MainFrame
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Posts posted by MainFrame
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On 9/17/2017 at 4:58 PM, Dr Morbius said:
Just to let you know, I had NOS Valves redo my 4 different HH Scott tube amps over a 5 year period and they sound fabulous!!! $125 each is really not a lot of money for heaven! Also for goodness sakes drop the bose and get a pair of Klipsch for those amps, you will not be sorry.
I might go ahead and hit him up to run through the big amp.. I'm trying to get in touch with the dwilawyer guy to test the 811 output tubes but he hasn't responded yet.
I asked a sound engineer friend of mine about getting someone local to test everything for me. He referred me to a guy he has had restore some guitar tube amps that are worth close to $10k, but when I talked to that guy he was saying it'd run me about $1100 to have him go through all three of them. He said all the caps have to be replaced regardless due to their age, and the Heathkits need to be converted back to push-pull because the transformers won't work right with the single ended setup (as well as testing all the tubes). I don't want to fool with converting the Heathkits since I'm sure my father in law set them up like that for a reason. Replacing the caps should be easy enough and I figured I would go ahead and do that even if they've barely been used and test out fine.
I'm definitely going to get some either Klipsch, or maybe some Tannoy speakers.. I'll have to see what all is still in storage because there should be a set of speakers to go with the rest of it. The Bose are just being used on my TV temporarily until I can get around to fixing my Cambridge Soundworks 7.1 surround system. They sound decent for watching TV, but their frequency response is pretty poor IMO. I'm only planning on using the tube amps for music.. I'll keep the 7.1 system hooked to the TV for computer games and movies.
On a side note.. some of my wife's relatives came to visit a couple months back, and they brought with them three big boxes of vacuum tubes that my father in law had collected over the years. I haven't opened them up yet, but I plan on sorting through them and selling many of the less desirable ones to pay for any repairs that need to be made on the amps. -
15 hours ago, TubeHiFiNut said:
@MainFrame - Your call. Everything might be all nice and discharged now but the minute you power things up, that is no longer the case.
Just urging caution when you are not used to playing with 1000+ volt (at decent amperage) B+ supplies like my 845 amps run.
Best of luck with your amps - sounds like they could be pretty special.
I'm out.
Definitely.. I'm sure there are plenty of people who don't understand how capacitors work (when I was repairing the HVAC system in my house earlier this summer I went in to a supply store to buy a replacement main run capacitor for the A/C compressor and the lady told me that people come in all the time carrying fully charged caps in their pockets). 1250V is a lot of juice, so I'll be sure to be cautious. Any time I put power to a capacitor then need to work on the unit later I fully discharge everything with a resistor I wired up specifically for that purpose.. then double check each one with my DMM before touching anything else. I also inspect everything for possible shorts and burnt out components prior to hitting it with any power.
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On 9/4/2017 at 12:15 PM, TubeHiFiNut said:
Glad to hear that the PAS3 worked and that you are getting it sorted out.
As has been previously stated, please do not poke around in the amps. This type of amp has LETHAL voltages. Touching the wrong thing can really ruin your day - forever.
@NOS Valves is correct: Get the amp into the hands of a qualified tech who is used to the protocols required to safely work on amps that use big transmitter tubes.
The reward for doing this the right way will be an amp that should satisfy your audio needs for many years to come - especially with efficient speakers like Klipsch.
I have 845 based amps and am amazed at how good they sound.
Good luck.
I really don't see what the safety concern is when A: I'm obviously not working on ANYTHING while it's plugged in, and B: the capacitors have no charge in them (I tested all the caps in the amps and they had no charge, but would take a charge.. so they're still functional to some point, but I'm planning on replacing them regardless before putting any power to the amps. After testing out the PAS3 I discharged the caps before fixing the loose connection I found and cleaning the volume dial more thoroughly). As I said, I have a background in electronics.. if there's no charge in the amp it is virtually impossible to get injured poking around in it (aside from the occasional cut on sharp metal and/or soldering iron burn, but I already have plenty of those.. non-lethal). I've been around enough electricity to know to follow safety procedures.. I wouldn't exactly say installing a new breaker box in a 50 year old house is non-lethal. Sure, it's not a lot of volts, but I assure you two 120V legs running in from a meter with 200 amp service is certainly enough to kill you.. and the fun part is, you can't shut it off. I've worked on plenty of home appliances with high voltage, and not once have I had a problem after properly discharging the capacitors. ¯\_(ツ)_/¯
I would love to have the luxury to just hand them off to someone and say fix these up and call me when you're done.. problem is, I can't afford to pay someone over $1k to look at them, so unless I'm shipping them out of town paying a "tech" go through them is out of the question (and I doubt you're offering to pay the bench fees for me). My other options would be to sell them, or trash them. As much as it seems like some people on here think I should get rid of the amps rather than take the time to get them all checked out and fixed up myself.. I'm not willing to do that. This was one of my father in law's passions, and I'm not just going to throw them away. -
On 7/6/2017 at 7:09 PM, mike stehr said:
It's Summer. Amp projects are for the Winter.
