I just wanted to pop up and say thank you to those who made this amplifier happen, and thank you to all of you who have contributed to this thread.
I just ordered all the electronics for the amp, PS, and all the input stages.
I still have not made a decision about the chassis though.
A quick question,
Could someone please confirm the JFET set on the DIYAudio Store is the correct set for the Ishikawa.
https://diyaudiostore.com/collections/parts/products/linear-systems-matched-jfet-pairs-grade-b
I also have a very complete BOM that I think many would find useful since it contains alot of the parts people get stuck on, as well as parts that seem to always be left out.
Would it be a problem to upload the BOM to this thread, or should I start a separate build thread and put it there?
Thanks again,
-Josh
I just ordered all the electronics for the amp, PS, and all the input stages.
I still have not made a decision about the chassis though.
A quick question,
Could someone please confirm the JFET set on the DIYAudio Store is the correct set for the Ishikawa.
https://diyaudiostore.com/collections/parts/products/linear-systems-matched-jfet-pairs-grade-b
I also have a very complete BOM that I think many would find useful since it contains alot of the parts people get stuck on, as well as parts that seem to always be left out.
Would it be a problem to upload the BOM to this thread, or should I start a separate build thread and put it there?
Thanks again,
-Josh
I would very much like to have this: to compare with mine, to have as a 'second check list'. So if you decide not to post it here, please post a link to where you posted it.
But, as long as it is clear that this is 'your' BOM and not 'THE' BOM, I think it would be nice to have it here. But that is just my opinion.
Best regards and good luck with your build,
Rafa.
Well said Rafa, utterly true words.
I posted something similar a few posts back with the hope that the guy will take note and maybe acknowledge he was sort of wrong.
All to no avail.
Ignorance (and arrogance) is a bliss in this interconnected world.
Cheers
Stan
Thanks Dennis! This build was more of a diy effort so as of yet I don’t have the final front panel I’m going to use installed. Once I’m 100% done I’ll post some pics. I just couldn’t wait any longer to get my M2x up and running
Here is my BOM, I converted it to .xls from .xlsx so the formatting will survive. I think it will be easier to figure out than if I converted it to .csv.
I created this BOM during the course of reading this thread, the M2 build thread, and the FW Power Supply thread. I started with the official BOM's and began picking parts, and changing parts as I read the threads. Since I favor Mouser's search engine, the BOM favors Mouser a bit.
Included are Manufacturers part numbers, and the corresponding Mouser and Digikey part numbers. The list also includes current prices, and quantities available from each distributor. I was able to source all of the parts from Mouser and Digikey with the the exception of 1 pair of resistors (in red font) that I sourced from Arrow. If this seems like alot of work, it is... but part of my duties as a lab manager is compiling this kind of thing, so just another days work
I chose non-specified parts as follows:
Medical>Milspec>general spec.
For resistors in the audio portions I chose 1/4W when possible, I gave priority to Vishay RN, then RL, and used the lowest tolerance available. These resistors tend to be about 10x the cost of general use resistors, but only increase the actual cost by about $35.00 for the entire amp. Many of these could be downgraded, but it is easier to err on the side of caution, and the added cost is not too great.
Resistors in the PS and amp power section should all be flame-proof, but there might be some in the amp section that are not.
The PS caps where the hardest choice, I finally went with CDE SLP series 35V 22KuF. These caps have a 5.48A ripple capacity and are 3000hr @105C so should last a very long time. They are intended specifically for power supplies, are competitively priced, and will give me some elbow room in choosing fuses.
I did skimp on the power entry. I opted for a less expensive medical grade unit that does not have the ground snubber. My plan is to try the amp with out a filter as well, and make a choice based on how it sounds. This unit is cheap enough that I will not feel compelled to use it even if it makes things worse than no filter.
I purchased thermal pads on Ebay by searching for TO247 insulators.
One notable change I made from the original BOM is the choice of standoffs.
I feel quite strongly that the specified star washers and screws are entirely wrong. Repeated installation will damage the gold leaf on the boards unless they are left loose enough that they will eventually loosen from vibration and thermal cycling. I did choose the same coating for the input board standoffs, but I have mis-givings that the coating is acceptable. Ideally, these should be gold plated, or nickel plated. I was not able to find standoffs that had a large surface area though, so I will try these.
