Replacement edcor is good! I've got the ishikawas in and the amp is ready to relocate upstairs. I did the voltage tweak - both channels are in the single-digit mv range. I can't get it any better - even the slightest move and its going negative.
I have the ishikawa, tucson and mountain view tested / known working. I tried to assemble the austin - fried 2 bjts so I need to order replacement parts. The Norwood I twitched and knocked 2 of the ICs ( separate incidents ;( ) and can't find them. For now I'm just going to play with what I have. I'll get the other stuff ordered eventually!
Thanks for the help all. Time to just listen to this amp for a while! First input stage to listen to will be the ishikawa - just because no other reason. I was tossing around all 3 and just picked ishikawa.
I have the ishikawa, tucson and mountain view tested / known working. I tried to assemble the austin - fried 2 bjts so I need to order replacement parts. The Norwood I twitched and knocked 2 of the ICs ( separate incidents ;( ) and can't find them. For now I'm just going to play with what I have. I'll get the other stuff ordered eventually!
Thanks for the help all. Time to just listen to this amp for a while! First input stage to listen to will be the ishikawa - just because no other reason. I was tossing around all 3 and just picked ishikawa.
Awesome! Enjoy the great tunes.
Each module has its own character. Enjoy listening to each of them.
Carl
Each module has its own character. Enjoy listening to each of them.
Carl
Glad you are back up and listening! Enjoy the Ishikawa, but you should try Milpitas - it is shockingly good and simple to build, IMO.
Tuesday the board and parts arrive 😉
So that i can avoid frying input stage boards in the future how does one go about testing one without going direct to the amp board?
I have a bench supply and can set voltage and current but iirc you need positive negative and ground right?
Is there a way to use this kind of supply to test the board with limited current and hopefully avoid frying things?
I have a bench supply and can set voltage and current but iirc you need positive negative and ground right?
Is there a way to use this kind of supply to test the board with limited current and hopefully avoid frying things?
I built myself an input-board test bench (requires an extra amp board). Only a couple of input resistors are required and a load resistor. The green power resistors sits there as load (1k) just so the input board output stage has a bit of load. The RCA in/out for easy interfacing. For power the usual connector are used.
Both my M2X boards are now out of the chassis (mono blocks) as I reuse chassis / PSU for my ZM F8 build 🙂
Such an input board test bench can be built "from scratch" using these "DIY solder boards".
Edit: for limited current use a lab-PSU that has current limiter.
Both my M2X boards are now out of the chassis (mono blocks) as I reuse chassis / PSU for my ZM F8 build 🙂
Such an input board test bench can be built "from scratch" using these "DIY solder boards".
Edit: for limited current use a lab-PSU that has current limiter.
Attachments
How are you powering it though just using the power supply from the amp?
Do i just take the plus and minus and connect to vpos and vneg of the board? Where do i get ground?
Do i just take the plus and minus and connect to vpos and vneg of the board? Where do i get ground?
I used a lab supply that has dual supply. Then it can be connected as a symmetrical supply by serial connecting the two supplies. It is like serial connecting two batteries. Then the "center-point" is defined as Gnd and you have V+ and V- relative to the Gnd-definition.
I just connected Gnd to Gnd-terminal and V+ to Vpos and V- to Vneg terminals indicated at the amp-board.
I just connected Gnd to Gnd-terminal and V+ to Vpos and V- to Vneg terminals indicated at the amp-board.
An idea I was talking to @birdbox about.
Is it possible to switch between all the IPS’s? Either by some sort of switch or design a board to be able to do it? I haven’t seen it much in this thread from what I can remember.
Would be fun to swap between the IPS’s for A/B listening.
Is it possible to switch between all the IPS’s? Either by some sort of switch or design a board to be able to do it? I haven’t seen it much in this thread from what I can remember.
Would be fun to swap between the IPS’s for A/B listening.
“Switch” as in, “on the fly”? Yes, why not?
There’s no reason it couldn’t be done. A lot of complexity would be required, however swapping the various stages in and out with the existing hardware wouldn’t be particularly onerous, and would require no modifications.
And when it’s all done you’re only going to listen to one of the stages, that is, whichever you find you like the best.
