mobile homeless Posted September 4, 2002 Share Posted September 4, 2002 Those HF-14 got WAY too rich for my blood. Now that IS an amp you could make very easily with some vintage iron! kh This message has been edited by mobile homeless on 09-04-2002 at 09:38 PM Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 4, 2002 Share Posted September 4, 2002 Actually I was suprised they went that cheap ! I really figured $400 to $500. I probably should of bid. Naaaaahhh Craig Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted September 4, 2002 Share Posted September 4, 2002 I was watching it too. I was refreshing the screen and had a mid $250 bid ready in another window. What was funny was checking the hit counter on each refresh. A LOT of people were watching that thing. The hit counter increased over a 100 in couple minutes. mdeneen, good info there. interleaved windings maybe aren't as rare as the guy was hinting. He might be prepping me for a price point. I won't forget that. I've seen elsewhere that a pair of these is considered a pretty nice amp. A pretty simple 6BQ5 circuit, looks like. Tom Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted September 4, 2002 Share Posted September 4, 2002 Paul, Thanks for giving it a try. You never know what might develop from something unlikely. Tom Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted September 4, 2002 Share Posted September 4, 2002 The HF-81 I have here has the lipped bells, they are numbered as 32013. The power trannie is S30021/ 798840. I am not sure what I am going to do with this unit. Correcting the wiring mistakes around the selector may not be a picnic. Then there is the prospect of replacing all the cheesy looking original cheapo parts, and there are a lot of them. I am curious, of the folks here who have units that work well, how many of those parts have been upgraded? There is this temptation to dustpan it and start fresh, but the question is whether I really want to DIY the same integrated circuit as original, or perhaps just make the amp section or some modified EL84 circuit using the same trannies etc. and then use an external preamp. This question is kind of related to the discussion since there had been talk of streamlining the circuit a bit in the possible modernized remake. Meanwhile I will keep it on the shelf for some future attention. Seems to have mostly Mullard and Bugle Boy tubes, probably the originals. I could probably break even if I parted it out. Just not sure yet what I will want to do with it. If I could just tweeze out that problem in the wiring, we could at least hear what you are all hearing for comparison. Now that I have had a taste of the dust pan approach, it is hard to reisist the temptation (Russian Roulette ala Deer Hunter). -C&S ------------------ Cornwalls currently upgrading to all tube components Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted September 4, 2002 Share Posted September 4, 2002 Tom, I've seen this reference regarding EBay bidding (having another bid ready in another window) a few times now on this board, and I really don't understand it. Why not just place your maximum bid via the EBay proxy bidding widget, and let it worry about it? I mean, if your personal max on that item was $250.37, then why not just place a proxy bid for $250.37 and let the EBay proxy bidding widget worry about it? If the winning bid was $15.00, that's what you'd pay... Why don't people use the proxy? Confused and curious, Ray Garrison ------------------ Music is art Audio is engineering Ray's Music System Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted September 4, 2002 Share Posted September 4, 2002 Ray, If everybody operated on the kind of level-headed, common-sense basis you're expressing here, your approach would work perfect. Are you an engineer? But that's not the way people work. People get caught up in their own excitement, get emotionally committed to the item after they've bid on it a couple times, etc. Sellers hope to encourage this by whatever means available, experienced buyers lay back waiting for the moment of truth, greenhorns get caught up in an emotionally driven bidding frenzy. Experienced buyers try avoid encouraging the newbies to run up the price unnecessarily. Check the guy that bought the 14's, he bid once at the very beginning, then again at the very end. His bid hit within seconds of the end, and it ended on an even dollar, probably his max was higher. And, the truth is I'm not any better than others on this. I had changed my max bid to 312.87 from 257.76, but pulled the trigger probably a fraction of a second too late. Might not have won it anyway, no telling what his max was. This does demo conclusively that I had no real idea how much I was willing to pay for those known defective things. Crazy. Tom I'm gonna go buy the rusty HF-81 before I ruin my wallet. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted September 5, 2002 Share Posted September 5, 2002 C&S, thanks for taking time to look and post. All data points are gratefully accepted. Kelly, somehow I missed your post at 7:26/7:31. I'm not copping out on my guy yet, suffice it to say he's not a name recognized in audio. But, he also alluded to quality differences in what he termed "electrical steel", the lamination material. He also mentioned a couple different grades of wire and differences in that varnish-like insulation. <-- tip-off to the depth of my ignorance there, I don't know what that's correctly called. I'm wondering if the fact that these transformers have the ability to support all these different load impedences (esp. the four ohm) is an indication of their native quality. Tom This message has been edited by Tom Mobley on 09-05-2002 at 12:44 AM Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted September 5, 2002 Share Posted September 5, 2002 mdeneen, Yeah, I'm sort of up on that stuff, I didn't really understand it's really varnish. When I built my ALK crossovers I had a nasty time to get that stuff off the ends of the Litz wire inductors. I burned it with the