Rolling 6SN7s

[Nick Tam]

Okay so I've been running through the forums and have not been able to come to a straight conclusive answer as to if the 6SN7 is a direct drop in for the 12AU7 with adapter, so I just want to be sure that I don't kill the precious internals.

So from what I know, it IS a drop in replacement as long as I use a 9 to 8 pin adapter that has the bias set and rewired pin layouts for the 6SN7?

Also is it possible to run the ECC32/33 tube variants?

I'm running the Speedball so I'm just stuck at the voltage issue, someone clarify, thanks.

Also, I'm if anyone are able to give their impressions as to how the 6SN7's family sound characteristics compared to say the 12AU7 and 12BH7 and E80CC tubes would be great. Ever since getting my Crack I've only ever rolled in a RCA 12BH7A Foil D and a Tungsram E80CC, was wondering if the 6SN7 does any better in the soundstage and "spaciousness" department.

Thanks~

[Paul Birkeland]

Yes, the 6SN7 will function identically in the circuit.  (The adapter just reroutes the pins, no other adjustments are made)

[Paul Joppa]

To clarify, the only significant difference is that the 6SN7 needs twice the heater current - which is no problem with the Crack, it has plenty to spare.

[Nick Tam]

Does this apply to the 6CG7/6FQ7 as well? Thanks

And if anybody knows, if it is safe to use the ECC32/CV181

[Lar]

I have used the CV181, but was not impressed with there sound.

[Grainger49]

Does this apply to the 6CG7/6FQ7 as well? Thanks

And if anybody knows, if it is safe to use the ECC32/CV181

The 6CG7/6FQ7 is not a direct sub for the 12AU7.  It might work.  I have used a 12AX7 in the socket for a 6DJ8 and it worked, not well but made sound.  Those are not direct substitutes either.

[Paul Birkeland]

The 6CG7/FQ7 works if you rewire the heaters.

[karl]

Where can I find the adaptor?

Regards,

Karl

[Paul Birkeland]

http://www.ebay.com/itm/Two-adapters-for-12AU7-ECC82-6CG7-TUBES-amplifier-/260716251584?pt=Vintage_Electronics_R2&hash=item3cb3e649c0

I'm not affiliated with the seller, and if you're going from a 12AU7 to a 6CG7, the adapter would connect pins 4/5 to 4 and pin 9 to 5, going from a 6CG7 to a 12AU7, the adapter would connect pin 4 to pins 4 and 5, and pin 5 to pin 9.  Consequently, one adapter wouldn't go both ways, so I'd contact the seller before buying!

[Lar]

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=320659633166&ssPageName=STRK:MEWAX:IT#ht_1080wt_793

[Laudanum]

Karl, I can confirm that the adaptors linked by Lars do work perfectly well for the 6SN7's.

[Nick Tam]

Hey guys, i dont want to pick up any flashy 6SN7s yet but how does the average 6SN7 sound fare against the best of 12AU7s, 12BH7s and E80CCs?

[Laudanum]

Dont know about the E80CC but for a very general description ... tubier (if thats a word).   That's how I would probably describe it but it's a generalization.   I prefer them, but some dont.    BTW, as far as non flashy 6SN7's go, I like the readily available Sylvania "T" plates just fine and they can be had for not much money.  These generally come as 6SN7 GTA and GTB.   Parallel T plates and angled T plates.   I think the Parallel T plates that I have I may prefer a little bit over the others but I wouldnt swear on it.  I think it is some (not all) of the GTA's with the parallel plates.   Many affordable old production 6SN7's to try.  I have a few of the VT 231's which are pretty well regarded, usually in the top 5 lists.  They are better but I dont think they throw the regular old GTA's and GTB's under the bus.   Google "best 6SN7 tubes"  and you will pull up a good deal of info and reviews.

[Nick Tam]

Hi guys. I ordered from that seller and they made the simplest messup and sent me a 6CG7>6sn7 converter instead. Should I just send the package back? it's a complete pain in the arse that they messed up and it took a whole week to deliver, even for a local delivery!

From what I understand, all I have to do is ground the 9 pin connection within the Crack if I were to use a 6CG7? Or I don't have to at all since the 9th pin doesn't go anywhere in a 6SN7 tube?

[Grainger49]

I would ask the seller to pay return postage for sending the wrong adapter.  Contact him through ebay so there is a record of the screw up within ebay.