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HENRY RADIO experimental "transformers,
- Thread starter cbkidd1
- Start date
What do you mean by "experimental" transformers? Wait a minute......hold that thought..............NO. 
Certainly not "experimental", whatever that means ,but perhaps equipment specific as in have a transformer designed to suit the application rather than build an amp around an existing unit but that happens all the time. There were however different transformers used. IIRC it was an 1120 and an 1120A. One of them had more taps than the other but I can't remember which was which.
Certainly not "experimental", whatever that means ,but perhaps equipment specific as in have a transformer designed to suit the application rather than build an amp around an existing unit but that happens all the time. There were however different transformers used. IIRC it was an 1120 and an 1120A. One of them had more taps than the other but I can't remember which was which.I was just using the frace that was given to me, I recently bought a henry 2kd5. Here is a copy of what was told to me about the amp that i just uploaded. After receiving the amp I started to research the transformer. I do know henry used a Magnespec part number is 112000A (originally 1120A) and was used in the 2KD5 and 2KD Classic. Here is the transformer that is in the 2kd5 now. Henry never used a Ferrodyne 7497 transformer. Additionally, that specific transformer has a date code of 1975 and henry didn't start building the 2KD5 until 1979. The gentlemen insist this is what the amp came with new. So Captain Kilowatt what do you think?
Hmmmmm......I find it odd that Henry would suggest replacing the filter caps because of HIGH voltage. When caps go bad you will see lower voltage. Now that I see the context on which the word "experimental " was used I suppose it could have been simply an earlier part that was later replaced due to insuitability perhaps. The tech that used that word to a customer was probably just using non-tech speak. When I think of experimental I think of something not meant to be released to the public but fell thru the cracks and ended up on someones shack.
Thank you for your thoughts on the transformer, I have been unable to find any info at all on the transformer itself. I have been speaking to Ted henry over the last few weeks. Very nice gentlemen. Do you believe that it is possible the Ferrodyne 120 Volt only transformer has such a high secondary that the plate voltage would be higher than specs, And that it would supply the 3-500z tubes with the voltage "that they really need". And not need the 240V? Ted told me that No other tech that worked for him in 1979 is still alive to ask.
Transformers can be wound for whatever you want. I find it odd that a 2KD5 would be set uo for ONLY 120 volt operation. I wouldn't run a pair of 3-500z's on 120 volts regardless of the amps behind the plug.The higher output voltage may have been to compensate for voltage sag under full load.
The most notable difference between the "classic" and the desktop "D" versions of a Henry amplifier were found in the HV supply.
The "classic" versions in the upright console cabinets used a choke-input filter for the high voltage.
The desktop versions used a simpler capacitor-input filter. As in capacitors only, no big filter choke like the console power supplies.
The AC voltage delivered by the power transformer's HV secondary is roughly two-thirds as much in the desktop version compared to the console version.
The console power supply uses a "choke input" filtering method. The pros and cons are for someone else to argue, but the layout of this setup requires several hundred Watts of bleeder resistors. These are needed to draw sufficient current on standby so that the HV stays below the danger level. The conventional wisdom is that this setup has better regulation. The less "droop" in the high voltage when you modulate a SSB signal the cleaner the amplifier's output, all in all. The 'step down" from the HV winding's AC output to the DC output is about 10 percent. A 3300-Volt AC winding feeding a rectifier bridge into a big filter choke-type supply gets you about 3000 Volts DC.
The drawback is the 150 or 200 Watts of heat you must dissipate on standby from those bleeder resistors. When they fail and go open-circuit from old age and mileage, the standby high voltage will jump way above the danger level. Causes filter capacitors to fail from excessive voltage. Requires replacement of both filter choke and filter capacitors when this happens. Can clobber the HV rectifiers, as well.
But there's no room for a massive, heavy choke in the desktop models. Henry uses a transformer with about 2/3 the AC output on the HV winding as found in a console model. This matches the requirements of the capacitor-only filtering. Using only capacitors to filter the HV saves enough space and weight to cram it all into a smaller desktop cabinet.
