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Williamson type amps (EICO-81)

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Sure wish I understood everything I just read. Still a good read though.

I wonder why there is such a disparity between the inferiority of the design, and what people are hearing out of this design? Most really seem to like the sound of these little buggars.

BTW John, I don't agree with you that the Cerametallic cones are marketing hype. Cerametallic may just be anodized aluminum -- but anodization results in a electro-chemical transformation of the base metal.

It works good.

Ever read this white paper by Toole & Devantier?



Cary AE-25f>s>SuperAmpf>s> - Sonic Frontiers Line 1 - Sony DVP-S9000ES - Klipsch RF7's

SVS 20-39 CS Plus - Samson S1000 - HSU Research elec. crossover - MIT/Monsters


Inside every small problem is a large problem struggling to get outf>c>s>-- 2nd Law of Blissful Ignorancef>s>c>

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Either Eico modified the Williamson circuit or the article is nonsense.

If the Eico's Williamson-type circuit were that bad, would there be so many units still running fine after more than 40 years have passed since they were built?

Would there be so many people raving about the sound?

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a *typical* anodized layer is between .0001 and .0002 inches thick. it is a process that converts aluminum base material to aluminum oxide. the woofer cones are anodized because if they weren't the cones would

look ratty since bare aluminum *selectively* oxidizes.

I can understand why they anodize the cones. for this

particular application (a loudspeaker) it is purely cosmetic, but why they have to go into this "cerametallic" nonsense and how it improves the sound makes me want to throw-up.

So, why do a couple of people think Williamson amps sound so good? Who knows, why do people buy Bose cubes.

It usually depends on what else they've got to compare it against AND experience. I've got a Heathkit Williamson, it's in real good condition. It's a better amp qualty wise than the EICO, the Heathkit Williamson is a dog.

Remember too, one of the proponents is also pushing the *green pen* CD trick which was a Usenet rec.audio.opinion "joke" that somehow took on a life of its own.


The article is not nonsense. The Williamson amp was very popular with builders because it was a decent amp early in the field of audio. The plethora of Williamson amps out there is due more to the fact that kits were a cheap way to go in the 50s. Like Dyna in the 70s. I've got two Williamson DIYer amps (Heathkit and Scott) given to me by my mentors. It does not sound terrible, BUT tube design peaked LONG AFTER

the introduction of the Williamson amp. Yes, there are variants to the design and the original has been improved. BUT if your going to go to the trouble of buying into tubes, at least get amps designed by the best and brightest of the era.

This message has been edited by John Warren on 06-08-2002 at 04:48 PM

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So what's your beef? Is it with the Williamson circuit design, Heathkit or just anything EICO? Design is one part of the equation of a product, implementation is another. Rear engine design in auto had it's detractors for years. Chevy took it to new lows. Porche has taken it to new highs of refinement, we won't even mention F1 here.

Yes, I have an HF81, and it does sound very good. Sorry your Heathkit doesn't sound better. I hope you feel better soon.

Klipsch out.

2 Channel system

1974 Belle Klipsch

Welborne Labs 2A3 Moondogs

Cary SLP90L Preamplifier

Asusa modified PP-1 Phono preamplifier

Rega 3 turntable, Rega 300 tonearm; Grado

Rega Planet CD player

AudioQuest Bedrock speaker cables

Silver Audio Hyacinth interconnects

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I dont think I have ever agreed with a thing from John Warren's keyboard besides his use of Klink as an amusing sidelight.

These new examples of sweeping generalizations are right on par with his other posts, in my opinion.

Each to his own. His use of distortion figures points to problems unknown.

Nice Troll, though. I would say I listened to quite a few tube amps from 30k down to $100. I have never thought McIntosh tube amps to be the pinnicle of tube design sonically speaking. I have heard directly heated triodes, triode wired, class A, Williamson, Ultralinear, SET, etc. I own more ultralinear wired amps than strictly Williamson. I currently have a Class A, Triode Wired KT-88/EL-34 amp going right now in one room while a pure Class A, true directly heated triode amp in another. In the last room, I have a basically stock Williamson derived 1960 amp. All have great characteristics.

The directly heated triode amplifier sounds the absolute best to me and to 99% of the people (audio goons or not) that drop in.

To say all Williamson amplifiers sound the same is absurd and shows a lack if knowledge of the difference between transformers and use of the circuit.

Frankly, you wont read this type of tripe from me these days. Many versions of tube amps sound excellent and some of the oldest circuits sound amazing if implemented correctly. In addition, the use of IM distortion in a blanket statement shows a basic lack of understanding of how these figures correlate with good sonics.


ps- I came back in here for this? Christ... A vacation never felt so good.

