Tube Rolling - Golden Audio SEP-1

RuSsMaN

Well, what the title implies.

I decided it was time to pop the hood on the SEP-1 line stage, and try some different tubes out. The tube that WAS in it, was a Westinghouse.

I just popped in an NOS Amperex Bugle Boy 6DJ8, and WOW. I thought it sounded good before, it's like the soundstage grew even wider and deeper - and there seems to be a little more 'airiness' to the music. The mids aren't rolled off, but they seem to sound a little more natural, not as sharp as they were prior.

Honestly, I wasn't expecting it to sound so much better, just different (good or bad). God I love tubes, it amazes me how a simple, fast swap can change the tonal signature of your entire rig. With sand preamps, I might try a cable swap, but more often than not, if I didn't like it - it meant selling it and getting something else to try.

I have a couple more 6DJ8's from a good friend to try later.

Cheers,
Russ

madmax

The Bugle Boys are one of the best 6922's out there from what I've heard. That is what I have. Now you got me thinking, do I have them in the preamp or amp?? Maybe both? Be sure to get ones with the logo, I hear they are older and better. If you find something you like better let me know what it is and I'll give it a try also.
madmax

RuSsMaN

These have pristine logos, I have 2 identical tubes, both are NOS from 1961 and 1962 respectively.

I guess since these tested military spec, I should be saying 6922.

Cheers,
Russ

madmax

Mine are in the preamp. Two for the phono stage and two for the preamp stage. Currently one makes a little noise but I can flick it with my finger once per session to quiet it down. Of course I leave the cover off at all times. Nothing like having 400 volts open for anyone to touch. I like the idea that my system will punish the ignorant. More things in life need to be that way.

madmax

organ

Super cool Russ. There's still plenty of NOS 6DJ8/6922 tubes out there. You should also give some of the JAN tubes a try. They're cheaper and were built to strict specs back in the days.

So do you get the SET sound from this pre amp? I've always wanted to hear a SET amp but their price and power output is a turn off for me. Where can I find that same pre amp online? How much is a good price to pay for one?

Maurice

scottdawg

Great post, I have discovered the same thing. I have 4 pair of 6922's and they all have a different uniqueness to them. Another thing I found is that the difference is not the same from one rig to the other, for instance my pair of Hewlett Packard (Amperex) sound overall best in my ASL preamp with the SRS 2's and NAD amp but with the B & K amp and monitor 7's (same preamp) the Mullards sound overall best. Each combination offers a particular strength and weakness but never bad. Im interested in some Bugle Boys and Telefunken. We should have a tube swap sometime but maybe a bad idea unless packaged for shipment very good.

RuSsMaN

I'm looking into JAN and Sovtek, just for grins.

Golden Tube is no longer is business, however you do see them from time to time on ebay / agon. This particular preamp had 2 models, the SEP-1 (which I have), and the SEP-1A (special edition model). I'm not up to speed on what exactly was different between the two - the only source of REAL info on them is through a yahoo group that has been up for a few years.

Retail on the 1 was $880, 1A brought $1090, if I recall correctly. They had an optional phono stage, which may or may not have been installed. The last SEP-1 I saw on ebay closed at $365 with the box, manual, etc. A real giant-killer in its day, but some of the designated amp models were problematic, from what I've read and heard.

Funny you should ask about SET. Technically, this unit is not built as any other 'preamp' would be. It is actually a SET amplifier! It just doesn't have enough power to drive speakers, but enough to drive a line-stage signal as a pre-amp would. So in a nutshell, I don't have a pre-amp, I have a SET amp, driving my Carver amp.

Balanced outputs, dual power supplies, 2 additional sets of RCA outputs - one in phase, one out for bi-amping, a *single* 6DJ8, and more capacitance than your typical 40w amplifier would have - all make for a GREAT sounding SET amp (preamp).

Cheers,
Russ

organ

Thanks for the info. I'll keep an eye out for a used one. That thing must pass the sweet SET sound all the way to the amp. I don't think there's any other pre amps (amps) quite like it.

You can find both the JAN and Sovtek tubes here. Not sure if Svetlana is making 6DJ8's but if they are, you should try it out.

http://www.thetubestore.com/6dj86922types.html

They have Amperex (Holland) that looks a little different than yours. Not Bugle Boy though. Damn NOS prices just keeps getting higher.

Maurice

HBombToo

Russ

Let me get my act together and I'll ship you 3 pair for a thorough inspection. They are all classified as the 6dj8 configuration.

pair AEG ECC 88 Look clean but see note below
pair Amperex ECC88/6dj8 This pair has 1 tube without a logo. It visually looks like the ECC88 from a construction standpoint.
pair P.R.C Look clean but see note below


after careful inspection I see no signes of vacuum loss anywhere from oxidation. The big difference between the pairs is that the silver plating on the pins(except the ECC88's) and internal tig welds + leads seem to be evaporating. Probably soon ta croak because the copper will exaust oxygen and kill the cathode.

I am running a pair of P.R.C.'s for my life test(continuous on since ~November and there is no sign of copper inside the tube!)

I have no idea if prc is good but I'll keepem till they die.

1/4Twin

RuSsMaN

I know the 6922/6DJ8 is a **** to test (what, 6 tests on EACH tube?)... but did you get a chance to test them?

Actually, my Analogic Design Group (Scott Nixon modded Phillips CDP) uses a pair of 6DJ8's - so I'll probably test there first. It has some Russians in it now, but I'm always game for trying something out.

Cheers,
Russ

HBombToo

I was supposed to travel prior to Christmas but couldn't so no hard data was collected. many redirections and multitasking is a way of life in my company so oh well...

For about a 5 week period I rolled the pairs until I got the match I liked best. so far so good... just a matter of opinion I guess;)

The remaining tubes have been sitting on a shelf which is unfair for the tubes:p they told me they needed excercised

anywho... they are yours until the next rotation.

1/4twin

sucks2beme

RuSsMaN wrote:

I know the 6922/6DJ8 is a **** to test (what, 6 tests on EACH tube?)... but did you get a chance to test them?

Actually, my Analogic Design Group (Scott Nixon modded Phillips CDP) uses a pair of 6DJ8's - so I'll probably test there first. It has some Russians in it now, but I'm always game for trying something out.

Cheers,
Russ

Sorry to bring this thread back from the stone age.
One of these Analogic CDP's just came up for sale.
Opinions?