Textbook name for the "capacitor only" filtering in the desktop models is "capacitor input". This configuration gets you an actual voltage "step up" from the AC voltage on the HV winding of the transformer. It's a step up of about 1.4 to 1. To get 3000 Volts DC, the transformer's AC output will be about 2100 Volts. That's roughly two-thirds the AC voltage coming out of the HV winding used for the choke-input setup in the console models.
Google did not turn up any reference to a transformer manufacturer named "Ferrodyne". There are motor and transformer shops all around the country. They all pretty much buy the materials used to make a transformer from the same handful of suppliers. That one looks like a custom job.
Only a moron would configure a power supply for two 3-500 tubes for 120 Volts ONLY. The inevitable voltage drop you will see on the 120-Volt circuit causes trouble for the chemistry of the tungsten alloy used for the tubes' cathodes. If the filament voltage falls, the temperature of the cathode falls too. If you don't keep up the temperature of the 3-500Z cathode, it will wear out and the tube becomes "weak" prematurely.
There is a "double whammy" effect on the filament voltage at a line voltage of 120. The step-down ratio from the AC line to the tube's cathode is 24 to 1. That means that a 12-Volt drop at the wall socket becomes a half-Volt drop at the tube's filament. Doesn't sound like much, but it comes close to the tubes lower-limit "danger zone".
Residential building codes generally forbid using wire larger than #12 for a 120-Volt socket. Unless the outlet is within six or ten feet of the breaker box, you'll need to run that amplifier at half throttle or less to hold that line-voltage drop to a level safe for the tubes. Keeping your outlet within a few feet of the breaker box can circumvent the voltage drop problem.
But at 240 Volts, the amplifier only draws half the current from the outlet for the same RF wattage. The same-size wire now drops only half the voltage feeding the wall outlet.
The double-whammy comes from the 48-to-1 stepdown ratio between the 240-Volt wall outlet and the 5-Volt filaments. That same 12-Volt drop at the outlet now only causes the filament voltage to fall by a quarter of a Volt, not a full half.
And since the current draw on the wire feeding the outlet is half what it was at 120 Volts, the voltage drop at the outlet is cut in half as well, reducing the actual drop in filament voltage to be one-fourth of what it was at 120 Volts with the same size wire feeding the wall outlet. A theoretical 6-Volt drop at the 240-Volt outlet only reduces the filament voltage by one-eighth of a Volt instead of a full half Volt. Not enough to be a problem at all.
I have seen folks 'double up' 12-gauge Romex feeding a 120-Volt outlet to reduce this problem. That helps, but it could get your homeowner's fire insurance canceled.
I can't imagine Henry Radio would have ever built a custom version of that box for 120 Volts only. I really think you have a custom-made aftermarket transformer in that box.
73
The "classic" versions in the upright console cabinets used a choke-input filter for the high voltage.
The desktop versions used a simpler capacitor-input filter. As in capacitors only, no big filter choke like the console power supplies.
The AC voltage delivered by the power transformer's HV secondary is roughly two-thirds as much in the desktop version compared to the console version.
The console power supply uses a "choke input" filtering method. The pros and cons are for someone else to argue, but the layout of this setup requires several hundred Watts of bleeder resistors. These are needed to draw sufficient current on standby so that the HV stays below the danger level. The conventional wisdom is that this setup has better regulation. The less "droop" in the high voltage when you modulate a SSB signal the cleaner the amplifier's output, all in all. The 'step down" from the HV winding's AC output to the DC output is about 10 percent. A 3300-Volt AC winding feeding a rectifier bridge into a big filter choke-type supply gets you about 3000 Volts DC.
The drawback is the 150 or 200 Watts of heat you must dissipate on standby from those bleeder resistors. When they fail and go open-circuit from old age and mileage, the standby high voltage will jump way above the danger level. Causes filter capacitors to fail from excessive voltage. Requires replacement of both filter choke and filter capacitors when this happens. Can clobber the HV rectifiers, as well.
