NOSValves Posted November 15, 2002 Share Posted November 15, 2002 Well finished up Chris Robinsons HF-81 today here's some photos. I replaced all resistors on the 2 12AX7 phono section tubes and all the coupling caps with Auricaps. Also replace all the small value Electrolytics with Sprague Atoms. The phono section is real quite now and sounds pretty darn good. I haven't really given it a serious listen yet though most likely tomorrow I will feeling a little under the weather today. Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted November 15, 2002 Share Posted November 15, 2002 Dang, looks like a ton of soldering ... thanks for all your hard work. Since you already have an -81, you're in a good position to compare the sound of the different components. Looking forward to hearing it! Maybe we'll get Jeff over here with some Megadeath LPs ... Quote Link to comment Share on other sites More sharing options...
JCturboT Posted November 15, 2002 Share Posted November 15, 2002 ---------------- On 11/15/2002 10:30:05 PM Chris Robinson wrote: Looking forward to hearing it! Maybe we'll get Jeff over here with some Megadeath LPs ... ---------------- Sweet!-I'll bring the Chardonnay & the Heinekens-you supply the tunes and toys for the kids. Jeff Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 16, 2002 Share Posted November 16, 2002 Great work, Craig! I think it will take a good 100 hours or so for those caps and parts to break in. I was hoping to give it a listen but I'll probably save it for when I get up there some day. Some additional tweaks you might address before giving it back: 1. Tie down the two PS Atoms somehow. Roger Stevens actually stuck them to the chassis with two-sided sticky foam tape. IF you can do it with anything more solid, that would be even better. I agree that tying down the PS caps makes a difference. Here are the two tie downs for the orginal caps. And to the right of that, are the tie downs for my Solen Metal Can in my Cary Preamp 2. Measure the cathode bias resistors and make sure they are exactly equal at 165 ohms. If wanting to cool the amp a bit and perhaps more equal it to modern voltages, move to two exactly equal 180ohm 5w resistors. Stevens suggest buying four and taking the two closest measuring ones. I havent done this with my units but my Quebec friend Jean-Francois did his and said it ran his Ei EL-84 better and was cooler for amp. At the least, the two 165 need to be right. 3. I would perhaps put either Black Gate or ATOMS in the Cathode Bypass Capacitor slots. As I remember, there are some lame looking Cathode Bypass caps in Chris' unit right now. Take a look. As is, it looks like some nice work there. I wonder how it will compare to stock. Strangely enough, I think I have seen some of the same caps as you took out in the Wright amps. It will probably sound a bit harsh and compressed for awhile although I know some within here believe nothing about part breakin. Again, nice work, Craig. kh ps- I just noticed that with this post, I hit "answering machine" status. I dont know which is more depressing, NO LIFE or ANSWERING MACHINE. Either one is a reason to seek help.... Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 16, 2002 Author Share Posted November 16, 2002 Mobile, Take a closer look all Lytics they are Sprague atoms ! I always replace all axial lead Lyctics. I already tide the PS caps down used RTV worked like a charm. Although I think you guys are a bit over the edge hearing a difference there LOL !! I have not checked any voltages in the amp yet but rest assured it was my next step. I will agree that it takes time for parts to break in but there over all signature will be there from the minute you fire it up. I really don't mind you making suggestions but how many amps have you rebuilt ? I think I really do have a clue what I'm doing here Craig Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 16, 2002 Share Posted November 16, 2002 Who said you didnt have a clue? No need to get defensive here. Why would you conclude with the "I think I know what I am doing" remark? I just thought I saw the same cathode bypass caps as was in there before as the pic was a bit dark and blurry. I also was thinking the 180ohm might be the better choice for the stock 165ohm to equal modern voltages and I know Chris didnt ask for this. As for tying the PS caps down, this is done almost across the board and I really do believe it makes for a quieter background. IT should be done to all the bigger PS caps and even though those 40uf ATOMs