[Sean H]

I'm looking to put together a Grado based rig which will start with my SR-60's and later a plan to acquire SR-225's to stay home. Used at home it would find company with quality source and cabling as outlined in my signature, at work M-Audio Sonica. Smaller size interests me for transportability to work.

I'm always amazed at how damn good my SR-60's sound, period, but how good they sound out of my computer with no amp. I remember they did sing to fullest potential with a Gilmore V2 I used to tote to work and back but damned if they don't sound good out of my computer too. I'm convinced very simple amps can work great with Grado's. So I've been looking at some very affordable options out there in the way of quality CMoy's, the RA-1, Mint's and even DIY Gilmore Lite style amps. I like the idea of keeping things very "budget", not looking to get into expensive amps here or seemingly more "complex" amps.

I am most interested in CMoy style amps. I really like some of Drew Dunn's offerings, particularly his Maxi Moy which is kind of a maxed out CMoy with AC power. One question I have is are CMoy's good amplifying circuit's for Grado's? I am assuming so. Another question is battery versus AC power with simple amps like this. Is part of why people are so excited about how good CMoy's sound the fact that they use the clean sound of battery power? The Maxi Moy is AC power only so I'm wondering if it would lose some magic due to that (although maybe it could be built for battery power in addition to the AC power). Lastly, I am considering the RA-1 or maybe a maxed out clone version. I once owned this amp and definitely liked it a lot but I have never heard how it compares to a nice CMoy. How do RA-1's and nice CMoy's compare driving Grado's? Very similar circuit's, correct?

Based on my favorable dealing with the Gilmore V2, a Gilmore dynamic (lite style) might be on the table too but right now CMoy's have my interest for their simplicity and lower cost.

Thanks!

 

[rayofsi]

that maxi moy is a Mint

http://tangentsoft.net/audio/mint/

btw this is regarding the link you posted. there is a mint in the background.

 

[slindeman]

Quote:

Lastly, I am considering the RA-1 or maybe a maxed out clone version. I once owned this amp and definitely liked it a lot but I have never heard how it compares to a nice CMoy. How do RA-1's and nice CMoy's compare driving Grado's? Very similar circuit's, correct?

So similar they are essentially the same.

What Grados want are current, and whether a cmoy can supply the current necessary will depend almost completely on which opamp is in the circuit. The RA-1 is a cmoy circuit using a high-current opamp, the NJM4556. So if you choose a cmoy amp I would suggest using that opamp. Whether such an amp would be called an RA-1 clone or not, who knows, I guess it depends on whether you use the same caps, resistors, power supply, etc.

What I seem to recall from my Headwize days, however, is that the discrete Szekeres amp or the Gilmore amp are even better matches for Grados because they can supply a lot of current. Both are Class A amps also.

Since I'm a DIY'er, if I had Grados I'd probably build the Szerekes first, then the Gilmore. If I weren't a DIY'er I'd probably buy a Gilmore lite.

Oh, and another amp that I really love that I'm fairly sure would sing with Grados is the Pete Millet Hybrid Tube amp. It can be built for under $150 DIY, and I believe Headroom will sell it commercially in the near future. I love this amp.

 

[rickcr42]

the Max Moy has no resemlance to any Chu Moy Pocket Amp which is nothing more than a high current output,low current drawing op-amp gain stage.

the RA-1 is a "sister" amp in that it is also a basic gain stage using a single opamp in a similiar configuration but has nore current delivery than the Chu Moy IF they use the specced op-amp.

put a OPA2134 in the RA-1 or the "grado" op-amp in the Chu moy and there are more simularities than there are differences but put a buffer on the output and both become something entirely different.

you can double up the opamp of either for twice thje current delivery or choose an amp using a buffer that was spewcifically designed from the beginning for use with the buffer or you can try to weasle a buffer into a standing design.

Grados are all about getting the current to the drivers so the spec to look for is current output of the amp .

50ma is good ,100 REAL good and 250 up heaven !

but always at a price-every time you gain something in one area you lose in another-no perfect amps

 

[Mpemba Effect]

I'm a big fan of the Grado 225 and Szekeres combo