Rolling 6SN7s

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Nubtam94

New member
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~

 
Yes, the 6SN7 will function identically in the circuit.  (The adapter just reroutes the pins, no other adjustments are made)
 
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.
 
Nubtam94 said:
Does this apply to the 6CG7/6FQ7 as well? Thanks

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

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.
 
http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=320659633166&ssPageName=STRK:MEWAX:IT#ht_1080wt_793
 
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?
 
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.
 
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?
 
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.
 
Nick ... Supposedly, most 6CG7's have an internal shield.  6FQ7 does not.   I have a few of these tubes and I believe that all of mine are labeled as "6CG7/6FQ7", none are shielded.   Also read that supposedly they all sound the same.

Anyway ... IF the tube is not shielded the quick and dirty wiring option is to cut the existing connection between pins 4 and 5 on the 12AU7 9 pin socket and then jumper over from pin 9 to whichever pin, 4 or 5 which is no longer connected to heater voltage.   If you have a shielded 6CG7, ground pin 9, seperate pins 4 and 5 and the connection from heater supply that was going to pin 9 (black wire) goes to the now electrically unconnected pin (4 or 5).   In other words,  on the 6CG7 and 6FQ7, pins 4 and 5 get the heater connection and pin 9 is open if the particular tube has no shield, or grounded if it does.    Safest bet is to ground pin 9 which allows for all 6FQ7's and both shielded or unshielded 6CG7's.

The quick and dirty option makes it easier to go back to 12AU7's or subs with same pinouts if you just want to try an unshielded 6CG7/6FQ7.  
 
I don't have a single 6CG7... the point I was making was that I was sent a wrong adapter from the seller for the 6CG7>6SN7 instead of the 12AU7>6SN7 one and was wondering if I could just use this as a 12AU7 adapter since the 6SN7 doesn't have that 9 pin, the 12AU7 socket to 6CG7 adapter basically has no connection and is technically free floating.

I'm just impatient to rolling in the 6SN7s I've ordered and I don't have the correct adapter.

12AU7 socket > 6CG7 adapter to 6SN7 pinouts > 6SN7 tube

Seller just said he'll send out the correct adapter and I don't have to return the old one... no questions asked. Although it's probably because he's just going to overlook the loss since the actual adapter was merely 5 dollars in value plus that 2 dollars shipping... basically breakeven since I bought the adapter for 15.5USD with shipping. What a nice seller...
 
I picked up one of the Ebay adapters.  I had some nice 6SN7s from a previous amp hanging around.  Nice to have some more options to stick in your Crack.  Yes the 6SN7s sound very, good.
 
They are indeed. Now I don't want to go back to the 12BH7/E80CCs I was using. They do music justice. They don't have the technicalities of the good E80CCs but that vintage sound that's just superior to the musicality of the 12BH7/12AU7s.
 
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