Sure, you could do that. They all have different input impedances and different output impedances, so as you change sources and change loads, there's a chance you might notice some sonic differences among the various boards.
I don't need more than x1 voltage gain and I was think of how Tucson with OPA604 would sound if it had an easier load than Edcor. I had also the Pass B1 buffer in mind but then I thought about the Ishikawa input boards…..why not use them….and make a generic 4-bolt interface for these input boards?
Something to do after the few projects already in pipeline 🙂
Something to do after the few projects already in pipeline 🙂
Slightly to my surprise and relief my M2x is playing happily (with the Austin boards) and sounding sweet already. I'll give it a week or two before trying the alternatives.
In the meantime, many thanks to Nelson and everyone else who helped make it possible.
Edit - The mains toroid is vertically mounted and has a metal cover. Hum from my Frugalhorns is negligible and I've yet to add any shielding to the auto-transformers.
In the meantime, many thanks to Nelson and everyone else who helped make it possible.
Edit - The mains toroid is vertically mounted and has a metal cover. Hum from my Frugalhorns is negligible and I've yet to add any shielding to the auto-transformers.
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Dumb question:
Is M2 suited for bridging to balanced monoblocks?
If so, is it safe to load it with 4ohm drivers?
I know bridging means the amp sees half the load (so 8ohm looks like 4ohm), so i want to make sure that this would still be a safe configuration. M2 manual generally states that it can handle <4ohm, but really doesn't recommend it (understandable).
I've read through MEPER's posts, and it looks like his approach was mono with individual PSUs, rather than bridged to balanced mono.
Thanks!
Is M2 suited for bridging to balanced monoblocks?
If so, is it safe to load it with 4ohm drivers?
I know bridging means the amp sees half the load (so 8ohm looks like 4ohm), so i want to make sure that this would still be a safe configuration. M2 manual generally states that it can handle <4ohm, but really doesn't recommend it (understandable).
I've read through MEPER's posts, and it looks like his approach was mono with individual PSUs, rather than bridged to balanced mono.
Thanks!
Yes, I just built M2X mono blocks in large chassis to be able to build a CRCLC PSU for each and have the transformer as far as way from Edcor as possible.
Bridged amps will double the output impedance of the amp and I don't think that is a good solution for driving load impedance speakers. For low impedance speakers you don't need higher voltage but more current?
If your speakers was 16 ohm if would make more sense to bridge amps?
Bridged amps will double the output impedance of the amp and I don't think that is a good solution for driving load impedance speakers. For low impedance speakers you don't need higher voltage but more current?
If your speakers was 16 ohm if would make more sense to bridge amps?
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Thanks for confirming my suspicion MEPER!
As a follow up: how about operating an M2 in SE parallel?
If I understand correctly (I may not, so please correct me!), if the correct ultra low ohm series resistors (i think < .2ohm? for 4ohm load) are added to output and DC offset is extremely low, this would result in more current output and less voltage output via PPP configuration?
I would think this would be a better fit for low impedance & low-efficiency/current hungry speakers?
Thanks again for your input!
As a follow up: how about operating an M2 in SE parallel?
If I understand correctly (I may not, so please correct me!), if the correct ultra low ohm series resistors (i think < .2ohm? for 4ohm load) are added to output and DC offset is extremely low, this would result in more current output and less voltage output via PPP configuration?
I would think this would be a better fit for low impedance & low-efficiency/current hungry speakers?
Thanks again for your input!
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I would try out a standard M2X first and see how it behaves driving your speakes or maybe consider a F5/F5 turbo. I think this amp is the best FW amp for driving low impedance speakers.
Maybe if you mention which speakers you have some of the experts may indicate which FW amp fits your speakers and if M2X would be a good choice.
Maybe if you mention which speakers you have some of the experts may indicate which FW amp fits your speakers and if M2X would be a good choice.
Thanks MEPER.
So, I currently have an M2X almost done, and the parts to build a second one. I'm gonna finish it in the next week or two as time permits. I currently have some HSU horn speakers that I've been driving with a diy16w tube amp (w/ OPTs) that works pretty well.
My plan is to give the tube amp and horns to my father as a gift, and replace the setup with M2s and some new speakers.
