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Rockhopper M^3 - The Review - Page 3

post #31 of 523
Quote:
Originally Posted by grawk View Post
Try 3x AD843
i know you've got quite a monstrous M^3, and have had it for much longer than some of us. would you care to elaborate on the differences between the OPAs and the AD843? can you do better when it comes to opamps?

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post #32 of 523
I'm running at 36v, so I can't try the 637s, but the 843s sound great.
post #33 of 523
Quote:
Originally Posted by Shahrose View Post
yes but was the M^3 powered by a good external PSU?
Yes, separate PSU - two boxes, and bass contour knob too.
post #34 of 523
Quote:
Originally Posted by grawk View Post
I'm running at 36v, so I can't try the 637s, but the 843s sound great.
That would be +18 - 18V for the OPA 's ? Sorry I'm just trying to clarify. If that is so audio-gd discrete modules run their absolute best at that V.

Might be worth exploring as a alternative to IC based OPA's. You never know it might be a killer upgrade.

This amp has tons of potential and room for tweaking which I love. It's certainly interesting to see what each individual does with his or her own iteration of this amp.


Peete.
post #35 of 523
OK, I have a 24v M^3. What do I need for a OPA627/637 set up? On Ebay I see a couple of options. Do I need a mono to dual adapter or can I plug the 627/637 right into the sockets?
post #36 of 523
Quote:
Originally Posted by Pricklely Peete View Post
That would be +18 - 18V for the OPA 's ? Sorry I'm just trying to clarify. If that is so audio-gd discrete modules run their absolute best at that V.
Peete.
No, +/- 36v. And the discrete modules haven't been tested and approved in this circuit. But I really don't feel a need to tweak my m3 any farther. It's pretty stellar.
post #37 of 523
Quote:
Originally Posted by grawk View Post
No, +/- 36v. And the discrete modules haven't been tested and approved in this circuit. But I really don't feel a need to tweak my m3 any farther. It's pretty stellar.
I'm glad you like your M³, but I believe you're mistaken about the supply voltage. The maximum rating for the AD843 is 36V (aka +/-18V). The only other officially-recommended opamp for the M³ which has higher supply voltage limit is the OPA604 (40V or +/-20V, but that is limited not by the opamp, but by the TLE2426 rail splitter whose maximum rating is 40V). Also, the maximum listed output voltage configuration for the σ11 PSU is also 36V (which is split into +/-18V onboard the M³).

It is true, however, that I have not tested and verified any discrete opamps for use in the M³. The lack of true substantive and objective specifications is a major roadblock. If a company is offering an opamp-replacement module, then they should publish a datasheet that is comparable in technical detail to those from Analog Devices, Texas Instruments or National Semiconductor, etc. I can't do a proper engineering evaluation of the product based on subjective impressions and hype.
post #38 of 523
Quote:
Originally Posted by ciphercomplete View Post
OK, I have a 24v M^3. What do I need for a OPA627/637 set up? On Ebay I see a couple of options. Do I need a mono to dual adapter or can I plug the 627/637 right into the sockets?
It's plug and play, no adapters needed if you get the DIP-8 versions of the opamps.
post #39 of 523
Ok then, yup, I was mistaken. I have a 36v sigma11, so I guess that translates to +/-18. Gives me lots of headroom and sounds great.

The 637 doesn't work in my amp because the minimum gain would blow my eardrums out in my m3. I spend most of my time at unity.
post #40 of 523
This has to be one of the most rock solid looking amps!

Great review, I'll be sure to consider this in the future if I ever have a need to upgrade to a better amp.
post #41 of 523
Thanks for a great review, this amp is finally getting the air it deserves.
IMHO I think it’s represents value way beyond it’s price point, and is often sadly overlooked.

I have a Darkvoice 337 (excellent tubes see sig), I prefer my balanced M^3 amp by a wide margin. I consider the difference to be in another stratosphere although they are of similar cost.

This amp has been the only product (in my 25 years in this hobby) that has caused me to stop in my tracks and evaluate true value in audio. I’m now strongly DIY and regret not getting into it sooner.

Thanks to AMB and associated DIY community who make these projects possible.
post #42 of 523
Quote:
Originally Posted by johnwmclean View Post
Thanks for a great review, this amp is finally getting the air it deserves.
IMHO I think it’s represents value way beyond it’s price point, and is often sadly overlooked.

I have a Darkvoice 337 (excellent tubes see sig), I prefer my balanced M^3 amp by a wide margin. I consider the difference to be in another stratosphere although they are of similar cost.

This amp has been the only product (in my 25 years in this hobby) that has caused me to stop in my tracks and evaluate true value in audio. I’m now strongly DIY and regret not getting into it sooner.

Thanks to AMB and associated DIY community who make these projects possible.
i agree. IME, DIY products have presented much greater value compared to commercial offerings.
post #43 of 523
Thread Starter 
Yep, just get the OPA637AP (two of them) for the left/right channels, and one OPA627BP for the ground channel. They're 8-pin DIP packaged so plug n play. Mouser and Digikey both have them in stock, I like Mouser cuz they're in Texas so 1 day shipping woohoo. If you're noob then make sure that the 627 is going into the ground socket marked ICG or something like that and not the left/right, and that you pre-bend the pins before sticking it in so that they're straight and you don't fail horribly, I'm not much at sticking them in, that's for sure - I get nervous when touching the M3's board. Using an anti static wrist strap is probably not a bad call when handling the $26 rice grain sized item.

I just built a DIY Silver Spirit interconnect kit ($60) which saves about $140 over the inflated cost of a pre built one. It was about 2-3 hours of careful work, and my tools are rather poor (my soldering iron got unhappy halfway through and I could not find a suitable heat gun in time so I had to use a lighter) but worth the effort. It sounds way better than my Transparent Musiclink which is kinda old and questionable (it's headed into my analog system).

No need to post pictures but if anyone is bored and wants a nice solid silver cable, it's worth building, got it from Homegrown Audio.
post #44 of 523
Thread Starter 
Quote:
Originally Posted by Shahrose View Post
i agree. IME, DIY products have presented much greater value compared to commercial offerings.
I'm all about the M3 love, there's just no way that for the same money you can get as high-performing of an amp. I only wish that Stephen from Rockhopper would expand and everyone could get one.
post #45 of 523
Here’s a pic of my balanced M^3.
LL
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