are not too big, it WILL make a difference. This has something to do with why oil caps and different cap cases affect the sound. Keeping the caps tightly secure helps with these. If I were you, I would do it to all your mods. Nine months ago, none of this made that much difference if you remember - Lord, take a compliment when I toss it your way! Nice work said at the start and end of that post should be enough. Almost ALL of this stuff makes a difference; the point is whether it is good or bad as difference does not always mean for the better; nor is it easly discernable or worth the cost, depending. Once again GOOD JOB, Craig; I know you put a lot of effort into your work here and do a careful job to boot, something that not all can claim. kh ps - Not that this needs to be said, or that it applies to you, but I have known guys that have worked on amps for 40 years that are more clueless about sonics or parts than an open-minded newbie; indeed, these are usually the guys that are THE most close-minded. So the "how many amps have you rebuilt" line is really a moot point. Besides, how soon we forget... Heh... But why argue? Hell, that ole Scott is coming your way and we'll have plenty of time to debate then! Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted November 16, 2002 Share Posted November 16, 2002 Nice work,Craig. If you ever decide to use some Black gates,please be aware that the WKZ (heart of muse) series do sound excellent for the first 5 hours but after that they can sound pretty harsh and unmusical for about 150 hours more and they reach their full potential after 300 hours.These can be the longest 300 hours of your life. Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 16, 2002 Share Posted November 16, 2002 I dont think Craig is going to be using Black Gate WKZ anytime soon, at least not for any Scott/EICO etc mod! Lordy, at over $110 and up a PIECE, they are not for the faint of heart or light of pocketbook. I would ONLY recommend those in really serious SET or ultra DIY PP amps. Putting something like the WKZ series in a vintage integrated would be a waste of ducats besides being impossible to fit in something like the EICO without a chassis mod. MY Quebec buddy just put some ELNA Cerafines in his EICO HF-81 and reported a slightly blacker background and quieter... but NO WHERE near worth the price they are currently fetchintg since they are no longer made ($40 for one 47uF 500v cap). The WKZ Black Gates are notorious for taking a VERY long time to reach their potential just like Guy reports. Audio Note's Peter Qvortrup just goes ahead and leaves his SET amps on ALL the time to keep from having to go through the near days for the Black Gate WKZ to sound their best. I have to admit, I leave my amps on most of the time as well. I was going to say that the EICO takes at least a few hours to sound its best. Which is why on quick listens, you really need to let these amps warm up. For Solid State gear, I would NEVER turn the damn things off. Literally. kh Quote Link to comment Share on other sites More sharing options...
Pland Posted November 16, 2002 Share Posted November 16, 2002 Craig, If you can ,run this amp all day long to get some time on the caps.They sound a little "crisp"at first,but smooth out and warm up with some time.I'd be shocked if you didn't love the Auricaps.This amp looks like a real winner.What are the driver tubes? Pat Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 16, 2002 Author Share Posted November 16, 2002 Mobile, Like my post said at the beginning I wasn't feeling all that well and what struck me offensive was the fact that I have been waiting for parts for Chris's amp for 2 weeks and now you suggest more !! You should of did this weeks ago its like your trying to one up me or something here ! Although I don't think it will need new cathode resistors I believe I already tested them but that was weeks ago. It doesn't seem to heat up all that much more than any other amp I have worked on EICO or Scott. Pland, The unit played yesterday for about 6 hours it will play today for at least 12 and tomorrow I'm going to give it some serious listening and compare it to mine that has Vintage Russian caps my first impression is the russians bring better detail but I agree they all take break in. But again I believe there initial performance is a good indicator of what they will sound like with time all capacitors and resistors smooth out and settle in. Craig Quote Link to comment Share on other sites More sharing options...
