Henry amp. question

Discussion in 'Amateur Radio Amplifiers' started by NM7G, Jun 25, 2012.

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  1. NM7G

    NM7G Ham Member QRZ Page

    What's the difference between an ECA 1092 plate transformer, used in some Henry amps, and transformers with P/N ECA 1092A?

    I'd really rather not go down the path about transformer reliability here; just a straightforward spec. issue if you please.
  2. N3JBH

    N3JBH Ham Member QRZ Page

    I know the 1092A is 3200 VDC @ 800 ma. But not sure what the Non A version is sorry.
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Sounds to me like they just rolled a revision ("Rev A") and there may not be any real difference, but I don't know.

    Have you checked with "Radio Dan?" He is pretty familiar with Henry BOMs...http://www.radiodan.com
  4. NM7G

    NM7G Ham Member QRZ Page

    In which model amp.? Are 3200V and 800 mA. from a manual?
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    That's the rating of the entire power supply, not the transformer!
  6. NM7G

    NM7G Ham Member QRZ Page

    Of course, Steve. I was hoping to learn if that 3200/800 was with their typical tuned choke-input filter p.s.
  7. NM7G

    NM7G Ham Member QRZ Page

    If you're correct about ECA 1092 and ECA 1092A being made by different builders, it seems strange they would keep the ECA prefix(which identified a supplier, Electrical Corp. of America), when they changed to a new supplier.

    From what I've read about Henry p.s. iron, consistency wasn't a high priority. The 2K manual, for example, shows that when Peter Dahl started building 2K plate xfmrs, voltage changed from 2800 to 3kV, ostensibly not for engineering reasons.
  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Do you have personal experience with that? Mine is just the opposite. I live very close to the old Henry plant in Venice, have been there several dozen times over the years, and sold them very expensive parts when much cheaper stuff was available. When I was working for Semtech, Henry selected our SDHD15KS 15kV 3A rectifier assemblies, which cost about double what Solitron, RCC and others sold them for simply because they had verified longer operating life under high temp, surge and transient conditions. They used to pay $54 each for those, with two in each amplifier. They also bought controlled avalanche assemblies from us, used a "zeners" for cathode biasing; a 50W DO-5 zener for $5 would have done this job, while our assemblies were about $15 each; but our assemblies could handle 150A peak avalanche current so in the event of a fault they wouldn't fail. They made their own roller inductor assemblies in-house which was enormously labor-intensive, and they tumble deburred all their tuning capacitors (walnut shell tumble). They actually fabricated a lot of stuff that could have been less expensively done with outsourcing.

    The chief RF amp designer from Henry is still very much in business, and running a highly successful RF amplifier company locally: ASI (Amplifier Systems Inc.) in Northridge: http://www.ampsystems.com/asiprod-old.htm He doesn't sell much into the ham market unless a ham has deep pockets and wants a very "big" amplifier (some do, and a few locals do run his stuff). His amps "start" with 3CX3000A7s and go up from there, so nothing as small as 8877s or such. The reason Henry stopped making amateur amps was mostly because Ted Henry became quite old and retired, and his stepson who took over the business wasn't a ham and evidently didn't care much about amplifiers or the family business. I think that was just typical "bad planning," as Ted Sr. just never groomed anyone to take his place. Happens all the time.

    The reason Henry made a lot of 4000W+ amps is they sold them into commercial and government markets (at higher prices, and more successfully than into amateur markets), and also they got a really good deal on piles of 3CX3000A7s. Charlie told me years ago he could buy 3CX3000A7s new from Eimac for a lower cost per tube than 8877s, so the only drawback was more filament power and a more expensive socket. But overall, even including those added costs, a 3CX3000A7 amp was less expensive for them to build than an 8877 amplifier, and the 3000A7 had 3dB more headroom when used in amateur service, which yielded some amazing IMD numbers (-43 dBc and better was typical IM3 at 1500W PEP output).
  9. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I doubt they were making good profits once Ted Sr. left the business entirely. The younger Ted wasn't very easy to get along with, that goes back to the mid-to-late 1980s.

    As an example: Prior to the 3K Classic MK III (later called the 3K Premier), Henry never made an amp that covered 160 meters. I convinced them to by giving them an order for twelve (12) amps, giving them the choice of the 3CX1200D7 or 8877 -- either one was fine -- and the 1200D7 was a brand new tube on the market at the time (1985) so I didn't know much about it but was assured it was a good design, very rugged, and instant-on, which was a great feature. So, I gave Ted a purchase order for twelve amps (about $36,000) along with a check in that amount.

    He didn't want to take the order or the check. Finally, "Dad" agreed to the order and started the process going which resulted in their first 160-10m model. Charlie Asimoto did the design and used a HUGE 160m air wound coil in series with the roller, as well as more switched in padders at both ends. It was a success (although I don't know what they had against toroids, which would have occupied a lot less space and likely done just as well) and the amps delivered 1500W+ output easily with 55-60W drive and very smooth and easy tuning on 160. But "little Ted" rejected the order, initially.

