tillmbil Posted November 7, 2003 Share Posted November 7, 2003 Great response Clipped, and yes you took the meds first. I thought the pics and square waves were great for me. You see I am not a math man and had absolutely no idea what any of that meant until now. Thanks Craig, Ryan and Medneed(however you spell that). Can I see mine when its completed Craig? Quote Link to comment Share on other sites More sharing options...
tillmbil Posted November 7, 2003 Share Posted November 7, 2003 Hey , my 99 F150 has $146,000 mile and runs like a top. Unlike the rust bucket chevy's with bad paint jobs. JMO. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 7, 2003 Author Share Posted November 7, 2003 Everyone want a laugh !! The funny thing about this entire thread is that I never said one derogatory word about what showed on the scope ! THIS IS SOMEWHAT NORMAL FOR ALL INTEGRATED AMPS FROM THE 60's ! They still sound very good ! None of the integrated amps hold up at the bottom and top of the spectrum ! They all do very well in the Mid Range area where we all live. They litterally can't without major modification that there PS by design can never withstand and was never disigned to do. I never intended to compare the Mark III to the HF-81 I was provoked by a redicules statement. You could never expect a HF81 , Scott or whatever integrated amp to produce the square wave results of the Mark III no way no how ! You wouldn't believe how good this amp actually sounds very Mid range sweet. In fact this HF81 does better in the bass region then the 299A on the scope but the 299A does a better job and is flatter from 80HZ to and 12Khz . The HF-81 extends slightly higher also but seems to do this in a crude manner which I expect and contribute mostly to its low quality controls. This entire thread was very funny to me. Craig Quote Link to comment Share on other sites More sharing options...
maxg Posted November 7, 2003 Share Posted November 7, 2003 there is a question on My Yahoo about chocolate cravings to which they have responded thus: "The initial chocolate buzz is probably the result of caffeine and several other stimulants, including theobrimine, a substance toxic to dogs. But what about the languid, almost post-coital state of chocolate-induced reverie that many people experience? Scientists at the Neurosciences Institute in San Diego, California, suggest that the chemicals in chocolate have roughly the same effect on the brain as marijuana. Chocolate contains a neurotransmitter called anandide that latches on to the brain's receptors for THC, the active agent in marijuana." I suggest the more excited members of this forum go smoke a Hershey bar... Relax everyone - this is only audio. Actually it isnt even audio - its a discussion forum about audio (sometimes). Not worth getting all hot under the colar about. BTW - I looked at the pictures and knew immediately what was wrong, and, that it would not particularly affect the sound!! So ha ha ha. (Craig - just plug the antenna lead back into that TV and the picture will return - and stop drawing on it with a magic marker - that cant be good!!) Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted November 7, 2003 Share Posted November 7, 2003 Science (knowledge) is a process of "comparing" the empirical (test results) with the theory (how it sounds). I have one thing to say: STRING THEORY! With this new breakthrough involving parallel universes etc., I am finally able to bring back to reality all the things I have been scoring when I dream. Last night I was dreaming about some vintage Marantz units and a mint pair of Patrician speakers (both $15 at an estate sale) which I was able to deliver to my actual living room from the dream ....this is cool and I cannot wait to go to sleep again. Science is fun. This may have enormous implications to eBay stockholders. C&S Quote Link to comment Share on other sites More sharing options...
leok Posted November 7, 2003 Share Posted November 7, 2003 I still think that what is shown in the 800Hz and 1.5KHz pictures is appropriate for an amp that doesn't appear to go much higher that 20KHz. If the 800Hz and 1.5KHz waves were more overdamped (no overshoot), there would be energy missing from 5KHz to 20KHz. The fact that the amp has a sharp cutoff above 20KHz (as evidenced by the fact that the 20KHz sq wave has mostly sine wave energy) indicates to me that, if 5KHz to 20KHz energy is present at proper power, the 800Hz and 1.5KHz square waves have to show some overshoot. This is not ringing, necessarily, it is simply a bandwidth limited square wave with a sharp rolloff above 20KHz. leok Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 7, 2003 Author Share Posted November 7, 2003 Leo, Not sure which photo's your looking at . The first photos are what should really be looked at. The second ones are just the power section. Which is not the way that amp should be scoped or any amp for that matter. They should be done like Mark suggested with the preamp section since this is how the amp is used. Not sure if you have heard or had someone tell you what a HF81 sounds like running just the power section but it seems very thin and sharp at least every one I have tried that way sounds completely different then with the front preamp section. Craig Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted November 7, 2003 Share Posted November 7, 2003 One of the many things I learned from hours of watching maestro mdeneen at his bench (oscilloscope running) was how certain imperfections revealed on the scope were soncially forgiveable, eg. within the acceptable range of positive subjective sonic experience, and how other more glaring imperfections (xfrmr ringing or worse manifestations) were sonically disastrous. Noise and hum were, of course, extremely obvious on the scope, ouch. My eico HF-35 looked rather nice on the scope, my HF-81 not so nice, I could then fire them up in my system and compare what I saw on the scope with what I could hear. Invaluable experience! Later, after Craig corrected some of the rat's nest problems with the HF-81 and upgraded some parts, the sound was greatly improved on the HF-81, however, certain inherent differences (observable on the scope in spite of the solvable problems with the HF-81) are still evident sonically. That is to say, the scope could reveal the characteristics of the the transformers which I am now able to discern sonically between these two units. I am pretty sure, for my ears, the HF-35 is a better sounding unit and I am able to compare what I hear with what I did see on the bench. I do use both units, so all is within the acceptable range. There are so many other variables involved, I would not be able to assert something like a preference for EL-84 over EL-34. I am using NOS mullards all around and they seem to sing pretty nice. C&S Quote Link to comment Share on other sites More sharing options...
