Tube preamp for Adcom amp
- Thread starter highend64
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How did sound with the Counterpoint?
Bodhi1
Super Member
The main issue with matching a tube preamp with a ss power amp is ensuring there is no impedance mismatch, and that tonally the amps have good synergy. I found a good match with my modded Ayon CD-5s as linestage and a Boulder 1060 driving my old Marten Coltrane Alto's. The Boulder is neutral and has an input impedance of 100k ohms (balanced) and 50k ohms (unbalanced) which is benign to even the weakest tube preamp. To be a good match for impedance, ideally the preamp will have the lowest possible output impedance (as close to zero as possible) and the amp the highest possible input impedance. The Adcom's input impedance is 49.9kΩ which opens up more options for tube preamps. As a starting point, what is your budget?
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well, not quite. There are plenty of really old ones that have no output buffer that want to work into a much higher than 50k load. The old Dyna PAS in stock form is tuned to work into 470k, but will go down to about 150k without too much bad happening. There are some ways to tweak it so it will work into a lower load but I don't know what exactly the lower limit is, but its probably somewhere in the 50k ballpark.
Anything with an output buffer will drive that no issue though. Thats most of your better preamps. Just watch some of the really old and more budget minded ones.
RVT1K
Super Member
It has been a very long time since I've heard his system but I remember it being very nice.
He is certainly happy and hasn't changed anything in over 25 years.
2k is my limit for the moment.
I just bought a Schiit Freya + tube amp (it has two other modes too that don't use the 6SN7 tubes) I'll get it on the 21st... going to use it with my two bi-amped Parasound A21+ (it costs about half your budget, then you'll have plenty of $$ left over to try out different tubes).
www.schiit.com
Schiit Audio
Schiit Audio designs and builds headphone amps, DACs, preamps and power amps in California.
Bodhi1
Super Member
There is a recently serviced/upgraded Sonic Frontiers Line 3 preamp with the matching external psu on Audiomart in claimed excellent condition, asking $2200. The upgrades (incl: new tubes) cost $1200. That is a highly regarded Stereophile Class A rated amp, and of possible interest, was paired with an Adcom amp in the seller's system. Though fyi the ad is for local pickup only in South Jersey.
This Conrad Johnson ET3SE tube preamp is very nice. The seller is asking $2250 which is just slightly over your budget. Parts quality is very high, and the preamp is in claimed mint condition. The only caveat is that CJ preamps are single-ended only in case you run balanced cables. Here is some further info on that pre fyi. There is no mention of local pickup only, so I assume shipping is offered.
Finally if you're an ARC fan, there is a vintage all-tube SP8 preamp on Audiomart in claimed excellent condition which has been overhauled, incl: replacement of two electrolytics with Nichicons. The seller is asking $2k and will ship to the US and Canada.
If you want a fully balanced, quiet and neutral-sounding pre, the Sonic Frontiers is hard to beat. But if you lean toward a more musical sound, then one of the other two preamps might be easier to live with. Hope that helps.
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Thank you for the information. I am kind of leaning towards the CJ pre. What I want is a better warmer sound without losing articulate tight bass
What preamp are you using now?
I've got 14 different preamps (OK, three are the same - APT Holman) from various eras, and can tell you that you can get a warmer sound without going with tubes. I'm not per se against tubes - I've built two 120W KT120 monoblocks, and have 3 tube preamps, and have built/repaired a bunch of tube guitar amps. However, unless you absolutely don't like any SS device in the front end, only the amp, you may want to widen your scope. The 5500 is already a bit soft in the low bass, compared to the 555 II and other amps, in my experience.
The advice about impedance matching is excellent, so whether SS or tubes - be aware of that interaction with the amplifier.
I've got 14 different preamps (OK, three are the same - APT Holman) from various eras, and can tell you that you can get a warmer sound without going with tubes. I'm not per se against tubes - I've built two 120W KT120 monoblocks, and have 3 tube preamps, and have built/repaired a bunch of tube guitar amps. However, unless you absolutely don't like any SS device in the front end, only the amp, you may want to widen your scope. The 5500 is already a bit soft in the low bass, compared to the 555 II and other amps, in my experience.
The advice about impedance matching is excellent, so whether SS or tubes - be aware of that interaction with the amplifier.
I currently have a Rotel RC-995.
Bodhi1
Super Member
Yeah that is a nice preamp which was designed as a baby version of their flagship GAT preamp, hence my comments. At just north of $2k it's a good deal. The only thing i'd suggest asking the seller to post, or email you actual photos of the preamp & clarify shipping arrangements/cost. Cheers.
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as others have posted, main thing is to make sure you get a tube preamp with pretty low output impedance. 100R to 200R should be ok.
N0rt0n
Super Member
I have had a system with a tube pre and ss amp for many years. Started with a Sound Valves 101i with a Hafler 9180 amp. Changes amp to a Stratos. Now the Stratos is paired with an old VAC dual mono tube pre. I have always liked this setup style. Can't comment on your amp, but it's a good direction to introduce some tube sound because the pre makes the nice sounds while the amp amplifies them.
fredgarvin
Super Member
I'm using a Freya N with a CODA amp. It sounds great and displaced my Khozmo, which also sound great. This with efficient Klipsch Quartets.I just bought a Schiit Freya + tube amp (it has two other modes too that don't use the 6SN7 tubes) I'll get it on the 21st... going to use it with my two bi-amped Parasound A21+ (it costs about half your budget, then you'll have plenty of $$ left over to try out different tubes).
Schiit Audio
Schiit Audio designs and builds headphone amps, DACs, preamps and power amps in California.
I have a Frenzel tube preamp spx72.
works well with a vintage Luxman,120 ss power amp.
made in the USA.
check the impedance specs for your power amp.
www.frenzeltubeamps.com
works well with a vintage Luxman,120 ss power amp.
made in the USA.
check the impedance specs for your power amp.
SPX72 Stereo Hi-Fi Preamp | frenzeltubeamps.com
The FRENZEL SPX72 Stereo Hi-Fi Preamp was designed as a stereo tube preamp platform for all your audio gear. It will transform you back to the time when tubes ruled the audio world. If you love the vintage high fidelity tube sound....you will love this preamp.
www.frenzeltubeamps.com
