YJC Yellowjackets

[LivewireBlanco]

Do these things really work and are they safe??? http://thetubestore.com/yjcd.html

[DeanM]

that looks pretty interesting!!

[slowpokerhino]

I tried them in my Twin a few years ago. They do work but...
The change to el34s obviously changed the tone of the amp. Didn't sound bad but I prefer the 6L6s.
Didn't really notice any real difference volume wise. The amp may have started to break up a bit earlier, but not much.

I had them in for a couple of weeks but ended up going back & selling them. Not a bad product, but the difference (except in tone) is very subtle.

[LivewireBlanco]

Yeah, I kinda thought that the EL84s would change the tone of 6l6 style tubes. I bet they would work nice for El34s though.

[Green Manalishi]

I have used YJs before, and I currently have the Groove Tubes Substi-tubes. I like the GTs alot better. It reduces power more than the YJs do and they sound better, especially cranked. The YJs I always thought had a lowend cutoff, but the GTs didn't.

Plus the GT are cheaper. They seem better built as well.

For Marshalls, use the YJSD model.

BTW, hated the YJs in the VM.

[MKB]

I've never used the Yellowjackets, but if you think about it a bit they are probably not very complicated. They take advantage of the fact that an EL84 tube can handle a significant amount of voltage on the plates as long as you keep the screen voltages below 300V. They also have cathode bias so that you don't require the bias on the host amp to be adjusted. Using these specs I built a pair that worked very well in my 1987 non master volume head. You do get the EL84 tone in place of the big power tube tone, which may be good or bad depending on what you like. One thing is for sure; it would NOT sound like a normal Vintage Modern any more.

I would be extremely wary of using the Yellowjackets in a model 2466 Vintage Modern, as they have quite a bit of plate voltage available (over 500V). You might want to make sure that THD recommends them for such high plate voltages. But that's quite a bit of juice to lay to a tiny EL84 I'd think.