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Recommend AM linear




 
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WB2YGF
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« Reply #50 on: April 05, 2009, 12:05:25 PM »

the only warning i will give about the henrys is that they are louuuuuuuuuuuuud...  fan sounds like i jet turbin with the afterburners on. 
I forgot to mention...The AL-80B is very quiet IMHO.  The 12V Icom supply for the Pro II actually make more noise then the AL-80B.
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WBear2GCR
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« Reply #51 on: April 05, 2009, 10:08:06 PM »


One has to be cautious and careful about the old Henry 2K series amplifiers.

A few things to look out for - none of which can not be overcome, but will require some effort to get right. I own two of the vintage units - a 2KD-3 and a 2K-3 (floor console)

- the power transformers can fry ( the one in the KD desktop unit is fried)
- there is no separate filament transformer in either, so you can't just throw in a random HV xfmr and go
- the TR switch is a relay that probably isn't really up to the task long term, ought to be replaced with something better
- it's not QSK, if you need QSK ur looking at one of those nice DIY PCBs for amplifier control as a retrofit
- the FRONT PANEL METERS - if they are the "heart" shaped ones are almost unobtainium (about $80 a pop if you can find them) are known to be blown for the Plate meter often. Since the are surface mounting you can't just throw in a random meter, you need surface mounting (stupid design, imho)
- the SWR adjust pot and switch is prone to failure (if it has been used a lot)
- the resistor at the end of the B+ supply is known to fail
- the "ballast" resistors on the B+ supply (big ceramic resistors) are known to crack, sizzle and fry (they get hot)
- the RF deck is designed for 3-400z tubes, if you try to use 4-400 or 3-500 you have to find shorty plate caps (or make 'em) and/or lower the sockets in the "well" as far as you can go (about 3/8") to find clearance
- imho the entire deck is max'd out at 3kv, if the B+ gets up there things tend to arc to ground a whole bunch (you may get different results than I did) stock B+ is 2.8kv and it will run forever at that voltage
- the tubes need to be biased slightly, and earlier models did not have the zener (it looks like a transistor on the back panel) so you have to add a diode string for bias - a small rotary switch on the back with taps on the string is not a bad idea
- the two 3-400z use a common filament choke and series fils, so you can not ever use just one tube. This can be a PIA in the event of a crap out or if you want to test one tube.
- the small resistors (i think on the grid?) that are on the bottom of the socket can be open or cracked - replace 'em.
- oh, replace the HV wire, it's shot - too old now.
- I added a heavy bottom plate, casters and a Hubbel twist lock AC connector on the rear of the PS...

If you go to QRZ.com and look me up, I think I still have a link to the work in progress on my Henry 2K... it's still not done. I need to put in the bias diodes and repair the meters, etc. etc...

So unless you buy one that has been gone through, or is of newer vintage than mine there will likely be some work involved in getting it fully operational.

                     _-_-WBear2GCR
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WB2YGF
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« Reply #52 on: April 05, 2009, 11:01:07 PM »

Thanks Bear. Now I KNOW I will never get one of those.  Grin
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WBear2GCR
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« Reply #53 on: April 05, 2009, 11:21:04 PM »


Yeah, but otoh, if you buy one that is working ok, ur good to go.
Or, if you fix one up, it will stay working.
And it has pretty good snot for a pair of 3-500z...

Not a bad amp at all.

Price & condition is everything...

 Grin

                _-_-bear
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K1JJ
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« Reply #54 on: April 05, 2009, 11:30:02 PM »


One has to be cautious and careful about the old Henry 2K series amplifiers.
A few things to look out for - none of which can not be overcome, but will require some effort to get right. I own two of the vintage units - a 2KD-3 and a 2K-3 (floor console)

Yep, the items you listed are the things I found wrong in my Henry 2K also. Though, I usually go through any commercial amp I buy and heavily modify it, so they didn't seem like a big issue. But, someone who wants a plug and play unit might not be happy... Grin

I ended up using just the RF deck with the common 0-4000v HV supply from the shack I use for all the amps.  I also stripped out all socket wiring and used copper strap for the grid connections to ground.  I added a quiet squirrel cage blower on the rear w/ a variac for air for the 3-500Z's.   I also added a string of diodes for the bias.  The ant relay hasn't failed yet, but I thought the same thing when I looked at it.

