Using 2 transformers for a HV Power Supply.

[AH6RR]

I have looked at the Ameritron transformers and the one for the 572 would be just about right or better yet a transformer from a Dentron MLA-2500 (anyone got one for sale cheap?) would be better since it has the correct filament windings. But everyone I contacted about transformers wants to ship via UPS and that company rakes us over the coals shipping to Hawaii and USPS you can ship a flat rate box up to 70lb for under $15 for a Medium Flat Rate Box and a 40 pound box on UPS is well over $70 or they will not ship to Hawaii (Since when did we become a foreign country?). I did think the 830 transformers were a bit wimpy for the project so I will put them on the market along with a bunch of other radio parts I have for the 830's and some for a IC-751 and keep looking for a more suitable plate transformer. As far as the Blower goes I have one that will keep them quite cool in fact it will keep a 8877 cool. I have most all the other parts to build this amp including some Vacuum Variable caps so I am good to go just need the Plate transformer.

Thanks
Roland AH6RR

[VK4TUX]

I'm for reversing both the primary and secondary windings.

Tubes run cooler that way.

TOM K8ERV Montrose Colo

Stop with the stupidity

[N2EY]

The TS-830S transformers are best used to keep TS-830's alive.

Besides their limited power rating, they probably don't have the insulation level you need for the job.

73 de Jim, N2EY

[N3JBH]

Stop with the stupidity

Haa Haa Tom flogged by Rich's groupie now that was funny

[AF6LJ]

I have looked at the Ameritron transformers and the one for the 572 would be just about right or better yet a transformer from a Dentron MLA-2500 (anyone got one for sale cheap?) would be better since it has the correct filament windings. But everyone I contacted about transformers wants to ship via UPS and that company rakes us over the coals shipping to Hawaii and USPS you can ship a flat rate box up to 70lb for under $15 for a Medium Flat Rate Box and a 40 pound box on UPS is well over $70 or they will not ship to Hawaii (Since when did we become a foreign country?). I did think the 830 transformers were a bit wimpy for the project so I will put them on the market along with a bunch of other radio parts I have for the 830's and some for a IC-751 and keep looking for a more suitable plate transformer. As far as the Blower goes I have one that will keep them quite cool in fact it will keep a 8877 cool. I have most all the other parts to build this amp including some Vacuum Variable caps so I am good to go just need the Plate transformer.

Thanks
Roland AH6RR

the flat rate box could be reinforced or a heavy duty box placed inside with the transformer inside.

Maybe you could work something out with a ham here in the states.

[AH6RR]

the flat rate box could be reinforced or a heavy duty box placed inside with the transformer inside.

Maybe you could work something out with a ham here in the states.

I set a Plate transformer for a HT-41 in a flat rate box with other cut up boxes around it to hold it in place and it got to AZ just fine. Now that I think about it I should have never sold it and used it for this amp project.

[AF6LJ]

I set a Plate transformer for a HT-41 in a flat rate box with other cut up boxes around it to hold it in place and it got to AZ just fine. Now that I think about it I should have never sold it and used it for this amp project.

I haven't too impressed with the strength of the flat rate boxes.
Nice thing about transformers is they are hard to damage, like shipping an anvil.


I have some parts rat-holed for a 4CX250 amplifier.
One of those someday projects, as a find something I throw it in the box.

[AG6K]

I am thinking on building a 6 Meter amp using a pair of 4CX250B's Cathode Driven but I can not locate a suitable transformer for the HV locally I am trying to build it on the very low buget that I have and shipping a transformer here is out because shipping is outrageous. I do have 2 transformers from a Kenwood TS-830 that has 800V @250mA each if I ran them in paralell the into a voltage doubler to obtain the HV needed for the tubes or am I asking for troubles? I have a filament transformer. So before I get started on this I wanted someone that had more experience input on the matter. I was going to use a Microwave transformer that had the voltage I need but it hummed even with no load on it so I nixed that.

Roland AH6RR

 A TS-830 xfmr has a 350v-rms secondary winding with a FWD that produces c. 1000Vdc no load.

[WA7PRC]

I was going to use a Microwave transformer that had the voltage I need but it hummed even with no load on it so I nixed that.

Microwave oven xfmrs are run at 100% duty cycle so, they don't need to worry about minimizing magnetizing current ("idle" current). They typically have a pretty low primary reactance from having not so many turns of wire. This results in higher primary current with no load. Tom K8ERV probably knows more about that than anyone else on the Zed.

[KM1H]

I own a couple of 830's and the unloaded HV is 900V dipping to 800 under a 300ma load.

The AL-811/811H uses the same transformer and it holds up well at 700W out at 1600-1700VDC (at least with 572B's in place). It also has a buck-boost winding for more HV as well as 6.3V @16A which can easily be brought to 6.0V with a little resistance in the secondary leads.

Shipping is cheap in a medium Flat Rate box for that and the 830 transformers when you sell them.

All you need now is a small transformer for regulated screen and bias voltages which can come from a small tube radio as well as provide relay voltage.

Carl