rjguitar low voltage Rocket proto

[M Fowler]

Worked up a rough build for rj which uses an Edcor 180-0-180 PT and Hammond 260 series OT around 20w. Unknown choke values or make. (old Hadley per rj) EDIT

Added PPIMV and foot switch boost.

I need to take one more picture showing the changes made to the dropping string.

rj can fill in the rest of the story.

Mark

[Bob S]

Nice Mark. The Rocket Man is back.
I'm interested in what you think the lower B+ does to the Rocket sound.
I'm thinking that once the string voltages are sorted out, it will be a killer
Practice / recording amp.
So much going on with TW design lately.
Impressive Mark.

[Colossal]

Another nice amp Mark! Looking forward to the tone report.

[Zippy]

Nice twist on the power supply, Mark. I always enjoy seeing what you pull out of the hat.

I can't wait to hear The Rest of the Story - I've already pinged RJ.

[M Fowler]

Thanks guys, rj is on vacation so he needs to spend some quality time with family and enjoy life.

The post is premature since I haven't dialed in my voltage yet, my bad.

The choke doesn't pull down the B+2 voltage much so I will try various sag resistors to get the voltage down from 332vdc to the normal 285vdc required.
B+1 is 337vdc solid state rectified.

Naturally the plate voltage is too high but the amp sounded so clean, nice bass and treble. It would make a wonderful practice amp for sure.

Should I be rectifying this differently? 360v CT. (180-0-180)

Mark

[RJ Guitars]

thanks Mark for building up this amp. It is one of many of my big ideas that sat unfinished for a couple years. Recently I recruited Mark to do some prototyping for me... It was only a chassis with a some transformers mounted to it when I sent it to him. He has been a great Rocket amp developer since way back so I was really pleased that he said he would finish this up for me.

I wanted to build a lower power Rocket using a variety of parts that I had on hand at the time. The choke is a very classy old Hadley but I don't know anything about it except the DC resistance is pretty low... I can't recall the actual value now. The tubes I sent Mark were old stock Russian 6P1P, a 9 pin ~ equivalent of the 6AQ5 or 6V6GT. He will have to confirm for us that he used these tubes. They are not rated for as much voltage as a EL84 which is why I chose the Lower voltage Edcor transformer. This is a two hole rocket so it will start out at a lower power... I haven't done any calculations but I'm expecting 10 or 12 watts based on the tube specifications.

I also wanted to avoid the use of a rectifier tube in this amp. I've never been convinced that it was essential in the pursuit of good tone for an AC30ish builds. Since the good GZ34 tubes have become so expensive I wanted to see if we could get the tone we wanted with 50 cents worth of diodes.

So that was the story behind this amp... the reality is that Mark really came thru with his own touch and I am really pleased to have this prototype completed and can't wait to hear it.

rj

[M Fowler]

I tested the amp with my tubes rj and after I get the voltages tamed I'll try the tubes you sent.

Mark