[gerG]

Hi Bangraman. Tradeoffs (that I can think of) relative to a balanced Max:

+ Cost. I put this together out of used parts that are pretty easy to find. Total is around $2500.
+ Incremental benefits. Each piece is standalone, so from the first outlay of $ I had an amp to use.
+ Flexibility. I can swap the DAC section or amp section as needed. It also works with any balanced source.
+ Breaks down into small parts that will fit into a briefcase.

- Special cables required (easy to make).
- Multiple pieces, vs single unit. More complex to set up.
- Takes 3 power cords.
- 2 volume controls vs 1.

Those are off the top of my head. I bet the inmates will think of more.

Sound is amazing. Some of this is due to the DAC1, but the detail without harshness is what I love about the Grace amps. The balanced setup has brought along better channel separation, larger soundstage, and maybe better dynamics. I think that the headphones are the limiting factor on the last one.


gerG

 

[BrianS]

wow that is awesome. i have my DAC on its side too for both heat and space constraints. i bet it sounds great

 

[agile_one]

The desert lunatic strikes again.

gerG, you were, are, and will remain my hero. What a cool use of really great, affordable pro gear to create an amalgam that I am sure equals or bests the boutique balanced amps so far available. Amazing work on the cables/terminations, too - I guess all that sun and heat hasn't totally burned you out, yet.

Rock on, brother ...

 

[Otto]

The 901 has ballanced inputs on the back. No ballanced outs?

Any reason to use a ballanced source without ballanced out?

 

[Alwayswantmore]

Quote:

Originally Posted by Otto The 901 has ballanced inputs on the back. No ballanced outs? Any reason to use a ballanced source without ballanced out?

Note there are two phono plus on the headphone cable. As configured, this rig does run balanced out.

 

[gerG]

Hey Gene, great to hear from you! I figured you would have one of these wired up by now. You must have a couple of Grace amps kicking around there somewhere. It is a pity that the 902 doesn't have balanced outputs, otherwise I would have had this done last year. Of course, there is always the M904...

Hi otto. Although the 901 has balanced inputs, they are not used in this configuration. I used the unbalanced inputs to split the balanced signal into 2 channels. That drives the outputs with a mirror imaged signal (push pull) to yield a true balanced output. It can be done with most any matched pair of amps. The trick is having a balanced source.

If someone really wanted to use the balanced inputs, it could be done with a similar Y cable, and swap the polarity on one side. That would require all XLR plugs (not a bad thing) and would limit the amps which could be used. The cable configuration would be identical, since each of the Mogami cables has a twisted pair and a shield. Hmmm, interesting...

gerG

 

[Alwayswantmore]

Hi gerG,

Nice looking setup. Q: I know someone who wants to try running balanced 600s directly from the DAC1. Have you ever tried this?

 

[grandenigma1]

Quote:

Originally Posted by bangraman Intriguing idea. However presuming you don't necessarily need two headphone amps floating around, is there any practical benefit to this vs a bal. Max?

the benefit would be ummm... it costs as much as the Balanced Max to buy that setup new

Quote:

Originally Posted by Alwayswantmore Hi gerG, Nice looking setup. Q: I know someone who wants to try running balanced 600s directly from the DAC1. Have you ever tried this?

Yes you can do that... you will need female XLR - female XLR adapters and a balanced cable or a balanced cable with female XLRs. The DAC1 is not the ideal budget balanced amp though... other balanced DACs out there can do much better.

 

[tkam]

Quote:

Originally Posted by grandenigma1 the benefit would be ummm... it costs as much as the Balanced Max to buy that setup new

LOL yep I was thinking the same thing. I think you'd be better off with a balanced m3, dynamight or gs-x.

 

[gerG]

From my perspective the setup was free. It is gear that I already had, and all I am out is some cable and connectors. For me a single mega-amp would get boring. This is why I consider myself an enthusiast and not an audiophile.

One significant benefit for me is that I already knew that I love the sound of the Grace amps. I like the sound of my M^3, so I might get curious enough to try a balanced variant of it some day. I have not liked the sound of the Gilmore variants that I have owned, so I am less inclined to go that route. Just my preferences. I would still love to hear one of the monster variants that I have seen discussed.

I have not tried driving headphones with the signal output of the DAC1. Although it will probably tolerate the low impedance, it must be way out of its design envelope.

I wonder if it would be practical to add a buffer stage to the balanced signal output of the DAC1? It has plenty of voltage swing, so how about a current stage (times 4) to make it an all in one balanced headphone amp? Anybody know if this is feasible/reasonable?


gerG

 

[Alwayswantmore]

Quote:

Originally Posted by gerG I have not tried driving headphones with the signal output of the DAC1. Although it will probably tolerate the low impedance, it must be way out of its design envelope. I wonder if it would be practical to add a buffer stage to the balanced signal output of the DAC1? It has plenty of voltage swing, so how about a current stage (times 4) to make it an all in one balanced headphone amp? Anybody know if this is feasible/reasonable? gerG

The DAC1 has a very low impediance (about 15 ohms). And I've forgotten the output voltage, but do remember it was higher than I use (with my internal DIP switches). Beyond that, I do not know if it is suitable.

 

[Ferbose]

DAC1 XLR has 60 ohm output impedance (30/30 for plus/minus).
I think quite a few people have used its XLR to directly drive balanced HD6x0.

 

[gradofan]

Love the setup gerG! I bet it sounds incredible. One quick question, though:

"From my perspective the setup was free." Hmm.... perhaps, but didn't you buy the DAC1 just so you could put that killer balanced rig together?

hehehe

 

[heymaceo]

This is a semi-off topic question, but could this be done with, with beneficial results, to hook up two Sonic Impact T-Amps (using a balanced source) to loudspeakers?

 

[gerG]

heymaceo, you don't by chance play sax do you? Just checking

I would be very careful about trying this with the T-amps. They may not react well to bridged operation. Running in this mode will also double current delivered, so the min driveable impedance is doubled, or you risk smoking the amps.

Another drawback to this approach is that the volume pots must be closely matched between the 2 channels in each stereo amp. I have been finding a lot of variation in the lowest part of the VC range for inexpensive amps. The Alps pots seem to be very good, and the discrete resistor attenuator are excellent.

Hey Tony! I am not sure what I bought the DAC1 for, but it is my preamp/headphone amp at the office right now. The rackmount ears work great for padlocking it to the shelf where it sits. It worked out nicely since my electronic crossover takes balanced inputs, so one less pair of adapter cables.


gerG