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Audio Research LS-27 preamp tube replacement

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Posted on February 25, 2017 at 15:38:53
audioman
Audiophile

Posts: 348
Location: Van. CA
Joined: June 3, 2000
 Hi.

Audio Research LS-27 preamplifier comes stock with a pair of Sovtek 6H30Pi tubes. I recently bought one of these preamplifiers used which has about 3800 hours on the original tubes.

I hear no real evidence that the preamplifier is lacking in any way sound wise, yet it was suggested by a local ARC dealer that I might consider replacing the tubes soon just in order to be certain I am obtaining the best overall sonics from the preamp.

Two questions here:

Anyone out there having practical experience with this particular model, would you agree with the dealers recommendation and secondly, would there be another tube brand besides Sovtek which might be a better choice over the Sovteks for a sensible price?

I did see on one reputable tube sellers site that the Electro Harmonix Gold was recommended over the Sovteks suggesting this tube would be an upgrade over the originals?

Please chime in with your thoughts......

thanks !

 

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RE: Audio Research LS-27 preamp tube replacement, posted on February 25, 2017 at 18:11:29
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Generally when the dealer recommends you change the tube that soon it's because they are driving that tube hard.

If you can find a more rugged 6H30 that may help. My advice is contact Jim McShane over at the tube forum. He's the tube man. If there is an answer most likely Jim has it.

 

+1 airtimes suggestion and also..., posted on February 26, 2017 at 08:51:08
Jonesy
Audiophile

Posts: 3156
Location: Winnipeg, Manitoba
Joined: September 1, 2005
Contributor
  Since: March 1, 2018
 you'll want a back up set on hand anyways.

Cheers!

Jonesy


"I know just enough to get into trouble. But not enough to get out of it."




 

RE: +1 airtimes suggestion and also..., posted on February 26, 2017 at 09:36:39
SpotcheckBilly12345
 +2

Keep in mind that some Audio Research models are rather hard on tubes. Perhaps that was what the dealer was alluding to?

Cheers,
SB

 

ahhh preamp tubes either work, or are noisy.. If your tubes work.., posted on February 26, 2017 at 09:44:55
3+4=5
 Preamp tubes do not get 'tired' (LOL) MY preamp tubes last over 50,000 hours, 8,760 is one year on 24/7/365. And my last tubes went SIX years being on 24/7/365, which is over 50,000 hours. And then they were just getting a few scratchy noises now and then. Even preamp tubes which are stressed more will last a lot longer than 3,800 hours!
Plus a preamp tube total fail is never a big deal. Unlike some power amp tubes!

Your old tubes might get noisy, but then you can hear them and say, gee, this preamp hums, or whatever..
So IMO the dealer is just wanting to sell some tubes. Or, be certain you do not come back in five months saying it is now making noises.

I would say maybe buy the set of 'spare' tubes.. So if and when the current tubes get noisy, you can immediately replace them.
I would not just replace the tubes for no actual reason

PS: do you have a warranty which allows you to replace the tubes yourself? and/or can you swap tubes yourself without trepidation?

 

Using the 6H30 "super tube" narrows the choice, posted on February 26, 2017 at 10:15:00
E-Stat
Audiophile

Posts: 37650
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 Which is fine by me. AFAIK, there are three choices:

1. Current production Sovtek
2. Current production Sovtek with gold pins
3. NOS 6H30-DR

While the third choice is the best, they are quite pricey when you can find the genuine article. I have an SP20 and purchased a replacement set of choice 2 for when the time comes.

I'm with 3+4 in that my experience parallels his that small signal tubes don't seem to "wear out" like power tubes. I know when the 6550Cs are dying in my VTL amps because they require higher bias settings and eventually start taking out the B+ fuse.

I used to have a Manley DAC with a simple 12AU7 tube output and just for grins, left the tubes in for years. Seemed to not make much difference with that model. At around 4000 hours (ARC recommendation), I might try swapping out the original 6H30s with the new set and see if I can hear any difference.

