Review: Coffman Labs G1A Tube preamp

Category: Preamps

Stop what you’re doing and prepare for a trip back to the past; back to a time when American manufacturing was at its peak, quality won out over quantity and China was something you ate off of. This was a time when audio equipment could be purchased and it would last a lifetime. People were excited about music and there were even brick and mortar shops the sold it. Those of us that are old enough to remember those days are sad they are gone. I have never met Mr. Damon Coffman personally but it’s my understanding he has an innate love of music. I think he has done something to bridge the past and present and that something is the G1A preamplifier.
If you live in Portland and are an audio nut, chances are you know Kurt Doslu. Kurt is a quite amazing individual and over the years I have grown to trust him. For many in Portland, Kurt’s audio store is more than a retail store, it’s a hang out. I have to confess I am one who likes to spend time in Echo Audio. Like most audio shops, Echo is filled with cool electronic devices, some new and some used. Unlike most audio shops; when you enter Echo Audio you are welcomed as a guest. You won’t have salesmen lurking over your shoulder or hear someone muttering “don’t touch that”. It’s for that reason I have spent countless hours in the store talking, laughing and learning from the staff. Last summer I was asking Kurt about my audio system and suggestions for taking it to the next level. I am happy with the current level of fidelity but like all audio nuts, I am always thinking about the next step. I’m a man of limited resources, so when I come to Kurt it’s with the understanding that price is very much an issue for me. This particular day Kurt asked me to go have a beer with him. We headed around the corner and stepped into a little Portland dive for a micro brew. The whole time he had this little grin on his face. The conversation eventually wandered from our kids to audio gear and that’s when he told me about the Coffman G1A. Kurt isn’t a fellow that gets real hung up on gear, I see him as more of audio encyclopedia music guy so when his eyes light up, I sit up and pay attention. Kurt has talked me out of more purchases at Echo Audio than I can remember, so he caught me a bit by surprise. He told me about Damon Coffman and his pursuit of the perfect phono pre. You see, as the story goes; Damon started out trying to build a phono pre which ultimately morphed into the G1A. This isn’t a guy that just threw something together on a tech bench; he was going for success of design. He took plenty of swings at it and ultimately hit a home run. The whole time I am speaking with Kurt, I am thinking “but I don’t need a new preamplifier”. I am a diehard Modwright fan. I’d still be listening to PA gear through studio monitors if it wasn’t for Dan’s SWL 9.0 SE. Then again, it was Kurt’s advice that brought me to tubes and ultimately the Modwright pre. We left that conversation with the promise of a demo when the G1A showed up at Echo Audio.
After the units showed up, I started to get the “itch” and posted on the forum to see if anyone had any more info. I live quite a ways from Echo and I can’t always get down there. I did get a reply and it sounded very promising. I got a call from Kurt about a month ago and he had a unit for me to try. By this time, I had a chance to take a peek at the G1A but hadn’t got to really sit down with a demo system. What I had heard was very good, but it’s always hard to say what’s going to fit in my system. You can link to my main system if you want to have a peek. I am running the system in a pretty small space. It’s a converted bedroom that serves as a listening room and computer work area. Next, I moved the Coffman out to the garage to try a larger space and a different array of gear.

On to the Review:

I picked up the G1A up on a Friday and had everything ready to go. It came nicely packed in a fairly plain box with the Coffman Labs stamped on the front. I opened it up to find a well packed two chassis preamp and a small, concise owner’s manual. I breezed through the manual and didn’t see anything too far off the normal “best practices” list but I missed something, which I will explain later. My point here is, I should have read the manual more closely but like a kid at Christmas, I wanted to get to the batteries and see the toy spin. Take your time, read the manual. You would think an IT guy would know that. When I got my first look at her, still in the clear plastic, it was even more impressive than the photos and the demo unit. The first thing I thought of was the old Ferrari 250TR Spider with six Weber two barrel carburetors. I have since nick named the main chassis “The Coffman Carburetor”. I imagine everything under this hood is probably in line with a Ferrari; for a preamp it’s got some heft to it. I spent some time just looking at it. The chassis is heavy duty … no stamped metal here, machined aluminum panels securely screwed together. The sides have been machined to give the unit a distinctive look but I prefer a more standard look. Never the less, it does give you something to admire for your $5600. The last time I took something new home to demo, I ended up buying it. I know what this baby cost and knew it was going to be a rough ride if I fell in love with it. So I think my first glance had an ounce of worry, and for good reason. Just like the top the back of the unit was equally impressive. Two rows of gold RCA connectors and just enough inputs to keep me happy. With a modern D/A converter all the digital stuff comes in on one analog input and that leaves me a couple of extra for whatever comes along. I have been thinking about a Modwright SACD player at some point in the future. The phono section is broken into two inputs with a toggle switch to select what type of cartridge you want to use. I imagine you could setup two turntables simultaneously if need be but I don’t think that will be an issue with me. This brings me to my first point of contention. The ground lug seems less substantial than the rest of the unit and its red … just seems wrong to me. I expected to see a big ole brass Cardas lug with a machined knob, knurled with some exotic pattern, not this little red thing. I’m glad to report everything else is beefy as all get out and Costco sized so whining about a ground lug may seem petty but it’s a review, so I thought I would throw it all out there. The other aspect of design I found really cool are the machined feet. They look like they took should, not some giant bathtub claw. The machined aluminum feet fit the design nicely and make the unit look even classier. There is nothing loose or cheap about this preamp. I have had my share of vintage McIntosh and Harmon Kardon equipment on the rack and it has the same feel to it; like it could survive (God forbid) a drop to the floor. The G1A reminds me of classic, well made vintage gear but this thing is brand new. Imagine getting a chance at an NOS, McIntosh C20, add into it all the modern advances in materials for the passive components and a warranty. What’s that worth? Man, $5600 wasn’t looking so far out of line (gulp). I initially set the two chassis side by side which was a mistake – there is a reason they are separate. A quick email to Kurt and I had that slight hum sorted out (read the manual).

