Yea it defaults to Fedx. You'll have to request USPS for the cheaper rate I believe. I think mine was $18 to Texas
The linear parts I can't find, but both punkydogs and Spencer have plenty of the Toshiba parts, and I believe there is a genuine source in Israel who did have as well. I have built up a good stash. Maybe I will try Tucson based on 6l6's statement, it may be a while, other projects are in line...
.. need chassis, power supply etc. Not willing to sacrifice current M2!
Russellc
A very rough calculation:
Each of the output MOSFETs needs about 4.5 to 5.0 volts from gate to source, to drive an 8 ohm load to full rated power. Figure another 0.75 volts dropped across the source resistor R13.
So the output swing is 5.25 to 5.75 volts less than the rail voltage, call it 5.5.
Using 19 volt supply rails, power delivered into 8.0 ohms is [(19-5.5)/sqrt(2)]^2 / 8.0 = 11.4 watts. Very roughly.
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I haven't tried that myself; I don't even own an F5t or a BA gain stage.
It'd be surprising if the mounting holes for M2x daughter cards (see drawing in post #56) happened to perfectly line up with convenient mounting posts in another PCB design. So I expect you'd probably need to DIY some kind of mounting arrangement. You'd also need to create electrically & mechanically solid connections to the four required signals (IN, +25VDC, OUT, -25VDC).
Equally important, you'd need to verify that the electronic interfaces of the mother and daughter are compatible, especially the supply voltages and whether or not they need input- or output-coupling capacitors. You could check this yourself, or in collaboration with the F5t & BA gain stage builder community.
Probably the safest route to a completely successful result on the first try, is to use the M2x daughter cards as a starting point for your own design of an outrigger board for F5t or BA gain stage. Take off the chassis lid and get inside the box with your calipers. Measure how much room there is for a new pair of cards. Measure where the I/O connectors should go. Find and measure the places where it's most convenient (least inconvenient?) to make mechanical attachment.
Then lay out your own custom PCB of exactly those dimensions, with exactly those mechanical mounts, and exactly those I/O terminal positions. Drop the Tucson (or Austin, or ...) circuit inside, run the AutoRouter, make it all pretty, done.
OR, if you don't want to lay out a PCB, you can cut a piece of experimenter's perfboard to those dimensions. Drill it to match those mechanical mounts, and mark it with the I/O terminal positions. Then play with the circuit layout on graph paper, draw out the component positions and the necessary wiring. Stuff and solder onto the perfboard, wire it up, done. Not as pretty as a PCB but you can do it without any CAD software & without waiting for shipping from an overseas PCB fab. (n.b. it's a lot more difficult to do this with the Norwood design, which is all-SMD)
The short answer -
No. In your specific question, using them in a BA or F5 won't work, as the M2x daughtercards are all buffers, and have no gain.
Could the footprint and general layout be used, yes, see above, and remember you'll likely need/want a place to add a reference to GND which the cards currently don't have.
No. In your specific question, using them in a BA or F5 won't work, as the M2x daughtercards are all buffers, and have no gain.
Could the footprint and general layout be used, yes, see above, and remember you'll likely need/want a place to add a reference to GND which the cards currently don't have.
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I will say one thing I know about the Tucson so far... It hasn't given me any reasons to change it out and try another!
I would appreciate your input upon trying the mother board with the original Toshiba jfets, very interested to hear your opinion.
Russellc
While it is indeed interesting now, and may become mandatory in the future, this idea of different input topologies, there really is no problem as such with the Toshiba parts, I have a matched quad on the way from Punkydawgs, and they are very much available from Spencer as well as one other source that I am aware of.
I would suggest laying in a small stash of them now, and when using them leave the legs as long as is practicable to facilitate reuse. I bought the board set and have intention on using them, but V-fet is next in the line. I have a sneaking suspicion that the Toshiba parts may be the best combo....I base this on the fact Mr Pass chose them, but that said he does buy in extreme quantity, so that is what is in his drawer of course. As already stated, there will come that day...and the Linear Parts may become more available.
The first alternative front end I want to try will be Tucson, based on 6L6 statement in regard.
Russellc
The entire point of the amp having swappable daughter cards is so you can play with it and make your own observations!
But that said, of course the Ishikawa is going to sound good... that’s the original circuit.
Yes, I know, but I have V-Fet up next, still need power supply and Chassis for that, so it will be awhile. I do have the board set from Mark. Just interested in your take on Tucson vs. original front end. Now that you have one up and running, you will no doubt beat me to the punch on the comparison.
