2. amps-preamps
  3. 150326-134951

Eico HF-81 question for those that have one and moved on from it or returned

I've been running a restored, complete stripped chassis upgraded wiring/resistors/caps, Eico HF-81 since 2000. It's running NOS Mullard 12au7, 12ax7 and Tungsram EL-84 tubes and Telefunken 12ax7 pulls from a Fisher tuner in the phone section. Sounds wonderful with Bozak 302a and N.E.A.R. Model 80 speakers. My source is mostly vinyl on a Thorens TD 126 MkII with Ortofon Super OM-40 and a Musical Fidelity A2 CD. I do stream Pandora through a tube buffered DAC on occasion.

I've got the itch to try something else but am wondering if I'll be chasing my tail and end up right back with the Eico after having spent a bunch of money.

I'm considering a Mapletree Ultra 4C preamp as I have a good supply of NOS 12sn7/12sx7  tubes. Amps I'm looking at is a Bob Latino ST-70 or Primaluna.

Listening material I'm classical, jazz, country, opera, big band, choral, etc...

So for you that have had a HF-81 and moved on what did you go to and was it a real improvement? Those that returned why did you and from what?

Thanks


gawgaboy
roberjerman
4,319 posts
 
You might just have the best HF-81 in the US! I'd keep it and just go for a speaker upgrade instead of another tube amp. Altec Valencia's or LS3/5A's, eh!
roberjerman
4,319 posts
 
I have two nicely restored Scott tube integrateds so I know the appeal of such classic gear! Especially when paired with classic speakers!
atmasphere's avatar
atmasphere
11,807 posts
 
A Stereo 70 will have more power of course.
But if your Eico is as heavily rebuilt as you say, the sound differences will be mostly about the output transformers and other parts quality. Eicos came stock with ceramic disk caps for coupling caps but it sounds like those have all been changed out; OTOH the HF-81 had pretty good output transformers. The only big difference I see is the Mapletree stuff uses the 6SN7 family which IMO/IME is a better sounding tube than 12AU7s.
So my opinion is that you will be making a bit of a change for more power, not more bandwidth and otherwise slightly different sound (you'll have to play with interconnects between the preamp and amp which will affect things). I don't think it will be a dramatic improvement; with your amp you don't have to deal with the interconnect issue. It might be possible to have your amp set up with 6SN7s - that would be possible if the power transformer can support their filament requirements.
dekay's avatar
dekay
5,570 posts
 
I owned a stock refurbished 81 in the 70's 80's.

The can caps were replaced and something feeding the rectifier tube was changed.  

The coupling caps were also replaced with Yellow Illinois brand caps which I was told would sound similar to the originals.

Sources were various Thorens TT's, Nakamichi cassette decks and believe it or not Beta and VCR video decks used to record LP's and to record/mix live music.

The only thing I found lacking was the 81's phono section.

I patched in the phono section of an Advent 300 receiver which easily bested the stock Eico phono section.

So maybe just try an outboard phono preamp for starters.

Though I haven't used it for years I now own a Pilot 240 integrated amp and the same thing goes.

The line inputs sound great, but the phono section is lacking.

During the time I owned/used the 81 I also used Mac 30's and various modified Dynaco Stereo 70's (in mono block and stereo versions).

The 30's were stock/refurbished and the 70 mono blocks had a tiny transformer and other parts added to the power supply (maybe used as a choke).

The above were used with the preamp section of an Advent 300 and sometimes a Dynaco PAS 3X preamp.

The 81 held it's own against the Mac and Dynaco gear.

I sold them all in 1986 and didn't own another decent rig until the late 1990's.

DeKay
More to discover