Rocket with 6V6's...

[riscado]

How would a circuit such as the rocket (using exactly the same schematic) work but with 4 6V6's and the correct bias resistor?

[nickt]

How would a circuit such as the rocket (using exactly the same schematic) work but with 4 6V6's and the correct bias resistor?

Not a guru but at 18 watt the concensus seemed to be - it worked but the gain of the PI was a little low for the 6V6's. 6V6's are less sensitive than EL84's. Whether this translates to the Rocket - don't know.

[rhinson]

lots of people and boutique companies (divided by 13 for example) have ac 30 pre's matched with 6v6's and make no p.i. changes at all. it's just a matter of taste. when using the vox style pi (depending on what the rest of the preamp circuit is) i usually change the cathode resistors to 820ohms/39k but the standard 1.2k/47k works just fine. i've build a few amps of this style with a mixed power section-----2 el84's and 2 6v6's or 6aq5's----sounds great and no problems. just use separate cathode resistor/cap to bias your el84's (125-150 ohms) and 6v6's (250ohms) and you're good to go. rh

[riscado]

yeah I guess the 6V6's are a little lower gain, I tend to prefer their sonic characteristics even though I realize a lot comes from the inherent circuit I guess I'll have to tweak

thanks

[rfgordon]

I built a Rocket, but with both sides of the first pnut in parallel, and into a pair of hot (405 VDC on the plates) cathode bias 6V6s. It's cabbed into a small 1x12 combo. I added a Mid control on mine.

Results? Well, with all vintage/NOS tubes (except for the 5AR4) it sounds great. Not really much clean headroom, but it sings and has the most amazing crunch. It cleans up a bit with the guittar volume rolled back.

I would think that a quad of 6V6s would yield more headroom, particularly if you grid-bias them. Between the Cut and Treble controls you can find a sweet spot for almost any guitar.

6V6s definitely have a different voice than the EL84s, so I don't think either way is "right" only different.

I'm going to use the same preamp for an upcoming amp order, but the guy wants reverb (I'll add it post tone stack) and a pair of each 6V6 and 6L6, all into a 15" speaker. Should make for an interesting amp.

I've come to believe that it's pretty hard to go wrong by using one of Ken Fischer's preamps as a starting point!

[jelle]

I build one with two 6V6 tubes and I thought that the pi change was needed to get into gainland again. I lowered the tail- and the cathode resistor of the pi. I'd say adjust to taste! My amp rocks but I sold it....Dunno the values, sorry!

Have fun,
Jelle