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AUDIO FORUMS >> Replacement Tubes >> Tube Substitution Questions for SE34I.3
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Message started by bm2352 on 03/02/23 at 17:54:15

Title: Tube Substitution Questions for SE34I.3
Post by bm2352 on 03/02/23 at 17:54:15

Hi,

Wondering if anyone has used or knows for sure if the following tubes are compatible with the Rachel?

1) EL37 in place of EL34? There's a thread here (https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1502541755/1) about using them in the Torii.

2) Can GZ37 be used as a rectifier? I'd been using a Mullard GZ32 for the last couple years but it seems to be on it's way out and the Mullard GZ37s seem like a reasonably priced equivalent, but with a higher current rating.

3) Can 6SN7s be used in place of the 6n1p with these 6922 to 6sn7 adapters from garage1217? (http://www.garage1217.com/g1217_011.htm) I have a few 6sn7s on hand and am curious to know what they'd sound like in the Rachel if this will work.

Thanks!

Title: Re: Tube Substitution Questions for SE34I.3
Post by GroovySauce on 03/02/23 at 18:17:18

I'll let others answer 1 & 2.

3. Yes you can use the 6SN7 to 6922 adapters.

Garage1217 makes the best adapters I've used. One thing with them is I HIGHLY recommend some sort of rubber o-ring to go between the adapter and the chassis. The adapters have exposed "live" metal on the bottom if they come in contact with the amp chassis it can create issues like popping a fuse. They do have extra long 9 pins so you can let them "float" above the chassis. I like the reassurance of an isolator between them though.

Title: Re: Tube Substitution Questions for SE34I.3
Post by Lon on 03/02/23 at 18:17:23

It's been a long time since I have had a Rachel and I'm not certain about 1) and 2) but 3) yes. . . 6SN7 with converters certainly do make for a nice full sound.

Title: Re: Tube Substitution Questions for SE34I.3
Post by jec3504 on 03/02/23 at 19:14:36

Update: "Each adapter now has an insulator on the bottom as of June 20th 2021. This allows the use of our adapter with sockets recessed below a metal chassis plate." from Garage1217

I think Garage1217 fixed the grounding issue. Very nice adapters.

Title: Re: Tube Substitution Questions for SE34I.3
Post by LiquidBlue on 03/02/23 at 19:16:52

Just to add to what GroovySauce said, I’ve also found the adapters by Garage1217 on eBay to be the best adapters and built well.
https://www.ebay.com/itm/255994277784
I would mention that he has updated his adapters with a plastic insulator, so there’s no more concern about contact with the metal chassis. As noted on his listing,
“Update: Each adapter now has an insulator on the bottom as of June 20th 2021. This insulator is shown in the last photo of this listing. This allows the use of our adapter with sockets recessed below a metal chassis plate.”

Title: Re: Tube Substitution Questions for SE34I.3
Post by Lon on 03/02/23 at 19:23:28

Those are good bases. . . but I must add that the only pair I have immediately broke the guide pins on a pair of Crytone 6SN7 I tried them in. . .not a good thing. Perhaps too tight a fit. I put the tubes in. When I pulled them out a bit later. . . the guide pins remained inside. Expensive tubes, expensive bases. It wwould be better if I liked the tubes more. I've put the combo up for sale.

Title: Re: Tube Substitution Questions for SE34I.3
Post by jec3504 on 03/02/23 at 20:02:52

Puzzling Lon, I've used those tubes in these adapters many times. No problems with any other 6SN7. Sorry you couldn't get them to work for you. They are well built using a far superior substrate and double copper traces compared to the cheap Chinese adapters IMHO.

Title: Re: Tube Substitution Questions for SE34I.3
Post by GroovySauce on 03/02/23 at 20:56:57

My 5670 to 6922 tube adapters from Garage 1217 the sockets where so freaking tight I actually cracked a tube inserting it! I took that tube ripped one of the pins out. With pliers holding the pin I worked the socket pin holders until they loosened up a bit.

Glad they addressed the exposed live metal.

Title: Re: Tube Substitution Questions for SE34I.3
Post by CAJames on 03/02/23 at 20:58:50

Re: GZ37, yes it can absolutely be used and (in my UFOs, at least) sounds fantastic.

Re: EL37, yes they are similar to a 6L6 and ought to be perfectly fine.

Title: Re: Tube Substitution Questions for SE34I.3
Post by jec3504 on 03/02/23 at 21:09:21

Since the first time I starting using socket savers and adapters always used an old tube to break them in. Tip I learned from Jim at valvesNmore. Thanks Jim!

Title: Re: Tube Substitution Questions for SE34I.3
Post by bm2352 on 03/02/23 at 23:19:24

Very cool. Thank you everybody for responding so quickly.

Title: Re: Tube Substitution Questions for SE34I.3
Post by jec3504 on 03/02/23 at 23:38:23

Your welcome bm2352. No shortage of knowledgeable friendly folks on this forum.