leok Posted November 7, 2003 Share Posted November 7, 2003 I am refering to the first set on page 1 of this thread. leok Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 7, 2003 Author Share Posted November 7, 2003 Mark, Well the test setup is Identical on my Mark III's so I seriously don't think the test equipment is at fault ! I'll do bunch of amps and see. But to be honest I think these amps just don't reach that low. Remember were dealing with 30 to 60 UF on the center tap that's it for filtering and no choke here also small value main coupling caps. I'm sure tacking a load of filtering on the center tap and upping the coupling caps values would improve this picture but then they wouldn't be Scott's and EICO's anymore. Plus the 5AR4 is only going to take so much. Craig Quote Link to comment Share on other sites More sharing options...
Deang Posted November 7, 2003 Share Posted November 7, 2003 Why don't you just tell the freaking truth for once. You rigged the whole test, and hell, for all we know these were the results of damn table radio. Anything to make an Eico look bad you bastard. I don't see how you can live with yourself. Quote Link to comment Share on other sites More sharing options...
rtaylor Posted November 7, 2003 Share Posted November 7, 2003 ---------------- On 11/7/2003 2:07:22 PM DeanG wrote: Why don't you just tell the freaking truth for once. You rigged the whole test, and hell, for all we know these were the results of damn table radio. Anything to make an Eico look bad you bastard. I don't see how you can live with yourself. ---------------- He doesn't live with himself, the long suffering wife has to! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 7, 2003 Author Share Posted November 7, 2003 Mark, I think we found why you quit messing with integrated amps back in 1975 Remember my first impression of Dales Mark III's when I was rebuilding them back a year or more ago ! Remember me saying the Dynaimics were incredible ! Well !!! These amps sound very good the way they are ! Are they a absolute honest reproduction of the source nope ! Do they nock your socks off on the scope nope. The scope is great and I love using it but it just doesn't mean everything. The thing is that what will nock your socks off on the scope also cost 2 to 3 to 4 times what these little Jewels cost. Heck I have $1200 to $1300 into my Mark III's doing them myself no Labor cost. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 7, 2003 Author Share Posted November 7, 2003 Mark, This amp is off the bench now and we will have to revisit this subject with other amps I have 2 more EICO's here now and a number of Scott's all different models. I will wait to return this one to its rightfull owner since your so concerned here. I truly do think this is entirely normal but hey who knows I just started using Square waves on a regular basis I used to just use Sine wave for full power tests like Ryan does which all these amps pass with flying colors usually slight roll off at the top and bottom . Once I test the other 2 and if they turn out similar results then I'm done putzing with them. You can only do so much. Give me a day or two to investigate I have to pay the bills hear you now Craig Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted November 7, 2003 Share Posted November 7, 2003 ---------------- On 11/7/2003 2:07:22 PM DeanG wrote: Why don't you just tell the freaking truth for once. You rigged the whole test, and hell, for all we know these were the results of damn table radio. Anything to make an Eico look bad you bastard. I don't see how you can live with yourself. ---------------- Dean, You are COLD man. REally cold Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 7, 2003 Author Share Posted November 7, 2003 Dee, Trust me Dean was just trying to get my Goat ! If he didn't ribb me now and then I would think he was madd at me ! Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 8, 2003 Author Share Posted November 8, 2003 Well folks Just to confirm my original tests I unpacked a completely stock HF81 that a bought on Audiogon the other day (thanks to someone on the EICO news group for the heads up that it was there with a HFT90 tuner for $200 ) It arrived and who ever wired it was a pro ! This guy was so meticulous that he used clear plastic sleeving on about 75% of the resistors and capacitor leads ! I tested all the tubes and installed 3 Mullards out of my stash to replace the worn out ones , checked all important voltages, Checked all cap values and for leakage, Tested the cathode resistor values , Fixed the broken fuse holder . Brought it up over a few hours on the variac. This is the quietest none vibrating HF81 I have ever owned and this is my 4th. It is dead silent on the high level inputs. So I let it play for a few hours while I was testing some tubes and matching some quads. Then I hooked it up to the Wavetec function generator and my Scope. If someone wants to question my word I will go to the trouble of taking the pictures and uploading to prove it. This test turned out absolutely dead Identical