System Synergy: Boy, Do I Love My Preamp

Well...I gotta say that after some tube rolling I'm pretty satisfied with my ARC LS7.
This thing is really clear. So clear in fact, I realized my phono stage had a noisy tube in the amplification stage.
I've never been a big fan of Telefunken tubes but they sound better in the amplification stage of this cathode follower preamp than any of my fancy Amperex 7308's.
The SoundValves is no slouch and will be my spare.
 
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Nothing new...I still prefer the ARC LS7.

I swapped the VTP101 back in a couple of months ago, I think the LS7 has a clearer, more open sound.

The LS7 is my go to preamp, the VTP101 collects dust on a shelf as my spare.
 
I've only had a few preamps that really sounded right to me. Some of the preamps that I didn't care for were highly regarded,.but I found them lacking in various ways. All that matters is what sounds right to you.
 
Having had tubes beat new Luxman SS with my Fosgate Signature phono preamp and my (currently broken) PrimaLuna Dialogue Premium power amp, I can easily see how an excellent tube line-stage could give a wonderful sound. BUT... I'm really leery of tube-rolling and especially the NOS scene. I bought KT-120s for the PrimaLuna because that was how Art Dudley reviewed it (and boy did he have some good ears, IMO!). But having a couple dozen possible combinations of sound from one unit sure can get confusing, and I'm not patient enough nor certain enough to want to depend on my own judgement between more than a very few select candidates.

Which is why I really like my passive preamp with only source selection, and a transformer volume control. The transformers eliminate impedance and matching concerns successfully, and the small (but surprisingly heavy) unit reveals everything coming from upstream with seemingly zero editorializing. Rolling tubes to get a preamp to sound 'right' is not a task I want to undertake. Doing it again when I change something else is right-out. Perhaps this is due to my preferring a single change to a very familiar baseline over rapid A/B switching when evaluating differences in sound quality. Getting good and familiar with a setup, over time and with lots of music, takes a lot of calendar time, and must be repeated for every non-trivial change made.

But, it seems like you have the patience for the task, so more power to you, and congratulations. And thanks for reporting back! :)
 
I'm just hitting the midpoint of really learning about the abilities of the ARC LS7.

I was at a very busy point in my life when I purchased the preamp from a friend, who hadn't bothered to tube roll. (2017)
So it came to me with a set of JJs that eventually developed a hiss. (2018)
I bought new EH tubes which immediately cleaned up the sound and I became convinced that tubes really do have signature sounds.
A purchase of two pair of Amperex Holland A-frames opened the sound. (Thanks Brent Jessee!)
I used these for a full two years (they're still good), but developed a bug to try more types.

I started following forums and downloaded the manual and circuit schematic and realized that the 4 tubes were not in the same role. (believing V1 and V2 are gain, and V3 and V4 are followers)
Then a purchase of Philips JAN tubes for the gain stage, and it was obvious one channel was worse than the other. Then a left-to-right swap and the bad channel also swapped.
One JAN tube was definitely worse than the other, and both are the most microphonic tubes I've ever tried. (To be clear, these did not come from Brent)
Then going through a variety of tubes one at a time until I discovered some pairs really weren't, especially a bunch of EH tubes from three sets of matching date codes.
Then discovering that I could successfully breath new life into a couple of 'bad' tubes by whacking them on a counter. (per Brent Jessee's advice during the purchase of a Telefunken pair)
All this while still believing that the back two tubes were both serving duty as cathode followers.
Now starting to be convinced that only the very back tube is a follower, and that tube 3 (V3) actually performs a unique role.

I still need to try different tubes in the V3 position, but I'm fairly happy with old Telefunkens in V1 and V2, with EH in V3 and V4. (I don't want expensive tubes in a non-critical role)

It's a journey, and I fully understand wanting to stick with predictable SS gear, but I've never had a SS preamp of this caliber.
 
I still need to try different tubes in the V3 position, but I'm fairly happy with old Telefunkens in V1 and V2, with EH in V3 and V4. (I don't want expensive tubes in a non-critical role)

I've rolled tubes in my LS-7 and finally hit on some magic thanks to your posts.

A while back, I found one lone Tele 6dj8 in my stash, didn't even know I had it. What good is "1"?. Been using Amperex 6922 white labels in V1 and V2, tried other premiums in V3 and V4 but settled on a pair of nos 6h23's and life was good. Couple days ago I dropped the Tele in V3 and...nice. Put a Mullard CV2493 in V4... step backwards. Had an RCA 'made in Germany' all by 'itself'... put that in V4 and this is the best it's ever sounded. Serendipity at it's best.

