otl amplifier
in OTL you can always use any output tube you like,the first OTL by Frank Gilbert use 2A3 in 1951 in class A configuration,most available schematics are in class AB with 3 to 4 pre-stages,8417 tube is one of my favorite OTL tube in class A operation with single stage front driver which I can also rol it with the new Tungsol KT 120,sound wise,transformer coupled amp can't even come close in imaging and transparency of an OTL.
in OTL you can always use any output tube you like,the first OTL by Frank Gilbert use 2A3 in 1951 in class A configuration,most available schematics are in class AB with 3 to 4 pre-stages,8417 tube is one of my favorite OTL tube in class A operation with single stage front driver which I can also rol it with the new Tungsol KT 120,sound wise,transformer coupled amp can't even come close in imaging and transparency of an OTL.
Good day all,
It's a bit silent on this thread.
I am very curious about how everyone has perished with the construction of the M60 clone.
I myself am also building the M60, but I get quite a few problems.
There is quite some hum present, and I do not know how I can solve it.
I've done everything Ralph Karsten and Mullard EL34 suggested, but I have no options left to pull it off.
Maybe someone has more ideas.
Regards Hans
Netherlands
It's a bit silent on this thread.
I am very curious about how everyone has perished with the construction of the M60 clone.
I myself am also building the M60, but I get quite a few problems.
There is quite some hum present, and I do not know how I can solve it.
I've done everything Ralph Karsten and Mullard EL34 suggested, but I have no options left to pull it off.
Maybe someone has more ideas.
Regards Hans
Netherlands
Hi Hans, I've been lurking here for some time now. I don't need much power as my drivers are 113db eff so I am building the Tim Mellow OTL at 25 wpc.
Hi DJN,
I do not have such high efficiency speakers,
I play with Roger Monitors, not world known, but the design of Dr Balley, and a pair of Jaen Mary Reynoud Opus 1 and a set Celestions 6sl6i. it is all old stuff, but surprisingly good, so i can swap every now and then
These are average speakers and my listening room is not that big.
I know nothing of the TIM MELLOW amplifiers.
But each his thing.
I was not looking for much power, but it seemed to me a challenge to build these amps.
I started with a set of 211SE amplifiers to the design of Triode Dick, a world known person in the Netherlands.
These amplifiers play very well, the challenge is, if I can surpass the sound with the M60.
And I like to do some fiddling with old electronics.
Not that I know much.
Greats Hans
I do not have such high efficiency speakers,
I play with Roger Monitors, not world known, but the design of Dr Balley, and a pair of Jaen Mary Reynoud Opus 1 and a set Celestions 6sl6i. it is all old stuff, but surprisingly good, so i can swap every now and then
These are average speakers and my listening room is not that big.
I know nothing of the TIM MELLOW amplifiers.
But each his thing.
I was not looking for much power, but it seemed to me a challenge to build these amps.
I started with a set of 211SE amplifiers to the design of Triode Dick, a world known person in the Netherlands.
These amplifiers play very well, the challenge is, if I can surpass the sound with the M60.
And I like to do some fiddling with old electronics.
Not that I know much.
Greats Hans
Well I'm alive but only just found this thread.
Currently building Transcendent Beasts but the Class A2 has me intrigued.....
Currently building Transcendent Beasts but the Class A2 has me intrigued.....
Hi,
I'm alive, just got 32 Svetlana 6H13C, but now I'm very busy and I think I'll build M60 in a couple of months or so.
Andrea
Hi,
about 6$ each, 235$ for 32 valves including shipping.
I bought them on eBay from an Ukrainian.
Andrea
Thanks Atma, sorry for not answer before, I have wallet for transistors and cocacola.
Still is a dream for me. Get a Atma kit and build it. Thanks again for your kindly patience
Dear Mr Mori, is possible to say where you get the valves and if you receive them, how looks, did you try them?
The best and now is no good for summer time connect the OTL or only for cook.😀
Hi,
I boutght vallves from eBay user delax777mechanics, he told me that stock more Svetlana "C" winged 6H13C NOS/NIB.
I have not still tried them, but they look fine, all in the original military box.
Since they are 50 or more years old, it's a good thing to pre-conditioning them (72 hours each, 4 per time).
I'll plan to do that in a pair of months.
Andrea
It is certainly a good idea, to heat up the valves for a few days before using them.
I have made a kind of testbench to pre-conditioning them.
I can head 14 tubes at once.
I have made a kind of testbench to pre-conditioning them.
I can head 14 tubes at once.
Thanks Andrea. Thanks for your data and replies.
I didn't know that measure. Precondition them? What is meaning?
Please could anybody explain the how and why? The valves have they own bed and they own stand room with voltage in the heaters. Mr Buizerd, Is possible is this device your cooking machine
Men! You looks professionals.
I didn't know that measure. Precondition them? What is meaning?
Please could anybody explain the how and why? The valves have they own bed and they own stand room with voltage in the heaters. Mr Buizerd, Is possible is this device your cooking machine
Men! You looks professionals.
For Dady,
Everything you want to know about pre conditioning the tubes can be found in this thread.
Regarding the testbench, it is actually one phase of the amplifier.
But with fixed HT and a controllable bias.
For each cathode resistor is a measuring sockets installed, to measure each tube half for current.
In this way you can also pair the tubes.
Everything you want to know about pre conditioning the tubes can be found in this thread.
Regarding the testbench, it is actually one phase of the amplifier.
But with fixed HT and a controllable bias.
For each cathode resistor is a measuring sockets installed, to measure each tube half for current.
In this way you can also pair the tubes.
Attachments
Thanks Buizerd. I got an idea.
If a group in this blog start to take measure from pools of valves. Register the data of current with Bias voltage. We can publicize the results and interchange the valves we have for better matched.
If a group in this blog start to take measure from pools of valves. Register the data of current with Bias voltage. We can publicize the results and interchange the valves we have for better matched.
Anybody get 32 the other one 40...etc. Me 40. I start to measure under the same conditions we fix by convention and make a common pool. We can see the more similar and make a smooth matching.
You Mr Buizerd have the mother bench and can establish the standard parameters.
Respect to pre-conditioning what is this and which is the object to do.
Does Improve the emission? Does de poison the cathode? Does Is necessary DC or AC ? What amount of Its? Does Prolonged the live?
Best Regards for all and good sumer time. Here on Menorca the season come with the best. My family is enjoying every day.
Respect to pre-conditioning what is this and which is the object to do.
Does Improve the emission? Does de poison the cathode? Does Is necessary DC or AC ? What amount of Its? Does Prolonged the live?
Best Regards for all and good sumer time. Here on Menorca the season come with the best. My family is enjoying every day.