Russellc
I would wager a case of french champagne (or W. Hansel Pinot Noir) that Nelson Pass did not prototype, evaluate, or listen to ANY M2 input stage that included integrated circuits, bipolar transistors, or surface mounted capacitors. Which means he didn't listen to M2x's Mountain View circuit, or Austin circuit, or Tucson circuit, or Norwood circuit. He chose the Ishikawa circuit for his own very good reasons, but winning a listening test against the aforementioned M2x boards is assuredly not one of them.
In the fullness of time we will all learn what the consensus of M2x builder/listener opinions, turns out to be. 6L6 and I made predictions about it back in March, before the first M2x boards were back from PCB fab. No we are not going to reveal our predictions. Better to remain silent and be thought a dunce, than to speak and remove all doubt.
In the fullness of time we will all learn what the consensus of M2x builder/listener opinions, turns out to be. 6L6 and I made predictions about it back in March, before the first M2x boards were back from PCB fab. No we are not going to reveal our predictions. Better to remain silent and be thought a dunce, than to speak and remove all doubt.
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As already stated, he is famous for using what is in his drawer, and in it are tons of the Toshiba parts. My inquiry to 6L6 only underscores what you just stated, he may not have compared these particular front ends....and I do say may.....lord only knows how many of what kinds of front ends he has tried. Would offer same bet, except I had to give up alcohol a little over a year ago....how about a case of the Toshiba Jfets? LOL
BTW, all Champagne is French, it refers to a geographical region...
Russellc
Think I'm gonna start building out the PS this weekend and have a question regarding inductors. I used some on my Aleph J build w great success but given I used a 4U chassis, it was a tight fit. I'll be using an encapsulated transformer and since this build will have edcors, will using the inductors increase the chance of hum? I'll be using a steel 4U chassis again and will forgo the better ripple control of the CLC and rather use a CRC for a hum free build.
Sorry to say, I haven't built an amp using great big iron core inductors in transformer-like chassis mounted boxes. So I can offer no anecdotes from personal experience, or hard won pragmatic advice.
However I think it might be worthwhile to remember a few things. First, M2 and M2x have excellent PSRR, thanks to having no VAS at all; thus they need less wonderful supplies than other amplifiers, and they benefit less when the supply is made more wonderful. Second, the nice people at First Watt built and shipped their entire production run of for-sale M2's, with the simple power supply attached to post #189 in this thread; it contains only a CRC filter. If you have decided "Good enough for Nelson Pass might not be good enough for ME," that's rather brave. Third, when you install series inductance in a power supply lowpass filter, you create the very real possibility of inductance-capacitance resonance on the supply. So I recommend you obtain the necessary test gear (function generator, 50 watt 8 ohm noninductive dummy load resistors, oscilloscope) to verify and validate that your as-built power supply, driving your M2x amplifier as it delivers power to 8 ohm loads, does not exhibit resonance.
However I think it might be worthwhile to remember a few things. First, M2 and M2x have excellent PSRR, thanks to having no VAS at all; thus they need less wonderful supplies than other amplifiers, and they benefit less when the supply is made more wonderful. Second, the nice people at First Watt built and shipped their entire production run of for-sale M2's, with the simple power supply attached to post #189 in this thread; it contains only a CRC filter. If you have decided "Good enough for Nelson Pass might not be good enough for ME," that's rather brave. Third, when you install series inductance in a power supply lowpass filter, you create the very real possibility of inductance-capacitance resonance on the supply. So I recommend you obtain the necessary test gear (function generator, 50 watt 8 ohm noninductive dummy load resistors, oscilloscope) to verify and validate that your as-built power supply, driving your M2x amplifier as it delivers power to 8 ohm loads, does not exhibit resonance.
I'm still piecing together the proper gear to do such tests and since that will be while from now, I'll stick to a CRC and save the inductors on another build. Thank you!
I haven't had a lot of chance to visit my favourite web site for a while, wow, Iv'e missed a lot of interesting stuff.
I think people may still like a hint on the core sound of each module, ie. out of the amplifier, I don't think it would spoil the fun, only add to the anticipation when you've built it; it may help in choosing to decide which one to build first, especially if your hobby time is tight.
Most hobbyists will have little experience with all the topologies, and will therefore be unfamiliar with their sonic signatures; only the hard core won't need the description, and they probably aren't reading this thread.
Lets face it, most people will want the ISHIKAWA, and no doubt they will ask 'what are the main (audiable) differences between it and the....'
I think people may still like a hint on the core sound of each module, ie. out of the amplifier, I don't think it would spoil the fun, only add to the anticipation when you've built it; it may help in choosing to decide which one to build first, especially if your hobby time is tight.
Most hobbyists will have little experience with all the topologies, and will therefore be unfamiliar with their sonic signatures; only the hard core won't need the description, and they probably aren't reading this thread.
Lets face it, most people will want the ISHIKAWA, and no doubt they will ask 'what are the main (audiable) differences between it and the....'