🙂
There’s no reason it couldn’t be done. A lot of complexity would be required, however swapping the various stages in and out with the existing hardware wouldn’t be particularly onerous, and would require no modifications.
And when it’s all done you’re only going to listen to one of the stages, that is, whichever you find you like the best.
🙂
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When @uptownsquash asked me about the idea, I "double dared" him to post the question as it sounds like a pretty sweet idea if it is possible. We just theorized how fun it would be to simply rotate a switch on the amp chassis to activate a different IPS board and have possibly all 9 IPS inside ready to go. Probably not so simple in reality (you likely want to power everything down first and let PSU discharge before switching), but the idea of quickly being able to switch between IPS boards without opening the amp and physically changing the boards was the point. Just a fun idea to float even if it's not practical in reality. This was uptownsquash's idea, so I can take no credit. Maybe someone much smarter than me could come up with a practical approach.
On my next M2x build I plan to ensure I leave adequate space to use a a standard screwdriver to access the 4 bolts on the amp board to remove/install the IPS. On my first M2x build, I didn't consider the "ease of swapping" and my tall PSU capacitors make accessing the lower two IPS board bolts a real challenge. I have to use those small L-shaped allen wrenches to finish tightening after I struggle to get the lower two bolts started by getting my fat fingers in there. I can't count how many times I dropped the bolts trying to get those lower two to start threading when I made the swap between IPS.
Lesson Learned: Anyone building the M2x should consider access to the 4 bolts that connect the IPS to the amp board when doing their layout so it's easy/quick/simple to swap IPS boards.
On my next M2x build I plan to ensure I leave adequate space to use a a standard screwdriver to access the 4 bolts on the amp board to remove/install the IPS. On my first M2x build, I didn't consider the "ease of swapping" and my tall PSU capacitors make accessing the lower two IPS board bolts a real challenge. I have to use those small L-shaped allen wrenches to finish tightening after I struggle to get the lower two bolts started by getting my fat fingers in there. I can't count how many times I dropped the bolts trying to get those lower two to start threading when I made the swap between IPS.
Lesson Learned: Anyone building the M2x should consider access to the 4 bolts that connect the IPS to the amp board when doing their layout so it's easy/quick/simple to swap IPS boards.
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Would a board that had the ability to mount a selection of IPS and select through them be cool? Absolutely!
Envisioning a motherboard (per channel) that has multiple places to mount IPS boards, a couple of relays per board and a switching scheme not dissimilar to the twister board from Iron Pre - there’s no reason it couldn’t be done. Then an umbilical to a card in the place of the ‘normal’ IPS and bob’s your uncle. I wonder how much it would click and pop on selection… but as the output stage of M2x is isolated through the transformer and biases itself, in theory it seems doable.
Envisioning a motherboard (per channel) that has multiple places to mount IPS boards, a couple of relays per board and a switching scheme not dissimilar to the twister board from Iron Pre - there’s no reason it couldn’t be done. Then an umbilical to a card in the place of the ‘normal’ IPS and bob’s your uncle. I wonder how much it would click and pop on selection… but as the output stage of M2x is isolated through the transformer and biases itself, in theory it seems doable.
I've found in my experience over the years that "ideas" are really easy to come up with. The real challenge is the other 99% of the effort required to turn that idea into reality. I fully admit I don't currently have the skills to even attempt it.
It would be a pretty sweet amplifier concept though for folks interested in comparing all the wonderful IPS circuits that Mark has generously given all of us to use. I'm certainly happy doing the physical swap of the IPS. In no way is this a request for someone to take on the challenge. Just a fun idea to float out to the community for some head scratching while falling asleep at night
It would be a pretty sweet amplifier concept though for folks interested in comparing all the wonderful IPS circuits that Mark has generously given all of us to use. I'm certainly happy doing the physical swap of the IPS. In no way is this a request for someone to take on the challenge. Just a fun idea to float out to the community for some head scratching while falling asleep at night
Hello uptownsquash and birdbox,
I have done this. Switchable inputboards for the M2X... my posts ## 1327, 1340, 4075 in this thread.
Works great.
Cheers
Dirk
I have done this. Switchable inputboards for the M2X... my posts ## 1327, 1340, 4075 in this thread.
Works great.