    Charlie quit and formed his own company. With that occurrence they lost a big part of their design team.
  10. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I suspect my last post may have put an end to crazy rants about Henry amplifiers, which I've actually found to be very reliable over 40 years.:eek:

    I think the best commercially built amp I've ever owned was the Henry 4K Ultra. Wish I still had it. It didn't cover 160m but was full coverage from 3.5 through 30 MHz and the most robust amplifier product I've ever owned, including the 30S1 and several Alphas. 1500W output was easy with 60W drive and low IMD, and it included a dual directional Bird coupler (two element version) to monitor F/R power on one of its panel meters. Even had a filament voltage adjustment and meter for that (so does the 30S1). Really nice product, we used it at multi-multi contest stations for years with many different operators and it never glitched in any way.

    I'd like to have one, again.
  11. NM7G

    NM7G Ham Member QRZ Page

    Back to the transformer in question, gents....

    The ECA 1092A I have was in relatively dry basement storage for over twenty years. Is there value in giving it a modest bake-out, to rid it of any accumulated moisture, before applying 240 VAC? I'd probably bake it from within by applying a few volts through a Variac plus fil. transformer to the primary, and resistively loading the HV winding; then slowly ramping up the Variac until I detect a little heat. It would then soak for 3+ days. Is this idea a waste of time and or power?
  12. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Of course, you could be right. However, as of 1980-ish, Henry had sold more amateur amps than anyone except Heathkit. Now Ameritron holds that title, and has also passed Heathkit.

    Again, maybe, but couldn't prove it by me: I was a vendor to Henry and they paid "top dollar" to buy good stuff like HV rectifiers.

    Anything's possible but this sounds a bit like a sour grapes story. I sold them thousands of parts for very high prices because they had value. I never had a Henry amp fail, and I've owned six of them. "Abuse" is a common cause of failure. Frankly, I'm not even sure why they ever used chokes with SS rectifiers; it might have been to reduce the size of the filter capacitor required, but most Henry amps used oil-filled HV caps like GE Pyranol (which were never cheap) and they had room for larger ones. The pedestal amps had power supplies that weighed over 100 lbs in most cases. My 4K Ultra weighed in at 192 lbs, and most of that was the power supply.

    How do fans lower thermal resistance? It is what it is. Fans can only keep the heatsinks cooler, but I don't think they have any impact on Rthj-c.

    Might be, I never had a Henry SS amp.

    I don't know. But if you're referring to Ameritron, they sure sell a lot of amplifiers and I've used most of them without any issues at all. Or maybe you're referring to someone else. Of course, knowing how to actually use an amplifier is a benefit.:eek:

    I designed RF stuff for HP for several years, and we tried to make stuff "bulletproof" to avoid dissatisfied customers and limit RMAs. But it was all very expensive. You get what you pay for.
  13. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    In my experience, I "bake out" devices like this by leaving them on my patio table in the sun for a few days. A few hours in an oven at low temp (like 250F) might do just as well. Not so sure that exciting the windings at reduced power does much.

    Edit: I don't know much about ECA, but I never, ever had a Henry amp fail and most of those had magnetic components made by that company. The only "failures" I've ever experienced with Henry amps were due to catastrophic circumstances, like when my 3K Premier fell completely off the bench to the floor in the 1994 Northridge earthquake. It stopped tuning up properly. Inspection revealed the roller inductor sliding contact wedged between two of the windings. I took it back to Henry (a 20 mile drive) and they replaced the inductor for free while I waited, and also replaced the plate RFC for free because they found the original one had resonances that wouldn't let it work properly on 17m. So, the amp I ended up with was better than the one I brought to them, all at no cost other than my gas.
  14. NM7G

    NM7G Ham Member QRZ Page

    O.K., Steve. Thanks.

    I live in NW oregon, and don't want to wait 'til the rain stops entirely for a sun-bake. The only oven at my disposal is in the kitchen and draws way too many Amps for a worthwhile bake. Besides, I want the heat on the inside, not on outer portions. If I load it properly, it will warm adequately. When I feel heat on the outside I'll know the inside is hot, whereas the converse may not be true. 73
  15. K6AF

    K6AF Ham Member QRZ Page

    If you have the plate transformer out of the supply now - you might consider having it 'dipped and baked' at a motor rewind place. I took both my plate transformer and choke from a Henry 2K-4 that buzzed a lot under load and did that. $50 each and they don't make a sound now. After 40 years the varnish dries and the innards buzz around some. In my case they preheated the transformer and choke, dipped in varnish, then baked. This is apparently the standard process they used for electric motors. Vacuum dipping wasn't required because the windings aren't tightly wrapped - they said the varnish would just wick up. Money well spent IMHO.
  16. AG6K

    AG6K Ham Member QRZ Page

     Indeed. One of their better blunders was putting the glitch-R in the HV negative lead instead of the HV positive lead -- i.e., a virtual invitation the xfmr insulation failure during a HV arc to chassis. Also Henry deserves credit for using the highest VHF-Q suppressors in the business. Example: 3KA, Suppressor Q was an impressive 5.5 @ 100MHz, which at 3900Vdc is a virtual invitation to intermittent parasitic oscillation.

    "Stupid is as stupid does." - - Forrest Gump".
  17. AG6K

    AG6K Ham Member QRZ Page

     potting xfmrs and chokes yourself in polyester laminating resin has the advantage that it does not shrink as it cures, does not require a vacuum chamber, and it costs about 8% as much. Instructions for doing this:

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