Search found 35 matches

by lonote
Thu Oct 31, 2024 12:05 pm
Forum: Technical Discussion
Topic: c-clips for fender jewels
Replies: 2
Views: 114

Re: c-clips for fender jewels

I hadn't thought to try that, I will have to give the a try. They are "snap rings" in old-school mechanic speak. External or internal, as needed I have ditched the regular bulbs for LEDs myself & insert them into the jewel. I have been buying the whole assembly, so it comes with the correct nut. But...
by lonote
Wed Oct 30, 2024 4:29 pm
Forum: Technical Discussion
Topic: 6K6 Reverb Driver Issue
Replies: 2
Views: 68

Re: 6K6 Reverb Driver Issue

Pretty interesting project. Looking at the schematic, & a disclaimer that I am not an expert, it looks to me like you are shunting a good bit of signal to ground, right at the 6K6 grid with only a 250K dwell pot. I have built a 6G15 w/a 6K6 driver (works great), as well as added a dwell control to m...
by lonote
Mon Oct 28, 2024 12:00 am
Forum: Technical Discussion
Topic: Single Ended Parallel Lead - review my planned overhaul
Replies: 72
Views: 11138

Re: Single Ended Parallel Lead - review my planned overhaul

Looks to me like the 5K (R6) & C5 (10uF) are creating a B+ side node, lowering the screen voltage without affecting the downstream main B+ rail voltage by making it all pass through the 5K. I would have to guess that was an intentional design choice.
by lonote
Sun Oct 27, 2024 4:58 pm
Forum: Speakers and Cabinets
Topic: Hide Glue Tips/tricks?
Replies: 8
Views: 361

Re: Hide Glue Tips/tricks?

jabguit wrote: Sun Oct 27, 2024 12:56 pmI was initially impressed with the results. With time though all of my joints have opened up after only a couple years.

Disappointed to hear that things are opening up. Fingers crossed on the ones I just completed.
by lonote
Sun Oct 27, 2024 11:59 am
Forum: Speakers and Cabinets
Topic: Hide Glue Tips/tricks?
Replies: 8
Views: 361

Re: Hide Glue Tips/tricks?

While I don't love it, I have done tolex, as needed, for years & years. I used traditional solvent-based contact cement the most frequently, but recently tried the Wilsonart water-based contact adhesive on the last batch of cabs, with pretty good results. It doesn't have the instant hi-bond stick th...
by lonote
Fri Oct 25, 2024 10:54 pm
Forum: Technical Discussion
Topic: A simple "master volume" mod -- adjust PI bias
Replies: 11
Views: 456

Re: A simple "master volume" mod -- adjust PI bias

Or use two resistors and one filter cap to make a voltage divider connected to the B+ rail and reference your heater CT to that. I just used that set-up for the first time, on the amp I am finishing up, borrowed directly from one of your power supply drawings. Works great & I plan to make that a re...
by lonote
Thu Oct 24, 2024 8:40 pm
Forum: Technical Discussion
Topic: AB763/BLJr mash-up
Replies: 8
Views: 442

Re: AB763/BLJr mash-up

Thanks all for the insights. I have the amp here, as I am still working on the cabinet.

I will revisit that section & try out some alternate values.
by lonote
Thu Oct 24, 2024 11:50 am
Forum: Technical Discussion
Topic: AB763/BLJr mash-up
Replies: 8
Views: 442

Re: AB763/BLJr mash-up

Do you have a coupling cap after the 3rd gain stage? As it is right now there's basically 147k to ground from that node. Also I'd recommend going the other way with the reverb driver cathode resistor since it's got a MV. Try 1.5k to start. There is indeed a coupling cap between those resistors & th...
by lonote
Wed Oct 23, 2024 1:12 pm
Forum: Technical Discussion
Topic: BAXANDALL EQ Question....
Replies: 7
Views: 319

Re: BAXANDALL EQ Question....

I've been wondering why my Ampeg GU12's don't rock nearly as well as my AC12's.... My GU's are both wonderfully clean, but NOWHERE as 'Stones'y as the AC's once its NFB is clipped. I can't offer any insights other than the AC has the much simpler tone control. But I am not familiar with either of t...
by lonote
Tue Oct 22, 2024 11:50 am
Forum: Technical Discussion
Topic: Weak bias wiggle trem
Replies: 11
Views: 376

Re: Weak bias wiggle trem

I have only mid-level tube knowledge & pretty much zero regarding SS. The appealing thing about the MOSFETs was that they were kind of a plug & play replacement with a tube, relying on similar outboard components/functions. I think that this drawing below (not mine, but from the smart guys at Hoffma...
by lonote
Fri Oct 18, 2024 3:12 pm
Forum: Technical Discussion
Topic: Weak bias wiggle trem
Replies: 11
Views: 376

Re: Weak bias wiggle trem

I built a MOSFET version of a typical LFO which worked well & tried various ways to tie it in, but never really followed through to any acceptable design. I wish I had taken some notes, which I didn't but, I was in a similar place to where you are & was coming to the conclusion that there just wasn'...
by lonote
Fri Oct 18, 2024 1:41 pm
Forum: Technical Discussion
Topic: Weak bias wiggle trem
Replies: 11
Views: 376

Re: Weak bias wiggle trem

Looking at a VibroChamp schematic (& similar on the Airline), the tube being wiggled has a dedicated cathode resistor to establish the bias, then the LFO signal is applied to the cathode side of that resistor. Looks to me like you have the pot itself establishing the bias.
by lonote
Wed Oct 16, 2024 4:59 pm
Forum: Technical Discussion
Topic: Musings on the State of the 5e3 Art in 2024
Replies: 23
Views: 843

Re: Musings on the State of the 5e3 Art in 2024

Any way to physically float/isolate the junction of the B+ feed to the 100K plate resistors?
by lonote
Wed Oct 16, 2024 4:55 pm
Forum: Technical Discussion
Topic: Musings on the State of the 5e3 Art in 2024
Replies: 23
Views: 843

Re: Musings on the State of the 5e3 Art in 2024

It's unfortunate and regrettable that such an unsuitable material is the default board substrate used for builders of Fender type amps. Agreed. If I were to intentionally do a vintage layout AB763, etc. I would likely use eyelets, but there is GR10 glass board stock available in 1/16" thickness tha...
by lonote
Wed Oct 16, 2024 12:14 pm
Forum: Technical Discussion
Topic: Musings on the State of the 5e3 Art in 2024
Replies: 23
Views: 843

Re: Musings on the State of the 5e3 Art in 2024

On V1 I have 130V and 121V on the plates. However, the DC on the inputs remains even if I take the V1 tube out. So I don't think it's that. Since I posted, I found a similar thread on here where the consensus was that the Mojotone eyelet board conducts(!), and plate voltage creeps across the board ...