ARC LS22 and pre tubes

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!

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!

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.

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.......

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

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.

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.

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

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

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.

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.