Phono Linn LP-12 Vahalla / Linn Basic Plus / Sumiko Blue Point

CD Player Rega Planet

Preamp Cary Audio SLP-70 w/Phono Modified

Amplifier Welborne Labs 2A3 Moondog Monoblocks

Cable DIYCable Superlative / Twisted Cross Connect

Speaker 1977 Klipsch Cornwall I w/Alnico & Type B Crossover

system one online / alternate components / Asylum Listing f>s>

This message has been edited by mobile homeless on 06-08-2002 at 05:55 PM

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oh, a vacation?.....I figured that with all your *knowledge* about electronics you might of

electrocuted yourself.

ps- so your sh*tting on a pair of McIntosh Mc30s?

Ok, you win, I'd trade you the Macs for the Eico unit but sounds to me like you wouldn't be interested.

This message has been edited by John Warren on 06-08-2002 at 07:58 PM

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I'm not touching the subject with a ten foot pole Wink.gif



HH Scott 299 Amp

HH Scott LT-110B Tuner

HH Scott P-87 Turn Table

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1985 Walnut Heresey I W/Layne Audio Woofers

KSW-15 Subs>c>

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John, I believe "vacation" was a rhetorical metaphor. BGO (Brilliant Glimpse of the Obvious).

I will state up-front that I have neither the technical knowledge nor the listening experience to adequately challenge your opinion. But what I can state (as an adult, and I tell this to my kids all the time), be very careful when making "absolute", all-encompassing statements, e.g., "ANY Williamson type amplifier". I have found, in life, that whenever I made a statement like that, the other proverbial shoe was moments from falling on my head. I now keep my statements a little more moderated to allow for "wiggle room" when I find I am wrong, either somewhat or totally.

I have always been a McIntosh fan. My grandfather was the first audio dude I knew, and he had Mc's 'n Tubes going back to the '50's. I've owned a MC240, a MC30 (for mono), an MX113 and MC2105 (yeah I know, there's SS in there). Cool stuff, and they sound great with Klipsch boxes. I highly regard Allen Songer's input on these as well, and I have great respect for Mobile's open-mindedness on a lot of products he's reviewed for me (I know that that must sound a little surprising to you, but he IS very open-minded, believe it or not). Anyway, I have a very emotional and nostalgic link to McIntosh gear and I'll leave it at that.

When I bought my used and very clean Eico HF-81, loaded with Mullards, I wasn't expecting to hear what I heard at all. My amp at the time was Cary's Triode-wired SuperAmp, which actually sounded great, if not a bit too articulate at break-in. I listened to it for about two months, and sent it down to Kelly for a work-over and another opinion. In the meantime, I scored this little Eico to fill as a second amp, and when I hooked it up to my Klipschorns, the music just danced. The sound was articulate but rich, and it just felt like a "montage" thing, more than the sum of the parts. My wife, an innocent bystander, agreed by sitting silent for ten minutes, listening, and finally saying that it beat the heck out of my wonderful Cary. I would certainly say that this little Williamson gave my McIntosh's a serious chase. In fact, I'll just come out and say it ... this little Eico, Mullards and all, is the nicest sounding amp I've owned at any price, not that that means a lot since I'm not in many people's league in terms of experience.

But music is emotion, and when the hair on your arms stands up, either you're looking at a pretty naked woman with a martini, or you're listening to some damned fine music through a great sound system.

My very humble, undignified, $0.02.

Over and out.






Eico HF-81

Eico HFT-90

AES AE-25 "Superamp" (in temporary retirement)

AES AE-3 Pre-amp (in temporary retirement)

New Tube 4000 CD Player

1976 Klipschorns (KCBR's & ALK'ed)


Klipsch 1968 ALK Cornwall "II"s (LF/RF)

ALK Belle Klipsch (Center)

Klipsch Heresy (RR/LR)

Klipsch KSW-12 sub

Sonic Frontiers Anthem AMP1 (driving Cornwalls)

Sonic Frontiers Anthem AMP1 (driving Heresy's)

Denon AVR-4800

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Regarding the Super Amp and your description of it being a little too articulate.

I think the word you are really looking for is 'incisive'.

A bit of a cutting quality. Sharp edged I think.

Maybe not the best match for the K-horn, that might probably like an amp that rolls the top off a little, or a bit warmer midrange.

With Reference however, that little thing smokes, huh, I mean - sizzles, well - whatever.