I'm still looking around at different speakers, but i'm quite intrigued by the new Magenpan LRS. I've been a big fan of planar headphones, and currently have STAX and diy amps paired with them, and i simply love the planar and estat sound. I'm probably gonna go demo the LRS and 1.7 at a local dealer in the next month or so to see how I like them.
Maggies seem to be lower efficiency and 4ohms. Currently talking to a local dealer about his experiences with amp synergy and waiting to hear back on some questions I have out to him. I've read lots of conflicting things about amp pairing with Maggies, and I'm sure there's still no truly good recommendations for the LRS yet since it's so new...
My 'preamp' is a balanced autoformer volume attenuator from intact audio. Upstream are all fully balanced sources.
I'm not completely married to M2X if I decide I want to go the Maggies route. I could always sell them once they're done and build something else. I just generally like the philosophy of the autoformer voltage gain stage and the lack of feedback in the design. I'm open to trying other amps, I've just been wanting to build the M2X for awhile, so when it came back in stock I snatched up a pair of boards right away!
Thanks in advance for everyone's guidance!
So, I currently have an M2X almost done, and the parts to build a second one. I'm gonna finish it in the next week or two as time permits. I currently have some HSU horn speakers that I've been driving with a diy16w tube amp (w/ OPTs) that works pretty well.
My plan is to give the tube amp and horns to my father as a gift, and replace the setup with M2s and some new speakers.
I'm still looking around at different speakers, but i'm quite intrigued by the new Magenpan LRS. I've been a big fan of planar headphones, and currently have STAX and diy amps paired with them, and i simply love the planar and estat sound. I'm probably gonna go demo the LRS and 1.7 at a local dealer in the next month or so to see how I like them.
Maggies seem to be lower efficiency and 4ohms. Currently talking to a local dealer about his experiences with amp synergy and waiting to hear back on some questions I have out to him. I've read lots of conflicting things about amp pairing with Maggies, and I'm sure there's still no truly good recommendations for the LRS yet since it's so new...
My 'preamp' is a balanced autoformer volume attenuator from intact audio. Upstream are all fully balanced sources.
I'm not completely married to M2X if I decide I want to go the Maggies route. I could always sell them once they're done and build something else. I just generally like the philosophy of the autoformer voltage gain stage and the lack of feedback in the design. I'm open to trying other amps, I've just been wanting to build the M2X for awhile, so when it came back in stock I snatched up a pair of boards right away!
Thanks in advance for everyone's guidance!
No questions are dumb if it keeps the magic smoke inside 😀
You just need more current for maggies, why not graft on some BA2 output boards (minus the BA2 bias board) 😉
Or if you are FAB, have a look at the Beast Builders thread F4 Beast Builders
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So the BA2 output board is a type of universal push-pull board for paralleling output devices? This may make my 2020 resolutions much easier to keep.😉
input impedance M2X amp
Hi, I am new to this forum. This is the very first time I build this amplifier. Can anyone tell me what the input impedance of the M2X ampfier is?
Thanks
Hi, I am new to this forum. This is the very first time I build this amplifier. Can anyone tell me what the input impedance of the M2X ampfier is?
Thanks
You can almost decide your self but schematic shows a 100k input resistor to unity gain buffer so approx. 100k input impedance.
Thanks Meper, I thought this was a dumb question but I am not a technicion. I have never build an amplifier befor...
So I tested the output of the power supply on my M2X and this is what I got:
No Load
Loaded with M2X boards
So the hum I'm hearing at the speakers is basically the ~300mV of ripple I'm seeing on the scope? I have 40K uF per rail...how much does that need to be increased to eliminate the ripple?
No Load
Loaded with M2X boards
So the hum I'm hearing at the speakers is basically the ~300mV of ripple I'm seeing on the scope? I have 40K uF per rail...how much does that need to be increased to eliminate the ripple?
Are you hearing ripple or ground loop? Or is it something induced from the power transformer to the signal transformers?
Could be any/all of those.
Could be any/all of those.
Put the power trafo away, maybe a meter, and see what happens.
If no change try a Cap Mx for both positive and negative rails.
If no change try a Cap Mx for both positive and negative rails.
To have something to compare with I have attached one channel M2X measurement. It was with 4W output. I have no audible hum or hiss. My 50 Hz is about 100 dB down and noise floor about 120 dB down. It is with shielded Edcor and toroid and using CRCLC supply.
Attachments
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