to the original tests posted in this thread. Like I said earlier I also tested a Scott 299A and now a 299C (really a 299D) they all test similar with the Scott amps being slightly cleaner from 800H to 12Khz . The 2 Scott's seem to fall off harder down low and up top which in all honesty surprises me but the scope doesn't lie (please don't take this to mean that I take scope results to be the end all to what your hear) These amps truly do sound great ! I truly think its been a long time since Mark has looked at these vintage integrated amps and has forgotten what they were designed to play on. The speakers that the average Joe owned back then didn't go down to even 60 Hz or above maybe 12Khz ? I think these unit were made to play the Mid range beatifully and they must do it well because they all sound so good. My biggest gripe with the HF81 is actually its build quality is so bad or good depending on the original builder and how the unit was cared for by its users ! When you get a good one it really is a surprise so many of them vibrate like the dickens and this is usually transmitted into the output in the form of a buzzy hum ! I spent many a hour on one I had for a long time trying to find a reasonably affordable fix. The only true answer is what Tom Mobley did buy a new Power transformer that hasn't been stressed and isn't built to just barely get the job done. The problem with this is trying to keep the rebuild affordable for customers ! As far as I'm concerned there is nothing abnormal with these test results they are completely normal and eceptable for a Vintage integrated amp in this price range. Craig Quote Link to comment Share on other sites More sharing options...
Parrot Posted November 8, 2003 Share Posted November 8, 2003 That is very true about the average person in 1959 not having speakers that could play really low or really high frequencies. I hadn't thought about it in this context. Also, LPs used to have far less really low and really high frequencies on them than could be put on vinyl now. And for the same reason. There was no point in taking up valuable space on a side of vinyl with big low frequencies when almost no one had equipment that would handle it. So the lowest frequencies, *if* they were on the master tape to begin with, were shaved off before the record was cut. I think it's remarkable the EICO HF-81 sounds as nice as it does when it falls apart on the lowest and highest ends. But as has been said many times, we live in the midrange. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 8, 2003 Author Share Posted November 8, 2003 Absolutely correct Ryan. Sine wave is the standard and all of these amps are pretty much flat using it 20Hz to 20Khz this is what started me on the quest to send something a little more complex into these amps because they all scored the same but sound very different. The square wave performance shows the story clearer to me ! I mean if you go by sine wave the Scott's, Eico's or whatever looks the same as my Mark III's but the sound is very different and very much a step above in the transient impact area and dynamics. I'm going to keep going with this to help me understand what my customers like in relation to the results of the square waves. I think this will help me give better advise as to what will please my customers which is what really counts to me in all this ! I could careless what scores the best its what pleases the owner that matters. I'm am just dying to get a good quality SET amp in here and see what it looks like. I bet total precision in the Mid Range and rolled top and bottom in a real clean gradual manner. I have a standing offer to anyone that is interested in getting there existing Quality SET amps upgraded with some better coupling caps, Power supply or repaired. I will even wire up a set of Ron Welbourne's DRD for next to nothing just to get a chance to investigate the love of these amps here. I will do whatever they like on the cheap !! Remember folks a tube amp is a tube amp they all work in generally the same manner so just because I generally work on PP doesn't mean SET is not within my abilities to tweak. Besides 99% of the available upgrades are all listed right here on the forum. Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 8, 2003 Author Share Posted November 8, 2003 Mark, I just do not see your point in all this. Yes these are not the Ideal results but Chopping things out of the circuit to achieve perfect Square Wave result to amps that people actually are really pleased with seems extreme and also costly rewiring and redesign. A vintage integrated amp is a vintage Integrated amp. Trying to make it into a modern test king is just not worth the trouble and will change the sound most of these people are very happy with in my opinion. If that is what people are after either buy newer amps or power amps that are much easier to accomplish this with and give you the benefit that are inherent to separates. Craig Quote Link to comment Share on other sites More sharing options...
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