I think it's the Tele magic that's doing it. I'm a big fan of their 12ax7's I use in my other preamps.

:beerchug:
 
Excellent!
Interesting tube. Each iteration seems to have a "character" of its own.
I think the LS7 is a keeper, really works well in my system.
 
I'm really satisfied. For me...there's nothing about my system that I don't like. Everything plays nice together.

I consider myself lucky. I'm very happy to simply sit back and enjoy the music.
 
So...Last night I found a pair of Sovtek 6922 (probably originals that came with this 1994 LS7 preamp) that had become separated from the greater collection.
I was expecting at least one to be bad, but was pleasantly surprised.
No formal declarations yet, just some hours of music on these tubes that likely haven't seen daylight in many years.
More to follow.

Thanks to all who were part of the original thread, and also to those who are active in reviving it!

A note about whacking bad tubes on a counter that I mentioned earlier: although recommended by one dealer (and it worked for me), another dealer (Kevin Deal) firmly advises against this practice.
I don't see any harm if the tube sounds like crap and is already unusable.
 
I had one issue with my LS7 that I thought was from a microphonic tube. Touching any part of the preamp (cabinet, knob, tubes) transferred sound right through the speakers. I re-seated and replaced tubes, no help.
Finally, I sprayed the contacts of the input selector, "exercised" the switch a little and the problem went away.
 
I wish I could have cleared up my microphonic JAN tubes; they have potential to be good gain tubes in another linestage.
Five (?) totally different varieties of tubes were quiet and not microphonic in the LS7: Holland Amperex, Great Britain Mullard/Amperex versions of prior, West German Telefunken, Russian EH, Russian Sovtek, Czech/Slovak JJ (I forget without double-checking).
All but Philips JAN 6922 passed my personally-administrated microphonics test. (I've decided that some 'ting' is allowed when switching sources, but not allowed when tapping on faceplate of line source/preamp.

Who else has determined where to draw a line for go vs. no-go?
 
I had one issue with my LS7 that I thought was from a microphonic tube. Touching any part of the preamp (cabinet, knob, tubes) transferred sound right through the speakers. I re-seated and replaced tubes, no help.
Finally, I sprayed the contacts of the input selector, "exercised" the switch a little and the problem went away.
Hi there, I’m new to this forum and have been reading this thread with great interest. I’ve just bought an LS7 and suspect I’ll be tube swapping in the near future. I’d greatly appreciated knowing which tubes you finally settled on in your LS7 and in which positions. Sonically I’m after the usual things, great midrange, nice separation, soundstage and well defined bass.
I’m using Sonus Faber Concertino speakers, ARC D130 power amp and the source is digital and CD. Many thanks!
 
Hi there, I’m new to this forum and have been reading this thread with great interest. I’ve just bought an LS7 and suspect I’ll be tube swapping in the near future. I’d greatly appreciated knowing which tubes you finally settled on in your LS7 and in which positions. Sonically I’m after the usual things, great midrange, nice separation, soundstage and well defined bass.
I’m using Sonus Faber Concertino speakers, ARC D130 power amp and the source is digital and CD. Many thanks!
Hi,
V1 and V2: Amperex 7308 PQ White Label, Made in USA
PXL_20240129_050122321.jpg
PXL_20240129_050149961.jpgPXL_20240129_050306493.jpg
V3: Siemens labeled RCA 6922 / E88CC Made in Germany
PXL_20240129_050515108.jpg
PXL_20240129_050550250.jpg
V4: Amperex JAN 7308 Made in USA Orange Globe:
PXL_20240129_050844457.jpg
PXL_20240129_050858199.jpg
Hope this helps.
Enjoy your LS7
 
Well, this is what mine looks like. It's cap city in there, whoever did the work was definetly on a mission! Why so many, what are they doing, big cluster of caps to the left???? Looks like it's had a new power lead as well. So many questions! It's got Brimars' in there at the moment

1.JPG
 
At first, I thought someone went crazy with bypass capacitors.
But now I'm thinking perhaps someone wanting to replace the electrolytic capacitors couldn't find replacements that fit.

I also have an ARC PH3 phono preamp with what looks like some of the same capacitors as the LS7. My PH3 takes too long to come out of mute when switched on so I thought maybe changing the electrolytics's might help. Unfortunately, I couldn't find same size replacement capacitors for the big ones in stock anywhere.
 
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