Don't let the low price fool ya
This is the pre-amp tube that came with a '58 Champ kit that I built and I figured it was included with the kit because it is economical. I was so very wrong. After testing a myriad of tube combinations I have found that for that amp, this little inexpensive pre-amp is head and shoulders over anything else. Different brand tubes sound different in different amps. JJ long plate gold pin sucks in this amp but is tops for V1 in a much modded BJIII I have. Genalex Gold Lion golds are great phase inverter tubes but suck in the Champ. After one spends a small fortune on tubes they learn the secret to the magic mojo for each different amp. Electronically speaking, capacitance in the filter stage have a huge effect on the performance, tone, etc. of pre-amp tubes and coupling caps effect the output tubes. Tubes are just one part of the recipe.