The Sound:

The first thing I noticed was its dead quiet. With nothing playing, or when things are paused, I hear nothing. What you hear is what is being played and that’s all. I imagine if you have power issues that might play into the mix but I am running pretty standard after market power cables and a power conditioner that is also run of the mill. From a cold start to 60 minutes in, which is as long as I have tested a warm up, I get no noise from the pre at all. As for the music selection, I slanted towards rock, blues and a bit of jazz. I’m a rock and roll guy so I’m not about to sit here and listen to orchestral music for a review if that’s not my cup of tea. In addition, the pre has made several back and forth trips from the garage system to the main system so I injected a fair amount of variance to the testing. I wanted to know how this thing sounded vs. what I already have.
The first test was impressive; I started out with the MoFi gold pressing of Fragile Yes. I have always considered it a suitable test CD with its dramatic swings in intensity and instrumentation. First improvement I noticed was the sense of space. Not just imaging but it really made me feel like the smaller room was larger. I had the sense that the instruments had spread out. I was typing out notes and as I would spin around, I kept stopping to just listen. I can honestly say, I have heard the disc many times but I never hear it sound like that. Then I did an odd experiment; I put the MP3 on my iPod and went out on the deck and listened to the same song. Then back to the bedroom for another spin … holy cow, I always struggle with describing what things sound like and I hate drawn out sonic explanations with adjectives like “chocolaty” and “velvet”. What I noticed was the equivalent of having the music smashed down and bled together. In the MP3, the instruments were much more difficult to pick out and they seemed quite dull and lifeless. Conversely the main system was sharp and spot on, drums snapped keyboards jumped out and vocals were clear and defined. It really gave me a sense of scaled improvement which is what I wanted. I went to my 24/96 HD track collection next. I tried out Jackson Browne – Running on Empty. I stopped typing at that point and just fell into my chair. Snap, an hour went by. I lost the whole thing … I remember a big smile and renewed love for audio but where did the time go? I guess a preamp can make that big of a difference but is this thing a time machine?
The next major moment with the Coffman came out in the garage system. I was running a Threshold T-200 and my Paradigm S4’s. The table was a Technics SL-1210 M5G with a Denon 103r mounted. I had a good friend over for the first spin of Pink Floyd – Wish You Were Here. My friend is not a big audio guy but loves all things Pink Floyd. We spent about 2 hours warming up, we had a few beers and I was playing our normal Rush, Zeppelin and classic 70’s rock staples but then the time had come. I set up two chairs about 8 feet back from the Paradigms, the speakers were set about 2 feet back from the wall and had 4-5 feet of space to each side wall. The Coffman had run for about 3 hours and was ready for its first phono test. Every few years I have these defining audio moments where I just get leveled. This was one of those nights. Not sure if it was the beer, the company or a lucky speaker placement but I have rarely heard anything like that LP played that night. My good friend Dave’s jaw was on the floor. He insisted on playing the first side twice and we them listened to the whole album. He went on and on about how good it sounded, so I know it couldn’t have just been me. The pre spent about two weeks in the garage but now has retreated back into the computer room. For the second time I have noticed a wider soundstage and better imaging and I don’t consider my Modwright SWL 9.0 SE a slouch. I have everything done to the Modwright I can, including a new set of Amprex 7119’s and an ARC PH3 SE phono stage with NOS Mullard 6922’s. I have to say, the Coffman G1A with its standard tube set bested it twice. I have noticed my Pandora seems improved and all my FLAC collection seems to enjoy that same increase in clarity and wider soundstage. I have tested some female vocalists and the quietness of the pre seems to bring out detail in the voice I hadn’t noticed before. Jazz instrumentation also seems to benefit from the addition of this component. The imaging allows the music to flow better and give a more “live” effect to the music. Another amazing LP that jumped was Steely Dan – Aja (Mofi Pressing). This moment was in the smaller room with everything turned down … I waited until the girls hit the mall so the house was absolutely quiet. I played the whole thing … amazing LP, amazing sound.

