Coffman Labs H1-A. Holy.... what a piece of gear

[fjhuerta]

Hello all.
 
I was looking for a preamp and a friend of mine sold me something I had never heard about... a Coffman Labs H1-A.
 
He showed me pics. I fell in love. 
 
Now that I have it, I'm speechless. It's a hunk of aluminum. A huge hunk of it. It's heavy. It's beautiful. And I can't find much info on it.
 
I don't know what impedance setting to use with my headphones, nor what position to use the grounding switch.
 
But oh boy, is it beautiful.. stunning.. easily the prettiest piece of gear I own. It'd definitely look astounding next to my MC-30 monoblocks.
 
I'll keep on writing in this thread with my impressions.

 

[fjhuerta]

Well, the love affair was short-lived.
 
The pre is stunning and beautiful. So far, that's pretty much it.
 
The headphone amp is broken. Frequency response is -26 / +3 dB from 20 to 20 KHz. THD is close to 10%. Separation is around 40dB. It's useless.
 
The preamp has very high distortion levels - when compared to, say, a Foreplay III.
 
After 5 minutes of using it, smoke started blowing from inside. A resistor went up in flames. I took it apart and saw a rat's nest of wiring, blobs of solder everywhere and - A LOOSE WIRE inside. I don't know if it was supposed to be soldered. It had solder on one end and a crimped and inuslated end. 
 
My Foreplay 3 is better made than this - and I built it.
 
So, in all honesty, I feel I wasted my money.I'm waiting for Coffman Labs to send me the schematic diagram and to have it fixed locally, but I have this nagging feeling that this pre's design is nothing out of the ordinary. Again, I stress this point - the pre section seems to be OK, and a stock Foreplay III outperforms it in all objective measurements. A Music Reference RM-5 absolutely smokes it, again, in all objective measurements. Sure, the H1-A is beautiful and nothing else looks like it, but I should have heeded Stereophile's review on the G1-A about its build quality and problems and just stayed away.

 

[Amish]

"Hello all.
 
I was looking for a preamp and a friend of mine sold me something I had never heard about... a Coffman Labs H1-A.
 
He showed me pics. I fell in love."

 
 
And your friend didn't bother to mention this? Good friend.

 

[fjhuerta]

Nah, he's a good friend. I think he only used it as a pre and never noticed the headphone amp was shot. I may even argue that there's so much 2nd Harmonic Distortion this pre sounds "special" because of it.
 
I'm still waiting for a schematic to get the unit fixed. I'll try to review it again.
 
One thing I noticed is - I used RMAA to measure distortion, FR, etc. of an Aune T1, a fully modded X-Can V2 and the Coffman unit. From the looks of it, I do not think the Coffman will be able to approach the objective performance of the Aune T1. It's pretty much the cleanest pre / headphone amp I've ever measured. The X-Can is in second place currently, and the Coffman in dead last.
 
We'll see. It's been months since I bought the thing, and haven't been able to get it working. Caveat emptor, and all that.

 

[SodaBoy]

  Well, the love affair was short-lived.
 
The pre is stunning and beautiful. So far, that's pretty much it.
 
The headphone amp is broken. Frequency response is -26 / +3 dB from 20 to 20 KHz. THD is close to 10%. Separation is around 40dB. It's useless.
 
The preamp has very high distortion levels - when compared to, say, a Foreplay III.
 
After 5 minutes of using it, smoke started blowing from inside. A resistor went up in flames. I took it apart and saw a rat's nest of wiring, blobs of solder everywhere and - A LOOSE WIRE inside. I don't know if it was supposed to be soldered. It had solder on one end and a crimped and inuslated end. 
 
My Foreplay 3 is better made than this - and I built it.
 
So, in all honesty, I feel I wasted my money.I'm waiting for Coffman Labs to send me the schematic diagram and to have it fixed locally, but I have this nagging feeling that this pre's design is nothing out of the ordinary. Again, I stress this point - the pre section seems to be OK, and a stock Foreplay III outperforms it in all objective measurements. A Music Reference RM-5 absolutely smokes it, again, in all objective measurements. Sure, the H1-A is beautiful and nothing else looks like it, but I should have heeded Stereophile's review on the G1-A about its build quality and problems and just stayed away.

I can't believe there's a preamp named Foreplay III lol.

 

[fjhuerta]

http://bottlehead.com/
 
I'm guessing you are going to have a blast with the rest of the product's names.
 
I won't be reviewing the G1-A after all. The designer was in contact with me and he told me I have a prototype, not the final product. So every observation would be invalid. The amp is supposed to be built that way, since it was a test mule. And problems are to be expected. Damon Coffman is a most excellent person, and he'll help me get the G1-A as close to the final product as possible, but that wouldn't be any sort of guarantee that my unit would perform to the specs of a real product. Also, he mentioned the unit has the line output as sort of a bonus, and that the strengths are as a headphone amp, so my previous observations may be pointless, too. So I guess I won't be updating this thread anymore.