The Austin input stage is especially designed to appeal to the GreedyBoi aficionados of Pass Labs discussion threads.
First of all, Austin anticipates rampant substitution or optimization of individual components: all possible pinouts of TO92 transistors (and E-Line transistors) work equally well in the board layout; their footprints are intentionally symmetric.
Second, GreedyBois and their simulators will (I suspect!) quickly discover which parts to finagle and which parts to futz with, to allow themselves to eliminate Austin's output capacitor. I'm confident the GreedyBoi modification will turn out to be difficult, requiring lots of painstaking care. Perfect for masochists!
Third, there's a lot of components on the board, providing a lot of opportunities to make a soldering error. GreedyBois just love do-overs and revisions.
I added the following paragraph to post #1 at the top of this thread:
My poor quality photograph is below; I'm sure 6L6 will snap at least one very very good photo of an Austin, when he receives my shipment. edit- if you look closely you can see in my photo that Q5 and Q6 are Zetex transistors in the slender E-Line package. All others are TO92.
The good news is: when you build a couple of Austin boards and bolt them into your M2x amplifier, I think you'll be very pleased with the results.
_
First of all, Austin anticipates rampant substitution or optimization of individual components: all possible pinouts of TO92 transistors (and E-Line transistors) work equally well in the board layout; their footprints are intentionally symmetric.
Second, GreedyBois and their simulators will (I suspect!) quickly discover which parts to finagle and which parts to futz with, to allow themselves to eliminate Austin's output capacitor. I'm confident the GreedyBoi modification will turn out to be difficult, requiring lots of painstaking care. Perfect for masochists!
Third, there's a lot of components on the board, providing a lot of opportunities to make a soldering error. GreedyBois just love do-overs and revisions.
I added the following paragraph to post #1 at the top of this thread:
AUSTIN is a thru-hole board with 4X more components than the other boards; its resistors are mounted vertically to save PCB area. This permits a Diamond Buffer circuit with high performance, precision current source loads. Builders who love parts substitutions / optimizations will appreciate that Austin's PCB silkscreen doesn't indicate transistor orientation. Instead, transistor pins are labeled B, C, E in a perfect circle; allowing you to drop in Japanese 2SA/2SC transistors (pinout ECB) or European BC transistors (pinout CBE) or American 2N transistors (pinout EBC) however you please. Austin is recommended ONLY for experienced builders. If you're a newbie, hire someone to solder your Austin board!!
Compared to the other M2x daughter cards, Austin is kinda busy. That's not to say you can't successfully solder it yourself. You can. I did. But it's not especially easy and you need to go very very slowly, check and double check before each component.My poor quality photograph is below; I'm sure 6L6 will snap at least one very very good photo of an Austin, when he receives my shipment. edit- if you look closely you can see in my photo that Q5 and Q6 are Zetex transistors in the slender E-Line package. All others are TO92.
The good news is: when you build a couple of Austin boards and bolt them into your M2x amplifier, I think you'll be very pleased with the results.
_
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that's Sissy busy ........ piece of cake 
DB can sound very good ..... for now I have it as (penultimate) iteration of buffer in my Iron
, soon to be effectively replaced ........ not so because of sound , as much because of search for even better TempCo (no caps in signal path) and less mechanical work involved
DB can sound very good ..... for now I have it as (penultimate) iteration of buffer in my Iron
, soon to be effectively replaced ........ not so because of sound , as much because of search for even better TempCo (no caps in signal path) and less mechanical work involved
The build guides are moving to the new Dozuki powered platform here;
diyAudio Guides - diyAudio Guides
Take a look a the new ACA --
Amp Camp Amp Build Guide - diyAudio Guides
And also the Whammy --
WHAMMY headphone amplifier - diyAudio Guides
Anyway, the M2x guide will be there when it goes live. In the time being here's a bunch of photos that will be incorporated into that guide, and if you don't want to wait, get the PCBs from Mark now and dive right in! This is a straightforward build and there's no hangups or gotchas that I've found. The boards are very well laid out and I'm sure the biggest difference between the initial run and the production run will be something as trivial as the color of the PCB.
Let's start seeing some amps!
There is a left and a right board, so that the signal transformer can be mounted away from the power transformer.
Optocoupler alignment
Daughtercard standoff assembly
No star washer on the bottom
Star washer under the standoff/spacer to make it solid.
Star on top of spacer
You can see the keyed corner of the daughter is marked, as is the corner of the mainboard
Star under the nut for security. You can also loctite or add heatshrink to further secure the assembly
Main board fully stuffed (except Mosfets)
Test one amp channel at a time! If you made a big mistake you might be lucky enough to find it on the first and correct it on the second. The PSU wires are individually taped off so there are no shorts.
diyAudio Guides - diyAudio Guides
Take a look a the new ACA --
Amp Camp Amp Build Guide - diyAudio Guides
And also the Whammy --
WHAMMY headphone amplifier - diyAudio Guides
Anyway, the M2x guide will be there when it goes live. In the time being here's a bunch of photos that will be incorporated into that guide, and if you don't want to wait, get the PCBs from Mark now and dive right in! This is a straightforward build and there's no hangups or gotchas that I've found. The boards are very well laid out and I'm sure the biggest difference between the initial run and the production run will be something as trivial as the color of the PCB.
Let's start seeing some amps!
There is a left and a right board, so that the signal transformer can be mounted away from the power transformer.
Optocoupler alignment
Daughtercard standoff assembly
No star washer on the bottom
Star washer under the standoff/spacer to make it solid.
