Anyone using KT88's in D series ARC gear?

Audio Research offered an upgrade to the Classic Series amplifiers which replaced 6550 output tubes with KT88 tubes. I believe the change over required a resister replacement in order to properly use the KT88 tube.

I would not change anything in your D-70 if it is not broken. I have owned ARC equipment much older than the D-70 which were still operating perfectly.

The barrier strips are not a problem. You just need the proper spades to fit the barrier strips. Why would you change the amp instead of the cable connectors?

The power cord is hardwired for a reason. It is a solid connection and the power cord was voiced by ARC for your amplifier.

The RCA connectors are not cheap. ARC used those connectors for years on some of the best sounding equipment ever made until the Tiffany style connectors came along. I have never heard of anyone complain about those connectors on a D-79B and I doubt that anyone has ever changed the power cord or barrier strip on that amp either.

You will only degrade the D-70 by making any changes. Buy some 6550s and enjoy the amp the way it was intended to be used. They will cost less than making the changes you mentioned.

Check around for smaller spades. I know someone like Audioquest or Cardas makes them.

I agree with Rrog, The amp is a classic and I wouldn't change anything on it. I would have the caps checked because they can leak when they get old. You said that it is currently down. Instead of spending money to modify it. I would consider sending it to Audio Research to have it fixed. They will go over everything and bring it back to the original specs. Put a set of new tubes reputable dealer in it first. That way ARC will not have to replace tubes. I sent my V70 in a while back and I was amazed at how good it sounded when it came back.

To replace the captive power cord with a IEC socket might be difficult. There in probably not enough clearance between the case and the board.

There are some speaker cables with smaller spades or you can replace the spades with smaller ones. As I mentioned I used and still do use Audio Research speaker cables. They are really nice cables and can be picked up used for not a lot of money. The spades will fit between the dividers on the strip.

Hi Lostbears and Rrog, Thanks for the info. I think it is wise not to modify the amp after what you have said. I too believe the amp is truly a classic and I agree with what you are saying.
I may send it to ARC for the repairs, although they are very pricey, so IF I can find a very good local tech who is familiar with these amps, I would prefer to go that way.
The smaller spades required for the speaker cable are proving a little more challenging, But hopefully I can find a supplier of these. Again thanks for the help.

I recommend using ARC for repairs and maintenance. It may cost a little more, but it will be done right. You will never know the true sound of your amplifier if it is not set up properly.

Hello Davey,
For starters, Gold Lion KT88s do not fit inside the ARC D-70 tube cage, the tube bottles are too fat.
Vampire makes spades sized for barrier strips. I believe the part # is Bar-8.
You may also want to search Banana Spade plug Adapter.
Good luck