No Disc Posted March 30, 2002 Share Posted March 30, 2002 Thanks to the informative people here at the Klipsch forums, and of course Mobile Homeless for spreading the word on this great AMP. What a great sounding unit ! Here is a web site I setup to show the photos of my unit. http://home.attbi.com/~tbabb/eico.html - tb Quote Link to comment Share on other sites More sharing options...
edster00 Posted March 30, 2002 Share Posted March 30, 2002 Great looking Eico you have there. Nice photos on your website also! Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted March 30, 2002 Share Posted March 30, 2002 Great job with the exterior of your 81, Tim! Both you and Chris did top notch work on cleaning your units up. Nice site as well with some good pics. You could probably eek out some even better performance with some better caps within your unit (as well as matching them). But glad it is sounding great as is. Get the best 12AU7/12AX7 you can muster. And NOS valves really shine here. Again, great job with the paint and brass (as well as pics). kelly ps-Here you see the two bell covers on the Output transformers. At one time, I thought the plate thickness was different as well - I was preferring the units with the thinner laminations but some feel they are the same but stacked slightly different. The bell covers without the lip are newer than the lip variety. I have both and prefer the sound of the unit with the lip outs, yet I really believe they might be the same (the look thicker from afar). That earlier unit has better caps with some oils in critical places. This message has been edited by mobile homeless on 03-30-2002 at 11:57 PM Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 31, 2002 Share Posted March 31, 2002 Nice Amp you have there !! I sure wish mine was even in the same ball park as that beauty. It looks like it was wired yesterday ! ! Nothing in the under chassis looks to be 40 years old thats for sure. Someone must of had it sealed in a plastic bag and stores since it was built LOL Where did you score that beatiful example ?? Craig Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted March 31, 2002 Share Posted March 31, 2002 Not only is there a wide variation in the people who assembled these, but I think there must be different vintages. My knobs are funky brown and someone had to scratch in a zero mark into them. Parts look much much older than these. I've got lips on the transformer bells, how about you Craig? Maybe that is the problem. We should have been warned to stay away from the lipped bells. Hey mobile, is there no way to actually determine which plates are thicker -or same?, with bells or sans bells. So which style did you say you thought might sound better, with lips (earlier) or sans bells (later)? I couldn't tell from the way you said it. Does "lip out " in your description mean the later version? Sometimes "out" could mean "turned out" in which case it could connote the one with the lip. Maybe we got some old dogs or lemons Craig. Is the only thing wrong with yours at this point the harsh sound? All the hum and obvious problems already remedied? Have you tried other speakers? When we get mine running at least we can report on the circuit characteristics from what we see on the scope. Maybe some of those transformers are not as good as others in the line. Who knows. All that wiring does look tedious to fix and or upgrade. You have been a dedicated trouper. One thing for sure, getting one on eBay is indeed a crapshoot and not for the faint hearted expecting to immediately synchronize with the hype on this thing. Also not a unit for just anyone to attempt resurrecting if you happen to get a beater. Caveat Emptor. -burnt umbered and telephone umbered. ------------------ Cornwalls currently upgrading to all tube components This message has been edited by Clipped and Shorn on 03-31-2002 at 02:32 AM Quote Link to comment Share on other sites More sharing options...
No Disc Posted March 31, 2002 Author Share Posted March 31, 2002 Thanks for the suggestions and compliments. I got this gem from a collector from Texas. He responded to a AD I placed on Audiogon. It was a bit of a wait to find him, and he was irresolute at first and changed his mind about selling it to me. After many emails, he came around and told me he would sell it to me, but I would have to wait until his replacement amp was finished. I waited and watched as about 5-6 EICO's on ebay had come and gone while waiting for this one. This unit has absolutely no hum at all and is dead quiet. I'm really blown away with the Sonics. I can't wait to roll some better tubes in it. Suggestions very welcome. Mobile, I would appreciate any specific tube recommendations. What's good? I'm about 30 minutes away from Triode and actually I might be going there on Monday. So if you got suggestions, please give me some specific suggestions. I also see tube-world has loads of stuff, and if you have suggestions from their inventory, speak up please. Mobile - You mentioned replacing Caps? Which caps?? Please refer to your numbered diagram from your web site if you can. Thanks. P.S. Remember I'm new to this stuff Quote Link to comment Share on other sites More sharing options...
No Disc Posted March 31, 2002 Author Share Posted March 31, 2002 Mobile, I was reading up on the 12AX7 / 12AU7 tube info. Can you tell me what you have in your two units, and why you like them? Also, I just can help wondering, based on Joes Tube Lore, how a 5751 would sound instead of the 12AX7s ? Have you tried this? Gosh, those 12AX7s can get mighty expensive ! Has Tube Rolling the EICO been discussed here before? Quote Link to comment Share on other sites More sharing options...
leok Posted March 31, 2002 Share Posted March 31, 2002 tbabb, That's a classy little amp, and I'm beginning to suspect, one of the best. It's an interesting combination of technology (pentode pp), scale, component quality, and overall design. Mobile provided a pointer to the schematic recently, and it was not at all what I expected. I'd love to hear one of those. Is this your first tube amp? If so, it's a double treat: tubes and one of the best. Enjoy it. leok Quote Link to comment Share on other sites More sharing options...