Cary AE-25/ S F Line 1/ S9000ES/ HSU x-over/ SVS CS+/ RF-7 Klipschcones®f>s>

Exigency is the matriarch of ingenious contrivancef>c>s>

This message has been edited by deang on 06-08-2002 at 10:51 PM

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John, quite a pithy retort although a bit easy, if not over the top. Where is the Klink picture when you need it? I expected a lovely "jellyfishing" Cornwall graphic, a remembrance from days gone by.

I would like to apologize for my first sentence in my previous post. I think you do have some vintage horn construction knowledge, some of which I have found enlightening.

As for your MC30 statement, another over the top rejoinder, I was doing anything but lambasting the MC30. As I have said in the past, I think McIntosh made some amazing amps build wise as well as doing some very interesting and innovated designs, designs that are built to last with just about the easiest on tubes circuits there are. Vintage tubes in a McIntosh are about the safest place they could be. What I said was that McIntosh sonics have just never lit a fire for me. Others love them and there is no denying their lasting value. I just prefer to go a different route in tube amp sound. But dont take my statements as me "sh*tting" on McIntosh!

I would gladly have an MC30 for sampling and since you have suddenly taken a love to thy EICO HF-81, I would be happy to mail out my second one in fine shape for your enjoyment, in temporary exchange. I find the kindness of your offer quite touching. Indeed, I get a bit misty eyed when I see your soft side come to surface.

Yours as always,


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Your posting is interesting from many angles. I enjoyed the article by Stan White. I can't figure out what you are saying here, however.

The HF-81 appears to be a derivative of the Williamson, having addressed the listed problems. For the HF-81:

* Initial gain uses a pentode. Due to the inherent non-linearity, but high gain of pentode operation, this is a commitment to a feedback design. Possibly the Williamson problem here is that although triode gain is linear, it is not high gain and limits feedback effectiveness.

* Phase splitter is common cathode (not concertina like the Williamson). Unlike the concertina, the cc also provides additional gain for effective feedback.

* The high voltage problems in the Williamson design are not repeated in the HF-81.

* Both designs use triode connected pp output. I don't know why the HF-81 didn't use the ultra-linear connection. But I don't think it was to try to be as much as possible like a Williamson. Maybe Eico got a deal on thousands of non-ultra-linear transformers.

After all of the above, I don't understand the point in comparing the HF-81 to a Williamson design, except to explore the evolution, which I believe is important. They are certainly not equivalent designs. Along those lines I do want to explore a few points possibly at the expense of readers of my earlier postings).

* The HF-81 appears to effectively operate in the single digit to fractional watt power region utilized by Klipsch speakers. I believe this because of its overwhelming acceptance among many individuals who contribute to this site. I believe this is because its distortion and noise are low in that region. Also, because the word "detail" is frequently brought up in reference to the HF-81, I suspect the fractional watt operation is exceptional, especially for a feedback design.

* One way to improve low level performance in a feedback design is to increase feedback. The Job amplifier does this. Also, the "Horn Mono" by Quicksilver uses increased feedback to improve low level performance. The HF-81 appears to follow this approach.

* I suspect that the "detail" capability is enhanced by the small output transformer in the HF-81. I have traded 25W and 10W transformers in a no-feedback pp design, and found the smaller transformer to achieve much better high frequency extension and detail. Note that in my application, using Klipsch RF-7s, I normally use less than a watt of power.

* In the end, the HF-81 is a mystery to me. But I don't doubt that it is effective with Klipsch speakers. I wonder: Is this what the designer had in mind, or was he just lucky? In either case, now, it's reality. And rather than deny it, we should learn from it.

Why then are some no-feedback amplifiers so effective with Klipsch speakers? I believe this is due to inherent linearity of the tube triode. As the signal reduces, the device becomes more linear and the resulting musical detail improves. Without feedback, there is no feedback noise which makes for that "black" background that is so striking in well implemented no-feedback designs.

So there are two very diferent approaches:

1) feedback, where more appears to be better.

2) no feedback, where linearity of each stage must be optimized.

Currently I enjoy a no feedback design: triode initial gain, concertina ps with added cathode resistance to match anode output impedance, 2 KT66 in triode mode to Hammond 1608 10W transformer (I am interested in your comments about KT66 in triode mode. what IS the problem? the curves look great). Input and ps is E88CC.

In the end, I think this is a simpler problem than people make it out to be, and specifications can help us. I think we should be focusing of fractional watt distortion and noise. In that context, even the original Williamson probably outperforms most of today's transistor amps.

