[JackD]

I think you had two problems here, neither one pertains to heater voltage, that are working themselves out on their own.  First the tubes (40+) years old needed breaking in and the caps in the preamp (unused for years) needed time to work back into shape.  If you just let it run for a couple of more days, 24/7 is prefered, it will get back to what you remember.  Whether or not it pleases you years later or works with you current system is another matter. Valvos like Telefunken should not be "tubey" in character.  The Matsushita will be more like a Mullard in character.

[ACHiPo]

I think you had two problems here, neither one pertains to heater voltage, that are working themselves out on their own.  First the tubes (40+) years old needed breaking in and the caps in the preamp (unused for years) needed time to work back into shape.  If you just let it run for a couple of more days, 24/7 is prefered, it will get back to what you remember.  Whether or not it pleases you years later or works with you current system is another matter. Valvos like Telefunken should not be "tubey" in character.  The Matsushita will be more like a Mullard in character.

Jack,
I tend to agree with you.  I'll let the pre run in for a couple more days.

AC

[JackD]

AC

If you haven't heard back from Dean check the A'gon archive threads about your preamp as someone posted his phone number.  As of a couple of years ago he was supposedly still offering advice.  See if he thinks it may need to have the caps check or re-capped.  Back in it's day that preamp got rave reviews, as did his amps.  A lot of people dropped much more expensive ones to go with the PSE.  I had a friend from college that was a Vandersteen dealer in Iowa for 20 years.  He loved Dean's gear but found it hard to sell due to it's plain looks compared to the Classe' and ARC gear he carried.  You might want to see if there are any current hybrid type preamps that fit you requirements unless you just want to go back to SS. Also when Dean was still in business 6DJ8 family tubes were plentiful so he probably never gave the 7DJ8 tubes a thought. People like Kevin started to push them when the others started drying up.

[ACHiPo]

AC

If you haven't heard back from Dean check the A'gon archive threads about your preamp as someone posted his phone number.  As of a couple of years ago he was supposedly still offering advice.  See if he thinks it may need to have the caps check or re-capped.  Back in it's day that preamp got rave reviews, as did his amps.  A lot of people dropped much more expensive ones to go with the PSE.  I had a friend from college that was a Vandersteen dealer in Iowa for 20 years.  He loved Dean's gear but found it hard to sell due to it's plain looks compared to the Classe' and ARC gear he carried.  You might want to see if there are any current hybrid type preamps that fit you requirements unless you just want to go back to SS. Also when Dean was still in business 6DJ8 family tubes were plentiful so he probably never gave the 7DJ8 tubes a thought. People like Kevin started to push them when the others started drying up.

Jack,
I tried calling the phone number last week and it had been disconnected.  I'm leaning toward a B-stock Parasound JC2--it has all the features I want, and it was the preamp that was used when I decided to buy my speakers (against more expensive YG Kipods running on much more expensive electronics and ~$40k of cabling), so I'm pretty sure I'll like it.  Plus I'm to the point where I'm really kinda fed up with fixing things--I just want something I can plug in that works.

I do want to get the PSE back to its former glory, as it served me well for about 20 years.  The first time I opened it up was last week to put the tubes in, and it's built very well.  Oh, and did I mention tubes last a really long time in it--it still had the original Russion 6922s?

Thanks,
AC

[FullRangeMan]

E55,
Please take this in the way it is intended...

From your posts I suspect that English is not your first language, and that perhaps that gets in the way of your meaning.  As Starchild says, it is clear you (and FullRangeMan for that matter) know a lot about tubes, but any wisdom you have to impart gets lost as it is wrapped in inflammatory language.

Regards,
AC

Iam not a expert, I second E55 as he is a expert transformer builder w/years of experience and an clinic eye on what parts sound good in tube audio.

Iam surprised in this unsual 7DJ8 usage,
stm E55 also are surprised.

This unexpected use was created by the tube brokers,
the tube manufacturer could not predict that.
These oxide coated cathodes as in this tube works at 1200ºC,
w/1V less it will run cold and short tube life will result.
In this out of book use hope a catastrofic tube fail does not occurs.

[Guy 13]

Hi all,
this is a transcript from the Decware website (SE84UFO amplifier)

'' The input tube is a single 6N1P, 6922 or 6DJ8/7DJ8 - your choice. 6N1P's have the warmest tone,
6922's have the best dynamics, 6DJ8's have the most air
and micro-detail with a touch less bass.
Again, a powerful tool for voicing your amplifier to your particular tastes. ''

Thanks.

Guy 13

 

[ACHiPo]

Iam not a expert, I second E55 as he is a expert transformer builder w/years of experience and an clinic eye on what parts sound good in tube audio.

Iam surprised in this unsual 7DJ8 usage,
stm E55 also are surprised.

This unexpected use was created by the tube brokers,
the tube manufacturer could not predict that.
These oxide coated cathodes as in this tube works at 1200ºC,
w/1V less it will run cold and short tube life will result.
In this out of book use hope a catastrofic tube fail does not occurs.

FRM,
Your explanation is very helpful.  Thank you.  I got a PM from a member yesterday that suggested that as 6922s become harder to find (and thus more expensive), the tube vendors are getting creative in finding reasonable replacements.  The fact that Brent Jesse, in addition to Kevin, claims longer life, makes me think things are not going to fail catastrophically.  I got 20 years out of the Russian 6922s (ok, so that was about 5 years longer than I should have based on the occasional crackling I'd hear), so even if I get 10 years out of a pair of $60 tubes I'm pretty happy.

