for repairing a pair of ASL AQ-1006m i was paid a quad of 8045's, what do you think?
Attachments
Last edited by a moderator:
Well, it doesn't seem to be this 8045:
https://frank.pocnet.net/sheets/201/8/8045.pdf
12.6 V 285 Amperes (3591 heater Watts!) 90KW plate diss.
So it must be the Luxman 8045G, which supposedly is a 6550 wired as a triode:
http://www.turneraudio.com.au/loadmatch1-se-triodes_files/graph-6550eh-triode-anodecurves.gif
Seeing they came in 6550 boxes, are you sure these are actually internally triode wired? Maybe they were just intended as Luxman amplifier replacements. With a socket strapping.
https://frank.pocnet.net/sheets/201/8/8045.pdf
12.6 V 285 Amperes (3591 heater Watts!) 90KW plate diss.
So it must be the Luxman 8045G, which supposedly is a 6550 wired as a triode:
http://www.turneraudio.com.au/loadmatch1-se-triodes_files/graph-6550eh-triode-anodecurves.gif
Seeing they came in 6550 boxes, are you sure these are actually internally triode wired? Maybe they were just intended as Luxman amplifier replacements. With a socket strapping.
Last edited:
yes, smoking amp, the tube have screens and g1 with heatsinks, even the plates have extra fins the likes of which i saw on a 6LQ6 tube....
even the NEC 6ca10's have screens as well...
even the NEC 6ca10's have screens as well...
But is the screen grid actually connected to the plate within the tube? (or in the tube base more likely)
Maybe they -ARE- real 6550A tubes, and a jumper would be installed at the socket to make the triode connection for the Luxman substitute.
Maybe they -ARE- real 6550A tubes, and a jumper would be installed at the socket to make the triode connection for the Luxman substitute.
Below are the datasheet for the 8045G and the loadline based on the recommended operating conditions:
mu of 4.5 means that at 400v plate, grid bias is around 57 volts,
now this is the harder part...
now this is the harder part...
I don't recognize the internal construction of these tubes, but they don't look like the GE 6550's that I have.
I saw an amp years ago that had 8045 tubes in it. The tubes looked like the Russian Sovteks (6550WE maybe?) of the day that were obviously rebranded since they had a faded paint logo and type number.
There was a little spring clip on the outside of the base that connected pins 3 and 4 together. I don't remember the amp or tube brand, and I'm not 100% sure of the 8045 number either, but it makes since now.
Look at the bottom of your tubes!
I saw an amp years ago that had 8045 tubes in it. The tubes looked like the Russian Sovteks (6550WE maybe?) of the day that were obviously rebranded since they had a faded paint logo and type number.
There was a little spring clip on the outside of the base that connected pins 3 and 4 together. I don't remember the amp or tube brand, and I'm not 100% sure of the 8045 number either, but it makes since now.
Look at the bottom of your tubes!
RE: Jazbo8
What program are you using that gives the class AB loadline (the dark blue line)?
--------
The winglets on the tube plate edges would indicate a late manufacturing date.
If Luxman really was using that earlier 3600 Ohm P-P load, then they made a voracious tube eating amplifier. No wonder they made the tubes proprietary, a re-sale gold mine.
--------
Yeah, worth checking the base to see if there is a jumper/clip wire on pins 3,4
What program are you using that gives the class AB loadline (the dark blue line)?
--------
The winglets on the tube plate edges would indicate a late manufacturing date.
If Luxman really was using that earlier 3600 Ohm P-P load, then they made a voracious tube eating amplifier. No wonder they made the tubes proprietary, a re-sale gold mine.
--------
Yeah, worth checking the base to see if there is a jumper/clip wire on pins 3,4
Last edited:
R: The R Project for Statistical Computing and codes from Ayumi.
Yup, the recommended loadline from Luxman was pretty insane...😱
On checking into this 8045G (Matsushita) tube some more, it was not really ever a triode strapped 6550. Comparing the triode curves of the 6550 to the 8045G shows the 6550 rp in triode is twice as high as the 8045G, and the Mu is too (8 versus 4.5). 6550 was just a suggested sub when the 8045G was no longer available. Power output is considerably reduced with the 6550 sub also, due to the higher minimum plate voltage attainable in triode. (without going positive on grid 1) (from higher rp)
8045G is closer to a TV sweep tube. A 6LW6 with a cooler (lower gm2) screen grid. The 6LW6 Mu is like 3.7, instead of the 4.5 (more like 5.0 actually) of the 8045G. Probably a necessary mod. to increase the grid 2 voltage rating for triode use.
One could likely make a virtual 8045G by using a 6LW6 with a resistive divider from plate to cathode. The tap point (for resulting Mu 5.0) would drive the grid 2 via a Mosfet follower ( and a source pull down resistor to the cathode). (plate to cathode tap point at 3.7/5.0 of divider resistors)
AJT:
Something interesting to check on the 8045G tubes at hand: did they alter the support micas to provide better insulation (a longer surface path) between the grid 2 and grid 1 support posts?
..
8045G is closer to a TV sweep tube. A 6LW6 with a cooler (lower gm2) screen grid. The 6LW6 Mu is like 3.7, instead of the 4.5 (more like 5.0 actually) of the 8045G. Probably a necessary mod. to increase the grid 2 voltage rating for triode use.
One could likely make a virtual 8045G by using a 6LW6 with a resistive divider from plate to cathode. The tap point (for resulting Mu 5.0) would drive the grid 2 via a Mosfet follower ( and a source pull down resistor to the cathode). (plate to cathode tap point at 3.7/5.0 of divider resistors)
AJT:
Something interesting to check on the 8045G tubes at hand: did they alter the support micas to provide better insulation (a longer surface path) between the grid 2 and grid 1 support posts?
..
Last edited:
so i think i will run these tubes at no more than 350 volts plate and 60mA cathodes...