Star on top of spacer
You can see the keyed corner of the daughter is marked, as is the corner of the mainboard
Star under the nut for security. You can also loctite or add heatshrink to further secure the assembly
Main board fully stuffed (except Mosfets)
Test one amp channel at a time! If you made a big mistake you might be lucky enough to find it on the first and correct it on the second. The PSU wires are individually taped off so there are no shorts.
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If 13V is safe and 16V is safer then 50V is a whole lot safer. If you're scared, you could always solder a 1N5247B across the capacitor on the bottomside of the board.
I certainly don't mind spending your money on a capacitor with tremendous excess amounts of safety margin. Not when I know you're probably going to bypass the $3.00 electrolytic cap with an $8.00 (or is it $80.00?) film capacitor.
I certainly don't mind spending your money on a capacitor with tremendous excess amounts of safety margin. Not when I know you're probably going to bypass the $3.00 electrolytic cap with an $8.00 (or is it $80.00?) film capacitor.
Only four M2x board sets remain
I have received Private Messages saying "yes I'll buy an M2x board set for $40 (domestic) / $50 (international)" from 26 members. Their user names are:
I've only got a total of 30 board sets and when they're gone, they're gone.
Please read post # 89 for additional details.
Thanks,
Mark Johnson
I have received Private Messages saying "yes I'll buy an M2x board set for $40 (domestic) / $50 (international)" from 26 members. Their user names are:
mgmoore, kbergsson, jwjarch, vvs07(qty.2), wcwc, woofertester, redarc12, res07njc, Blk Dynamite, 1543, bk856er, TIC37, Joca, flocchini, JSA1971, manniraj, Stanislav, RKH, Johnny Canuck, jims, Loafimus, nycavsr2000, cosmo61, Russellc, mediumroast
Please take a moment to see if your name is here when it shouldn't be, or if it's NOT here when it should be. Send me a PM with any corrections.I've only got a total of 30 board sets and when they're gone, they're gone.
Please read post # 89 for additional details.
Thanks,
Mark Johnson
Mark
Fantastic job
Looking forward to experimenting
Currently enjoying my M2 with Toshiba 1530/201s.
Best
Bob
Why the toshibas? i have some on hold for an amp
29 board sets have been requested, only one set remains unsold.
This weekend I will send Private Messages with payment instructions. Buyers will please reply with their Ship-To address, formatted as appropriate for your country's postal service. Please include your local phone number, I need it for the US Customs declaration form.
This weekend I will send Private Messages with payment instructions. Buyers will please reply with their Ship-To address, formatted as appropriate for your country's postal service. Please include your local phone number, I need it for the US Customs declaration form.
SOLD OUT SOLD OUT ALL 30 BOARD SETS HAVE BEEN CLAIMED
I will send PMs to the buyers over the weekend, containing payment information and requesting your ship-to address & your local phone number (needed for the US Customs form).
For optimistic latecomers: I suppose it's possible that someone might cancel their purchase, or otherwise nullify the transaction. Why they would do so, I have no idea, but it might happen. If so I'll contact the person on top of the waiting list and ask whether they want to buy an M2x board set.
As of right this minute (9:22AM in San Francisco on Friday 11 May) there are zero names on the waiting list. Wanna join the waiting list? Send me a PM. Just don't get your hopes up too high.
I will send PMs to the buyers over the weekend, containing payment information and requesting your ship-to address & your local phone number (needed for the US Customs form).
For optimistic latecomers: I suppose it's possible that someone might cancel their purchase, or otherwise nullify the transaction. Why they would do so, I have no idea, but it might happen. If so I'll contact the person on top of the waiting list and ask whether they want to buy an M2x board set.
As of right this minute (9:22AM in San Francisco on Friday 11 May) there are zero names on the waiting list. Wanna join the waiting list? Send me a PM. Just don't get your hopes up too high.
Bob - The next run of boards will be in the diyAudio store. It was just a happy accident that Mark had as many extra as he did.
Things (sadly) always take much longer at this stage than we'd line to wait, but the PCB will be in the store in the not-too-distant future. I'll have the guide done my then and maybe even a cool PCB that will hold the big bridges, thermistors and all 8 wires of the transformer. There's a lot happening in the store and a lot of awesome projects all cooking at the same time - this is a great time to be into DIY!!
Things (sadly) always take much longer at this stage than we'd line to wait, but the PCB will be in the store in the not-too-distant future. I'll have the guide done my then and maybe even a cool PCB that will hold the big bridges, thermistors and all 8 wires of the transformer. There's a lot happening in the store and a lot of awesome projects all cooking at the same time - this is a great time to be into DIY!!
Perhaps? I'm fine with the idea, and we've done similar before with the F6 packaged with the Jensen transformers.
Having a parts kit would be fairly straightforward for this project. (Although having a parts kit that populated ALL of the input stages would be a complicated endeavor for sure... ) The Edcor transformers have a long lead time when ordering since they make everything to order... Once the PCB are made and available we can look into parts offerings. My gut says that yes, something like that will happen.
Having a parts kit would be fairly straightforward for this project. (Although having a parts kit that populated ALL of the input stages would be a complicated endeavor for sure...
) The Edcor transformers have a long lead time when ordering since they make everything to order... Once the PCB are made and available we can look into parts offerings. My gut says that yes, something like that will happen.
LOTS of amazing notes on this project added to posts #3 and #4 -
http://www.diyaudio.com/forums/pass-labs/321925-diyaudio-watt-m2x.html#post5416402
http://www.diyaudio.com/forums/pass-labs/321925-diyaudio-watt-m2x.html#post5416402