[Rico613]

Quote:

So, having been interested in previous discussions of tube rolling with the BHSE which comes up here on a regular basis and dating back to early posts by Elephas, I decided to swap my SED EL34's for an older "matched" quad of Shuguang 50 year Treasure 6CA7's that I possess that have about 300 hours of use.  I did not expect to hear a difference but there is a difference.  The treasures are more dynamic, "tube-like" if you will allow, and very revealing.  I really like them, but I have questions that I hope someone will answer for me.
 
First is that the Treasures run noticeably hotter.  I never thought of my BHSE as being a space heater until I installed these tubes.  Are they drawing more current?  The box reports what I assume is plate current at 40mAmps. This is a few milliamps higher than the EL34's I was using - does that account for the difference in heat and perceived performance?  And is it safe?  Have others here that have done this found this to be true?
 
Admittedly ignorant, please explain. 

I know next to nothing, but did you adjust the bias?

 

[justin w.]

Where is the datasheet for those tubes?

 

[Bones13]

Quote:

So, having been interested in previous discussions of tube rolling with the BHSE which comes up here on a regular basis and dating back to early posts by Elephas, I decided to swap my SED EL34's for an older "matched" quad of Shuguang 50 year Treasure 6CA7's that I possess that have about 300 hours of use.  I did not expect to hear a difference but there is a difference.  The treasures are more dynamic, "tube-like" if you will allow, and very revealing.  I really like them, but I have questions that I hope someone will answer for me.
 
First is that the Treasures run noticeably hotter.  I never thought of my BHSE as being a space heater until I installed these tubes.  Are they drawing more current?  The box reports what I assume is plate current at 40mAmps. This is a few milliamps higher than the EL34's I was using - does that account for the difference in heat and perceived performance?  And is it safe?  Have others here that have done this found this to be true?
 
Admittedly ignorant, please explain. 

This switch I did in my AudioNoteKits L4 (PP EL34) amp.  The kit dealer supplied the Treasures, I had the Winged "C" EL34 quad from an earlier amp.  I noticed the improved dynamics as well.  My speaker amp temp runs about the same, although I have nothing but random remembrances go by.  That amp is all inside the box, and in my audio stack at the time.

 

[nicholas029]

Thank you for replying.
I am not sure of what a data sheet contains but this is the available information that came with the tubes:
 
6CA7-Z
 
Uf=6.3V
Ug1= -41V
Ua= 465V
Ug2= 465V
 
Plate current: Ia1 = 40mA
 
that is all the information I have.  
Yes, I did adjust bias at the output jack.

 

[justin w.]

if it requires higher filament current that could explain the additional heat.  but, without a datasheet, i couldn't tell you.  it could also be doing a better job dissipating the heat into the air.

 

[nicholas029]

   
 
this was available online.

 

[wink]

Quote:

^ The one on the right is probably Wink's recycled beer cans . . . just a thought . . .

Too good for my beer cans. I've switched to aluminium foil to cut down on weight. The embossed pattern looks cool.

 

[Rico613]

Quote:

So, having been interested in previous discussions of tube rolling with the BHSE which comes up here on a regular basis and dating back to early posts by Elephas, I decided to swap my SED EL34's for an older "matched" quad of Shuguang 50 year Treasure 6CA7's that I possess that have about 300 hours of use.  I did not expect to hear a difference but there is a difference.  The treasures are more dynamic, "tube-like" if you will allow, and very revealing.  I really like them, but I have questions that I hope someone will answer for me.
 
First is that the Treasures run noticeably hotter.  I never thought of my BHSE as being a space heater until I installed these tubes.  Are they drawing more current?  The box reports what I assume is plate current at 40mAmps. This is a few milliamps higher than the EL34's I was using - does that account for the difference in heat and perceived performance?  And is it safe?  Have others here that have done this found this to be true?
 
Admittedly ignorant, please explain. 

I've got the Shuguang Treasures also, and I would like to try the Psvane 6CA7-Z / 6CA7-T (EL34) at some point.  But I'm not sure this is a good idea in the BHSE, others have commented it doesn't improve much and Justin has commented about people blowing up their amps with the wrong tubes.  So it is encouraging and curious that you are getting better results - and haven't exploded your amp . . . yet!

  Your profile shows that your BHSE is 'on order' so I'm not sure what you are using the Treasures in exactly.  Let us know what you find out, maybe shoot that data sheet to Justin in a PM or email.

 

[TheAttorney]

I posted my impressions of the Treasures here.
 
I also thought the Treasures gave off more heat than stock. Even though the plate current of mine were only 35mA (a minimal 2 mA above stock).
I also checked the BHSE's power consumption in both cases, and there was no discernible difference.
So maybe Justin's point is valid: The Treasures just do a better job of dissipating heat (maybe because they are bigger? More surface area?).
 
Anyway, whilst comparing my 3rd tweak (Power Conditioner, report coming up shortly), I've been back to the stock tubes a couple of times, with result that I stand by everything I said the first time.
So I don't care what the design theory states. In practice, the tubes make a real difference. Not night and day, but still well worth the price.
 
The comments about blowing up the amp only applies to the wrong tube models (and unreliable tubes I guess). My Treasures were so close to stock that I didn't even need to adjust balance/offset (I did anyway, because I'm like that). I see no reason to think the Psvane's will be unsuitable. A comparison would be interesting.

 

[David1961]

Correct me if I'm wrong, but I thought the only tubes that should be used on the BHSE, are EL34's.

 

[TheAttorney]

No doubt the tube experts can elaborate further, but in short the 6CA7 is the American version of the EL34. They should be completely interchangeable. Whether they are interchangeable depends I guess on how each manufacturer interprets the specs.
 
The only other model that may be interchangeable is the KT77, but I personally wouldn't try that because I don't know enough about it.

 

[spritzer]

The 6CA7 is an EL34 but Sylvania didn't want to pay Mullard for the privilege of making them so they altered the design just enough.  Ditto on the KT77. 

 

[Beefy]

Quote:

Well not so good.  This aluminum is not going to cut it.

 
Perhaps order some aluminium instead? 

 

[wink]

Spoken like A TRUE AUSSIE...

 

[nicholas029]

Quote:

I've got the Shuguang Treasures also, and I would like to try the Psvane 6CA7-Z / 6CA7-T (EL34) at some point.  But I'm not sure this is a good idea in the BHSE, others have commented it doesn't improve much and Justin has commented about people blowing up their amps with the wrong tubes.  So it is encouraging and curious that you are getting better results - and haven't exploded your amp . . . yet!

  Your profile shows that your BHSE is 'on order' so I'm not sure what you are using the Treasures in exactly.  Let us know what you find out, maybe shoot that data sheet to Justin in a PM or email.

Profile updated. My BHSE is from batch #2 and gets a lot of use. 
 
I would have some concern about the Psvane 6CA7.  I thought about them but you may notice that online information is almost exclusively from the N. American distributor.  They are shipped directly from a warehouse in Hong Kong, not Canada.  A couple of years ago there was an informative discussion about Psvane capacitors over at Audio Asylum where it was apparently revealed by someone from V-cap that the product was not in reality what was advertised - not Teflon.  When I inquired directly to the distributor as to how quality control over tube testing was monitored, i.e. you pay more for the "premium product," I was invited to not order at all if I did not trust them.  Shuguang Treasures are still being manufactured and Psvane's are potentially a knock-off with changes to avoid copyright infringement with a lot of attention to marketing.  Historically this has happened before in China. These may be great tubes but I would like to have some objective information about them before purchase.  Preferably from someone here.