The diyAudio First Watt M2x

[von Ah]

Very nice build, @Dneu2011. Honestly, my immediate reaction was, “Jesus, that’s huge.“ 😎

 

[KevinHeem]

Another M2x is born!

No doubt about that!

 

[ggetzoff]

Have a quick look at post #3355 of the Official M2 thread. Each of the amplifier channel boards ramps up its current sloooooooowly, as (R6 and R7) charges capacitor C3. The asymptotic final value after hundreds of seconds, is Vfwd_Q5_LED / (R13 series R14) which is around 1.3 amperes per channel for the push pull MOSFETs. Then add the worst case (biggest possible) Input Stage supply current. One point three something amperes per channel.


_

I’ll add to this statement that anyone building any of Nelson’s designs should always read his extremely well written manual before starting: the manuals are fun and very informative.

 

[ppinto1]

I made the R6/RV1 mod, and can get within .002v. That works like a champ! Thanks 6L6. If I ever do this again, though, I'm going with 25 turn pots. It's pretty touchy.

 

[Dneu2011]

I forgot to do the mods and couldn’t get my offset under 300mv.

I took 6l6’s recommendation and added a 332k ohm resistor in parallel with R6.

This fixed my issue and dialed both sides within 10mv!

 

[bullittstang]

Any chance someone has 2 extra HA9P5002-5z or 9z Ops Amps for the Norwood IPS? I have looked everywhere and even ordered both from Win Source who said they had 10,000+ of each version. Only to get an email on both orders telling me they have sold out and have no idea when they will get more back in stock. Mouser and Digi-Key both say Mid to Late 2023 for any stock. My mistake, but I ordered all the other parts needed from Mouser when I got order confirmation email from Win Source - only to get sold out email 24 hours later.

PM me and we can work out the details. Thanks.

 

[Audiobear]

I'll send you a PM. I have 3.

 

[bullittstang]

I'll send you a PM. I have 3.

Bruce, I sent you back a PM - thanks

 

[ppinto1]

My external power is complete, proving my metalworking skills aren't improving with time 🙂 The IEC/DC parts worked well.

I'm measuring a 0.3V difference in rail voltage between sides (+/- 23.2 vs +/- 23.5). Is that unusual? I've never run dual-mono before; so I have nothing to compare with.

It sounds fantastic. M2x is my all-time favorite. I'm looking forward to trying the other input buffers!

 

[Mark Johnson]

Good job on the top view photo. Very often those include the photographer's shoes or bare feet.

 

[sov]

@ppinto1 Once I got the advice from Mighty Z to include motor runs in amp chassi. Now I include them where ever the power goes.

 

[ppinto1]

@Mark Johnson my composition could definitely have been better! @sov Thank you. I'll read about that.

 

[TomServo]

@ppinto1 Once I got the advice from Mighty Z to include motor runs in amp chassi. Now I include them where ever the power goes.

SOV: Interested to know how those caps are wired in, and what the make/model/part number these are. Thanks!

 

[sov]

Ducati motor run or other motor run 60-100uF with a bleeder 1kR.

 

[TomServo]

Ducati motor run or other motor run 60-100uF with a bleeder 1kR.

Thanks for that info!

 

[Zen Mod]

@ppinto1 Once I got the advice from Mighty Z to include motor runs in amp chassi. Now I include them where ever the power goes.

what's wrong with having 33mF per rail too?

motor runs are cherry on top, but without local 33mF there is no top

 

[sov]

Of course, the mF is in the PSU-box. Cherries, mmmmm. 🙂

 

[jameshillj]

Why not get really extravagant and make that 100mF per rail? Just how many joules are required (per rail) for this 25w/8R amplifier and how much Power Supply Ripple will be acceptable?

 

[Plott]

what's wrong with having 33mF per rail too?

motor runs are cherry on top, but without local 33mF there is no top

Do you mean 33mF local in the amp chassis, additionally to the cap bank (with 33-47 mF) in the PSU?
And the bleeder resistor in the PSU only?

 

[sov]

It's OK with PSU bleeder. If You have motor runs in other chassi than PSU and disconnect power it's god to have small bleeder on motor run or disconnect after discharge.