[[email protected]]

Hi,

I've been using a pair of Erath LWE-1 speakers for a few years now, and
was preparing to ebay them; but while looking for info for my auction,
I became fascinated with all of the descriptions i read of how
incredible they sound using Erath's bass enhancing negative-feedback
circuit: "flat frequency response throughout 20-20khz" "pants flapping
bass" etc...

So, now I really want to hear these and am looking for a good SS amp,
at least 100w to drive these. I'm hoping some people will offer
suggestions to a newbie. To give you an idea how bad off I am as far
as gear is concerned, my amp is a Kenwood SS KR-A40-40 (40w) I would
like to spend $300 or less if possible, but could be convinced to spend
twice that or more if it is really worth it. Feel free to throw out
some good value, lower cost amps, or any other suggestions you might
have.

One of the things that really clinched my decision to keep these was
speaking to Louis
Erath earlier today on the phone. I thought it would be good to post
it on usenet as information about these speakers is rare.

---------------------------------------------------------------------
Here's a summary of what I asked him:

I first asked him for suggestions for a suitable amplifier and he said
that
since I still had the previous owner's clip kit for a McIntosh MA-5100
(SS amp/preamp) it
should work for just about any SS amp, but yes, clipping the negative
feedback from a
certain few amps can make them unstable. I asked him for any
suggestions as far as brands and he rattled off Pioneer and a few other
common brands so I got the impression that it really wasn't a situation
that demanded alot of apprehension. He did say that 100w is ideal,
especially if you like to listen at high volume, otherwise 50w is just
fine. In
fact, the original LWE-1 amplifiers were 60w and sounded great.

A side note: Previously I spoke with someone who had worked in Erath's
shop and he said that one of the amps they had problems were some of
the Sansui models.

He said to get a circuit diagram for whatever amp I use (probably from
a service manual as they are rarely included in users manuals) and send
it to him and he would be happy to mark where I needed to clip inside
the amp.

He mentioned that originally the LWE-1s were sold with their own
amplifiers which were 60w but during the early 70's, many Japanese-made
integrated amplifier/tuners were getting popular and, in order to sell
more speakers, he came up with the clip-kit idea so that people could
use those systems.

I told him that I checked out his schematics on the US patent website
and I wondered if
the "incandescent bulb" he used in his negative feedback circuit might
be burned out after 37 years. He said that there was a good chance that
the bulbs would still be good since it was a low power application and
that bulbs degrade with hours of use, not time. Also he said that the
bulbs served only a secondary function in the circuit; to attenuate the
amount of negative feedback needed for bass response at high volume,
because human ears are more sensitive to bass at those levels.
(Fletcher-Munson curve)

He said that there is one problem that can happen and that is that some
amps, not
many...would oscillate at high frequencies 40-50khz, and that it is
ideal to hook up an
oscilloscope or, lacking that, an LED + resistor to check if there is
any oscillation when
clipping into the negative feedback on your amp. For this reason, he
now includes an LED indicator in the chassis of his new stand-alone
negative feedback networks he builds for his newer generation LWE
speakers.

Finally, I asked about the room gain knob on the back of the speakers
and he said this
adjusted the negative feedback +/- for larger rooms.

He also mentioned that his listening room is 18' x 15' which is ideal
for listening to
these speakers.


Here is Erath's patent for the neg-feedback crossover Pat# 3,449,518 :

http://tinyurl.com/gkc9u

Pics of my LWE-1s

http://www.boomspeed.com/distopian/lwe02.jpg

http://www.boomspeed.com/distopian/lwe03.jpg

Page of an LWE review in Audio magazine from 1968:

http://www.boomspeed.com/distopian/lwe01.jpg

Reviews of Erath LWE-1 on audioreview:

http://tinyurl.com/pedle

Louis Eraths website for his new speakers:

http://lweloudspeakers.com/

[Eeyore]

wrote:

Hi,

I've been using a pair of Erath LWE-1 speakers for a few years now, and
was preparing to ebay them; but while looking for info for my auction,
I became fascinated with all of the descriptions i read of how
incredible they sound using Erath's bass enhancing negative-feedback
circuit: "flat frequency response throughout 20-20khz" "pants flapping
bass" etc...

So, now I really want to hear these and am looking for a good SS amp,
at least 100w to drive these.

Any good *modern* amplifier should be up to the task.

Don't believe those twits who talk about 'magic sound' etc.

It's really quite hard to make a bad amplifier these days unless you're
really trying !

Graham

[Eeyore]

wrote:

http://www.boomspeed.com/distopian/lwe03.jpg

EV T35 tweeters ? Wow ! I have a couple here on the shelf !

Why not treat yourself to some nice modern speakers ?

What's your budget ?

Graham

[[email protected]]

I am fascinated by this negative-feedback circuit; apperently it was
later licensed to CM labs who produced a line of amplifiers and
speakers based on this concept.

Also, I read that some of the earliest subwoofer designers may have
been inspired by the LWE-1's bass response. Read Steve Zipser's
comments on this old usenet thread:

http://tinyurl.com/h7h42

I don't know, I just can't help but be curious about a damn near 40
year old pair of speakers that are in this great of condition, with all
the original drivers, that consistently get rave reviews from anyone
who has ever heard them hooked up correctly. I just gotta hear 'em!
;-)


Eeyore wrote:
wrote:

http://www.boomspeed.com/distopian/lwe03.jpg

EV T35 tweeters ? Wow ! I have a couple here on the shelf !

Why not treat yourself to some nice modern speakers ?

What's your budget ?

Graham