ARC of the past compared to today

[tdh888]

Hi DaveyF ,

Thanks for the reply , your right regarding the resolution of the D79B when one is using the stock input tubes & output tubes . I purchased new old stock Telefunken 12AX7's , a pair of them and Svetlana KT88's and this transforms the amps resolution. Unfortunately I think all my Caps have dried up and in need of recapping .
Regarding the new vs old amps , I had the relunctanly sold my D250MK2 Servo and my Classic 150 monoblocks and my SP11MK 2 to purchase REF 610T's , REF 5SE and Phono 2SE and I did not regret it , these units are simply in another level compared to my old units, but because of their higher resolution careful cable matching and setup is critical to get the best from these newer equipment.
I still have my pair of D79B's , EC21 and SP10MK2 as my vintage system using them w/ my rebuilt stock Magnepan MG3A . I occasionally use these system once in a while.
Will let you know when a comparison had been made w/ the REF75 .

Best regards ,

tdh888

[daveyf]

tdh888, tube rolling usually ( not always) brings out a better presentation. I did this with my ARC D70Mk2 and it also gained in resolution and overall dynamics. However, I do believe that the inherent quality of both amps ( the D79B and the D70Mk2) are as I described above. This sort of makes sense as the D79B is from the older designs from WZJ. OTOH, one could say that the D70Mk2 was also...at least compared to the current series, however, i do not believe these newer ones were designed by WZJ. Therefore, IMHO, the D series and the M100's were from his 'golden age'. Question is whether the good folks at the 'world of Macintosh' can come up with something that can out-do these babies. Remains to be seen, LOL

[tdh888]

Hi DaveyF ,

According to Kalvin Dahl ( former customer service / parts manager ARC ) the REF610T was the last amp Bill Johnson designed . This is why Im kind of attached to these amps. I hope I will be still in love w/ them when its time to retube these behemoths.

Tdh888

[Picto]

Originally Posted by daveyf

tdh888, tube rolling usually ( not always) brings out a better presentation. I did this with my ARC D70Mk2 and it also gained in resolution and overall dynamics. However, I do believe that the inherent quality of both amps ( the D79B and the D70Mk2) are as I described above. This sort of makes sense as the D79B is from the older designs from WZJ. OTOH, one could say that the D70Mk2 was also...at least compared to the current series, however, i do not believe these newer ones were designed by WZJ. Therefore, IMHO, the D series and the M100's were from his 'golden age'. Question is whether the good folks at the 'world of Macintosh' can come up with something that can out-do these babies. Remains to be seen, LOL

Daveyf, can you tell us which tubes did you use when they brought more resolution and overall dynamics to your ARC D70Mk2? I am very interested by your feedbacks since I also use an ARC D70Mk2, with an ARC LS17SE preamp.

Bertrand

[daveyf]

Upgraded the power tubes from the past their prime GE 6550's ( which BTW in their prime are superb) to a matched quad of Winged C 6550's, the driver tubes to NOS RCA 12AX7 and NOS GE 6922's and NOS GE FQ7's.

[ariess]

Originally Posted by daveyf

Upgraded the power tubes from the past their prime GE 6550's ( which BTW in their prime are superb) to a matched quad of Winged C 6550's, the driver tubes to NOS RCA 12AX7 and NOS GE 6922's and NOS GE FQ7's.

Where did you get the winged C's?

[Picto]

On my ARC D70Mk2, I tried a matched quad of KT88 Gold Lion and found they brought better bass foundation (more power and control).

Bertrand

[daveyf]

Yes, I know that KT88's are excellent in the D70Mk2. However, I am very happy with the current Winged C 6550's. ( Sourced originally from Kevin at Upscale). The one thing that really puts a damper on tube rolling for me with this amp is the awful biasing procedure. ( Which I have left for a tech in the past, and would only let a tech play with...waay out of my league).

[ralf-11]

for the pre-amps, over time they have gotten more neutral

they have also unfortunately lost the wonderful feel of the knobs, their shapes, and even the nice toggle switches

gained remotes tho...

[ehoove]

Originally Posted by ralf-11

for the pre-amps, over time they have gotten more neutral

they have also unfortunately lost the wonderful feel of the knobs, their shapes, and even the nice toggle switches

gained remotes tho...

It is one of the reasons I still have my LS16MKII which was the first LS to use the 6H30 tube architecture. It does have a remote though
Regards,
Jim