We'll see...

 

Not in this case, posted on February 26, 2017 at 10:23:43
E-Stat
Audiophile

Posts: 37650
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 While it's true that ARC pushed 6550 output tubes in the day, the LS27 (like my SP20) is a hybrid with the 6H30s serving as cathode follower buffers for the JFET front end. And the tube itself was designed by the Russians for military duty.

It's a darn rugged tube. Arguably, the most knowledgeable expert on the use of the tube is an inmate here who pioneered the use of them in audio electronics. Search for posts by Victor Khomenko of BAT.

 

RE: Audio Research LS-27 preamp tube replacement, posted on February 26, 2017 at 10:57:00
audioman
Audiophile

Posts: 348
Location: Van. CA
Joined: June 3, 2000
 Thank you very much to all who contributed to this thread. I always sincerely appreciate the advice and suggestions based on your personal experience, there is audio-safety in numbers :>)

I have many years in audio, but have never ( until now ) owned an ARC product and just really did not know what to expect in terms of design . All I can tell you though is that I really like the sound of this preamp. It is a little more subtle / laid back than others I have tried, but I am using a speaker that is quite lively with an AMT tweeter and the LS-27 seems to work quite well with it even if the ARC might be accused of being a little " soft " in overall terms, at least it is very musical to my ears anyway.

I will just pick up a new pair of tubes to have on hand and maybe try swapping the old ones out and see if there are any positive changes. If so, I'll leave them in, if not, I'll just put the originals back in and be content with the sound !

Content? Is there such a thing in this hobby ? LOL

thanks again brothers....

 

RE: Audio Research LS-27 preamp tube replacement, posted on February 26, 2017 at 12:01:53
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 I know others will argue but sometimes small tubes do fade out slowly. A few months ago I would have been one of those arguing just that point, until it happened to me! I think hard driving tubes just start getting noisy. But some of them can start loosing their "zip".

It can't hurt to try a fresh set. If nothing else comes of it than at least you have a spare set sitting around.

I found in my preamp when I used EH 6922s they would dull out and then go noisy in a few months. I switched to Gold Lion 6922s and they seem to be going strong, and zippy, for three times the life I had with the EH tubes.

I would still contact Jim. Knows his tubes, his stereos and as honest as they get.

 

this may help , posted on February 27, 2017 at 07:02:54
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Still doesn't answer the question if they wear out? Personally I think hard driven tubes do fad.

 

RE: Audio Research LS-27 preamp tube replacement, posted on February 27, 2017 at 12:39:37
kentaja
Manufacturer

Posts: 4614
Joined: March 26, 2001
 Stick with the plain Sovtek 6H30. EH gold pin is the same tube with a different label and gold flash on the pins. No sonic difference to my ears with gold you just pay more money.

As for the sonic merits of the DR tube I was at ARC about 5 years ago talking to Warren Gehl about the DR version of the tube. He said they tried it and did not think it was any better than the EB version. For the ARC haters they would say the ARC circuit is just not that good so it probably does not make any difference. OK that works for me.

 

RE: Using the 6H30 "super tube" narrows the choice, posted on February 27, 2017 at 12:43:42
kentaja
Manufacturer

Posts: 4614
Joined: March 26, 2001
 While I now have several pieces of ARC gear that use the 6H30 I have only had one long enough to find out tube life on the 6H30.

My PH-6 phono stage definitely sounded tired after about 4000 hours. A new set of tubes brought back the magic. I would imagine the same will be true with the SP-20.

Generally ARC is pretty conservative on tube life and I can typically get good performance going beyond their recommended hours of use. But that has been with 6550 output tubes and 6922 small signal tubes. With the 6H30 I think they are correct on 4000 hours. Time to change.

 

Thanks for the tip! -nt, posted on February 28, 2017 at 05:39:29
E-Stat
Audiophile

Posts: 37650
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 .

 

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