No Disc Posted March 31, 2002 Author Share Posted March 31, 2002 mdeneen - The previous owner did the rebuild, and this is what he said was done: - Rebuilt power supply - Auricap coupling caps for the EL84's - Coupling caps are Auricaps - Electrolytics are Nichicon,and Sprague. - All grounds were cleaned during the rebuild. There were also some resistors and filters replaced to get rid of hum and some intermitent noise. I'm glad everyone feels this unit is in good shape, because I bought it sight unseen with a Money Order. I bascally took his word that it was as nice as it was. He assured me it was plug-and-play, which turned out to be true. I paid $350 for this unit. To me, it sounds every bit as good as the Manely Stingray tube AMP I tried out. ($2500). So for me, the $350 was money well spent. - tb Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 31, 2002 Share Posted March 31, 2002 tbabb You received a excellant deal on that amp. Chris Robinson paid just a few dollars more without getting the High dollar Caps and such you received. To me it looks like there isn't one original part in the under chassis or EICO did some serious changes to these amps as the years of production went on. Klipped My HF-81 has the Lipped version transformers and no I can't get rid of the noise in the amp not even close. I tried all kinds of bandaids some I thought of and some Mdeneen thought of. I've come to the conclusion that if I keep it I have to gut it if I want it to sound right period. So I'm waiting for the build manual from you. When I get it I'm going to get out the dust pan and start from scratch. Buy all new tube sockets and the works. That is unless I just decide to sell the parts. What will be the clincher will be Mdeneen's tests on yours at the bench. If it looks like this amp can be all that people say it can be sonically then I will give it the respect it deserves but until I have some proof I still say its way over rated. Craig Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted March 31, 2002 Share Posted March 31, 2002 So mdeneen's test on his bench will inform you if this amp "really can" be what people say it is sonically? And if it performs poorly on this bench, the amp is mediocre sonically. I have several bench tests from reviews of this amp in the 60s. You should, if you got the full contruction manual, have a full page of measurements and square wave reports in your hands. Personally, I have heard amps that perform horribly on the bench sound superior to amps with steller tests. Most solid state amps measure far superior to tube amplifiers on many bench tests (and worse in some others). Measurements can tell you a great deal about functioning circuits. But measurements can come WAY short in telling you the actual sound. My 2A3 amps have a higher basic distortion measuremnt at 4w than the EICO HF-81 at 20. Yet the clarity and absolute pure clean nature of a directly heated triode (the most linear tube there is), make the common pentode (either wired in triode or pentode) sound far less clear and open. If you heard a good DHT amp, it is very hard to go back to pentode tubes. btw, since you have a pretty good digital camera, do you mind uploading a photo of your work bench system setup as it has been configured? kh This message has been edited by mobile homeless on 03-31-2002 at 01:40 PM Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 31, 2002 Share Posted March 31, 2002 Craig, A friend and I listened to a 45 tube at 1 and half watts yesterday. WOW! Quote Link to comment Share on other sites More sharing options...
No Disc Posted March 31, 2002 Author Share Posted March 31, 2002 For those that are interested, I posted a high-res picture of the point-to-point wiring. Warning, this is a large file (about 480 k) http://home.attbi.com/~tbabb/images/EICOUNDERLRG.jpg - tb Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted March 31, 2002 Share Posted March 31, 2002 mobile stated: "Personally, I have heard amps that perform horribly on the bench sound superior to amps with steller tests." The key words here are "personally" and "heard". I have no doubt that those who were lucky enough to obtain an HF-81 that worked properly from the get-go or close to it have been able to enjoy something very good sounding. But those of us facing either a total rebuild or a major hair pulling overhaul just to get them working cannot simply rely on a subjective report to justify the potential expenditure of time and money. We cannot be really sure what comprises the underlying reason why many have claimed to like its sound, there are too many variables in this equation. Craig was merely stating that he would like to first know the actual physical realities of its potential from a bench test, before proceeding with the inevitable expenditure of time and energy. If he so proceeds on the basis of what the physics tell him is its potential, then, when finished he can make his own judgement as to how it sounds to his own ears. He will have then learned something about how the physics translates to his own subjective experience of the sound, as opposed to the process of comparing his subjective experience directly to that of the subjective experience from another human's set of ears, both of which cannot be ultimately defined in verbal terms meaningful enough to really communicate more than a strong recommendation, as in "Hey, I like the flavor of this Durian fruit, you are sure to like it too, it is the best darn thing I ever ate, it is so transparently delicious and focused, you will love it, I insist , take some". "Man, you were right, this is delicious, best thing I ever ate, thank you for turning me on to it. Forget