I raised the top inside cage about 1/4" so I could run 3500V w/o arcing.

All in all, I just love the stability,  mechanical and RF design of the unit.

In hindsight, I guess there WAS some work to be done on it, but it's all in a day's modifications to me... Wink
The time I spent modifying could have been spent building an amp, I suppose. Then again, I have seven homebrew linears in the shack for many different power levels and bands. It's nice to have at least ONE commercial amp to play with.


T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
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« Reply #55 on: April 06, 2009, 01:51:15 AM »

I'd have no objection to one with those problems, just be fun to mod and fix, and if it has those issues when examining it, you can point them out and bargain the price fairly (although the seller might be shocked to have any of those things pointed out!). Thanks for the tips on it!
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WBear2GCR
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« Reply #56 on: April 06, 2009, 10:38:01 AM »



Oh, I might add that there are a number of chassis layout variations in the early 2K series amps. The first ones (had a single red pilot light on the front) had a very different layout than the later ones, and the later ones have some variants too...

I suspect that the later versions mid 70s and after had many of these problems and issues resolved at the factory. Not sure though.

Tom, you can run 3500vdc on yours?
Mine arc'd a lot when the ballast resistors got open and the B+ rose above ~3kv...

Did you consider a shortie style plate cap instead of raising the covers?

               _-_-bear
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flintstone mop
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« Reply #57 on: April 06, 2009, 11:24:45 AM »

Burt,
If you have a little cash, buy the biggest thing out there and run 375 watts carrier.
You'll have plenty of headroom and it will sound wonderful. The headroom is the limiting factor for linear amp in A.M. mode
Joe, W3GMS is very happy with his Ameritron AL-82. Very scrotful power supply and he runs legal limit.

I run a Ten-Tec Titan 425. Nice big amplifier with 2500watts out so, there's a lot of headroom. But expensive to repair and then you have those ceramic pubes.
Fred
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K1JJ
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« Reply #58 on: April 06, 2009, 11:39:24 AM »


Tom, you can run 3500vdc on yours?
Mine arc'd a lot when the ballast resistors got open and the B+ rose above ~3kv...

Did you consider a shortie style plate cap instead of raising the covers?

               _-_-bear


Hi Bear,

Sounds like you could be the resident expert on Henry 2K's for sure... Wink

I can run 3500v on 80M, but on 40 and higher, I occassionally get arcing in the pi network cap plates. It doesn't do any damage, but it can't be run like that, of course.  I can get out an easy 1500w using 3kv with full pep drive on 80M - a little more with 3500v.

If I had the low profile  plate caps I wuda used them, but I just put some washers under the inside cover - that stopped the plate-cap-to-cover arcing.

BTW, I also have a 1979 Sigma XR-3000. Remember those?   I got the Henry and Sigma (pair of 3-500Z's also) in an even swap for a couple of older ssb transceivers I had lying around.  Anyway, when doing IMD tests between the Sigma and Henry, the Henry was much cleaner by maybe 5-6 db of side-trash.  Just a rough estimate listening to a local receiver with programmed material. Not sure why that wud be, other than maybe the tubes were softer in the Sigma. I used the same basic circuit except for the stock tanks in both. Both have input L/C.  So, I really like using the Henry in situations where IMD is important, like the DX window, etc.

All in all, if I was in the situation of needing a good pair of commercial 3-500Z's and didn't mind a little work, I'd put out a "wanted" ad - try to find a cheap Henry that had a blown out power supply for $200 or so. That wud be the perfect platform to work from for me.


Later -

T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
Steve - WB3HUZ
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« Reply #59 on: April 06, 2009, 10:45:55 PM »

The newer, Classic series of Henry amps are a better bet. (Yea, I know, they're newer but they are called Classic - makes no sense). These usually don't have the problems of the older 2k, 3k series. They also run higher plate voltage which means the 3-500s need less drive and put out more power. If you can find a 2K Classic-X like Mikey has, you'll be good for close to 2 kW PEP. That means you can run 300-400 watts carrier with plenty of headroom for audio munky swing.
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« Reply #60 on: April 07, 2009, 10:07:00 AM »

That Henry 8K sure has a pretty mouth. A 3CX-3000A7 - and costing 5 figures new.  Export only, of course. Like Cuban cigars.

