Tube Amp Archive

My personal speaker preference among the Celestion offerings I have tried.

romberg wrote: ↑Fri Mar 08, 2024 10:04 pm Nice! Is the new circuit a 2204 ish sorta thing?

I'm guessing the extra 12ax7 is for either an effects loop or more gain stages?

Mike

Yes, it's kinda like a stripped-down Friedman Smallbox with a tube-buffered loop and foot-switchable solo boost.

Using my own PCBs and some Heyboer transformers to turn a solid-state Marshall Master Lead into a killer tube amp.

romberg wrote: ↑Fri Jan 06, 2023 6:29 pm Pretty cool! It has gotta feel good to see something you no doubt spent many many hours drawing up become reality.

Are the four fuses for the PT HV secondaries and heaters?

Mike

for the HT and the DC heaters to the preamp.

Thanks Mark.

-- John

Hi All, Just wanted to share with you an amp that I am happy with. Everything is my own design, but the circuit shares DNA with Soldano SLO and Marshall. PCBs were designed in Eagle and manufactured (but not assembled) over seas. Power transformer is from Heyboer, output transformer and choke are fr...

What is V+ for this circuit?

The dark-brown 5w resistors are vitreous enamel.

It looks like the diameter is 20.3; the notch adds ~2 mm.

Does anyone have a bit or punch for 20.3 mm?

I prefer the 5k too. I just don't like the sweep of the 25kB (with || 4k7 R) pot.

I recently started using a wet tile saw to cut G10. It cuts well and keeps the hazardous dust down.

FourT6and2 wrote: ↑Sat Jul 29, 2017 1:14 am I really love having a power transformer with solder tags. Makes wiring it up much cleaner. Wish more companies would do it this way.

What gauge wire are you using on the primary side?

I think a lot of old amps have both. You have to hunt for them. Some have the fuse tucked away inside the chassis somewhere. I don't think I've seen a Marshall with just a Mains fuse and no other fuse. The JTM45 has another fuse tucked away inside the chassis. I think the fuse is on the PT center t...

I've never seen an amp without them. Yeah and I've only seen may 15-20% as a rough guess that actually fuse both, most only fuse mains. But then I mostly look at old amps, not newer stuff. ~Phil I think a lot of old amps have both. You have to hunt for them. Some have the fuse tucked away inside th...

A couple additional points to keep in mind: - different tube types have different limiting values for the grid leak resistance. - the limiting value is typically lower for fixed bias than for cathode bias. So, for example, a JJ 6V6S in fixed bias has a limiting value of 100k, whereas the limiting va...