I'm posting this in the Lab because it's about a DIY project even though it's also a review.
A few thoughts about the Hagerman Technologies Cornet phono preamplifier.First, this is a tubed phono stage using 2-12AX7, 1-12AU7 and 1-5Y3GT rectifier. For full details see the
web site.
Jim Hagerman sells 1/2 kits, which are just a PCB and an assembly manual. In the case of the Cornet, he also offers a fully machined and silkscreened chassis package which includes the power transformer, the IEC inlet, the power switch, a rectifier tube and some miscellaneous mounting hardware. I chose to order both the 1/2 kit and the optional chassis kit. I wanted to avoid the pain of chassis construction.
As with other Hagerman PCBs, it was of superb quality. Clean layout, silkscreened parts guide, nicely through plated holes and a full ground plane.
I choose to build mine in the fashion of his premium assembled version. This consists of using higher quality capacitors and the addition of a current source, although I haven't added the current source yet. I wanted to get a feel for the unit without it. Reliable Multicaps were used in all locations except for a small cap across the transformer input. High speed fast recovery diodes were used for the heater supply along with Panasonic FC series electrolytics.
Assembly was strait forward and the unit worked correctly the first time. I would not recommend this kit if you don't have some experience in electronics. High voltages are involved and the assembly instructions are, in my opinion, written for the builder with experience.
How does it sound you ask? Very nice indeed. The first thing that struck me was the depth and clarity of the bass. The bass was full and robust and not at all indistinct and uncontrolled as some tube equipment can be. Instead, the nuances of Ray Browns (Ray Brown - Soular Energy) playing were presented with seemingly great accuracy and power. I am not a fan the term "PRaT" but it does describe the feeling engendered by this preamp. A sense of the kick drums and bass being exactly timed.
The midrange was equally sweet and pure. Piano, saxophone and guitar were reproduced with great body and tone, as were vocals, both solo and harmonies. It may be that the tubes are editorializing the sound (what doesn't?) but if so, I very much enjoyed the effect.
The top end seems slightly rolled off and it may be that the Cornet needs some more break it. No question it takes time for the capacitors to fully form and the tubes to fully stabilize. I have only about 40 hours on it so far. I need to connect it to the FryKleaner for a few days and allow it to fully break in. The problem is that I have been enjoying it too much to remove it from my system.
I don't have any ultra high end phono stages to directly compare this with and my turntable certainly isn't the best but I was able to directly compare it with a Musical Fidelity X-LPS (BlackGate's, HexFred's, Film/Foil input caps) and a fully tricked out Hagerman Bugle. The Bugle was built with Bybee filters on the input, a Bolder Cables Nitro power cord and Bolder's Nitro wiring.
In my system the Bugle was noticeably better than the Musical Fidelity. It provided greater clarity and depth and a more extended, cleaner top end. I listened to the Cornet for a while and then swapped in the Bugle. I was quite surprised at the difference. I expected the Bugle to fare better than it did. Bass was softer and less distinct, the midrange lost much of the very natural sounding body. This made the sound seem flat and much less involving. The Cornet provided a better sonic image and the instruments were less connected with the speakers. The only place I thought the Bugle did a better job was on the high frequencies and that may simply be a break-in issue. Adding the constant current source should provide additional detail, and along with some additional break-in, will hopefully provide a little better top end. Not that it's bad, just a little softer than I believe is correct.
There are a few things I didn't like. None are major and all are easily addressed. First, while the chassis was accurately machined and well finished, I was somewhat disappointed in the thickness of the material. It was quite thin and very resonant and prone to ringing. The judicious application of damping compound took care of that but a slightly thicker gauge of material would be nice. Secondly, the locations of the tubes are not indicated anywhere in the manual or on the PCB. Not a problem if you read the schematic and trace it on the PCB but it would be nice to have a mention of locations in the manual. The third item was the addition of a .01uF capacitor across the power switch. In my system switching the Cornet off caused a pop from the speakers. This occurred even if the selector switch on the preamp was not set to the position where the Cornet was connected. The inclusion of the small cap eliminated any turn off noise.
Bottom line: A great project that sounds great. My total investment was about $500 or so. Not a lot less than the cost of a factory assembled unit but I gained the pleasure of building it and the knowledge of how it's built.
Mike
Edit - added images
