Amp/Preamp Asylum: REVIEW: JWN Amplifiers EICO HF20 Amplifier (Tube) by nurxhunter

Model:	EICO HF20
Category:	Amplifier (Tube)
Suggested Retail Price:	$2000
Description:	PP Tube Monoblocks JWN Modified
Manufacturer URL:	JWN Amplifiers

Review by nurxhunter on April 10, 2011 at 08:50:30
IP Address: 71.185.180.164 Add Your Review
for the EICO HF20

Eico HF-20 monos done over right. As usual, Jim guts the old caps and resistors and deploys his awesome self-balancing circuit. Old OPTs kept (of course) and uprated new PTs installed on each. With 420v to plates and screens the many power tubes can be used (I tried EHKT88, SED6550, NOS-EL34, JJKT77 and Sylvania and SED 6l6GC). I used Mullard M8080 6C4 and an old Sq.-getter LP Mullard 12Au7. Rectifier was Raytheon 5u4GB, for some reason, always my favorite in Jim's amps.

I tried these with my Hammer Dynamic S-12 (97db efficient) both crossed to a sub and not. I had the pleasure of listening to these over 3 long weekends.

These are the best I have heard from JWN. The mid-range was THE BEST I have ever heard from the Hammers, whose strength is mids. The vocals are person-height, about 1 foot forward of plane of speakers--just the way I like it. The sound stage width was excellent, and as usual in this circuit, the depth was excellent. I did not really need the sub. Insofar as Hammers go down to 50hz, a sub is not needed with the HF20 blocks, though with care in blending, a sub helps (the Hammers).

I need minimum of 15W in my large basement (20 x 30 x 8, with insulation all around over concrete and stuffed acoustical ceiling). These sounded MUCH more powerful that the rated 20W peer channel--in fact, with the new circuit, I am guessing 35W each--maybe more.

I am not a fan of vintage gear as to me they sound charming, but ultimately do not have the impact in transients that I like. JWN brings this to the vintage gear with his fastidious circuit. The soldering and layout are quite clean--even the wood surrounds and finished bottoms are way above typical DIY quality I have experienced from others.

I tried many power tubes. Interestingly, 6L6GC sounded best to my ear. I believe this is what the OPTs were originally designed for. The sounds was everything like an EL34--but clearer and with better upper frequency extension. Holland EL34 were excellent as well.

If I were not juggling 2 college tuitions with Tax Day coming, I would have kept them. I work near Jim's workshop, and I provide him with tubes and other treats just so I can listen to his amps on consignment. I have bought several (all the others I reviewed) in the past.

Product Weakness:	None.
Product Strengths:	Glorious mids, full bass, very good extension in highs. Well built. Cohesive in musicality and outstanding depth of stage with great width. PT runs only warm to touch. Point-to-point wired.

Associated Equipment for this Review:

Amplifier: JWN HF20 Monoblocks
Preamplifier (or None if Integrated): EAD Ovation
Sources (CDP/Turntable): Squeezebox 3--battery supplied
Speakers: Hammer Dynamic S-12
Cables/Interconnects: Luminous Audio Axiom Sigs
Music Used (Genre/Selections): Classic rock, RnB, Jazz, Hip Hop
Room Size (LxWxH): 30 x 20 x 8
Room Comments/Treatments: Acoustic damping
Time Period/Length of Audition: 3 weeks
Type of Audition/Review: Home Audition

Amplifier:	JWN HF20 Monoblocks
Preamplifier (or None if Integrated):	EAD Ovation
Sources (CDP/Turntable):	Squeezebox 3--battery supplied
Speakers:	Hammer Dynamic S-12
Cables/Interconnects:	Luminous Audio Axiom Sigs
Music Used (Genre/Selections):	Classic rock, RnB, Jazz, Hip Hop
Room Size (LxWxH):	30 x 20 x 8
Room Comments/Treatments:	Acoustic damping
Time Period/Length of Audition:	3 weeks
Type of Audition/Review:	Home Audition