Recommend new tubes for small combo amp

[Russtopher]

I picked up a Crate V50 in a trade the other day (ok stop laughing now ) and it sounds pretty good for nice cleans, and gives a decent rockish tone on the OD channel. I popped it open, it's still running the 3 stock Sovtek 12ax7s in the preamp.

My only other amp to date has been a Vox Valvetronix (I'm a drummer and pretend to be a guitarist every now and again) so I'm fairly clueless about various types of tubes. I know I'll never get any metal tones out of this amp without a pedal, and honestly I'm perfectly fine with having a nice solid rock tone. I'd like to get some of the mud out of the gain and maybe push it a little harder, so I wanted to get some toob recommendations to try. I searched around the forum last night and all the recs seem to be for high gain amp tubes, I wanted to see if anyone had any recommendations on upgrading the Sovteks and if swapping out all three, or just changing certain postions would help.

Thanks in advance!

PS I think this makes post 100 in nearly 2 years of being registered here. Hooray for lurking and learning

 

[Omega_Void]

For a combo avoid long-plate 12AX7 tubes as these are more sensitive (i.e. for JJs use ECC83S not ECC803S). In a combo amp the cabinet transmits the speaker vibrations to the tube socket very well, and sensitive tubes will be likely to squeal like a little piggy.

Non-linearity (= tube character) will be greatest where the triode is wired for most gain, which will be the input tube.

Sound character will also be affected by hot or cold the tubes are biased, and this depends on the tube gain. Individual tubes will have different gain, and may be quite far from the nominal for the type. So it can make a difference to swap the same set of tubes around into different sockets. Unless you pay a premium to get the tubes from a vendor who test them and select for tubes which happen to have some specific transconductance figure, that is.

Bear in mind also that the occasional duff tube does happen.

Brand-wise I've only owned Sovtek which I found quite grubby/ratty sounding, JJs which were nice and smooth and Shuguang which were brighter and quite sweet-sounding. None of these were actually measured for transconductance however, so there's no guarantee that I wasn't replacing particularly hot-biasing JJ with particularly cold-biasing Shuguang or vice-versa.

If I were in your shoes I'd probably start by getting one Shug, one JJ and one other brand with a good rep ("Winged-C" Svetlana, maybe?) then swapping the three around between the sockets, you'll probably get a variety of flavours out of the amp that way. Definitely lose the Sovteks, though IMHO.

 

[Russtopher]

Excellent, much thanks for the advice! I'm probably going to hit up dougstubes.com and get some in and try swapping them around as you suggested.