Audio Research CD7's 6H30 tube rolling

hi elberoth2:

i would be very interested to hear what players you owned before buying the arc.

i am considering a cd player and my short list includes the amr 77 and the marantz 7s1. i have heard the audio research player several times, but not in my own system.

i found the cd7 too focused for my taste, which is consistent with my impression of their preamps and amps, as well.

I've played around quite a bit with the NOS 6H30's and they do indeed sound noticeably different from the current production Sovtek 6H30. How much affect they have on the sound will depend upon the particular component they are used in. I would generalize and say that they sound richer in the midbass through the midrange and de-emphasize the highest treble and lowest reaches of the bass range a bit. They sound less sterile and thin but also a little less articulate than the Sovtek 6H30. I've used the NOS tubes in combination with the Sovteks to get the balance I want.

In the CD7 I would recommend not changing the power supply tubes, especially the two toward the back of the chassis because they are a closely matched pair. Pull the three power supply tubes and you will see that two of them have a matching color dot on them bottom. Leave those alone. I'd also probably leave the other supply tube alone too.

Conceptually it makes sense to leave the faster and tighter Sovtek tubes in power supply (non signal) locations and use the NOS tubes for signal. It also saves you a bundle of money.

As a possible alternative with many NOS flavors abundant , 6CG7/6FQ7 tubes are available. These tubes have the same pin out as 6H30, similiar GM and can handle 250v. Definitely don't sub 6922/6dJ8 in the CD7.

I thought that by the nature of what the 6H30 was designed for, tight tolerances were standard and that all 6H30DR tubes manufactured were already matched very tightly.

The tube store where I purchased the NOS 6H30DRs from has a matching service for some extra money. But I don't believe it's necessary for DR tubes.

With that said, it should be noted that the CD7 came with Sovtek tubes marked 1-7 with instructions to place them in their respective sockets marked 1-7. So perhaps there is some selection required in the standard 6H30 tubes.

Reb1208, have you tried 6CG7/6FQ7 tubes in the CD7 or to replace 6h30 tubes in CD players/amp before? During my research for 6H30 background info, I didn't find any mention that there were replacement tubes for the 6H30. Some people in Audiogon wanted to try but there were some comments that they should not be replaced. I forgot with what they wanted to use.

Is it only theoretically possible or is it practically possible? If so, with what results sound wise? Please share your experience.

Any of you guys still using a CD7 in 2016?