Word.. while I would love to fire this stuff up and see(hear) how they perform, I don't want to make a costly mistake and blow something up that was otherwise in good condition. I've always been a big proponent of doing things right the first time. Unfortunately in this situation that means putting it on hold until I have a decent block of time to go through testing everything and replacing components as needed before getting to experience what they have to offer.
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On 6/21/2017 at 10:47 PM, Dr Morbius said:
Hey, any updates on how your amps are doing? Just wondered....................................
Nothing yet. They've just been sitting on my work bench since my last update. I have so many other projects going on right now and these amps aren't time sensitive like a lot of the other things I'm working on. Once I finish remodeling our bathroom, change the timing belt and everything on our Honda, clean up the garage and finish repairing all the drywall and paint it, then I can move the rest of my father in law's stuff in from storage.. after that I should have some time to chip away at getting the amps all fixed up and running.-
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19 minutes ago, alzinski said:
Make sure you check the operating points of the valves. Those black molded capacitors are most likely used for AC coupling stages and in my experience they are extremely prone to failure and leak passing DC on to the next stage messing up bias and shifting operating points.
The wiring and layout around the full wave voltage doubler looks terrible. It shouldn't cost much money to have someone etch you a PCB to tidy things up. It would make things much more reliable and look much more professional.
Will do.. after putting it through its paces for a couple days I think I found an issue with one of those caps coming from the L bass control. I'm gonna have to tear into it a little deeper and see what I can find. Need to figure out why the gain is low on the spare channel as well.. plus there's a loose connection somewhere (I'm thinking around the "loudness" switch). If I jostle the unit around just right it will kick the loudness on/off. It definitely needs some TLC.. I wish I had just like, one whole day that I could work on it rather than 10-15 minutes every three or four days. :/
Agreed about the wiring at the voltage doubler, it's a mess, lol. I probably won't get around to tidying that up until I've got everything up and running at 100%. -
6 hours ago, NOSValves said:
In my professional opinion "most likely" all that this gear will require.....
1) Test all tubes replace as needed
2) thorough electrical cleaning 10 years on storage creates lots of oxidization.
3) basic testing of any possible problems found during visual inspection.
4) slowly ramp gear up starting at 50 VAC with variac over several hours testing for problems like excessive current draw, heating up components, smoke or spark show)
5) Once at full 120 VAC test for proper operation.
6) play some music!
With gear like this shipped in where I would have to unbox and re-box for return shipping I'd charge about $125 for each piece. If both pieces made it though the above process without needing repair I'd spend one bench day to complete 2 pieces of gear...
Perfect! This is pretty much my exact plan. I was thinking it might be a good idea to just go ahead and replace all the large capacitors at this point as well? I ran some basic tests on the power supply caps in the PAS-3 and they seemed fine, so I went ahead and fired it up. Now that I know it works I can do more thorough testing on them later on (I'll probably end up replacing them eventually anyways).. All of the caps in the amps look brand new, and they've barely been used, but that doesn't change the fact that they're 15+ years old. I know caps can test good, then fail under operating conditions, so if they're not too costly I might as well replace them. I figured if all the tubes are good, the big power supply caps are good, everything is clean, and there aren't any signs of damage I would be ready to start slowly putting power to them. I'm not going to go through the trouble of testing each and every little resistor/diode/cap individually when everything looks brand new. Hopefully if something small has failed while in storage it will show itself at low voltage, then I can discharge the unit and replace as needed.
$125 a piece actually seems like a reasonable charge for this type of work. I understand this stuff is vintage, and valuable, but when places are telling me they want a $600 deposit per amp just to look at them.. I might as well take the time to do it myself. My DMM doesn't lie, and as far as electronics go these things are VERY basic. I'm pretty familiar with all the components other than the tubes themselves. -
I was talking to my wife about it a little more today and she said her dad rarely used this stuff. He would mainly just fiddle around with it, then listen to a couple records to test it out, then go back to tinkering.
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1 hour ago, sheltie dave said:
Nice, clean unit!
Here are the Austin hams, they can help you without much bs.. http://austinhams.org/
Thanks! I'll get in touch with them..
I may have discovered one issue with the preamp (or maybe this is how it's supposed to be).. I initially had the source on the "spare" channel and it seemed like the gain was a little on the low side. When I put the case back on and set it up on my shelf I plugged into "special" and the gain is MUCH higher on this input channel. Is that intentional? -
Opened up the PAS-3 this afternoon. Everything looks great for the most part. There are a couple wires here and there with scorched insulation (looks to be from soldering), but not bad enough to expose the wire. Caps look new, nothing charred/discolored. No residual charge in the unit as I expected. As far as I can tell the tubes are OEM, the caps look new.