As an update, after another 24 hours (~100 hours total), the pre-amp is very close to what I remember.  Bass has tightened significantly, and volume is back to a reasonable level.  Still missing some of the detail of the Rowland or Oppo direct feed, as well as the bass is still a bit more romantic.  Air is better, however, and it's sounding very musical.  As Steve says, I suspect it's a combination of 50 year old tubes and caps that haven't been energized in over 2 years.  I'm just happy to be getting back to where it used to be.

AC

[JakeJ]

Son, yer actually lucky it didn't let some smoke out after sitting for two plus years.  Any tube gear I try to bring up that's been sitting for more than a year is done slowly on a variac.  I'd say it's a testament to PSE's build quality.

If you decide to keep the old girl for a backup you should get her out once a year and dust off the cobwebs and heat her up.  Just to keep the caps in shape.

Just my .02

[JakeJ]

Is this the unit we're talking about?
https://www.audiogon.com/listings/tube-pse-hl1-hl-1-tube-hybrid-preamp-w-remote-2014-03-12-preamplifiers-92009

[ACHiPo]

Is this the unit we're talking about?
https://www.audiogon.com/listings/tube-pse-hl1-hl-1-tube-hybrid-preamp-w-remote-2014-03-12-preamplifiers-92009

Jake,
That is her.  And I did have my fingers and toes crossed as I powered her up, and fortunately no smoke.

I noticed a bit of "motorboating" on the left channel this afternoon--not sure if it's one of my 6sn7s acting up, or if it is one of the 7DJ8s, or if the caps need to be replaced.  Meanwhile things are sounding better the longer I listen.

AC

[JakeJ]

I believe that is one of your power supply caps warning you of possible failure.

[ACHiPo]

I believe that is one of your power supply caps warning you of possible failure.

Was wondering about that, but from Google it sounded more likely to be in the feedback circuit (bypass caps?)

Would there be an external indication of cap failure, e.g. Corrosion, bulging, or residue?  I seem to recall reading about caps that were "self healing", but not sure if that applies here or not?

[FullRangeMan]

Son, yer actually lucky it didn't let some smoke out after sitting for two plus years.  Any tube gear I try to bring up that's been sitting for more than a year is done slowly on a variac.  I'd say it's a testament to PSE's build quality.

If you decide to keep the old girl for a backup you should get her out once a year and dust off the cobwebs and heat her up.  Just to keep the caps in shape.

Just my .02

Tube's getter are inactive after six months, it would be good heat the valves for a hour every 3 months to getter staying active and keeping the vacuum.

[ACHiPo]

I neglected to mention that the PSE HL-1 is constantly on when plugged in.  I plugged it in for several hours a couple times before hitting the "on" switch last week, which powers up the gain stages.  I'm not sure what all is powered up when the pre is plugged in, but at least the power supply caps should be energized.  It may also heat up the tubes?

[FullRangeMan]

I neglected to mention that the PSE HL-1 is constantly on when plugged in.  I plugged it in for several hours a couple times before hitting the "on" switch last week, which powers up the gain stages.  I'm not sure what all is powered up when the pre is plugged in, but at least the power supply caps should be energized.  It may also heat up the tubes?

To heat the tubes the power cord should be connected and the on switch should be on too.

[E55l2]

Here a measurement of a tube with normal heater voltage and the same tube with 17% lower heater voltage.
The dotter line is with lower voltage. It looks as an 2000 hours old tube now.....
Because the lower voltage the aging goes much quicker too.

Does anyone have transconductance curves for the 6922/6DJ8 vs. the 7DJ8 as a function of heater voltage?  It seems with that information it would be pretty easy to figure out what I'm giving up in performance by running the heater voltage below its designed level.

[ACHiPo]

Here a measurement of a tube with normal heater voltage and the same tube with 17% lower heater voltage.
The dotter line is with lower voltage. It looks as an 2000 hours old tube now.....
Because the lower voltage the aging goes much quicker too.

E55,
This is great info!  I'm a little dense when it comes to understanding this stuff, so a picture speaks volumes.  Thanks!

All,
The little PSE HL-1 keeps sounding better, but given the barely-audible motor-boating, I suspect that one of the filter caps on the left channel is compromised.  I have a pair of gen-u-ine 6922s coming in the mail, but it will be February before I get a chance to try them out.

I broke down and ordered a Parasound JC-2 line stage.  My rationalization is that I got a screamin' deal on a B-stock unit from someone with connections.  While listening to the PSE come back from the dead has been fun, I'm looking forward to getting the transparency and bass control that's still lacking with the HL-1.  In fact I unplugged it tonight when I got home, and am running straight from the Oppo--a very musical and enjoyable set up.

Thanks for the education and all the help.  I'll post an update when I get the 6922s installed, perhaps do a little A-B-A test.

Anyone that's interested in taking over the experimentation when I leave off?

AC

[E55l2]

The curves i published here are for a e88cc, a long life tube (10000 hours) .
To get the maximum life time the manufacturer say this:



btw read also the rest of the datasheet because there are more important things to know about tubes.http://www.mif.pg.gda.pl/homepages/frank/sheets/030/e/E88CC.pdf

[FullRangeMan]

Question: +-5% is  -2.5% and +2.5%??
or is -5% and +5%??

[E55l2]

5% of 6,3V = 0,3V

+/- 5% = between 6,0V and 6,6V

17% lower means 5,2V ( or if you have a 7dj8 7,6V....6,3V )