I built my mono blocks based on the Atmasphere M-60 about two years ago.
It's a proven circuit and I've had zero issues with them other than putting
the large toroid transformers in a separate box to lower hum.
They sound amazing and drive my super Heresies effortlessly.
Seems to be a lot of myths and misinformation going around.
If OTL is such a bad design then why is Atmasphere still thriving after many
years? I wouldn't condemn a whole topology based on one defective amp.
Just my 2 cents
It's a proven circuit and I've had zero issues with them other than putting
the large toroid transformers in a separate box to lower hum.
They sound amazing and drive my super Heresies effortlessly.
Seems to be a lot of myths and misinformation going around.
If OTL is such a bad design then why is Atmasphere still thriving after many
years? I wouldn't condemn a whole topology based on one defective amp.
Just my 2 cents
Attachments
https://frank.pocnet.net/sheets/164/6/6AS7.pdf
The split supplies operate at 140V
Rating looks to be 300V Max.
Should be well within the specs
The split supplies operate at 140V
Rating looks to be 300V Max.
Should be well within the specs
The schematic should be here somewhere in this thread.
My old laptop died but I think I still have it in my head.
It’s based on the atma sphere M60 amp but uses ecc88 in the differential cascode and individual cathode follower DC coupled for each output tube.
I run the cascode at 2.5mA per side and the tail is also a tube based cascoded ccs.
Input stage cascode loads are 100k 0.1% precision wirewound resistors.
No, on the 6SN7.
If you have a differential cascode with a 6SN7 acting as a cascode CCS, you have cathodes at a wide variety of voltages.
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I haven’t done anything as of yet. No issues thus far.
All filaments are suppled by a SMPS.
I could add a separate supply for the 12SN7GTA’s and elevate it.
All filaments are suppled by a SMPS.
I could add a separate supply for the 12SN7GTA’s and elevate it.
I think you'd need 2 or 3 separate heater supplies for the drivers to keep the heater cathode voltages reasonable.
Yes you are right. I'm trying to decide on the best solution.
Properly done it should reduce the noise floor a little?
Thank you for the heads up. Will let you know what I come up with.
Thanks again
It will reduce the noise floor significantly and prevent damage from occurring to your driver tubes. If you hear a noise that's more of a sizzle than a power supply noise, that's your heather cathode insulation begging for mercy.
Aitos is a small company out of the Netherlands that has been making otl for a while. I have heard there 801 80 watt otl monoblocks with 4 large tv top cap output tubes I would love to build some but I can’t find a schematic or even figure out what the power tubes are. The 6ej7 and 6ef7 are listed as replacements for some of there products but I think they are the preamp tubes. Can anyone help me ID the power tubes or have any input about these otl amps?
Here’s some details in a YouTube video
YouTube
Here’s some details in a YouTube video
YouTube
The EV801 uses PL519. Max (average) cathode current is 500mA, so you could get some decent power in class A. Peak cathode current is listed at 1.5A, you could have some real fun with these...
You can read the type number on the tubes in the video. They are PL519's. That's similar to the US type 40KG6.
Wow that is a monster! 3x6AS7 and you have 7.5A as well, but only 75W plate dissipation. And you will not find all 6 triode parts in 3 6AS7s very well matched. The slightly higher mu is also helpful.