I have a rescued Yamaha M4 power transformer that has three secondaries: 62, 45, and 15 volts. The Yamaha circuit shows that the 62 volt secondaries were rectified to +/-80 volts. Is there a good amp design out there that I can cobble together so I can reuse this transformer? I've looked, and it seems that voltage is a bit high for most designs, and way too high for class A (my preference). A good class AB design would be nice. 50-100 wpc or so . . .
Thanks!
Thanks!
Hi,
Yes. The 45-0-45 taps are the high current amplifier taps.
The 15V is fused at 1A and the 62V fused at 0.5A per rail.
I'd surmise the 80V rails are for the driver stage of a MOSFET
output stage *, allowing the unity gain output devices to get near
the main 63V rails under heavy current (and thus high [>10V]
voltage drive) conditions. I'm no MOSFET expert or fan,
take at look at Cordell probably for suitable circuits.
I'd surmise here also the single 15V derived voltage rail is for
driving the logic circuits, switching, protection, metering, etc.
rgds, sreten.
* Probably used for the input stage as well.
Yes. The 45-0-45 taps are the high current amplifier taps.
The 15V is fused at 1A and the 62V fused at 0.5A per rail.
I'd surmise the 80V rails are for the driver stage of a MOSFET
output stage *, allowing the unity gain output devices to get near
the main 63V rails under heavy current (and thus high [>10V]
voltage drive) conditions. I'm no MOSFET expert or fan,
take at look at Cordell probably for suitable circuits.
I'd surmise here also the single 15V derived voltage rail is for
driving the logic circuits, switching, protection, metering, etc.
rgds, sreten.
* Probably used for the input stage as well.
Last edited:
Here is a 150WRMS lateral mosfet amplifier.
An externally hosted image should be here but it was not working when we last tested it.
Thanks, Nigel. I assume that it's the design for the "classic" Maplin? It's okay to go with 63V electrolytics? I would have expected most builders would err on the side of 80V caps, though I imagine the 63V caps are designed for . . . 63V rails.
I'll take it into consideration, along with the ESP P101.
I'll take it into consideration, along with the ESP P101.
you might want to try one of OPC's LME49830 with lateral mosfets.
the thread is here, and many have been built. You can bias the outputs at 1 amp or more depending on the rails voltage and heatsink size. OPC gives plots for different bias currents etc. I have built a stereo vesion and have had good results and I am very satisfied with the performance.
http://www.diyaudio.com/forums/soli...amplifier-based-lme49830-lateral-mosfets.html
the thread is here, and many have been built. You can bias the outputs at 1 amp or more depending on the rails voltage and heatsink size. OPC gives plots for different bias currents etc. I have built a stereo vesion and have had good results and I am very satisfied with the performance.
http://www.diyaudio.com/forums/soli...amplifier-based-lme49830-lateral-mosfets.html
I was attempting to answer Multisync and lost my long reply due to an "expired token" while tapping on the damn iPad. Oh well. Essentially I was enthusiastically affirming that The Wire Amp looked like a great project for my needs.
Then I saw Andrew's response. Hmm. Perhaps I'll take the more expensive and surer route: Aleph J with hardware from the diyaudio.com store. I would love to build something more "scratch built," but yeah, I'm not ready for that yet. I sort of know my limitations.
Lots to learn, lots to spend.
Then I saw Andrew's response. Hmm. Perhaps I'll take the more expensive and surer route: Aleph J with hardware from the diyaudio.com store. I would love to build something more "scratch built," but yeah, I'm not ready for that yet. I sort of know my limitations.
Lots to learn, lots to spend.
if you have read a litle more then the headline in the first post, you would see that it is 45Vac transformer. not 62Vac.
that said. the DIY honey badger is good candidate for this transformer. if it can deliver the current. does it say on the transformer ho much current the 45Vac taps deliver?
Last edited:
The Honeybadger is likely a good choice for this transformer. It likely won't have huge current available so an AB amp is likely a good choice.
I've searched high and low for more information on this PT, but to no avail. It weighs 7.5 kg and has ~1 mm diameter wires for the 45V taps (and noticeably smaller diameter wires for the 62V taps).
The only thing printed on the transformer is:
GA-6169
0
111H002
JK05b SMD
0
111H002
JK05b SMD
Researching HoneyBadger now. I'm wondering if I'm better off just using this damn thing as a paperweight. I just hate letting all that copper and iron go to waste.
Again, all of your help has been much appreciated.
The Yamaha would have likely been an AB amplifier. They aren't known to have overly robust power supplies but if you build an amplifier around the same power range at 8 ohms it should work out. If the finished product makes it into a chassis, it might be a good idea to leave some space to upgrade the transformer later if you find it's not up to the task.
M4 trafo is at least 500VA - one of the bigger EI old-school trafo's out there.
It would run a pair of Badgers well , you could even regulate that higher voltage
secondary down with some buffered zener shunt regulators.
I ran the original Badger prototype on a Nikko with 45 and 60V secondaries.
Made a CRC with the higher secondary , regulated to 68V .... ran the
input stage with it.
Badger board's onboard CRC is where you would attach the second supply.
PS - M4 was 120W/ch .... Badger might be about the same with this trafo.
OS
there is way too many variables.
main voltage
at wich load and main voltage are the transformer sec voltage testet
transformer regulation
singel or dual rectifier
LC filter, CRC or CLC filter
amp operation (class D,H,A/B,A)
++++++
Hi,
The M4 is a seriously chunky amplifier and unsurprisingly
the traffo would suit a seriously chunky Class AB Mosfet
amplifier, around 150W per channel, with big heatsinks
and at least 4, probably 6 output devices per channel.
Now.... someone would dearly like to to get their hands
on such a transformer for such an endeavour. If its not
your cup of tea, swap it it or trade it for somethings or
things more up your street.
And build :
Death of Zen - A new Class-A power amp
Minimalist Discrete Hi-Fi Preamp
rgds, sreten.
The M4 is a seriously chunky amplifier and unsurprisingly
the traffo would suit a seriously chunky Class AB Mosfet
amplifier, around 150W per channel, with big heatsinks
and at least 4, probably 6 output devices per channel.
Now.... someone would dearly like to to get their hands
on such a transformer for such an endeavour. If its not
your cup of tea, swap it it or trade it for somethings or
things more up your street.
And build :
Death of Zen - A new Class-A power amp
Minimalist Discrete Hi-Fi Preamp
rgds, sreten.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.