[heliosphann]

Earlier today I had a quad of 6080s in for two hours, the tubes themselves were again cooler than when ran as a pair, around 170C for the quad vs 220C as a pair. The chassis directly next to the tubes was 69C, 33C for the front panel, no heat whatsoever on the knob. Those temps are fine. I'll check the Bendix and 7802 tonight and measure the transformer too.

Where are you measuring the tubes at? The plates? One of the 7802's was running about 20C more than the other. Hot one was at 120C. The Bendix tubes are way hotter, running at 220C or so. They're up front, so that's probably why my front panel/knob is more than yours. Transformer was only at about 50C.

 

[L0rdGwyn]

Where are you measuring the tubes at? The plates? One of the 7802's was running about 20C more than the other. Hot one was at 120C. The Bendix tubes are way hotter, running at 220C or so. They're up front, so that's probably why my front panel/knob is more than yours. Transformer was only at about 50C.

Yeah I've been measuring right in the middle of plate, the hottest reading I can get. I dont think I've measured the 7802s in a quad setup yet, but they do run cooler than the 6080s. I'll check these temps when I get home!

 

[heliosphann]

I'm letting my GOTL cool down and take a break. Listening to my Milo w/Ether 2. The super low distortion is such a jump from the dynamics/tubes. Not necessarily better, but different.

 

[mordy]

Hi JV,
Finally got to reluctantly change the K-R 6N7 for the '53 Foton 6H8C, all in the interest of science:

So far sounds good, but I am auditorily (editorially?) overloaded and cannot pronounce any verdicts ATM.
The picture depicts an utopian early sunrise where Russia, Germany and the US coexist peacefully.
Actually sounds great with the HD650.
Make that awesome after a half hour warm-up!
PS: The top right corner of the picture is the answer to the overheating worries......That + Deyan's socket savers and adapters.

 

[L0rdGwyn]

Okay so with the temperatures plateaued, here's what I have:

• Bendix 6080 (front): 240C
• Tung-Sol 7802 (back): 130C
• Chassis in between tubes: 54C
• Transformer: 58C (inner shell, not outer)
• Front panel: 36C
• Knob: 36C

These temps are pretty good, something to think about though, I do not have a tube rectifier, so that will add some heat to the situation and it is near the front panel. The knob and front panel do feel a little warm to the touch, but I don't think 36C is anything to worry about.

The Bendix are hot but they are rated for it. Based on the temperatures I am getting, I think running a quad of 6080s is safe.

Do you see any issue with these temperatures, @2359glenn ? Is there a max temperature rating for the transformer?

 

[Zachik]

You can also try Billington in the UK

Langrex has 90 o them You have to go to stock list page 4

https://www.langrex.co.uk/stocklist/

Thanks guys - I have contacted both sellers.

 

[heliosphann]

Okay so with the temperatures plateaued, here's what I have:

• Bendix 6080 (front): 240C
• Tung-Sol 7802 (back): 130C
• Chassis in between tubes: 54C
• Transformer: 58C (inner shell, not outer)
• Front panel: 36C
• Knob: 36C

These temps are pretty good, something to think about though, I do not have a tube rectifier, so that will add some heat to the situation and it is near the front panel. The knob and front panel do feel a little warm to the touch, but I don't think 36C is anything to worry about.

The Bendix are hot but they are rated for it. Based on the temperatures I am getting, I think running a quad of 6080s is safe.

Do you see any issue with these temperatures, @2359glenn ? Is there a max temperature rating for the transformer?

Super similar to the readings I took, in pretty much all those areas.

 

[mordy]

Super similar to the readings I took, in pretty much all those areas.

Same here - around 3C lower, but I have the AC on and the room is cool.
However, turning on my 4" fan above the amp, drawing heat away from it (not blowing on it), the temperatures on the chassis are lowered by at least 10C - less than 42C between the tubes.

 

[mordy]

And I am mesmerized by the sound now with the Foton 6SN7 equivalent. The presentation is laid back, mellow, and really great detail and punch in the bass with a wide sound stage.
I have a feeling that Glenn would like this sound.....

 

[UntilThen]

A year or more ago I wrote to Langrex asking for Brimar 13D1. A few days later they replied. No more stock ! Then a few days later again... they replied. We have stock. How many do you need? I said only 2. So I bought a pair.

I have one left and I gave the other to Monster when he bought my pair of GEC 6as7g. The Brimar 13D1 is $10 each. The pair of GEC 6as7g is $500. Little did he know that combination is the bringer of mars, wars, jupiters and meteorites.

 

[L0rdGwyn]

For anyone interested in 6J5 tubes, there is quite a good deal here, quad of Italian Sicte 6J5GT for €40 plus shipping or Best Offer.

While they are all different rebrands, construction is the same and they are all definitely Sicte, identical to my pair. These are not common.

https://www.ebay.com/itm/4x-6J5-GT-...rentrq:d832a51816c0ad4a6ba34705ffe49ec9|iid:1

 

[L0rdGwyn]

Have I mentioned that I like 6J5 tubes?

I'm considering an experiment. My theory is that having the triodes in separate tubes is what accounts for the increased separation and soundstage of the 6J5s over the 6SN7s.

Deyan has a pair of 6SN7 to 6J5 adapters on eBay, each adapter from the pair uses a single triode section of a 6SN7 with the 6J5 pinout. So, I could take my matched pairs of 6SN7s and run them each with a single triode in my 6J5 to 6SN7 adapter and see if the increased staging is there relative to running a single tube with both triodes. Pairs I have to test would be Brimar CV1988, RFT 6SN7, Sylvania 6SN7W metal base, along with a few others.

I think it could be an interesting little experiment! Not to mention if my theory is true, I could squeeze a little more performance out of my 6SN7 pairs

Also, each adapter uses the opposite triode, so you can switch them back and forth to make sure the sections stay matched in each 6SN7.

 

[rosgr63]

Prolonged running a single section of double triode will damage the tube eventually.

 

[mordy]

Prolonged running a single section of double triode will damage the tube eventually.

Cathode poisoning?

 

[L0rdGwyn]

Prolonged running a single section of double triode will damage the tube eventually.

Thanks, Stavros, I may scrap the idea then. If curiosity takes hold, I would only do it long enough to confirm or deny my theory.