Cheers
Dirk
Well there ya go, @cubicincher gave this a go. Sounds like DC offset control would need to be moved off the M2x board and have a separate DC offset control for every single IPS board so each could be set individually (18 separate DC offset pots to cover all 9 IPS and two channels), otherwise you risk damaging speakers. All over my head. Still was fun to ponder the 'what ifs'.
To be honest the idea of switching input boards frequently is not that appealing - it’s just too tight to get in there. I can just not easily. I set it up such that i have nuts to twist into place instead of screws. Access to get in there and get the nuts into place without dropping - gotta be a contortionist 😉
I imagine I’m going to rotate boards after listening for a few weeks. I’ll take notes and then come back to the one i rated best or something.
Right not I’m just happy to have a working amplifier! It sounds freaking great! For sure some details i had not noticed with the aegir 2 i was using before. Nothing earth shattering just little stuff
It would be pretty awesome if there was a way to mount the input cards without needing tools though. Some kind of socket that you can just plug in. I saw a post talking about that kind if thing earlier in the thread
I imagine I’m going to rotate boards after listening for a few weeks. I’ll take notes and then come back to the one i rated best or something.
Right not I’m just happy to have a working amplifier! It sounds freaking great! For sure some details i had not noticed with the aegir 2 i was using before. Nothing earth shattering just little stuff
It would be pretty awesome if there was a way to mount the input cards without needing tools though. Some kind of socket that you can just plug in. I saw a post talking about that kind if thing earlier in the thread
There are a number of ways.
A specific model of male/female connector is mentioned quite often throughout the thread. At least one person went so far as to recommend a mounting procedure to ensure the pins are aligned. If you did not find it, search for "D-SUB" or similar.
What if... A person didn't think coupling caps were such a horrible thing and that any 'potential' sonic deterioration may be outweighed by the convenience of the footloose and fancy free fun of flipping a switch between input stages?
Separately, but related - What if a person's purpose for the switching might not be "permanent"? What if they were space limited, and they may not want to have (let's say 8 to 10) input stages immediately switchable? What if they wanted an easy way to switch between a few (let's say up to 4) of them quickly for forced ranking? What if they further assumed that even if there were a "coupling cap effect", that it would be equally beneficial or detrimental with all input stages and therefore be immaterial to a forced-rank comparison? What if once the IPSs were force ranked that (if desired) additional parts and wiring could be removed to ensure the sonic splendor of the original circuit was maintained?
Like this
Male: https://www.mouser.com/ProductDetail/Amphenol-CONEC/131A12049X?qs=4bORziRYUpSFIEnbnKcFzg==
Female: https://www.mouser.com/ProductDetail/Amphenol-CONEC/132C12049X?qs=orEPegL0vw%2B623QTfEdrvw==
There are other equivalents that are cheaper but come from overseas as I recall so you pay shipping. Search posts under pfarrell in this thread, we did discuss this years ago. Wait…found it. The next time you see/meet pfarrell give him a hug. And hug MJ as well since all this M2X talk wouldn’t be possible without his foresight and engineering prowess.
FWIW, whenever I have the M2X running, I am usually listening to it on a longterm basis to make an assessment about the current IPS as such my top cover is either off or just placed there (i.e. without the screws). Switching an IPS is easy with the D-sub contacts.
This is somewhat similar to fellas who do opamp switching in their gear (which is also available in M2X!). I see them always switching off their “test” gear first (i.e. dac typically or preamp), doing the switch, turning the unit back on and then listening again. With the M2X using D-sub contacts you can do this in 1-2 minutes and the heatsinks barely cool down. Bias is up within a few minutes and you are back to roll after your bathroom/coffee break.
I test my input boards with this: https://www.etsy.com/listing/1033151079/m2xyarra-format-breakout-test-board?click_key=74bf430a07adceb02ff11fc965234e5738291f53:1033151079&click_sum=c9e5121f&ref=shop_home_active_16&pro=1
Plug it into my bench supply and then run the tests I want to run on my scope. I do this with EVERY new IPS board. It ensures that I don’t plug a lemon IPS board into my M2X.
It also helps with perfectly aligning the male D sub connectors on new IPS board builds, provided you build the test breakout board properly with female D sub connectors.
Best,
Anand.
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