The diyAudio First Watt M2x

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#442
I just ordered qty=250 pieces of the MV5075C LED from an authorized distributor (DigiKey) and I'm confident these are not counterfeit. I paid USD 0.122 per piece, which is almost exactly 8 LEDs per USDollar.

These are used in the "Mountain View" input stage daughter card of the M2X amplifier.

I'd be glad to let other hobbyists have some of these at my cost, including my cost of postage and mailer envelope. If anyone wants to be a local re-distributor in parts of the world where Mouser doesn't sell the MV5075C (so far we know that Portugal and Finland are on this list), that would be a wonderful thing. Otherwise, small quantities only please. PM me with your needs and to get my PayPal info.

I estimate that shipping within the USA costs $4.50 and shipping outside the USA costs $14.50. Throw in the envelope and its 5 & 15.

~
 

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#443
Hello,

First channel is soldered, pretty easy to work with nice layout that isn't so tight. Since this LED-episode seems to come surprisingly expensive, I soldered "Tucson" to start up with SMD opamp (Texas Instrument). This time I bought some boutique resistors, don't know is there any other reason that they look really nice. Part count is so low that wasn't expensive choice.

I don't have suitable heatsinks for this project, I'm going to make monoblock build. What is recommended size, rather little bigger than just optimal? Where to get those in EU? 300 X 40 H 210 mm 0,18 C°/W, too much oversized?

Missing parts:
- Second trafo from Toroidy.pl
- PSU caps
- Heatsinks
- Casework

So long way to working amplifier 🙂
 
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#450
that's the same you already posted , and I confirmed - as more than enough for one case per channel

besides , remember that "U" is industrial unit for package height , where one U=44mm

so , you can't use it to ask me about deepness , 'couse then I'm confused (well , even more than usual)
 
#452
oh yes , this one will be also good for one channel

Dissipante 03/300N 3U 10mm NERO

in any case , take care , when placing two output mosfets on opposite side heastinks (one per ) best to keep gate resistors close to gates

either use small pcbs for mosfet pins , pcb bolted to heatsink and place gate resistor on pcb (use veroboard for simplest solution ) or solder resistor to gate and heatshrink together pin & resistor & wire
 
#454
Excuse my ignorance ZM, but if I understand correctly, is it ok in a monoblock to have amp pcb and one mosfet on one side ( one heatsink) and the other mosfet on the other side ( other heatsink) connected by wires to the pcb? That is if appropriate gate resistor is mounted close to the lone mosfet? Thus utilising both heatsinks?
Zen Mod said:
oh yes , this one will be also good for one channel

Dissipante 03/300N 3U 10mm NERO

in any case , take care , when placing two output mosfets on opposite side heastinks (one per ) best to keep gate resistors close to gates

either use small pcbs for mosfet pins , pcb bolted to heatsink and place gate resistor on pcb (use veroboard for simplest solution ) or solder resistor to gate and heatshrink together pin & resistor & wire
Click to expand...
 
#455
Just to clarify for myself this monoblock issue and heatsink capacity:
while the 2 heat sinks of the 3U case are enough, one of them is NOT enough, so this cannot be accomplished with the MOSTETs soldered to PCBS that were already provided, correct?

This will require actually splitting the MOSFETs to both heat sinks by other means, right?

Thanks,
Rafa.
 
#456
kbergsson said:
Excuse my ignorance ZM, but if I understand correctly, is it ok in a monoblock to have amp pcb and one mosfet on one side ( one heatsink) and the other mosfet on the other side ( other heatsink) connected by wires to the pcb? That is if appropriate gate resistor is mounted close to the lone mosfet? Thus utilising both heatsinks?
Click to expand...

I have done this once earlier on my first diy-attempt, just like ZM told, and worked like a charm.

Project | Homebuilt Hi-Fi - A user submitted image showcase of high quality home built hi-fi components.
 
#459
QUOTE: I also included (socketed) load resistors to see whether the input stage's performance degraded whe driving the ~600 ohm input impedance of the Edcor transformer + output stage components.​

analog_sa said:
600ohm impedance? How did you calculate this?
Click to expand...

See the third attachment to post #1, of this diyAudio thread: LINK Also see the measurements by Nelson Pass in post #27 of the same thread. The Cinemag transformer and the Jensen transformer have lower turns ratios than the Edcor, thus higher input impedances. This also results in lower "gain" (Vout/Vin).

The superdriver mention in post #20 of that thread, back in March, is now known as "Norwood" -- publicly unveiled in late April / early May.
 
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