At the end of the BOM is a cut and paste of my order receipt to McMaster Carr for the nuts, screws, and washers. All these parts are made from stainless, the washers have the teeth turned to the inside and will not damage the pads on the boards with repeated installation. Best results will probably be had by not using a washer between the board and standoff. Use a washer between the nut and main board, then add a drop of nail polish. Use a washer between the screw an input board.
Also included are most of the small parts like thyristors that seem to never get mentioned in build threads.
Total price for the electronics for all boards and PS ~$300.00. Additional approximate costs are toroidal transformer ~$51.00, Edcor transformers: ~$41.00 (inclds shipping), $49.00 for the Ishikawa JFETS, and a chassis.
One last note. Some of these parts are already obsolete, and some of the inventory levels fell dramatically while I was working out last details. My suggestion is that you buy what is going away now if you are collecting parts for this project.
I hope this is useful to others.
Yup. It works quite well for this build. I used the steel chassis to save a little cash
I live in the San Jose, California metropolitan area which Google tells me with great confidence, includes 1.9 million people.
I visited an extremely high-end jeweler in one of the fancy suburbs and handed over an M2X motherboard + bolts + washers + nuts + daughterboard. I asked: How much would it cost to have this entire signal path plated with (a) gold; (b) silver; (c) rhodium; (d) chromium.
The answer was: nobody in California will do that for you. Nobody. Your hardware needs to be plated with nickel first, and only then can it subsequently be plated with any of the options (a) thru (d) above.
But the one company in California who used to perform that type of service, stopped. The old man retired and his kids are not interested in pursuing that line of business any more.
Perhaps other diyAudio members living in other states, might have better luck if they shopped for precious metal plating of M2X hardware. I tried it, myself, and got nowhere.
I visited an extremely high-end jeweler in one of the fancy suburbs and handed over an M2X motherboard + bolts + washers + nuts + daughterboard. I asked: How much would it cost to have this entire signal path plated with (a) gold; (b) silver; (c) rhodium; (d) chromium.
The answer was: nobody in California will do that for you. Nobody. Your hardware needs to be plated with nickel first, and only then can it subsequently be plated with any of the options (a) thru (d) above.
But the one company in California who used to perform that type of service, stopped. The old man retired and his kids are not interested in pursuing that line of business any more.
Perhaps other diyAudio members living in other states, might have better luck if they shopped for precious metal plating of M2X hardware. I tried it, myself, and got nowhere.
Well, that is a very thoughtful and thorough list! I'll take a look at it carefully.
Although, for me, it's usually best if EVERYTHING comes from the same store.
I have just finished a minor purchase at Mouser and I had to battle through 3 different mails where they expected me to fill government forms of use intent, export details and credentials, exporting company, recipient company.
"Well, it's for personal use!"... More forms, disclaimers, waivers.
Digikey directly told me that a hotel cannot be my 'main' address :O .
Thanks again, I'll match them to my own notes, really appreciate it.
Rafa.
Jewlers, thats the problem, 'bling' plating - looks shiny, speak to the electroplaters directly.
Why not just heavily copper plate the hardware? a b & c ok, but why d?
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I'm an idiot, thank you. When he posted do not read this, I literally skipped over it...
Please feel free to conduct your own investigations. If you succeed I imagine you could make quite a tidy profit, selling electroplated hardware to nervous DIYers. There may even be an opportunity to bifurcate the market, selling jewelry-finish hardware to one set of buyers, and oxygen-free copper C10100 to another.
I get heartburn whenever someone sends me a gold-clad board. Copper with a one-minute bath in MG Liquid Tin makes life easy.
I was kinda given up with my M2x monoblocks, then dBel84 was super kind and sent me the needed led's for mtn_view..can you imagine! Well, now these are on my table again.
Going to use Dissipante 300mm/3u cases, one for each channel. Remote locate fets and gate resistors so that there is one device per heatsink.
I have one spare trafo; Toroidy.pl's with 2x20vac. Is that extra 2vac from secondaries too much for this amp to handle? Hope not, then I could order only one more same kinda trafo to complete monos.
Going to use Dissipante 300mm/3u cases, one for each channel. Remote locate fets and gate resistors so that there is one device per heatsink.
I have one spare trafo; Toroidy.pl's with 2x20vac. Is that extra 2vac from secondaries too much for this amp to handle? Hope not, then I could order only one more same kinda trafo to complete monos.