T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
ka2zni
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« Reply #61 on: April 07, 2009, 11:02:33 AM »


One has to be cautious and careful about the old Henry 2K series amplifiers.

A few things to look out for - none of which can not be overcome, but will require some effort to get right. I own two of the vintage units - a 2KD-3 and a 2K-3 (floor console)

- the power transformers can fry ( the one in the KD desktop unit is fried)
- there is no separate filament transformer in either, so you can't just throw in a random HV xfmr and go
- the TR switch is a relay that probably isn't really up to the task long term, ought to be replaced with something better
- it's not QSK, if you need QSK ur looking at one of those nice DIY PCBs for amplifier control as a retrofit
- the FRONT PANEL METERS - if they are the "heart" shaped ones are almost unobtainium (about $80 a pop if you can find them) are known to be blown for the Plate meter often. Since the are surface mounting you can't just throw in a random meter, you need surface mounting (stupid design, imho)
- the SWR adjust pot and switch is prone to failure (if it has been used a lot)
- the resistor at the end of the B+ supply is known to fail
- the "ballast" resistors on the B+ supply (big ceramic resistors) are known to crack, sizzle and fry (they get hot)
- the RF deck is designed for 3-400z tubes, if you try to use 4-400 or 3-500 you have to find shorty plate caps (or make 'em) and/or lower the sockets in the "well" as far as you can go (about 3/8") to find clearance
- imho the entire deck is max'd out at 3kv, if the B+ gets up there things tend to arc to ground a whole bunch (you may get different results than I did) stock B+ is 2.8kv and it will run forever at that voltage
- the tubes need to be biased slightly, and earlier models did not have the zener (it looks like a transistor on the back panel) so you have to add a diode string for bias - a small rotary switch on the back with taps on the string is not a bad idea
- the two 3-400z use a common filament choke and series fils, so you can not ever use just one tube. This can be a PIA in the event of a crap out or if you want to test one tube.
- the small resistors (i think on the grid?) that are on the bottom of the socket can be open or cracked - replace 'em.
- oh, replace the HV wire, it's shot - too old now.
- I added a heavy bottom plate, casters and a Hubbel twist lock AC connector on the rear of the PS...

If you go to QRZ.com and look me up, I think I still have a link to the work in progress on my Henry 2K... it's still not done. I need to put in the bias diodes and repair the meters, etc. etc...

So unless you buy one that has been gone through, or is of newer vintage than mine there will likely be some work involved in getting it fully operational.

                     _-_-WBear2GCR


Thank goodness I got a good one, a little work, a larger blower, a couple minor changes and 350 watts of carrier all day long... I'll stand behind my Henry any day...
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« Reply #62 on: April 07, 2009, 07:56:08 PM »

So many amps, so little time.  Pay attention to the cost of the tubes.  I had a Ten-Tec Titan I, 2 3CX800A7's, small desktop unit, separate power supply, big hypersil transformer, loafed at 375W carrier 125% peaks.

But I inadvertently hooked the output of the class E rig to the input of the Titan and discovered just how much 3CX800A7's fetch now.  Other big tubes have gotten expensive too.
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« Reply #63 on: April 08, 2009, 06:52:52 PM »

I have a couple of TransWorld sand state commercial leenyars, a TW500 (500W) and TW-1000 (1KW).  The TW500 easily does 250W 125%+ mudulated AM whereas the TW-1000 will do 400W 125% easily.  I can old buzzard for 10 minutes on the -1000 before the fans even kick in.  Strapping amps indeed.  They're around on the surplus market; Uncle Sam used them paired up with the TransWorld TW-100 transceiver.

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« Reply #64 on: April 08, 2009, 08:00:07 PM »

CTR Surplus has a pile of 3cx800s on ebay. Good dealer.
Solid state amps are cool. I'm having very good luck with my MRF150 amp and plan to mount two of them in an enclosure for 500 Watts PEP. Warm up project for the pair of 1200 watt modules I plan to shot gun marry. No tune just give it a load and drive it. Hoping to make it go from 160 to 6 meters.
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« Reply #65 on: April 09, 2009, 01:12:38 PM »

Thanks for the heads-up Frank,
I found out that I can also use 3CPX800A7'a in my Titan, if the need arises.
CTR prices are better than buying new.

