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Using a 6N6P in place of a 6DJ8?

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Posted on March 5, 2017 at 16:16:29
zacster
Audiophile

Posts: 1126
Location: NYC
Joined: November 22, 2003
I understand that these tubes are not equivalent, and that the heater needs almost double the power, and even maybe the heater pins need to be swapped around. But will they operate at the same point? If I understand this correctly, the gain will be less, but there will be more drive, and also the resulting impedance will be lower, all of which I want. I'm driving 6B4G push-pull with the Curcio CCDA 6DJ8 driver, and I'm looking to go transformer coupled, but the circuit with the 6DJ8 has an impedance that is just too high. So if I plugged 6N6P in I expect I would get sound, and from what little I could find, "better" sound, but would I burn something else up in the process? I do have a 6.3v transformer that I could use for the filaments to take some of the load off the main power transformer if that helps.

The alternative is to build an entirely different amp of course, but that is longer term. I'm just looking for something quick to try, and would probably not use it that way except as an experiment.

I'm not looking to do any damage, just try something new. These tubes are cheap enough that if I don't like them it isn't a great loss.

 

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You didn't want to drive it with a 6CG7?, posted on March 6, 2017 at 05:37:14
FenderLover
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  Since:
May 17, 2009
Or an octal 6SN7?

 

RE: You didn't want to drive it with a 6CG7?, posted on March 6, 2017 at 11:40:41
zacster
Audiophile

Posts: 1126
Location: NYC
Joined: November 22, 2003
No, I was originally looking at ECC99, and this is roughly equivalent. Pinout is the same as 6DJ8 and 6CG7. I'm not looking for an octal tube as I'm looking for plug and play compatibility.

I'll have to check my notes on what the operating points were on the 6DJ8 in my amp. I don't remember offhand.

 

RE: You didn't want to drive it with a 6CG7?, posted on March 6, 2017 at 12:49:02
FenderLover
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Posts: 12533
Joined: July 31, 2007
Contributor
  Since:
May 17, 2009
To me, if you are going to redo the section about that tube... I'd go 6CG7. IMHO, a very nice tube.

 

I would use a 6CG7 for splitter driver in most cases., posted on March 6, 2017 at 15:20:48
Timbo in Oz
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Posts: 19016
Location: Canberra - in the ACT - SE Australia
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  Since:
June 25, 2014
But I'd add a single SS (fet) CCS which will further lower distortion.

If you have a lot of HT current spare, you could use a tube for the CCS, I doubt it would sound any better.

A 6CG7 has the same pin-outs as a 6DJ8, doesn't it?

In that role it would be idling.


Warmest

Tim Bailey

Skeptical Measurer & Audio Scrounger


 

RE: I would use a 6CG7 for splitter driver in most cases., posted on March 6, 2017 at 16:48:21
zacster
Audiophile

Posts: 1126
Location: NYC
Joined: November 22, 2003
I was going to leave the 6DJ8 splitter. And yes, there is a SS CCS already in place. I was wondering if I would need to adjust the current from the CCS. If I knew what the current currently is I'd be in better shape I guess.

6CG7, 6N6P and 6DJ8 all have the same pin-outs. The ECC99 is almost the same, with the difference being the center tapped filament.

 

RE: I would use a 6CG7 for splitter driver in most cases., posted on March 7, 2017 at 06:30:39
Victor Khomenko
Manufacturer

Posts: 46301
Joined: April 5, 2000
*** And yes, there is a SS CCS already in place.***

If at all possible, try the tube one.


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  • RE: Using a 6N6P in place of a 6DJ8?, posted on March 10, 2017 at 17:08:48
    zacster
    Audiophile

    Posts: 1126
    Location: NYC
    Joined: November 22, 2003
    I bought a pair from Ukraine. I'll see first how long it takes to get here in the US, and then how they sound and report back.

    IF they work in the existing layout, and a big IF, then I'll try to transformer couple them with LL1692A transformers. If they don't in the existing circuit I'll build something else to make them work. I'll use the Amity schematic as a guide.

    And while I'm at it, I'll see if I can eliminate the last bit of hum, one channel only. It is probably wires crossing or something like that. The other side is quiet but of course they aren't quite mirror images. I haven't opened up this amp in years but in the interim have read up on grounding schemes and hum and applied it to my phono pre and killed all additional hum.

     

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