Headphone Amplifier:

Next is the headphone section which I have learned to love. I live in a relatively small house and I have received more than a few “in house” noise complaints. I often wake before 5AM and have the coffee flowing well before the sun rises. My significant other work swing shift so our schedules couldn’t be more opposite. I picked up a set of Sennhieser HD-650’s two years back and they have saved my relationship. When I get going in the AM, I like my music. Most days I can listen at low volume and I can get away with it but for those times you get the urge to air it out, a headphone amp and a good set of cans can really save … well, your can. I have been running an Antique Labs - MG Head OTL Mark III DT tube headphone amp and was quite pleased. I started with a Shanling PH-3000 and that was a huge step, then I jumped to the Antique Labs. The EL-84’s in the MK III were upgraded to Mullards and I have been a very happy camper so far. The Coffman is a real step up and it’s noticeable immediately. The Antique Labs is great but I always felt like the mids were a bit lacking and the top is slightly rolled off. Never the less, for what I paid I consider it a bargain. The Coffman clears up those problems and more. Lately in the mornings I have been reaching for the Sennheisers vs. firing up all the gear.

Decisions, Decisions:

What to do? I had been seeking out a Modwright phono stage to go with the SWL 9.0 SE but they are few and far between. The Coffman seems to be a big jump forward in the phono stage arena and eliminates two additional components with associated power and interconnect cables. Finally the G1A seems to give me all that I want from a headphone amp and is a nice upgrade as a bonus. It’s got a vintage style that I keep coming back to. $5600 opens up a ton of options but when you know you have a winner, it hard to go another direction.


The Coffman G1A seems to have bested my system in three ways:

1. Linestage seems livelier and projects a sound field a mile wide and a mile deep.

2. Phono pre is a big jump forward, dead quiet and with all the delicacy I was missing with my ARC PH3-SE.

3. Headphone amp is improved and allows me to get rid of yet another box.

It seemed to show improvements in both systems in particularly in the garage with the Altec horns and Threshold T-200 amplifier. It’s not an overly “tubey” sounding pre but it did soften the horns just a bit and brought the system to a whole new level. If $5600 isn’t out of your budget and given all you get for the money, then I think the Coffman should be somewhere on your list to try. Not sure where it will be marketed and I certainly wouldn’t advise buying equipment without listening to it first. Looks like six months of Romen noodles and bad TV for the horse because this unit has found a new home.

Associated gear
System 1 :
Proac D Two Monitors on Target sand filled stands
Paradigm Signature S4 Monitors
Threshold SA/6e Class A Monoblocks
Quicksilver Mini Mites tube monoblocks
Mark Levinson 360s D/A Converter
Monster Signature Power Conditioner
Wadia 23 CDP (run as a transport)
Rega P25 Turntable
Benz Micro Cartridge

System 2 :

Threshold T-200 Amplifier
Carver M500t Amplifier
Emotiva XDA-1 DAC
Sony NS9000 ES SACD
Altec Model 14
Klipsch Heresy
Paradigm Signature S4
ADS 710

Similar products
Modwright SWL 9.0 SE

Audio Research LS-15

Audio Research PH3-SE

Antique Labs MG Head OTL Mark III DT
Update :

One thing I forgot to put in the review is the use of a remote controlled DAC in the garage. It pretty much gives me my remote controlled volume, which is quite nice. It’s something to consider if a remote control is a must but you desire a pre that doesnt have it.

There are ways around everything.
Appreciate all the time and insight you put into this review. After auditioning a G1-A at home I could not part with it either. Damon Coffman created something really special.

Nice review, the build quality looks outstanding. Not surprising that you really enjoyed it. Enjoy your new amp.
Thank you very much for your review! Thanks also for calling attention to the ground lug; I'm adding a section to the FAQ to discuss it. There are two basic reasons I didn't go with a solid brass lug. One is technical (see FAQ), and the other is related to the vintage nature of the G1-A. If possible, I used vintage quality components--this is a 5-way grounding post from the 1950's. I like the extra flexibility of this post (multiple attachment methods) and decided to include it in the product. As you will read in the FAQ, it does not affect the quality of audio playback.

PS: You are right; I do love music.

Damon Coffman, Coffman Labs.
Hello Damon or Horseface,

I do live Oregon and have visited Echo Audio before, does Kurt have the Preamp available at his store to listen to? I am very interested in this preamp mostly because of the builtin phono section? Any professional reviews in the works?
Hi Bobheinatz - (re) your questions: ToneAudio Magazine also reviewed the G1-A in their Aug 2012 issue(#48). Jeff Dorgay gave the G1-A an "Exceptional Value" award and noted he bought the review unit. I know Echo has one hooked up in their main listening area, so you might want to check it out when you have a chance. Cheers
Last I checked Kurt had the G1A plugged into a pair of B&W Nautilus 802 D2's ... amazing sound. That was on Friday, and they were loaded with cool gear. I'm sure he can setup what ever you would like to demo. The new store is really nice that way.
Thanks for sharing your insights about this preamp. I have yet to be able to find the dimensions for this unit - and its associated power supply. Can you help me with this?
Hi Bjast -- I got out my tape measure...

the G1-A is about 14" deep (including front knobs), 7" high and 9 1/4" wide. You'll want to have plenty of extra clearance above tubes for cooling

The power supply is about 12" deep, 5 1/2" tall and 6" wide. Cheers