But there's no room for a massive, heavy choke in the desktop models. Henry uses a transformer with about 2/3 the AC output on the HV winding as found in a console model. This matches the requirements of the capacitor-only filtering. Using only capacitors to filter the HV saves enough space and weight to cram it all into a smaller desktop cabinet.
Textbook name for the "capacitor only" filtering in the desktop models is "capacitor input". This configuration gets you an actual voltage "step up" from the AC voltage on the HV winding of the transformer. It's a step up of about 1.4 to 1. To get 3000 Volts DC, the transformer's AC output will be about 2100 Volts. That's roughly two-thirds the AC voltage coming out of the HV winding used for the choke-input setup in the console models.
Google did not turn up any reference to a transformer manufacturer named "Ferrodyne". There are motor and transformer shops all around the country. They all pretty much buy the materials used to make a transformer from the same handful of suppliers. That one looks like a custom job.
Only a moron would configure a power supply for two 3-500 tubes for 120 Volts ONLY. The inevitable voltage drop you will see on the 120-Volt circuit causes trouble for the chemistry of the tungsten alloy used for the tubes' cathodes. If the filament voltage falls, the temperature of the cathode falls too. If you don't keep up the temperature of the 3-500Z cathode, it will wear out and the tube becomes "weak" prematurely.
There is a "double whammy" effect on the filament voltage at a line voltage of 120. The step-down ratio from the AC line to the tube's cathode is 24 to 1. That means that a 12-Volt drop at the wall socket becomes a half-Volt drop at the tube's filament. Doesn't sound like much, but it comes close to the tubes lower-limit "danger zone".
Residential building codes generally forbid using wire larger than #12 for a 120-Volt socket. Unless the outlet is within six or ten feet of the breaker box, you'll need to run that amplifier at half throttle or less to hold that line-voltage drop to a level safe for the tubes. Keeping your outlet within a few feet of the breaker box can circumvent the voltage drop problem.
But at 240 Volts, the amplifier only draws half the current from the outlet for the same RF wattage. The same-size wire now drops only half the voltage feeding the wall outlet.
The double-whammy comes from the 48-to-1 stepdown ratio between the 240-Volt wall outlet and the 5-Volt filaments. That same 12-Volt drop at the outlet now only causes the filament voltage to fall by a quarter of a Volt, not a full half.
And since the current draw on the wire feeding the outlet is half what it was at 120 Volts, the voltage drop at the outlet is cut in half as well, reducing the actual drop in filament voltage to be one-fourth of what it was at 120 Volts with the same size wire feeding the wall outlet. A theoretical 6-Volt drop at the 240-Volt outlet only reduces the filament voltage by one-eighth of a Volt instead of a full half Volt. Not enough to be a problem at all.
I have seen folks 'double up' 12-gauge Romex feeding a 120-Volt outlet to reduce this problem. That helps, but it could get your homeowner's fire insurance canceled.
I can't imagine Henry Radio would have ever built a custom version of that box for 120 Volts only. I really think you have a custom-made aftermarket transformer in that box.
73
Agreed with everything else you said too but this is the direction I was leaning as well. I cannot comprehend a reputable builder like Henry building a 2X3-500Z amp for 120 volts only.
Thank you all for the info and your time, I guess now the only way to make the amp right is to buy another plate transformer, I learned a lesson not to believe all that is told to me when buying a amp. Wish I could find a used plate transformer. I don't see that happening. So I am going to sell my Tektronix 465B Analog Oscilloscope and fv-102 done by MAL with box in order to buy a Peter Dahi transformer, This is one hard lesson learned about buying used amps, Again I appreciate you two helping me. 73,
BJ radionut
Supporting Member and 6m addict
Kidd: saw these listed
Plate transformers
Two hv transformers. One Peter Dahl 120/240 primary, 1800v at 1.2A secondary. Other from BTI LK-2000 amp.- 240v primary, 1250v at 1.6A secondary. $100.00 each plus freight.
