6v6 Plexi build question

[labb]

PT--Notes say that the Marshall 18 watt PT is good for this amp...Most of the 18 watt amps I look at show about 350 VDC on the power tube plates...The 6V6 plexi generally shows 400+ VDC. Will this be an issue as long as the pre amp voltages are correct. I'm looking to use a Hammond 270 FX which is 275-0-275 That I already have. 


The Plexi looks to have a normal pre amp section and a bright section that are connected together with a single input..So are these controlled with the volume controls to select the sound you want?


tks

[sluckey]

I think that 270FX will be fine. I have it in my Vox AC-15. It puts out 350VDC through an EZ81 to a cathode biased EL84 power amp. If you use a SS rectifier (like Hoffman) your B+ should be higher than 350. The fixed bias Plexi6V6 will draw less current than the cathode biased EL84s, so that will also result in a higher B+.

Using the two volume controls to blend the dark and bright channels together is my favorite feature of any Plexi style amp. You'll like it!

[labb]

Thanks Steve and again thanks for the info on your site. You have requested pic of builds so I intend to take some of this one. Just to show how sloppy one can be.   I tend to do some things mounting wise different than some, especially around the e-caps and the tone stack components.
One other ? if you would..on your November build you have switchable bias from fixed to cathode...Which do you like the best?

[sluckey]

I removed the bias switch a couple weeks after I built that amp. That was over 12 years ago. It's wired for fixed bias only.

[Big_Mike]

The 18 watt PT works great... On my build, I used a Trainwreck 30 watt OT, which is a little beefier than the 18 watt OT.  This combo worked very well.

The Hoffman layout is basically a four holed Marshall with the channels jumped.  Use the gain for each channel to blend together to taste.