soldering iron, used a little toothbrush shaped stainless steel brush and finally took them out to the garage and used the oxyacteylene cutting torch and wire wheel, fixed. Thanks for your postings, your experience is invaluable. Tom Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted September 5, 2002 Share Posted September 5, 2002 Just out of curiosity, would it be possible to use the HF-81 transformers to build a single ended amplifier with the same EL84 output tube(s). Or, in general, is it possible to use (pp) trannies for SET circuits? If not, I am sure the answer will be edifying. -C&S of three vintage Eico pp amps in my possession, two of them had their power transformers replaced, whereas the output transformers are all original. I guess those things do burn out after awhile. ------------------ Cornwalls currently upgrading to all tube components Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 5, 2002 Share Posted September 5, 2002 SET circuits really beg for transformers that have an "air gap" which in turn makes the transformers, in general, larger with more turns of wire to keep up the inducatance. The cost of air gap SET transformers is higher than regular transformers. In addition, there is a lot of experimentation going on these days on different materials. Cobalt is being used to great results although it is VERY expensive. In addition, there is also a move to combine cobalt with silver wire in the transformers, adding additional cost, this all to wring out the last bit of sonics from these SET amps. Different grades of steel makes a difference as well with Permalloy grades with M6 steel (MQ makes a "pinstripe" version that alternates this to reduce expense). Another option is the Parallel Feed transformer which is smaller but does require the use of a coil transformers to complete the package. This is the latest in transformer experimentation with cobalt Parafeed coming in big. My DIY friend just built his 300b SET around Cobalt Parallel Feed transformers that were larger than normal PF and VERY $$$$. The transformers alone cost what most pay for a whole amp (then again, modern Peerless output iron for PP is coming in over $1200). kh This message has been edited by mobile homeless on 09-05-2002 at 06:54 AM Quote Link to comment Share on other sites More sharing options...
BryanJ Posted September 5, 2002 Share Posted September 5, 2002 Was going to bid on the unbilt unit but my wife caught me looking over the ebay page on it. Needless to say, I cannot have 3 amps but she can have "Emelda Marcos'" closet!!!!! I know, those of you that are married may know the feeling possibly? Still might search for one in need of being refurbished at a lower price. Still might wait for one to pop on Ebay at a later date. Who knows, maybe for the best. I am curious though why you all that know these units and rebuild them, professions are most likely EE, feel that it should not be built? I just know my gut feeling would be to build it. Maybe that feeling comes from what I do? Not used to having something that needs assembling, not assembled and functioning in top form. A vintage auto is best seen in full form, lovingly rebuilt and shown but not driven often. I could not appreciate fully it if it were but just a colletion of parts. I'm not saying I'm right but would like your various input. Possibly I'm not seeing the situation as this forum does? Bryan Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted September 5, 2002 Share Posted September 5, 2002 In the unbuilt stage, it is more rare and thus more valuable. As soon as it is built, it will be kind of like most of the others that are built, and thus, not as rare. The inherent value of it in the unbuilt state is 1) a museum display piece {a Grecian Urn so to speak} or 2) a new old stock kit for someone to build. Once the kit would be built, however, it then no longer has the appeal as a new kit for someone (else) to build and thus can never again be sold as a preimium and rare unbuilt kit. I see your point though and like NOS tubes it would seem that the value is in their use. I calculated the total number of use hours left in all the vacuum tubes on Earth at this time and it does just fall short of the estimated life span of our Sun. It might be wise to set aside a few NOS tubes to be taken out at that time in order to have some warm sounds for those last days. That might be a good time to build the museum display units as well. As they say, you can't take them with you. Then again, there is the possibility of setting up museums in other galaxies where we might be living. That might also be the time to put it up on Ebay again to maximize the return on the investment. Happy bidding. -C&S ------------------ Cornwalls currently upgrading to all tube components Quote Link to comment Share on other sites More sharing options...
jazman Posted September 5, 2002 Share Posted September 5, 2002 Docj, I say if you want it, Buy it, Build it, and Enjoy it. C&S, I don't agree with the stated museum philosophy. We as humans are way too attached to material items and attaching some "collectors" value to them. I'd rather buy it for the purposes of reverse engineering to create more for future enjoyment by more people, than think it should be in a museum wasting the knowledge of how to create more. We are born into this world with nothing but our bare butts, and that's surely the way we all leave. If you can't find the desire to re-build your HF-81, then donate it to a museum and there will be one in a museum. Damn, it's just an amplifier, though a good one, it's still just an amplifier, not the Holy Grail! Klipsch out. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 5, 2002 Share Posted September 5, 2002 I really think most of the collector value is gone with this unit. Its not in its bought from EICO state. It is about half built someone started on it and never finished it. If I was to buy it I'd build it. I just would never pay what that will go for ! Craig Quote Link to comment Share on other sites More sharing options...