Deang Posted November 16, 2002 Share Posted November 16, 2002 Wow, really nice work Craig. Where do you find the time for all this! It's tough to see every detail from a digital pic, and I think Kelly was just making suggestions to help you cross your t's and dot your i's. I didn't really see you so much being offended as exasperated:) I sure don't think he doubts your abilities however. I will probably wade into these vintage waters at some point, and I find it curious that everyone seems to be opting for polypropylenes for most of the cap replacements. I would sure be interested in hearing one of these amps with some film and foils in the critical places. I'm curious -- what were the original caps? Were they all electrolytics? Welborne Labs is selling some new caps called the Jupiters. These things are made of bees wax of all things. Too bad we're not all independantly wealthy and try out the multitudes of options -- in the hope of coming to some definitive conclusions about what works and sounds best. My Apollos just had Blackgate Heart of Muse installed shortly before they were sold to me. The seller "warned" me that they were not broken in yet. These amps don't sound harsh to me in the least. I may just not be as discerning in this area -- I guess it will be interesting listening for any change in the signature over the next few months. Of course, I have no idea what part of the circuit the Blackgates are in, nor what part the Hovland's are in! I guess the Cerifines are the power supply caps. It sure sucks not knowing much about amplifiers. Can anyone tell from looking at my amp pics which is what? Quote Link to comment Share on other sites More sharing options...
Mike Lindsey Posted November 16, 2002 Share Posted November 16, 2002 Hey Craig, As usual, very nice work! I would be curious to hear your opinions of what upgraded caps and tubes can do for my 299? I have been listening to my unit (I love it by the way) for about 3 months now. The more I listen to it, the better I like it. I know you have some upgrades in your unit and just want to know if I will get more sonic benefit by spending a few more ducats? As you know, mine has the orange drops all the way around, I believe. DO you feel I should upgrade any of the caps? It also has the Russian 5AR4 and 7189's, and GE 12AX7's. If you were me, what would you replace first, if any? I don't have any backup tubes for this unit, so it wouldn't hurt to have what I have in there now in that capacity. Hey, I just ordered a cabinet from Marc (off the Scott Forum - he's back you know) that I plan on staining to match my La Scala's. I know I am going to have to replace two eloctrolytic cans in order for the wire mesh to fit. Can you explain to me how to do this? Will soldering be involved? Also, where do you suggest I buy two new ones? Thanks again, Mike Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 16, 2002 Share Posted November 16, 2002 Dean, see the pic below. Your amp is a bit different than some and I just quickly cobbled that together. There might some errors but I think it is correct by and large. Most people use Solens in the PS. Ditto with the big ELNA Cerafines and also the Black Gates. The ELNA and Black Gates are Electrolytic caps but of a much better makeup using graphite powder and other materials. If you have the Electrolytic Black Gate WKZ caps, then rest assured, the amp needs MANY MANY hours to come to its best, and this AFTER BREAK-IN. See the two posts above by Guy and me. The problem with putting film/foils and some of the better oil caps is the COST and SIZE. I think there is really a law of diminishing returns here and if you have a PP vintage circuit with 10 caps, going to all film/foil can be quite costly. In the case of the EICO, there is simply NO ROOM as you would have to modify the bottom. In addition, I think film/foils would make it a different sounding amp altogether and I am not so sure for the better anymore. Auricaps might be a good compromise here. The new Jupiter Beeswax caps are interesting as well but TOO LARGE to even experiment with. Hovlands wont fit in many of these vintage amps either. I am more inline with finding caps that keep what is so GREAT about the vintage sound. Musicality without over-etched detail that is NOT real but hyped, something that certain film/foil caps can bring out in the wrong situation. Since you have never heard a vintage amp, I dont think you quite know what I am talking about here. Rest assured, a good vintage amp like the HF-81 sounds quite different than most of the modern PP tube amps. And to be honest, this difference is a GOOD THING. Quote Link to comment Share on other sites More sharing options...
