ARC LS22 and pre tubes

Are you sure all 8 are bad? Usually you only use 1 main pair and 1 or 2 inputs? Save you a few tubes that way.

There is a recent ad here on Audiogon for some Philips JAN 6922 for $7 bucks each. These are pretty decent tubes, especially for that kind of money.

These are NOT my tubes and I have no affiliation with the seller, just passing on a good deal.

I assume you are looking for new production tubes, and something rugged and quiet (ARC's seem to like them best), and want something with a bit more warmth than Sovteks. My first choice would be EH6922's and, if you want a bit more color but not as balanced, the JJ's are OK too. I use them both, but neither in my ARC SP10 where I use NOS 6h23's.

FWIW

Thank you to all. Actually, comparing to McIntosh C20 preamp, ARC LS22 ( I just bought) is lacking of high and low frequency. It is OK in term of noise ( I think it is better than Mc Intosh C20). So, I am not sure what causes the problems I hope replacing tubes will fix the problem! I am going to try some tubes and let you guys know the results. Feel free to recommend.

Thanks

Hi Elevick,

Thanks for your tip. Do you know exactly how many tube (and which ones) used in LS22 for unbalance? I don't use balance cables so i can forget it and just replace tubes that i need. In the other words, which tubes are for balance purposes?
Thanks for your help.

You need the manual or schematics usually. AR will help if you call them. You need a pair of tubes for the gain stage (Most likely the pair closest to the outputs) and a pair for each input. The sockets should be labeled in some way such as v1, v2, v3 and so on.
If you only use cd, you only need 4 tubes.

Thanks Elevick. I will call ARC and ask for more details.

Ls22 has a pair of input tubes then 2 pairs of voltage gain tubes then a pair of Cathode Followers. The tubes have 2 channels per se and the Balanced uses both for a extra 6db of gain vs the unbalanced inputs.
So V1 and V2 are most important to be quiet and have the sound you like and V3-V6 will increase the gain and shape the sound some more. And maybe someone can learn me on what is important about the Cathode Follower positions.......

Jiceman, FWIW in my SP10 I used 6h23s (low noise/rugged) in the critical positions but I found I can put 'colored' tubes in the cathode follower positions (which do not add any gain and are less demanding on noise issues). I long ago gave up trying to get tone from the critical positions.

The cathode follower tube/circuit provides no gain but affects the output so that you can drive long runs of IC's. Google it - I'm sure there are many thorough explanations there.

V1 and v2 is the first stage ,v3,v4 is a cathode follower,v5 and v6 second stage and v7,8 cathode followers.Most important of all is to pair the inside tubes as close together[v1,2,,5,6]And you can not leave tubes out!

I took okkie300 's advice, it seems to work wonders, I use good nos in v1,2,5,6 and sovteks in the rest. I have 2 ls22 and love them, they're essentially a ref2 without a tube regulated power supply. Transformer is massive, sound is great, and the 6922 is a special tube with excellent sonics!