Listing #1325277 - Submitted on 05/05/17 by Callsign AB3IX - IP: c-174-60-15-71.hsd1.pa.comcast.net
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Kenwood 922/ Tokyo HP Plate Xmfr
Offering an OEM plate transformer for either the Kenwood TL922 or the Tokyo High Power amplifier with a pair of 3-500's. The plate transformer has multi-tap 110/220VAC primaries with 1400VCT output. Kenwood OEM part number visible in the digital. Has 4 mounting tabs for convenient chassis or side panel installation. The transformer was removed from a fully functional amplifier with wires cut sufficiently high above the solder tabs so the color code stubs are still visible to facilitate easy reassembly. Will produce 3600VDC at 1 amp in a typical doubler rectifier board circuit. Taps are also imprinted for easy ID. Transformer is also well suited for a compact, small footprint homebrew desktop amplifier project. Note:Accompanying filament xmfr sold.
$250 + shipping from zip 18426 in PA.
Listing #1325898 - Submitted on 05/09/17 by Callsign W2CQM, Modified on 05/11/17 - IP: 70.44.16.58.res-cmts.haw.ptd.net
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http://harbachelectronics.com/shop/...e-for-the-drake-l-4l-4b-and-l-7-power-supply/
Well since it looks like a total rebuild of the B+ supply...couple good components above.
Those Xformers from the old BTI amps are stout...I just recently rebuilt a 3-1000Z/BTI LK-2000 and using the FAR circuit boards...that hold the 12/filter caps...worked very well...3600VDC@34uF filtering using (4)20kv @ 3amp diode blocks for the doubler.
However the Drake rebuild board would do nicely also on either of the xformers listed above.I have a second BTI xformer which will be used with Harbach's board to make a upgraded PS for my Drake L4B...
Just remembered this is the desktop version...WOW spacing may be an issue...Most likely a true Hammond Transformer replacement may be required (They own the Peter Dahl name now)...Hold onto your wallet!!!
http://www.pwdahl.com/PWD_HamCatalog.html#Henry
HENRY 2KD-5 POWER XFMR
T1, P/N FDN-7497, DIRECT REPLACEMENT
CORE) EI-212 X 3 STYLE #) 04 E-I LAMINATED CORE
PR) 115/230 VAC 60 HZ 1PH
S1) 0-1780-2250 VAC @ 400 MA CCS
S2) 10.0 VCT @ 15A CCS
DM) HT = 6.375 WT = 5.313 DT = 5.678 MD = 4.250 MW = 4.250
PRICE) $375.00 Plus S&H FOB Buffalo, NY WEIGHT) 29 LBS
NON-STOCKED PART - HAMMOND Part Number: PWDP13121
GL
All the Best
Gary
PS: BOTH listing came from QTH.com an were still listed as of this posting...
Plate transformers
Two hv transformers. One Peter Dahl 120/240 primary, 1800v at 1.2A secondary. Other from BTI LK-2000 amp.- 240v primary, 1250v at 1.6A secondary. $100.00 each plus freight.
Listing #1325277 - Submitted on 05/05/17 by Callsign AB3IX - IP: c-174-60-15-71.hsd1.pa.comcast.net
Click Here to Email -- Send this Ad to a Friend
Kenwood 922/ Tokyo HP Plate Xmfr
Offering an OEM plate transformer for either the Kenwood TL922 or the Tokyo High Power amplifier with a pair of 3-500's. The plate transformer has multi-tap 110/220VAC primaries with 1400VCT output. Kenwood OEM part number visible in the digital. Has 4 mounting tabs for convenient chassis or side panel installation. The transformer was removed from a fully functional amplifier with wires cut sufficiently high above the solder tabs so the color code stubs are still visible to facilitate easy reassembly. Will produce 3600VDC at 1 amp in a typical doubler rectifier board circuit. Taps are also imprinted for easy ID. Transformer is also well suited for a compact, small footprint homebrew desktop amplifier project. Note:Accompanying filament xmfr sold.
$250 + shipping from zip 18426 in PA.
Listing #1325898 - Submitted on 05/09/17 by Callsign W2CQM, Modified on 05/11/17 - IP: 70.44.16.58.res-cmts.haw.ptd.net
Click Here to Email -- Click Here to View Picture -- Send this Ad to a Friend
http://harbachelectronics.com/shop/...e-for-the-drake-l-4l-4b-and-l-7-power-supply/
Well since it looks like a total rebuild of the B+ supply...couple good components above.