Peaches and Mangoes, its Durian for me from now on." The process of "going by someone elses recommendation" is a tempting short cut in the beginning when one does not wish to open up so many possibilities that one might be overwhelmed and thus not be able to make a timely decision {I want to buy something today that I can afford and be done with it- if 'so and so' likes it, that is good enough for me}. This is why salespeople have an important function and why successful salespeople know that the process is one of finding out what the customer wants and helping them to get it (hopefully from the range of products that the salesperson is selling that day). However, someone like Craig, is enjoying the deeper level of the hobby, in which he is savoring the acquisition of his own knowledge regarding how these things work and why. For him it is obviously more fun to enter the more complicated world of evaluating for himself how the "sound" is produced from the "physics" than it is to "buy from a recommendation". As HornEd recently pointed out, sometimes it is important for the teacher to let the student learn from his own mistakes rather than give them the shortcut which the teacher has already concluded is best. That teacher, then, shows he has a certain wisdom about human nature. To call into question the causal relationship of the physics (science) to the subjective experience is a post-modern notion which tends to also make the art from the Dark Ages more fashionable these days than the Modernist's light and color. It also provides many jobs for astrologers and homeopathetic healers. So I guess it is a good thing. -sliced and diced ------------------ Cornwalls currently upgrading to all tube components Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 31, 2002 Share Posted March 31, 2002 Well Well leave it to Mobile Homeless to only speak up when he can cause more confusion !!!!! I guess I should of said a little more knowing who would be reading the thread. Mobile....don't you think that when Klipped and Mdeneen put the HF-81 on the bench to put it thru its paces that they will listen to it also please !!!!!! I really beginning to think your just a big bag of Hot Air. You spout off your opinion's like they are written on tablets left over from the ten commandments. But then when we listen and buy because of your opinions where do you go ?? I asked you nicely a number of times for a good under chassis photo of a HF-81 what happened ?? Have you ever given me one bit of help to try to get my HF-81 working in a manner where I could say whether or not they are good or bad ?? Why exactly do you want a picture of my work bench ? WTF is that all about ? Dude your losing it !!!!! Craig This message has been edited by NOS440 on 03-31-2002 at 10:27 PM Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 31, 2002 Share Posted March 31, 2002 I just took a look at the under chassis photo tbabb posted for us and come to the conclusion that either EICO changed the parts used bigtime over the years or his amp does not have one single resistor , coupling cap , ceramic cap on it that matches the parts that were in mine and any others pictures I have seen so far even the wire is higher quality. In other words his amp is completely rebuilt. Which for him from my veiwpoint is a real good thing !! Craig This message has been edited by NOS440 on 03-31-2002 at 07:10 PM Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 31, 2002 Share Posted March 31, 2002 mike stehr Hey 45 tubes at 1 1/2 watts explain please !!! Quote Link to comment Share on other sites More sharing options...
No Disc Posted March 31, 2002 Author Share Posted March 31, 2002 NOS440. I must admit, I have not been following your issue with your EICO unit. For what it's worth, my unit came with a repair ticket for work done 8/2/01 I'll list here verbatim what's on the ticket. Perhaps it will help your situation, perhaps not. I know little to nothing about electronics, but perhaps this will help your situation. -------------------------------------------------- Customer Complaint: Hum, No sound, Also Intermittent Static, Noise. Explanation of Service Performed: Replaced open filter in HV supply. Replaced Open resistor to correct 1 CH out. replaced noisey resistor in B+ to correct static noise. rewired Audio Caps. Reass unit. $135 labor and $34 parts. Total $182 inluding tax. Parts: 3 VV Resistors 1 2X50AT500V Filter 2 40MFT500V Filter Word done by "The Sound Idea" San Antonio TX. Hope this helps. - tb ------------------ ----------------------------- Two Channel System(s) Phono - None now. Looking CD Player - Pioneer DV-414 (will be replacing with Rega Planet) AMP(s) - ASL Wave 8's - Stock, EICO HF-81, McIntosh 2205 Pre-AMP - McIntosh C-28 Speaker(s) - Klipsch 1.2s, Kg4s Tube Headphone AMP - ASL MG Head OTL ( 5751 -> EL-84 ) HeadPhones - Sennheiser HD-600 & Sennheiser HD-580 Home Theater Toshiba 57HX81, Yamaha 5790 Panasonic RP-91 DVD Toshiba DST-3000 Klipsch kg4 Fronts/Klipsch Academy Center/Klipsch kg2 Rears Quote Link to comment Share on other sites More sharing options...
edster00 Posted March 31, 2002 Share Posted March 31, 2002 When I was doing some research on getting an Eico I had looked at mh's HF-81 page. He has pointed folks to this page several times if my memory serves. Here is a shot of the innards of one of his HF-81s: (I hope it is okay to post this). This message has been edited by edster00 on 03-31-2002 at 08:17 PM Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted March 31, 2002 Share Posted March 31, 2002 Enjoy this place. kh Quote Link to comment Share on other sites More sharing options...
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