BryanJ Posted September 6, 2002 Share Posted September 6, 2002 Craig, indeed so, since semi built. Still awaiting my Scott 222A. I was able to put in a last bid on the bay for the 81 before the wife kind of gave me her "VULCAN" eyebrow of disapproval. Of course I brought up her Emelda Marcos closet of shoes. This was not a well thought out tactic. Women? Advice for all you non married people, do not marry a red head, all that is speculated, postulated and reported is true. Nice to look at but a tasmanian devil underneath!!! Once you marry them, they are right no matter what. You are wrong. You must apologize even if you are right... I know alot of you know what i'm talking about. I'll leave it at that Craig, As you know, I kind of took some bagering yesterday. Was somewhat dismayed but like true troopers the gents were just that I was very pleased and once again honored to be here. I have just enough space for one amp on top and one below the E system amp/reciver. I know it is not in audiofile fashion to have interupts as a selector switch but I'll have to to run all three with the La Scala's. I could run a speaker selector in reverse,granted there are not any anti directional diodes in it and the internal wiring is adequate. Labors of love I guess for me. Someting differnt than what I have to see everyday. I just burned a cdrw with some MP3's. Sound great through the LS. I am a very pleased person. Best speaker purchase I've ever made!!! Bryan Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 6, 2002 Share Posted September 6, 2002 Yeah, Doc... sorry for the angst. btw, when you DO get all this new vintage tube gear and you get your entire system optimized, you will hear a BIG difference between .mp3 and even normal redbook digital. The compression schemes via mp3 are pretty biased towards space and not sonics. There is a huge gap in the quality that will be easily ascertained once you get ever those LaScala running full steam ahead. Not so sure I would opt for this kind of switching device but I see your problem. For me, I would have to do the speaker wire switching. No need to switch back and forth at the flip of a coin. kh Quote Link to comment Share on other sites More sharing options...
BryanJ Posted September 6, 2002 Share Posted September 6, 2002 MH, I unfortunately only have "my" room to do this in. Kids room is thiers and thankfully so. My E system room is 22x21x22 high! I'm now at the computer about 30 feet from the La Scala's. I guess that maybe why I'm missing the bass punch of the old 501's but have the K sub coming in today I hope from the tracking #. I realize that mp3's are condensed and missing some valuble audio information. Motorola has a wireless option device to hook up to the main computer with the MP3's and transmit to amp. I've known in the past the khz limitation has been around 15??? Am I right here? I really look forward to hearing the difference. I'm a tubie and always will be. I know If I want raw current I'll turn on the 100watt ss amp, but for quality, color and that feeling of being there the tube must be. I wonder how much capital it would take to start up a defunct tube plant?? bryan Quote Link to comment Share on other sites More sharing options...
BryanJ Posted September 6, 2002 Share Posted September 6, 2002 MH, no problem as far as the agnst I'm new to bboards. Happy I'm here holding up the K. I have a few Count Basey(sp?), opera, clarinet ect type of music from the 30's,40's 50's on LP. MY dads. My mom threw so much of them away when he died. Not out of any type of anger but did not interest her and were taking up space!. I still get after her for not keeping his old equip. That was a major sore spot when she gave it away when I was 12!! I said it should be mine! but she still gave it away. I still remind her of that and I will not do the same and my wife will give all my equip to my son. Man! Yeah, that still gets a damn good rise out of me. Oh well. My dad was an Aerospace engineer at NASA Langley, in Hampton Va. He had 4 bs degrees. Loved his opera lp's. Different time I guess. I grew up in the 60's and the more I think about it the more I appreciate it! The wife works for Honeywell for Nasa in Las Cruces NM. She proclaims she will never ride in anything they make!!! OUCH!!! Lowest bidder I guess? Bryan Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted September 6, 2002 Share Posted September 6, 2002 A variation on my previous question: Are there transformers used in older electronics (perhaps prior to the days of push-pull) which are appropriate for DIY SET amp experimentation. Which brings up the question: what is the history of the SET amplifier, wasn't it the original concept in the early days of radio, thought I heard that somewhere. Might be interesting to hear about the history of the SET concept and how it eventually came to be what we see today in the current audio arena. Are there really old vintage SET amps to look out for? -C&S ------------------ Cornwalls currently upgrading to all tube components This message has been edited by Clipped and Shorn on 09-08-2002 at 04:03 AM Quote Link to comment Share on other sites More sharing options...
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