Tube adapters. Anyone?

I have noticed a growing amount of tube adapters on the market. Tube depot has them now. Adapters such as using a 6BQ5 in place of a 6V6. Or using a 12AX7 in place of a 6EU7. In various gear I use all of these types and the only one I may be tempted at would be the 12ax in place of the 6eu. Then again it is not a big deal to re-wire the 6eu socket to use the 12ax.
Any experience or thoughts on this?

 

If you're asking whether anyone has experience with tube adapters, yes, I do. Worked just fine.

You merely need to ensure the two tubes you're planning on using are electronically compatible and any competently made tube adapter should work fine.

 

I have used quite a few. . . 4 to 8 pin rectifier converter bases, 6SN7 to 6922 converter bases, 6BQ5 to EL83 converter bases. The first two I use daily in two systems (I love the 4 pin Type 80 Globe and Gray Glass RCA 6SN7 in my Decware components.) No reliability problems etc.

 

Just be wary of Chinese made tube socket adapters that you can find for low prices on eBay and other sources. Some of them are not assembled well. Some have been disassembled and the insides were a mess of sloppy solder and joints with connections that could very easily short and fry your amp. Be careful.

Don't buy cheap adapters. Pay more for ones that are backed by a reseller that will make sure they're good and safe to use. You don't want to fry an amp just to save a few bucks on a socket adapter.

 

Make sure your amps bias is set to accept different or is adjustable or you can experience undo damage

 

I regularly use a 2 x 6J5 (etc) to 6SN7 converter in my Schiit Saga+.

It works great, opens up the rolling options and keeps the cost down as the 6SN7 valves have got silly expensive.

 

It is absolutely safe to use as long as you buy from a reputable maker using good parts. Just keep in mind there is always a risk of short if the internal wiring is not properly soldered or more noise if the shielding is poor. I have been using 4-5 types of adapter regularly, all made with copper base for better shielding.

 

Damn near everything IME.
-Bill

 

They can work OK, with the quality caveats mentioned. One that I have used converts 7199 to 6U8. Saved money on the once hard to find 7199 tubes. The trouble with a socket is that it adds an inch or so to the height of the tube. That can be an issue if your amp has a cover that doesn't have a lot of headroom. You often also cannot use the original rube shields with the adapter in place as many shields connected directly to chassis.

You can alternatively rewire the original tube sockets to accept the substitute tube that you want to use. Generally without other circuit modifications in the case of preamp tubes. That causes a problem for any subsequent users though as the chassis will likely be stenciled with the original tube type at that location, so they need to be aware of it. Adapters can save the day here and also keep the value of the amp higher as many buyers would not want the mod.
-Bill

 

That is kinda what I am leaning toward for my old RCA Living Stereo amp that uses a 6eu7. For some reason I seem to have this tube fail more often in this amp and two others I have used in the past over any 12ax7 tubes. My stockpile of 6eu7 has dwindled, but I continue to score lot purchases of 12au, 12ax, and 12at tubes.
If I go this route I will re label the markings on the amp chassis somehow some way.

 

Check plate and cathode voltages.
-Bill