This thread will be about my DIY version of the Atma-Sphere M60 MK3.1 OTL Music Amplifiers original designed by Ralph Karsten.
I ended up with this chassis design:
I redesigned the high voltage PSU for the signal tubes as I wanted polypropylene caps after the chokes. I use the mini e-chokes MEC50 from Tentlabs as I had great success using them in other projects.
PCB for the high voltage PSU for the signal tubes ended up to look like this:
and with most of the parts mounted:
As I wanted potted toroidal transformers for my amps I designed a round PCB for the capacitance for the circlotron output stages which will be placed under the center transformer cover:
The parts for the chassis is custom made to my specs by HiFi2000 in Italy, here the top panel:
and part of the front panel housing a Yamamoto Vu Meter:
More pictures to come along the building process.
I ended up with this chassis design:
I redesigned the high voltage PSU for the signal tubes as I wanted polypropylene caps after the chokes. I use the mini e-chokes MEC50 from Tentlabs as I had great success using them in other projects.
PCB for the high voltage PSU for the signal tubes ended up to look like this:
and with most of the parts mounted:
As I wanted potted toroidal transformers for my amps I designed a round PCB for the capacitance for the circlotron output stages which will be placed under the center transformer cover:
The parts for the chassis is custom made to my specs by HiFi2000 in Italy, here the top panel:
and part of the front panel housing a Yamamoto Vu Meter:
More pictures to come along the building process.
Last edited:
No spare PCBs and no plans to get more made, sorry.
I highly recommend to buy a kit from Ralph and get the job done and listen to music! Oh boy these OTL amps are the real deal!
These plays great but whether they are better or worse than the original M60 I can't tell as I don't have access to the orignal M60s...
But I wanted polypropylene capacitors after the chokes and the e chokes ensure absolutely silence from these amps. Zero hum, zero noise. My speakers are 102dB/1W.
I implemented electronic e chokes in both the positive and the negative supply for the signal tubes. If the e choke in the negative supply dies the 6AS7s and my speaker will melt down... risky business! Or one can use a resistor instead of a choke in the negative supply.
I really recommend everyone to build the exact circuit designed by Ralph. It's safe(!) and properly also better than my version...!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.