Rocket and Rectifiers

[dartanion]

dartanion, can you point to a Rocket build you have done that uses the diode, resistor set-up in place of the tube please.

ange

My Torpedo amp is basically that. I have done quite a few of those. It's basically a Liverpool power supply.

Here's video of Billy Penn playing through a Torpedo 50:
http://www.youtube.com/user/MrTonicAmps ... -m9rY_KesQ

[rp]

Tell 'em two of the greatest amps in the history of the universe used SS rectifiers: JTM50 & Twin Reverb - 'nough said.

I actually prefer ss but I only know enough to clone so I stick with the schematic. I do like having the tube rectifier since if my voltages are off I can try different tubes or use a ss adapter doodad. Absolutely love having the SS / 5AR4 option in my 5F6A - voltages are almost identical too.

I'm not one for switches and confusion, but my 5F6A (@400V w/ NOS 5881) has a cathode bias/fixed switch and a pull boost .68 cap on V2. In retrospect I would have made the ss/tube rectifier switched too. The cathode bias isn't useful at higher volumes but it's just lovely at lower ones with the tube rectifier. These 3 options make for a seriously versatile amp w/o a lot of confusing nonsense.

[guitarmike2107]

If its a customer concern you can buy a octal base and build in two diodes and a sag resistor to plug into the rectifier socket.
That way you have a socket wired up to take a std rectifier that the customer can try if he wants to, and he can keep your solid
state plug in as a back up.

Also with the previous discussion about voltage, it would have been more interesting and telling to see how the voltages shifted under drive conditions, as that’s what we are hearing, not idle conditions. might not have proved anything... .anyway

[rawnster]

Tell 'em two of the greatest amps in the history of the universe used SS rectifiers: JTM50 & Twin Reverb - 'nough said.

...hmmm, I think that's not true...the bit about 'nough being sad. I would think the Princeton Reverb and an AC30 would have something to say about your statement.

[rp]

Tell 'em two of the greatest amps in the history of the universe used SS rectifiers: JTM50 & Twin Reverb - 'nough said.

...hmmm, I think that's not true...the bit about 'nough being sad. I would think the Princeton Reverb and an AC30 would have something to say about your statement.

Never said the two greatest - said two of the greatest. There are probably a dozen or more equally great and loved historic amps but the jtm50 and the twin reverb had a simply enormous impact and I was just noting few complained they lacked tube rectifier mojo.

[Zippy]

The cathode bias isn't useful at higher volumes ...

What's not working in that situation?

[rp]

The cathode bias isn't useful at higher volumes ...

What's not working in that situation?

Crunch mostly. Years ago when I built the 5F6A I was really into 5E3s and thought the CB would give me a 40W Deluxe (oh boy!) and one DPDT a resistor and a cap was an easy way to experiment. It's likely just my personal tastes, but I find as the dbs and watts go up I unquestionably prefer the definition, crunch and attack that the fixed bias gives. Loud in CB it actually sounds pretty similar to loud fixed but it's missing something, loud in fixed it just sounds right there. I like hard hitting amps when turned up, low powered amps don't hit hard so I don't notice what I'm missing, and I now know I don't want a 40W 5E3. If I was a touring musician playing out w/ it I'd remove the CB option.

But, played medium in CB it's really sweet, warm, and bouncy with a lot more headroom than a Deluxe, a really pretty sound especially for country licks. A bit like a Matchless, a lot of slam but more smooth and singy rather than grindy-crunchy. Two very different amps in one. I avoid that multi-tasker thing (probably cause I can just build two amps) but this works well (and I'm running out of space for amps.)

Anyway, for years I thought CB was better for under 20W and fixed above, and that was that. But, building a Harvard (small and fixed) made me realized that it's not cathode bias that's special it's just certain CB amps I like - at certain times. If I didn't know how to build amps I'd be a ceramic speaker, ss rec, fixed bias guy, but since I can build amps and I got the needle in deep, I get to play around and confuse myself.

BTW I keep meaning to try the SS adapter in the 5E3 now that I rebuilt it w/ a lower B+. Might suit me better, or it might loose it's mojo. I bet it looses it's mojo.

This whole amp thing is never straightforward.

[Zippy]

Well stated.

Thanks.

[Ian444]

but I find as the dbs and watts go up I unquestionably prefer the definition, crunch and attack that the fixed bias gives.

I hear the same thing with tube hifi amps, its like night and day, but there are also many people who like CB for hifi too. Must be a personal taste thing.