Those Xformers from the old BTI amps are stout...I just recently rebuilt a 3-1000Z/BTI LK-2000 and using the FAR circuit boards...that hold the 12/filter caps...worked very well...3600VDC@34uF filtering using (4)20kv @ 3amp diode blocks for the doubler.
However the Drake rebuild board would do nicely also on either of the xformers listed above.I have a second BTI xformer which will be used with Harbach's board to make a upgraded PS for my Drake L4B...
Just remembered this is the desktop version...WOW spacing may be an issue...Most likely a true Hammond Transformer replacement may be required (They own the Peter Dahl name now)...Hold onto your wallet!!!
http://www.pwdahl.com/PWD_HamCatalog.html#Henry
HENRY 2KD-5 POWER XFMR
T1, P/N FDN-7497, DIRECT REPLACEMENT
CORE) EI-212 X 3 STYLE #) 04 E-I LAMINATED CORE
PR) 115/230 VAC 60 HZ 1PH
S1) 0-1780-2250 VAC @ 400 MA CCS
S2) 10.0 VCT @ 15A CCS
DM) HT = 6.375 WT = 5.313 DT = 5.678 MD = 4.250 MW = 4.250
PRICE) $375.00 Plus S&H FOB Buffalo, NY WEIGHT) 29 LBS
NON-STOCKED PART - HAMMOND Part Number: PWDP13121
GL
All the Best
Gary
PS: BOTH listing came from QTH.com an were still listed as of this posting...
Last edited:
Good Evening BJ,
Thank you very much for your help and time, I know almost nothing about what transformer I could use. Or how I would go about wiring one unless someone was to draw me a diagram lol. The only transformer that I know for sure that will work and hopefully have a wiring diagram for dummies lol. Is the Peter Dahi Direct replacement part number PWDP13121. Just being honest. I have never replaced one until now. If the BTI LK-2000 was a drop in. I would be more then willing to trade him my Tektronix 465B Analog Oscilloscope in great looking and working condition as far as I know. Just bought it a few weeks ago. I have not yet learned how to use it. or cash he is close to me. DO you think both of them would do the job without any mods to the amp? 73,
Thank you very much for your help and time, I know almost nothing about what transformer I could use. Or how I would go about wiring one unless someone was to draw me a diagram lol. The only transformer that I know for sure that will work and hopefully have a wiring diagram for dummies lol. Is the Peter Dahi Direct replacement part number PWDP13121. Just being honest. I have never replaced one until now. If the BTI LK-2000 was a drop in. I would be more then willing to trade him my Tektronix 465B Analog Oscilloscope in great looking and working condition as far as I know. Just bought it a few weeks ago. I have not yet learned how to use it. or cash he is close to me. DO you think both of them would do the job without any mods to the amp? 73,
Here is a photo of my Tektronix 465B Analog Oscilloscope. Wish I Could find the right transformer for a trade,
BJ radionut
Supporting Member and 6m addict
Kidd: Sizing would be critical on the desktop version...Console version/ No issue on any of those.
However, if you have never worked with HV DC...those componets can kill you in a flash!
I personally would not trust ANY of the caps/diodes etc... at this point. I would replace everything, including upgrading HV wiring and all other connections with High temp Teflon or Thermoplastic 105 deg C+ cable all through... IMHO
GL
All the Best
Gary
However, if you have never worked with HV DC...those componets can kill you in a flash!
I personally would not trust ANY of the caps/diodes etc... at this point. I would replace everything, including upgrading HV wiring and all other connections with High temp Teflon or Thermoplastic 105 deg C+ cable all through... IMHO
GL
All the Best
Gary
I appreciate all your help with this, The owner said that he replaced all the electrolytic capacitors and bleeder resistors for the transformer, Do you believe the used Peter Dahi transformer would work in the 2kd5. If so I will get in touch with the seller, 73,
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