Mauro Penasa MyRef vs simple LM3886 circuit

[bcmbob]

Thanks hurtz,

I've been flirting with the xonar cards since they came out. Unfortunately, all my extra cash has been diverted to amp building. I do have a M-Audio Delta 66 and a Delta 1010 that might be usable with the rightmark program. I downloaded it a couple weeks ago, but now that I have someone to guide me, I'll start trying to get my head around it.

Thanks again.

[ClaveFremen]

Originally Posted by hurtz

Hmm too bad, would really interest me.

Hi Hurtz,

I realize now that maybe you want to see some measure of the orginal My_Ref to compare it to a Gainclone... Am I right?

In the original My_Ref thread there are several measurements made by Mauro Penasa (the designer) and some of Soongsc.

Read the attachment and from post #90 of the linked thread.

From the attached document:

Bandwith (tipical): 2Hz-70Khz
Output power(±37V): 40W/8ohm – 56W/4ohm
Damping Factor (8ohm): >200 (frequency and compensation depended)
S/N 600ohm: >90 dB (compensation depended)
THD e IMD (tipical), 20Hz-20Khz, 1-40W/8ohm: <0.05%

[hurtz]

Thanks!

That was pretty much what I was looking for. Sadly though I can only test my builds using rmaa and have no fancy test-equipment for phase shift and such. Maybe when I finish my studies I'll have the budget to afford such things :-)
In the meantime rmaa all the way ;-)

Also I think there a quite a few microphones out there to measure output of the speakers but they are much more expensive than a simple sound-card.


cheers!
hurtz

[bcmbob]

Hey hurtz,

I may be in good shape. I see that one of the default devices in RMAA is the M-Box 2. I got a great deal on eBay for one of those several months ago. I don't know if the signal is as clean as the best xonar cards, but it puts me in the ballpark. I'll start setting up a test bed sometime next week.

[Dufus]

Bob how about that review you promised? Did you compared it to some boutique amps?

[bcmbob]

Sadly, I'm going to have to push it off till Monday. I installed some Caddock resistors in a few positions a couple days ago and also want to change out two caps - C7 & C30 - to some top choice samples from Dario. It's also suggested to use an IsoTek burn-in process to get each cap (actually the entire system at each incremental change) close to optimum performance quickly and also determine which orientation sounds best. I decided it was worth the delay to get these last few adjustments completed.

Trust me, I'm as curious about the results/comparisons as anyone.

[hurtz]

Originally Posted by bcmbob

Hey hurtz,

I may be in good shape. I see that one of the default devices in RMAA is the M-Box 2. I got a great deal on eBay for one of those several months ago. I don't know if the signal is as clean as the best xonar cards, but it puts me in the ballpark. I'll start setting up a test bed sometime next week.

That sounds good! Make sure to post the resulting .sav of your loop-back test :-)

cheers!
hurtz

[soongsc]

Originally Posted by ra7

I don't want to be a party-pooper, but in my listening experience the MyRefC is very good, although probably not better than good Class-A designs. This includes tubes and SS.

Definitely worth the effort compared to a plain LM3886.

I think the MyRef can beat good Class A designs. I have compared against at least one, I certainly prefer the MyRef. General LM3886 design similar to the application note can be very good too. In my case, I have one of each that are under competition against each other. While taking turns to mod one to beat the other, I don't think I have a conclusion yet, but the MyRef may eventually win. The key issue how you get the power supply to work optimally with the circuit, which is not a small task.

[soundnovice]

for bi-amped application(woofer+ fostex full range, say crossed at 250-300hz), will it make sense to use plain LM3886 circuit for woofer and MyRef for fullranger? the basic question here is in which freq.band MyRef excels?

[soongsc]

I would use the same amp for all bands unless the woofer is something like 12" or more.