impedance characteristics. The combination has no trouble cleanly producing 105 db dynamic peaks at my 12 foot listening distance. Good luck, however you decide to proceed. Regards, -- Al |
@ricwa, appreciated your comments from someone that has the Pass XA25 and especially in using them with the Harbeth’s. @georgehifi , I looked up the ARC D115 MKII and it appears to be a nightmare to Bias so I need to pass on this recommendation but it was appreciated. @atmasphere , I have looked at your offerings already and I was really hoping for a one box solution. You raised a good point that I failed to mention. Amp is residing in a Two Bay Billy Bags Rack that is open on all sides plus the Classic 60 has two fans on the rear which is very handy. @dweller , I have seen the BAT VK-255SE previously and I like it very much. @bdp24 , ARC Ref 75SE has been on my Radar for close to 1 Year so this was a nice recommendation. I have also looked at the Ref 110. |
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djohn I’ve heard quite a few AR amps in Australia, new and old, and the one that sticks in my head is the AR D115 mkII, it had all AR is known for, yet the bass I heard was like it was big solid state EG: Gryphon, Krell ect. Get hold of a good well serviced one of these if you can. And it meets your measurements, just! And you guys have a good one by the looks of it over there, that's not expensive. https://www.usaudiomart.com/details/649288132-audio-research-d115-amp/ Cheers George |
I have an ARC LS28/VT80SE combo. I swap between Harbeth 30.1s and Paradigm Persona Bs. The speakers are night and day different but I like them both with my ARC gear. I recently acquired an XA25 so that I could swap amps as well. With the Personas, the XA25 blew my mind! Best sound ever in my room. The Harbeths also sounded good with the XA25, but I was surprised to prefer the VT80 with the Harbeths. Bottom line is that everything is system dependent. You will hear tighter, deeper bass with a blacker background with the XA25 for sure. BTW, the LS5 Mk III is a fantastic classic ARC pre. |
