You see that in a lot of British sheets, sometimes opposite Vb(o) (zero signal). It might be supply voltage, but that doesn't make much sense.martin manning wrote:No idea.Smokebreak wrote:My question concerns the Va (b) and Vg2 (b) @ 450V . What is that?
Search found 3022 matches
- Sat May 21, 2016 11:42 pm
- Forum: Technical Discussion
- Topic: Cathode biased kt66
- Replies: 17
- Views: 4430
Re: Cathode biased kt66
- Tue May 17, 2016 5:08 pm
- Forum: Technical Discussion
- Topic: Bassman 135 question
- Replies: 13
- Views: 2387
Re: Bassman 135 question
I'm sure Martin is right about the Bassman 135 schematic being in error. All of the other UL schematics show the 47K/68K flipped. Interestingly, it's only the UL versions have that 21K difference: in roughly the same period with 2x6L6, the grid returns are both 100K; with 4x6L6, they're both 68K; wi...
- Tue Apr 05, 2016 7:05 pm
- Forum: Garage Talk
- Topic: John Deere for sale
- Replies: 5
- Views: 1686
Re: John Deere for sale
Grilled meat, too.
- Sun Mar 27, 2016 10:20 pm
- Forum: Technical Discussion
- Topic: Can never beat a Mullard ECC83
- Replies: 22
- Views: 2988
Re: Can never beat a Mullard ECC83
There are some chemistry secrets that may have died with the last real tube engineers, but a major difference between the old stuff and the new was when old manufacture didn't come up to standards, it got binned. New manufacture rejects get sold.
- Thu Mar 17, 2016 4:19 am
- Forum: Technical Discussion
- Topic: Need help with building the right amp ( update)
- Replies: 94
- Views: 10518
Re: Need help with building the right amp ( update)
Gerald likes stiff power supplies, hence the 110uF for the main filter. But there iconic amps that are seriously underfiltered. Yes, they tend to produce ghost notes when pushed, but that's part of the "charm."
- Thu Mar 10, 2016 7:03 pm
- Forum: Garage Talk
- Topic: RIP George Martin
- Replies: 6
- Views: 1274
Re: RIP George Martin
I can't help but think that without George Martin, the Beatles might actually have been the Rutles.
- Thu Mar 10, 2016 7:01 pm
- Forum: Technical Discussion
- Topic: Setting up a new bench - need some seasoned advice
- Replies: 25
- Views: 2756
Re: Setting up a new bench - need some seasoned advice
I'd be thinking more than one bench (I have three, plus totally separate places for table saw and router table). Keep one space for amp and pedal building, something with drawers for some tools, wire, solder, miscellany. Put a peg board behind it for screwdrivers and pliers and cutters/strippers. Pu...
- Thu Mar 10, 2016 3:10 pm
- Forum: Technical Discussion
- Topic: Need help with building the right amp ( update)
- Replies: 94
- Views: 10518
Re: Need help with building the right amp ( update)
If we're speaking of vintage tubes, the 7025 had spiral filaments to reduce hum. When the 12AX7A was introduced, it did too. You'd be hard pressed to find a modern tube without a spiral heater (except maybe Sovtek 12AX7WA/B/C, but I'm not certain.
- Thu Mar 03, 2016 2:40 pm
- Forum: Technical Discussion
- Topic: Debris in a tube / valve
- Replies: 12
- Views: 1527
Re: Debris in a tube / valve
Looks like mica to me.
- Wed Mar 02, 2016 2:30 pm
- Forum: Technical Discussion
- Topic: Need help with building the right amp ( update)
- Replies: 94
- Views: 10518
Re: Need help with building the right amp ( update)
The first Pro Reverb is AA165. It uses a GZ34 rectifier. If you go that route, you'll want a good one: Mullard, GE or Matsushita. You can also go solid state like a Twin, maybe with a small sag resistor.
- Mon Feb 29, 2016 3:50 pm
- Forum: Technical Discussion
- Topic: bass head?
- Replies: 17
- Views: 2151
Re: bass head?
SS works great for electric bass (even though I'm "religiously" opposed to SS). But if you're looking for a sort of SVT sound or amplifying an acoustic bass with a piezo pickup, tubes are pretty cool. The last tube bass head I built used 4xKT88. Depending on B+, you'll want a PT North of 400mA. The ...
- Sun Feb 28, 2016 7:14 pm
- Forum: Trainwreck Discussion
- Topic: New Half Power Express
- Replies: 22
- Views: 4366
Re: New Half Power Express
Triode? Wouldn't sound the same either. Maybe big power resistors on the output to suck up half the power.
- Tue Feb 23, 2016 3:09 pm
- Forum: Technical Discussion
- Topic: Need help with building the right amp ( update)
- Replies: 94
- Views: 10518
Re: Need help with building the right amp ( update)
Maybe a Pro Reverb. One speaker or two. With a robust enough PT and high enough B+, it could certainly do 50W.
- Sun Jan 31, 2016 2:09 pm
- Forum: Technical Discussion
- Topic: SE EL34 Plexi-verb
- Replies: 137
- Views: 12337
Re: SE EL34 Plexi-verb
In my SEs, I put the tone stack in the middle, Fender style. Added gain in tone recovery.
- Sun Jan 31, 2016 12:59 pm
- Forum: Technical Discussion
- Topic: Output Stage Operation Question
- Replies: 11
- Views: 1282
Re: Output Stage Operation Question
https://en.m.wikipedia.org/wiki/Tetrode gives a different version: "The first true screen-grid valve, with a screen grid designed for this purpose [reducing Cg-a], was patented by Hiroshi Ando in 1919, and the first practical versions were built by N. H. Williams and Albert Hull at General Electric...