Deang Posted November 16, 2002 Share Posted November 16, 2002 Great post. Thanks Kelly. I actually knew what the caps were, I just didn't know in what capacity they were being used in. I had a feeling the Hovlands might be the coupling caps, I just couldn't be sure. I figured the Cerafines had to be power supply caps because of their size, but could'nt be sure about that either - LOL. Man, I've got so much to learn. At least with your cool pic, I can now make some sense out of the schematics in the manual. Ron W. never says what does what -- he just says "this" goes "here". I get what you are saying about the vintage p-p designs. Yes, that makes sense. They were built and voiced with certain parts, and it does make sense to keep things as close to original as possible. Steve from Layne Audio certainly agrees with your views here. I ran into a similiar thing while wrestling with the caps selection for the DQ crossovers. He basically told me that though the DQ's are fine speakers -- film and foils would be complete waste of money because the subtleties would be lost in the complexity of the crossover and mediocrity of the drivers, and warned me that the signature might change in a direction other than what I desired. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 16, 2002 Author Share Posted November 16, 2002 Mike, Well if your up to soldering there are quite a few upgrades that could be done and I'm researching more !! it will be a week or two yet. The only real option for your cans is Vibroworld and yes they require soldering and carefull removal and reinstallation of various wires and resistors. I can't remember what I did if anything to your phono section so there will be upgrades available there too ! I will also caution you that these upgrades don't make major differences so don't expect miracles !! They add detail for the most part. The phono section helps with upper volume noise so your back ground is blacker between notes and quite passages in music. Deang & Mobile, Your pretty much correct. I just found Mobiles suggestions untimely. I guess he doesn't realise that added parts at this point delays the process and adds shipping charges. Its not like you can run down to 7/11 and buy these components. Sorry Mobile I was feeling like sh!t so excuse the rant !! Craig Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 16, 2002 Share Posted November 16, 2002 Regarding your quote above from Steve and relating it to the mediocrity of the rest of the unit, I dont think this relates to the vintage units per say. In some ways yes, but mainly I think some of these offerings are actually not high on the list of muscially satisfying. I think a few bring detail that not inline with this goal of musicality nor is it always beneficial. If you listen to oil caps vs some film/foil, you will hear what I am talking about. There is an art to extracting all the detail while still keeping the musical side intact. One thing is for sure, good parts are no substitution for a good circuit/transformers. kh Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 16, 2002 Author Share Posted November 16, 2002 Mobile, Just retested the 165 ohm resistors and they test 175 and 173 so I believe this is why a didn't bother order 180 ohm resistors his transformer really doesn't get all that hot in my opinion. What you think ?? I believe everyone that has one of the amps that I have done describe them as very Musical ! Craig Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted November 16, 2002 Share Posted November 16, 2002 Well I for one am very excited about getting this amp back! Craig, thanks for the TLC you've imparted upon it. I don't remember if I asked you whether the L/R balance issue went away with the new tubes, c's and r's ... I was wondering whether it was just the aging potentiometer or the differing output of the aged tubes ... Just curious if you have a moment. BTW, it sure looks like the rat's nest of wiring was cleaned up considerably after your work. Thanks! Sorry you felt like crud this week. I did too. In fact, one of my afternoon sales calls in Cambridge (E-Ink, a cool, up and coming company with a revolutionary product -- www.eink.com) found me across the conference room table from one of their VP's ... both of us coughing and wheezing from the same malady ... diving for the same box of tissues ... We finally started giggling at the pointlessness of it, we both agreed to pack up and go home. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted November 16, 2002 Author Share Posted November 16, 2002 Chris, Yes I tried to clean up the wiring as best as possible and also went over most of the solder joints. I believe the channel imbalance is corrected. Not sure what did it but its sounds pretty balanced to me now. The amp does indeed sound much better. I'm getting ready to go down there now and give a afternoon of listening while I work on Pauls HF-12 phono section. Craig Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted November 16, 2002 Share Posted November 16, 2002 Craig, at least it's up from 165 although best to be almost exactly matched as these are important in the biasing. Still, perhaps they are close enough. I guess it's just a call as to how close you want. I think the 175 rating is fine. Just wish they were both 175. kh Quote Link to comment Share on other sites More sharing options...
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