The Valve Jr transformation is complete....

[marnold***]

Version 2 was an improvement over version 1, and version 3 takes very little modding to sound excellent. Some have even suggested that the stock version 3 output tranformer sounds almost as good as the Hammond 125ESE. For a Marshally sound, the V3 stock OT may even be better sounding as you get a little core saturation. The 125ESE will not saturate in a VJ circuit at all.

So would you be happy using a VJ v3 out of the box or would there be a tweak or two that you must needs make?

[tunghaichuan***]

So would you be happy using a VJ v3 out of the box or would there be a tweak or two that you must needs make?

I just pulled the chassis on a V3 head I got a GC a while back. I'd probably do a couple of tweaks:

Replace one of the power supply resistors with a higher value to cut down on the B+ voltage.

Rebias the EL84 with a 270 ohm resistor.

Replace the cathode bypass cap on the EL84 with a 1,000uF cap.

Replace three key resistors with 1W metal film types; the 1meg grid load on the first 12AX7 triode and the two 100k plate load resistors on the 12AX7.

Depending on whether or not I would be cranking it up all the way or not, I'd change the cathode bias resistors on the 12AX7 to 680-820 ohms. I'd also swap out the bypass caps for 2.2uF to 4.7uF caps.

I'm still debating on swapping out the stock V3 OT for this Edcor OT. The one I have is actually the multiple secondary version for use with 4, 8, and 16 ohm taps. Edcor doesn't show it on their webside, but you can order it for the same price as the one shown. The downside is that the OT has exposed solder terminals which is inherently unsafe. You never want B+ exposed outside the chassis. Edcor won't make it with flying leads anymore. As such I wouldn't recommend it for beginners, which is too bad, the price is right.

Edit: having said all that, I've got two V3 VJs that I am going to leave stock. I plan on running a stereo multiFX unit of some kind into them. The only tweak I plan on doing to the stock units is to replace the 12AX7s with a 5751 preamp tubes. The 5751 is like a lower gain version of the 12AX7. Hopefully this will give the amp more clean headroom.

tung