PTP 20W Rocket

[argonaut]

I posted this in another thread and had some requests for more info. I finally had a minute so I cut and pasted it here. Let me know if you need any other info.

I'm a poor photographer, but here's some pics as promised. Been tweaking a bit, and now have the input paralleled with 120k/750R/22uf. Sorry about the wrap on the components, not trying to hide anything, just get a bit artsy fartsy and weird on some builds. It's a rocket with a few exceptions.

Anyway, here's the poop:

PT-vintage Stancor 270-0-270
OT-vintage Hammond 1618
CDE 381LX 33uf reservoir cap
CE Manufacturing 20,10,10,10 multi cap
1K 10W resistor in lieu of choke
Holco H4P plate & grid R's
Sangamo dominoes
K-40Y-9 couplers
PVC tone caps
100R screen R's
100R/220uf cathode
NOS CTS pots
NOS Cinch sockets (used the grounding lugs on the pre/PI section)
Chily 15A switch
Cliff UK jacks
Baldwin label Sylvania in preamp and Russian 6n12n-k power, RCA 5y3

Pull Bright= 120pf mica across the standard 100pf
Pull Attenuate= 220k to ground at PI entrance
Pull Mid-Cut= two 50k trim, one set for desired mid (in lieu of 10kR) the other to dial in the amount of cut when pulled...
Pull Shift= cut set at .0022uf, .0044uf when pulled

B+
1-295v
2-284v
3-207v
4-177v
5-169v

I didn't plan this build, just unexpectedly got the chassis and it came together. I ordered the faceplates and multicap and pieced the rest together from what I had around. All the push/pull tweaks are very useful when playing with multiple guitars. I have to get busy making some head cabs now. I have too many naked chassis' piling up. Going to go picking through the wood pile tomorrow and make some dust!

Edit: Cabs in progress, will post pics when complete..

[statorvane]

Very, very nice. How does it sound?

[M Fowler]

argonaut,

I love PTP builds and yours is great using what you had on hand great job.

The lower voltages and use of lower uf caps must make this a great clean machine.

I'm interested in how you like these two options?

Pull Attenuate= 220k to ground at PI entrance
Pull Shift= cut set at .0022uf, .0044uf when pulled

[amplifiednation]

This is really cool! Great job. How do you retain the rocket circuit by reducing the tubes? Doesn't that change everything or does it just reduce the output? (I'm learning still)...so if you go for the less tubes, the PT and OT are rated lower too, right, so the voltage levels are less?

Then if all of those things are changed (assuming I am correct), how does it retain the "rocket" circuit?

[Reeltarded]

It's a Rocket that got modded.

It looks like jewelry. That is amazing.

[argonaut]

Hey fellas, thank you for the comments.

I had built a stock Rocket using, what I thought to be, the important original type components. https://tubeamparchive.com/viewtopic.ph ... rocket+fun

Using this as my tonal reference, some observations:

As one would expect, the stock rocket has much more headroom, tightness, and punch compared to its little bro.

The 20w is quite compressed and saggy (which I really like). It ramps up faster in gain and is thicker and more complex than stock. It really gets to the meat and potatoes at lower volumes. IMO, it works much better with the guitar volume for clean/mean volume levels. It's jangly, swirly cleans to fat gooey OD.

I really like the Pull Attenuate when using a hot guitar or when I want a cleaner tone. You can use other values than 220k to dial to taste. Best to use this with a switch, IMO. One might be surprised by how much the PI distorts in this amp.

The Pull Shift on the cut works great as well. I personally like a bit of sparkle in the clean and sizzle in the gain and the .0047uf original cut took a little too much off the top in general for my tastes. Although, having said that, I do find with certain cabs/speakers, I prefer .0047uf.

I'm a player first, and a builder second. The tweaks I made were based on my playing preference and the desire to make it more versatile with any guitar or cab.

[Reeltarded]

You must be one bad assed player.




M