[ttnl]

Hi, please help me with a good configuration for M^3 amp. My source will be Ipod, and my headphones include Senn Hd600, Grado SR225 and Ety ER4ps. Please recommend me an optimal gain setting for this amp (at least for use with Hd600 and Sr225). Is the default bass good enough to skip the bass boost feature (I am not a bass-head)? What opamps should I go with? What Voltage setting for the Sigma PSU is optimal? If you can, please answer all the questions, because those are issues I still confuse. Thanks so much for your help.

 

[penger]

This might work best in the DIY forum.

 

[Gradofan2]

Just had that conversation with one of the recommended builders.

He suggested the following as the "optimum":

1. Standard configuration: 24 volt, Alps POT, Panasonic/Elna caps, etc.
+++
2. OPA627 opamps.
3. S11 PSU w standard configuation - pretty much a requirement.
4. Gain: 5 - 8 /or/ adjustable gain w Alps POT, or "Hi / Low" switch.

That's about it... nothing really "exotic" adds much.

He said, if he were going to add one other option, it would be the STEPS attenuator... but... it really didn't need it... and many prefer the variable attentuation of the Alps POT.

Those would be my specs, if I were to try one - probably with the gain switch and settings of about 5 or 6 and 11 or 12, rather than a variable adjustment.

Oh... yes... and a Hammond or similar case w the thick / heavy aluminum face plate w engraved logos, etc. - to give it a class, commercial look.

But... I've been more impressed with the comparative reviews between the M^3 and Caliente - which indicate the SQ of the Caliente trumps the SQ of the M^3. I really don't care what it looks like on the inside - as long as the SQ is as good, or better for $300+ less.

 

[ttnl]

Thanks for your advice, Gradofan2. Regarding M^3 vs. Caliente, so far we only hear the opinion from one head-fier. To me, it's not enough to tell which one is better. I decide to go with M^3 because I can find more people happy with M^3, and more M^3 owners than Caliente owners. On the other hand, I missed out on the group-buy for the Caliente. According to the amp maker, the price will go back up to $399 after the delivery of the group-buy amps. So I guess with a few bucks more, I can get a separate PSU. It is not a bad deal after all. Please, more advice for me. I almost pull the trigger.

 

[scootermafia]

My M3 has plenty of bass. A gain of 8-11 should be sufficient, especially if you're driving HD650s. Rockhopper uses 11. I have 637s in the left/right and a 627 in the ground (ground must not be a 637, it's unstable) and they sound righteous. No bass boost is necessary, I'd be curious to hear it but it's probably superfluous. You can always crank the bass up in iTunes or something. Sadly it'd probably be cleaner vs. adding a bunch of extra solder joints.

I wouldn't be so sure that the Caliente is better...I'd need to hear it from more people. It all depends on the headphone too.

 

[Borat]

A gain switch would be really useful for you if you want to use it with both HD600's and your Etymotics.

Besides that, I don't think you need much else different from what Amb recommends on the M3 page.

I found the bass boost useful. But if it's between that and a gain switch, I would opt for the switch.

I hope the the amp works out for you.

 

[chris_ah1]

Just remember that you need a gain of at least 5 (and 6 is recommended) for OPA637. I definitely think a gain switch is a must if you are going to use low impedance high sensitivity IEM monitors as well as 300ohm beasts or low sensitivity low impedance cans. I would say a choice of 6 and 12 is a safe choice. Or even 6 and 15 or 8 and 15. Whatever you choose a spread like that is good.

Gain is really only important for volume knob control - even the NX-03 from rudistor with gain of 15 can work quietly with IEMs, but perhaps the volume knob doesn't give enough control.

The other consideration is if you go balanced a gain of 5 will turn out to be a gain of 10 to your ears. so a setting of 6 or 7 and no gain switch will probably be fine but perhaps not with 120db/mw and 30Ohm IEMS

As for opamps, I think OPA627 is good enough over the 637. And really most people most of the time cannot hear the difference between good opamps.

I know that AMB personally doesn't like the stepped attenuator. I must admit other than the channel imbalance at the extremes there is really no reason to go with a stepped one because often the gradations just aren't small enough. I certainly doubt you will hear noise or scratching as you move the volume either on this quality gear.

Glad you are trying to build one yourself...unless you contacted YBM or MisterX?

 

[Shahrose]

Quote:

Originally Posted by Gradofan2 /img/forum/go_quote.gif Just had that conversation with one of the recommended builders. He suggested the following as the "optimum": 1. Standard configuration: 24 volt, Alps POT, Panasonic/Elna caps, etc. +++ 2. OPA627 opamps. 3. S11 PSU w standard configuation - pretty much a requirement. 4. Gain: 5 - 8 /or/ adjustable gain w Alps POT, or "Hi / Low" switch. That's about it... nothing really "exotic" adds much. He said, if he were going to add one other option, it would be the STEPS attenuator... but... it really didn't need it... and many prefer the variable attentuation of the Alps POT. Those would be my specs, if I were to try one - probably with the gain switch and settings of about 5 or 6 and 11 or 12, rather than a variable adjustment. Oh... yes... and a Hammond or similar case w the thick / heavy aluminum face plate w engraved logos, etc. - to give it a class, commercial look. But... I've been more impressed with the comparative reviews between the M^3 and Caliente - which indicate the SQ of the Caliente trumps the SQ of the M^3. I really don't care what it looks like on the inside - as long as the SQ is as good, or better for $300+ less.

I've read 1 review of a person liking the Caliente more than M^3 and another of one preferring the M^3 over the Caliente significantly. As I said, M^3 is technically a better amp, but the sound signature will come down to preference and that's obviously going to be subjective. It would be premature at this point to say that the Caliente has better SQ.

 

[scootermafia]

x2

Check out the largest size split body case from context engineering, call em for a quote, they're really nice cases.

 

[cswann1]

Quote:

Originally Posted by scootermafia /img/forum/go_quote.gif x2 Check out the largest size split body case from context engineering, call em for a quote, they're really nice cases.

Thanks for the tip bro. I've been contemplating a M^3 build but I've been struggling with finding a case that I like. I don't know if I'll settle on a Context but options are good

 

[scootermafia]

It's a little hard to tell how nice it is based on pix but mine is the black anodized one you see in my M3 review. It's made of quite thick, unbendy aluminum and it's nicely finished with a brushed look - the only con is that some people like front panels that have overhang on the sides - the front and back caps are flush with the top and sides. I think they have a very clean look, my M3 is quite minimalist but very attractive. Admittedly I wasn't that keen about my M3 just looking at it in pictures but I like it a lot in person.