Search found 145 matches

by nworbetan
Wed Jan 03, 2024 3:37 pm
Forum: Garage Talk
Topic: Therians
Replies: 34
Views: 27716

Re: Therians

When parents are too uneducated (and/or busy with three jobs) to teach their kids anything at all, and assume the kids will learn everything they need to know at school, or on the internet... I suppose therians probably isn't as bad as actually believing in witchcraft, right? Would this be a good ti...
by nworbetan
Sun Dec 31, 2023 2:42 am
Forum: Technical Discussion
Topic: Interesting video on current flow
Replies: 7
Views: 1288

Re: Interesting video on current flow

It sort of invalidates your whole post. No, it doesn't. I stopped watching because he had started explaining things in a way that is absolutely incorrect because his foundation he had been building on for the previous 15 minutes is full of ignorance of basic fundamental facts. He needs to go back t...
by nworbetan
Wed Dec 27, 2023 6:40 pm
Forum: Technical Discussion
Topic: Interesting video on current flow
Replies: 7
Views: 1288

Re: Interesting video on current flow

That's an amazing experimental setup for sure, and the video was really entertaining. However, it's educational value feels dubious at best for at least a couple pretty significant reasons. I'm not a college professor, and I'm not really sure what level of competence to expect from people with only ...
by nworbetan
Fri Nov 10, 2023 8:18 pm
Forum: Fender Discussion
Topic: 5V4 recifier with 6L6WGB pair
Replies: 12
Views: 2553

Re: 5V4 recifier with 6L6WGB pair

You're one or two decisions away from making it work, and where the adjustments need to be made depends on which parts you're already set on. It sounds like you have a pair of 6L6WGB that you're designing for. Are there any other parts that you already have on hand that you're planning on incorporat...
by nworbetan
Fri Nov 10, 2023 1:18 am
Forum: Fender Discussion
Topic: 5V4 recifier with 6L6WGB pair
Replies: 12
Views: 2553

Re: 5V4 recifier with 6L6WGB pair

https://frank.pocnet.net/sheets/093/5/5V4GA.pdf I don't know if this datasheet is the same model of 5V4 that's relevant, but it says typical use is a 10uf reservoir and 100 ohms per plate, at 375v rms. A reservoir of 47uf feels like it could lead to some short rectifier tube lives with a 356vac tran...
by nworbetan
Thu Nov 09, 2023 7:58 pm
Forum: Fender Discussion
Topic: 5V4 recifier with 6L6WGB pair
Replies: 12
Views: 2553

Re: 5V4 recifier with 6L6WGB pair

It sounds like it's pretty reasonable so far, assuming you're also using a power transformer that isn't over the 5V4's 375v rms limit. What power transformer do you have in mind? Another related question is: Do you know how to ensure the PT secondary resistance and reservoir cap don't over-tax the 5...
by nworbetan
Wed Nov 01, 2023 11:35 pm
Forum: Technical Discussion
Topic: First amp build questions
Replies: 21
Views: 3266

Re: First amp build questions

The output impedance is going to be a little higher than ideal without any kind of buffer. That being said, it sounds like you have a fair bit of pedal experience and might be familiar with how to use a buffer when needed. So depending on what you're plugging into you might be just fine without any ...
by nworbetan
Fri Oct 20, 2023 5:37 pm
Forum: Technical Discussion
Topic: shielding with plate voltage
Replies: 19
Views: 3654

Re: shielding with plate voltage

It could have been born from necessity, fathered by someone modifying an amp and wanting to run a shielded input wire straight to the tube socket and realizing that the shortest wire that could get the job done was just one pin over from the grid pin. The extra capacitance being beneficial could hav...
by nworbetan
Thu Jul 13, 2023 7:26 am
Forum: Technical Discussion
Topic: PT dual secondaries
Replies: 6
Views: 674

Re: PT dual secondaries

The one part that looks a little bit "off" to me is the 220k bleeder/balancing resistors. It seems like maybe they might do a better job of balancing if the one on the 141v tap were ~30% higher than its companion on the 108v tap. edit: searched for the transformer part number to find the schematic, ...
by nworbetan
Wed Jul 12, 2023 11:38 pm
Forum: Technical Discussion
Topic: PT dual secondaries
Replies: 6
Views: 674

Re: PT dual secondaries

If transformers are available that have appropriate secondary voltages, then yes you can do that with two transformers.

If the transformers aren't available, then you can't.

The cost and size of two transformers might be prohibitive, but not an absolute no-go.
by nworbetan
Thu Feb 23, 2023 7:23 pm
Forum: Technical Discussion
Topic: Are carbon films worth the trouble?
Replies: 137
Views: 20323

Re: Are carbon films worth the trouble?

The problem is that instruments that measure very precisely and accurately in the gigahertz frequencies exist and electronics that operate very precisely and accurately using gigahertz frequencies are cheap and common. The vast majority of humans can't demonstrate any ability to hear past about ten...
by nworbetan
Thu Feb 23, 2023 6:04 pm
Forum: Technical Discussion
Topic: Are carbon films worth the trouble?
Replies: 137
Views: 20323

Re: Are carbon films worth the trouble?

I appreciate the amount of thinking that's going on. There is/was a school of thought that there are tiny tiny differences in sound from components that instruments and meters can't detect or can't detect yet. The human ear and mind are viewed as near infinite in their ability to discern effects wh...
by nworbetan
Thu Feb 23, 2023 3:53 pm
Forum: Technical Discussion
Topic: Are carbon films worth the trouble?
Replies: 137
Views: 20323

Re: Are carbon films worth the trouble?

This is not nearly as insurmountable of an obstacle as the long winded essay of low expectations would suggest… That would be really great! I'm always eager to learn. Sketch out for me in some detail how it's not nearly as insurmountable. Let’s pretend that’s not the issue…now go We can do that - p...
by nworbetan
Tue Feb 21, 2023 2:30 am
Forum: Technical Discussion
Topic: Are carbon films worth the trouble?
Replies: 137
Views: 20323

Re: Are carbon films worth the trouble?

Questions like this are where being able to express things in numbers is a huge advantage. Ever lower noise resistors only matter when their noise voltage/current outputs are large enough to matter compared to the circuit voltages. I did a quick calculate of the thermal noise of a 10K resistor (onl...
by nworbetan
Mon Feb 20, 2023 9:25 pm
Forum: Technical Discussion
Topic: Are carbon films worth the trouble?
Replies: 137
Views: 20323

Re: Are carbon films worth the trouble?

MOX are noisy. I still wonder if this resistor mojo isn't just about noise. I remember someone here once posted an article discussing how resistor noise significantly contributes to the tonal nuances of each resistor . I can’t cite it or find it but I remember reading about it all I can't say if th...