Mdeneen said it:

"The differences between Williamsons, UltraLinears, Class A triodes, and Class B pentodes is along the lines of comparing, filet mignon to New York steak to Porterhouse steak etc, where the SS receiver would be your basic ballpark hot dog. So of course most of them sound immediately superior."

I think the reason is in the fractional watt performance.


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A fraction of a watt huh?

So what do we do about an idiot like myself that listens to predominately rock music and metal, and likes to push the envelope a little.

I get quite a bit of satisfaction when listening at low levels in the early evening when everyone is at home. Yes, it sounds very good.

However, if I take off early from work, or if no one is home -- I find my little AE-25 sounds its best when driven to the point of clipping. The soundfield becomes all enveloping, and the transients are nothing short of remarkable.

I find the same when doing a DVD. I hook up the TV to the 9000es and let her rip. The sound is simply indescribable, and impossible to relate to a person who is doing all their listening with solid state gear.

Oh if I only had the money, I would buy another AE-25 and go with vertical biamping.

Maybe I can't understand the "fraction of a watt" thing, any more than my solid state friends can understand my '15 class A triode watts'.

I think I can say with great confidence however, that an EICO-81 would last about 15 minutes in my system -- before being reduced to a pile of molten metal and glass.



Cary AE-25/ S F Line 1/ S9000ES/ HSU x-over/ SVS CS+/ RF-7 Klipschcones®f>s>

Exigency is the matriarch of ingenious contrivancef>c>s>

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At last, a meaty thread about tube amps. Great to see all our heavy hitters contributing constructively, without too much emphasis on their personal beef. Keep up the good work while us tyros absorb.

I am making progress with mdeneen on the radical conversion of the Dynaco 70 to pp triode.

I consulted with him a while back about the notorious Heathkit W5M Williamson, and he has something up his sleeve which can help redeem them, although I cannot at the moment remember what it was, but it was enough for me to pick up a pair. Their questionable reputation keeps them fairly low in price, which, now that I think of it, is a primary reason why we are all fooling around with this whole family of vintage tube amps. It is all relatively inexpensive experimentation, a few hundred as opposed to a few thousand for the high class stuff. This is the basis for whole DIY thing for us beginners, eg. beating the system and gaining on hands experience, all with the hope that we get some cool sound.

-See and Ess



currently upgrading

to all tube components

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My point is that your 15 watts of class A may not deliver the most impressive distortion characteristics at 15 watts, but the reason they sound so great with Klipsch speakers is that their distortion drops at lower power rather than increasing (as distortion does with many ss amps). I think the detail you hear at 15 watts is due to the more constant power/distortion characteristics of tube and/or class A operation.

I'm not suggesting that everyone listen at a fraction of a watt, but that amps that perform well there will sound good with efficient speakers.


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Thanks for the additional info.

Am I correct in my understanding that this low power distortion inherent with solid state amps is not so prominent in amps not using transistors in pairs? Does this make sense what I am trying to say?



Cary AE-25/ S F Line 1/ S9000ES/ HSU x-over/ SVS CS+/ RF-7 Klipschcones®f>s>

Exigency is the matriarch of ingenious contrivancef>c>s>

This message has been edited by deang on 06-09-2002 at 02:58 PM

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Originally posted by deang:

I think I can say with great confidence however, that an EICO-81 would last about 15 minutes in my system -- before being reduced to a pile of molten metal and glass.

Dean, what is this? Are you joking? I dont know exactly what you are attempting to say here but this is so far from the truth, I cant stress it enough.

I have the AES/Cary Super Amp wired in 15w Triode, the exact same amp you have, as will as the EICO. The EICO performs much better with rock and indie. It really is not even close. This with NOS Mullard ECC88/RCA and VA KT-88. Over the last month, I have been doing major comparisons with the Super Amp and this is one of the avenues I compared. The EICO does VERy well opened up and does not harden. I think the Super Amp does VERY well at it's point of clipping, better than most. Dennis put some extra time in this recovery from overload. That being said, the EICO sounded far less stressed. In addition, the Cary would actually harden when really pushed via the CW. I thought the EICO was better at loud levels via my ProAcs Mini Towers as well. But I did like the Super Amp on this too.

If anything, this is one of the EICO HF-81 strengths. It does AMAZINGLY WELL with my vinyl rock and indie collection!

REduced to molten metal and glass? I still dont get this.


ps- Interesting post Leok.

pps- I personally think good Jensen/AudioNote Oils would be a warranted upgrade in the coupling positions to the Super Amp. These oils are VERY VERY nice. Others dont agree. I found them extraordinary in my 2A3 amps.

This message has been edited by mobile homeless on 06-09-2002 at 03:08 PM

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