I think these tubes can last a long time, if they're not overdriven Shocked

Fred
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« Reply #66 on: April 10, 2009, 07:42:03 AM »

And now to stir the pot!
20 Buck and a hand full of fets.....Build an E rig and you will strap CHEAP! Grin

I couldn't resist!

Brent(Tina)

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WB2YGF
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« Reply #67 on: April 10, 2009, 09:20:45 AM »

And now to stir the pot!
20 Buck and a hand full of fets.....Build an E rig and you will strap CHEAP! Grin

I couldn't resist!

Brent(Tina)


20 bucks for a class E rig?  Tell you what, Brent.  I'll send you $40 for one and that's 100% profit.
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flintstone mop
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« Reply #68 on: April 10, 2009, 11:26:22 AM »

YUP Brent
I'll send you $200 and you can build it for me.
Just kidding............I'm not a builder. I don't have a junque box and I don't have the patience to search for the parts on the cheap and build something to show others.
I graduated from Heathkit-101, that's it Tongue
Fred
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« Reply #69 on: April 11, 2009, 02:48:46 PM »

Class E isn't linear, no matter how expensive. And they are expensive, what with all the crap outs they have.

Quite a few of the more strapping amps have been mentioned but for the price, a SB-220 is hard to beat.
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« Reply #70 on: April 11, 2009, 11:43:01 PM »

I attempted to run My SB220 on AM with my Ranger and my FT1000D.  I think best case is 200 watts AM with a Good running SB220. They are simply not up to the task of AM use at higher levels.  If I talked for an hour, I had to back that down to 150 watts max. The amp got VERY hot. Its abuse for sure. The power supply is to small and the stock cooling fan is not enough. I know lots of people use them and I do as well. But its not really up to more then a couple hundred watts.  I think you need something MUCH larger to run full legal limit AM with out any time limits. I have watched friends with QROs and Alphas flat out burn them up on AM trying to run 400 watt of carrier. No time limit? Yeah right. The biggest problem is the Cooling.  The amps can take the power but they cant take the heat of an hour of AM let along a night of AM! The QRO 2500 is really maxing out at 300 watts AM use. Even with an external fan pulling through the amp it will overtemp in an hour of good use.

I kick myself for selling my 4-1000 amp.  I had a two piece amp that was built out of California. Cant remember the name builders call sign. 4-1000 pulse tube. BIG Dahl Trans on in a box on the ground. Vac caps and crank handles. 6600 volts on the plate at well over an amp. Nice BIG band switch that required two hands to turn. I never used it.. Now that I am on AM just about full time I wish I had it back! I am sure it would run full legal all night.


Clark
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WB2YGF
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« Reply #71 on: April 11, 2009, 11:52:56 PM »

200W is not so bad.  The difference between 200W and 350W db-wise is not that great.  That's one reason I ended up with the AL80.
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« Reply #72 on: April 12, 2009, 12:53:09 AM »

Class E isn't linear, no matter how expensive. And they are expensive, what with all the crap outs they have.

What a shit-stirrer!   Grin Grin
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
Steve - WB3HUZ
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« Reply #73 on: April 12, 2009, 01:01:48 AM »

True dat. But everyone I've ever heard on the air crapped out. Even Karl's recent bit the big one. Unreliable it seems.



Class E isn't linear, no matter how expensive. And they are expensive, what with all the crap outs they have.

What a shit-stirrer!   Grin Grin
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N3DRB The Derb
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« Reply #74 on: April 12, 2009, 02:44:18 AM »

I dont think the wimpy phonograph motor fan in the Gonsets is going to be good enough for AM.  I am going to take the cabs to a local machine shop and have em cut round holes on the back cab for a Rotron fan set I got.  2 chrome guards, 2 air guides, the fans.  I mocked it up and it looks like Gonset put it in at the factory. mount em on rubber. will be pulling hot air out the back of the amp. Old buzzard transmission protection.



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