Hi,
That is a working progress schematic. I found you don't need a grid leak resistor at all. So now I don't use one.
Currently I'm using 1100B+, 140ma.
Best wishes
Darren
That is a working progress schematic. I found you don't need a grid leak resistor at all. So now I don't use one.
Currently I'm using 1100B+, 140ma.
Best wishes
Darren
Hell...Darren
Thank you and in your schematic i found you used 10v/10A
as the power supply ,is it enough to deliver the juice for 833A.
and my plan will use we417A as a driver then via interstage NC-20F then feed thru 300B then interstage 4:1 thru 833A just like you...Question come in my mine is that do i need to use the cathode resistor and cathode capacitor for 833A.
Best Regards,
Triod Lover.
Thank you and in your schematic i found you used 10v/10A
as the power supply ,is it enough to deliver the juice for 833A.
and my plan will use we417A as a driver then via interstage NC-20F then feed thru 300B then interstage 4:1 thru 833A just like you...Question come in my mine is that do i need to use the cathode resistor and cathode capacitor for 833A.
Best Regards,
Triod Lover.
Hi,
I drive my 833s from the output transformer (speaker terminals) of my 2W PX4 SE mono blocks. I have also driven it from a 1W 6EM7 amp. Both work well.
The 833s are run at 0V grid bias A2, ie no cathode resistor or cap.
I tried a cathode resistor biased at 90V but it sounded the same.
You need very little to setup an 833, apart fron the PS that is.
My heater supplys iare two Farnel bench 0-30V 20A units.
Best wishes
Darren
I drive my 833s from the output transformer (speaker terminals) of my 2W PX4 SE mono blocks. I have also driven it from a 1W 6EM7 amp. Both work well.
The 833s are run at 0V grid bias A2, ie no cathode resistor or cap.
I tried a cathode resistor biased at 90V but it sounded the same.
You need very little to setup an 833, apart fron the PS that is.
My heater supplys iare two Farnel bench 0-30V 20A units.
Best wishes
Darren
Hello...Darren
Thank you again...What about the sound and it loud enough for normal speakers rated at 88db.?
I will set up my amp around next month and let you know the progress...Anyway, i plan to use the voltage around 1000V.
Thank you and Best Regards,
Triod Lover.
Thank you again...What about the sound and it loud enough for normal speakers rated at 88db.?
I will set up my amp around next month and let you know the progress...Anyway, i plan to use the voltage around 1000V.
Thank you and Best Regards,
Triod Lover.
I think for 88db speakers you are going to want lower ratio interstage transformers?
I'm using 3k/8R SE output trans and my system goes very loud. These work out to approx 20:1 ratio.
I would suggest somewhere between 4:1-10:1 ratios depending on your needs.
But try it with what you have first. You may be surprised
Best wishes
Darren
I'm using 3k/8R SE output trans and my system goes very loud. These work out to approx 20:1 ratio.
I would suggest somewhere between 4:1-10:1 ratios depending on your needs.
But try it with what you have first. You may be surprised
Best wishes
Darren
833 measurements and new topcaps
Hi all,
it's been a while since my last posting....just enjoined the music.
Just cranked up the anode voltage to 1100 V (220 mA) and it works GREAT. The music simply flows.....and the more reddish anode coloration is a nice extra......
I hooked my Fluke Scopemeter at the filaments (DC !) with the tester set at AC + DC. Result: 9,78 VDC and look at that ripple......where ?!
Maybe one of the reasons why the amp is so silent. And i mean in the music: when there is a silence required....there is SILENCE. No hum whatsoever.
Also scored some great topcaps; very retro. Stainless steel convection warmth dissipation caps. I found them in a dumpstore; never seen them before.
And now for my next change.....i'm going to use the Philips TB 3/1000. An European forerunner of the 833. I'll keep you posted.
Regards,
Reinout
Hi all,
it's been a while since my last posting....just enjoined the music.
Just cranked up the anode voltage to 1100 V (220 mA) and it works GREAT. The music simply flows.....and the more reddish anode coloration is a nice extra......
I hooked my Fluke Scopemeter at the filaments (DC !) with the tester set at AC + DC. Result: 9,78 VDC and look at that ripple......where ?!
Maybe one of the reasons why the amp is so silent. And i mean in the music: when there is a silence required....there is SILENCE. No hum whatsoever.
Also scored some great topcaps; very retro. Stainless steel convection warmth dissipation caps. I found them in a dumpstore; never seen them before.
And now for my next change.....i'm going to use the Philips TB 3/1000. An European forerunner of the 833. I'll keep you posted.
Regards,
Reinout
Attachments
we4212 said:
Darren,
The last post on that thread was sometime back in May. Any progress/changes on your 833 amp?
-- josé k.
Sadly no further progress as I have recently moved. We have the builders in doing major work so it's all safely packed up at the mo.
I will deff return to it, my plan is to try higher B+, I can go up to around 3Kv.
I did try up to 1.4Kv and this valve does like juice, gets better as you go up from what I found so far.
Best wishes
Darren
I will deff return to it, my plan is to try higher B+, I can go up to around 3Kv.
I did try up to 1.4Kv and this valve does like juice, gets better as you go up from what I found so far.
Best wishes
Darren
Interesting,
I have only used SS rectifiers with my 833's so far.
How to the merc's compare?
Best wishes
Darren
I have only used SS rectifiers with my 833's so far.
How to the merc's compare?
Best wishes
Darren
posted earlier
Hello Ranger,
the schematic was already earlier in this thread.
Today i changed only the powertriode. It is no more an 833A but an TB 3/1000. With that triode i started another thread.
The schematic remains the same.
You're planning for something like this ?
Regards, Reinout
(included a picture of the current stus: EML-300B as a driver; TB 3/1000 as output device)
Hello Ranger,
the schematic was already earlier in this thread.
Today i changed only the powertriode. It is no more an 833A but an TB 3/1000. With that triode i started another thread.
The schematic remains the same.
You're planning for something like this ?
Regards, Reinout
(included a picture of the current stus: EML-300B as a driver; TB 3/1000 as output device)
Attachments
Re: Tube Glow
Hi Jose,
Hope all is well... is this your new project? Anticipated completion date?
Regards, KM
korneluk said:
Hi Jose,
Hope all is well... is this your new project? Anticipated completion date?
Regards, KM
last time I saw this thread was years ago... 😀
I like the idea of driving it with another smaller amp.
I like the idea of driving it with another smaller amp.
BlackUnikorn said:
This thread certainly seems to be still breathing!
Driving from a smaller amp has proved to be convenient, I moved about a year ago and have yet to set-up my 833s. Currently using my PX4 amp on it's own.
Mind you, I'm at last starting to build my 833 amp properly. I was machining some new valve bases yesterday. Ran out of SS though so waiting for a delivery to finish them off.
Darren
100th Power amp, have you finished the 100th amp?
I have some Eimac 100th and I want to build a power, but I can't find a good schematic.
best regards
Karsten
I have some Eimac 100th and I want to build a power, but I can't find a good schematic.
best regards
Karsten