I wiped down the tubes with an alcohol wipe, ran through the dials and everything with electronics cleaner and compressed air.. then I figured I might as well hook it up and see what happens. It's plugged into a Bose setup I have for watching TV using my cell phone as a source, and I must say, it sounds fantastic! At least as good as can be expected with these speakers.. Everything on it works as expected. -
1 hour ago, sheltie dave said:
If they are a four pin tube, any tube based ham operator will know a guru who will test them for a six pack of microbrew. Don't fall into the $50 a tube bs, testing all four takes under ten minutes.
besides, these tubes normally last about fifty years in a dedicated ham outfit. They aren't breaking a sweat in these amps.
Yep, four pin.. that's good info. My options are expanding.
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1 hour ago, ricktate said:
From the looks of those tubes they look almost new I cant imagine anything being wrong with them. Even if there was wouldn't the amp just not work??? Why spend all that cash on testing the tubes??? Just wondering.
From what the guy at the shop told me I was under the impression that if a tube is bad it could potentially damage other components in the amp.. is this not the case?? If so then I might forego getting them tested at all.. or just test the $1 a piece ones.
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On 5/12/2017 at 6:58 PM, robert_kc said:
IME, you should expect to pay approximately $600 to have a professional technician restore a stereo tube amp. You're complaining about paying $50 for someone to do work for you? How much do you expect a skilled technician to be paid per hour (including their time, and the overhead associated with their test equipment, and shop space) ????
I totally agree (although I wouldn't really consider plugging a tube in and seeing if it works or not a lot of work). That's precisely why it makes so much sense for me to do the vast majority of work needed (if any IS needed) myself at home. A skilled tech will certainly have more experience, but not necessarily more skill, and likely no greater attention to detail. The main difference I can see is that it will take me a good deal longer to get it all done (depending on said technician's work load.. the guy I took them to week before last said he was backed up for months). I'm pretty busy myself, so I expect it to take some time to make sure everything is done 100% right.
On 5/13/2017 at 2:12 AM, sunburnwilly said:Nice score , I'm guessing your wife doesn't have any brothers .
How did you know?? lol
On 5/13/2017 at 2:35 AM, ricktate said:Well not sure how you found these and no speakers..lol.
My wife said she remembers seeing at least two of the speakers that went with this setup in the storage container, so I've got my fingers crossed.. I feel like I saw the turntable somewhere as well.
3 hours ago, sheltie dave said:Are you in the Seattle or St. Louis area? If St. Louis, I have a friend who can check these for free.
i have two 811 mono blocks; they are quite good with Klipsch. Congrats, your wife probably has a good head on her shoulders with an engineer dad like this.
Austin, TX..
I talked to a friend of mine in the recording business and he referred me to a guy who specializes in vintage guitars/amps, so hopefully he will be able to check the 811 output tubes. If not I'll probably end up footing the bill to have them tested at the place that quoted me $50 over the phone.. although I'm not positive that the lady I talked to really knew what I was asking about. I don't want to end up blowing a transformer or anything in the off chance that one of these tubes is bad.
As far as my wife goes, she is by far the most intelligent level headed woman I have ever known. Not a day goes by that I don't feel grateful to have her in my life.
I have set myself a goal to have the PAS-3 opened up, photographed, and tubes pulled by the end of the day today, have all the tubes from it tested, and barring any issues have it all back together and fired up by the end of the week. Then I'm going to move my attention onto the home brew amp with the VT4C tubes. If all goes as planned hopefully I'll have something hooked up to speakers and making noise within the next two weeks.-
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3 hours ago, EJC said:
The PreAmp is a Dynaco PAS-3. This is still a highly regarded and sought after preamp.
These were put out by Dynaco in Philidelphia in the late 50's early '60s
You can find the schematics on-line along with the manuals usually for free.It has also been used for numerous upgrades and modifications.
Tubes4Hifi makes updated kits and boards for this: http://tubes4hifi.com/
Thanks! I'm willing to bet he tore the preamp apart and upgraded a lot of stuff in it too.. I'll post photos when I get a chance to open it up.
2 hours ago, Marvel said:If you mess with the amps with the VT4C tubes, be especially careful. The plate voltage is 750 volts and up. El supremo class A operation.
See the attached pdf.
Bruce
I'll definitely take that into consideration. Not trying to blow a hole in my hand (or worse).
25 minutes ago, mike stehr said:You didn't happen to come across any paperwork or schematics for the amplifiers he made?
