So here it is:
The two HT dropper resistors for the first and second stages will have to be
adjusted on test.
It looks OK to me but I may have missed something.
Steve
Search found 10544 matches
- Sat Dec 04, 2010 9:28 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
- Sat Dec 04, 2010 12:32 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
this may be my usual 'foot in mouth' question...but... how does v3 cathode see ground...I can't fathom how there is a circuit there..... It's OK Ed The diagram is only a very very rough schematic (hurriedly put together) to give me an idea of what I'm going to do. You're right of course about there...
- Sat Dec 04, 2010 10:01 am
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
- Sat Dec 04, 2010 9:40 am
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
- Sat Dec 04, 2010 7:31 am
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
- Sat Dec 04, 2010 12:33 am
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
Here's a preliminary schematic for zero biasing of the output valve. The main power supply is included plus the 10V DC filament supply for the 8005. http://web.me.com/scress1958/Pictures/8005schem.gif Any thoughts? Instinct tells me that the cap is needed at the bottom of the IT secondary to isolate...
- Thu Dec 02, 2010 6:27 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
- Thu Dec 02, 2010 5:33 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
What do you get out of the 13E1 amp Steve? I get around 11WPC out of the 13E1. 16WPC single-ended is just possible with a 13E1 but you're running at around 85 watts plate dissipation and near enough 200mA current with 450V on the plates. OTOH, 11WPC sounds bloody good out of a 13E1, so the OT100 va...
- Thu Dec 02, 2010 5:24 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
Right! So a tiny compromise. With a 5K OPT, 600V @ 100mA fell very conveniently on the zero bias line so that's what I chose, giving a plate diss of 60W. http://web.me.com/scress1958/Pictures/OT100600V.gif Almost double the previous power output at 16WPC (that's more like it) nice and linear etc. I ...
- Thu Dec 02, 2010 4:22 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
- Wed Dec 01, 2010 9:29 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
Hi Nick, Funnily enough, 700V @ 100mA was what I was originally considering, but chickened out when I read the data sheet. I got frightened off by the class B designation for the max dissipation of 75W The 700V operating point would certainly be better in terms of power output. Do you reckon the dis...
- Wed Dec 01, 2010 8:34 pm
- Forum: Everyones Projects
- Topic: OT100/8005 Amplifier
- Replies: 45
- Views: 17485
OT100/8005 Amplifier
Ideas for an op point would be welcome. Transformer drive with zero bias might be nice looking at the curves. Maybe 450V, 50mA, 0 bias? Or, 450V, 100mA, +10V bias. Looks like needs about 10mA for the grid if it goes to +20V So I took this from the "valves" thread and have decided that it ...
- Tue Nov 30, 2010 8:13 pm
- Forum: Valves
- Topic: OT100/8005
- Replies: 3
- Views: 3169
OT100/8005
Managed to pick up a pair of these babies for £58 off ebay. They were used in the Macintosh M1 series of amplifiers in the '50s. http://web.me.com/scress1958/Pictures/8005.jpg This particular pair were made in the 70s by Tungsram. Here are the curves: http://frank.pocnet.net/sheets/049/8/8005.pdf I ...
- Sun Nov 28, 2010 8:05 am
- Forum: Your Fave Artists
- Topic: One for all you groovy hep cats
- Replies: 16
- Views: 4377
- Sat Nov 27, 2010 9:29 pm
- Forum: Your Fave Artists
- Topic: One for all you groovy hep cats
- Replies: 16
- Views: 4377