I did not, though I wouldn't be surprised if it's mixed in somewhere. He wasn't able to pack any of it away himself, otherwise I'm sure everything would still be together. -
31 minutes ago, mike stehr said:
No, he mentioned he could get the output tubes tested for 50 bucks each...which I assume are the big triode tubes tested at 50 bucks each. A bit rich...
1 hour ago, dwilawyer said:Those look recently (last five years) worked on based upon the tubes and caps (I'm no expert my any means).
..let you know how to avoid shocking yourselft to death when working on this stuff. If you don't know what "B+" is I would wait until the real experts dive in here.
They have been in storage since he died 18-19 years ago.. although the owner of the shop who looked at them said everything looked all up dated and ready to go. He also said the caps will discharge themselves withing a few days, couple weeks tops. I was going to go ahead and test the charge and drain them if there's anything left... I'm unfamiliar with vacuum tubes, but I did take a couple electronics courses in college and done a lot of various electronics repair at home in the past so I should be able to prevent killing myself.. hopefully.
58 minutes ago, robert_kc said:IME, you should expect to pay approximately $600 to have a professional technician restore a stereo tube amp. You're complaining about paying $50 for someone to do work for you? How much do you expect a skilled technician to be paid per hour (including their time, and the overhead associated with their test equipment, and shop space) ????
Thing is, money is tight right now. If we're talking paying someone $600+ to have someone else work on them then I'm afraid they're getting boxed up in the attic for the foreseeable future.
45 minutes ago, thebes said:Welcome to the Forum. You've got probably a couple of thousands in tube amps there and a classy preamp. I'm with Travis, those look ot be in tip top shape. Without puling off the bottoms and snapping some pics, I'm thinking they have been worked on extensively restored within he last few years.
Simplifying a bit, never turn on tube amps that are not connected to a speaker. Check your local Craigslst and get a pair of speakers and hook them up. Connect a source, cd player etc., and then fire them up, they should be fine. Or better yet, let the local tech fire them up for you using a variac. Start up order is preamp first, then amps. Shutdown is amps first then preamp.
You have a very valuable gift. You either spend a few bucks, be awed and enjoy, or sell them to someone else who will actually enjoy them.
I have a few sacrificial speakers kicking around that I was planning on using to test them.. somewhere we should still have my father in law's speakers and turntable that went with this stuff but we haven't gotten to finding those yet. I already have a variac that I was thinking I would use to slowly bring them up carefully and see what happens when the time comes.
I have no intention of selling any of it. My father in law died before I was able to meet him and I feel like these amps he built are a way to have a connection with him (other than my wife of course ).
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I was recently going through some of my father in law's stuff that my wife and I pulled out of storage and I came across this preamp and three tube amps. Tube amps are something I've always had interest in but figured I'd never have the spare cash to start up a new hobby. Now that I've got these amps I really want to get them all fixed up and running. My father in law was an electrical engineer at Boeing and from what I'm told would go way over the top whenever he would get into a new hobby.
I took all of this stuff to the local vintage stereo shop, but the owner there told me because the two Heathkits are so modified, and the other one is home brew I should fix these up myself at home. He said they looked to be in good shape and suggested I open them up, clean and inspect everything, pull the tubes and he'll test them for $1 each (but he doesn't have the equipment to test the four Class A tubes). After that he said I should just throw some speakers on, fire them up and see what happens. There is one other place in town who said they would test the Class A tubes for $50, but that seems pretty steep to me.If anyone has the time, would you mind walking me through what I've got here? From what I've gathered I have two mono amps that have been converted to single-ended Class A tubes, then another homemade two channel amp, also single-ended with two matched 811 output Class A tubes. The owner of the shop kept saying they were "exotic", but I'm not sure if he just meant it's an unusual way to go about doing things, or if he meant something else by that. Either way, he didn't want to mess with them.
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). 1250V is a lot of juice, so I'll be sure to be cautious. Any time I put power to a capacitor then need to work on the unit later I fully discharge everything with a resistor I wired up specifically for that purpose.. then double check each one with my DMM before touching anything else. I also inspect everything for possible shorts and burnt out components prior to hitting it with any power.
inherited some stuff.. please enlighten me
in Talkin' Tubes
Posted
I'm surprised that people even sell untested tubes.. who buys them?
Thanks for pointing me to the website, this will be a great resource for me. I'm assuming their prices are mostly fair and accurate? If so then I should have no problem funding any repairs needed for the amps, be able to buy a nice pair of speakers (if there's anything wrong with the ones that should still be in storage), and have cash left over for a nice glass case for everything to go in. I just took a quick look, and some of the tubes I have here are listed for over $300 a piece.. if the cheaper/less desirable ones can fetch about $10 each then I should have a couple thousand dollars worth of tubes to get rid of, assuming most of them test out good of course.