PL509 PP transformers?

[Balticnoiseforge]

Hallo is anyone here good at reading old datasheets?

I have had in mind of building a PL509 PP amp for a while now, but there is some things iam not totally sure of - namely OT watt and how much mA the tubes need.

I was thinking about something like 700vdc as B1 and for g2 trying to take it from a CT and let it pass through a VR150 tube.

So a power transformer with something like:
190 - 0 for B1
280 - 0 - 280 for preamp and CT to g2
20 - 0 - 20 @ 1a heater
6.3vac @ 2.5a heater
45 - 0 bias

With a OT of 4K @ "150w?" or could it for guitar / bass amp purpose be lowered to ~120w?

So there comes to problems, not really sure how much watt would be a safe point if you run them at 700vdc, and also not how many mA would be required for the secondaries to he safe when it comes to powertubes.

Why iam asking is because if you take a look at most datasheets they claim max watt ~30w and such, but if you dig deeper it looks like they can go over that by quite alot if increasing the anode voltage, which also would require more mA.



If anyone here are experienced reading old datasheets id be very grateful.
And yes i know these tubes arent specifically designed for amplifier use, but i still find them fascinating.

Thanks!

[kagliostro]

You can find the Svetlana datasheet of the EL509 (6KG6) that is the same of PL509 only heater voltage is different

https://frank.pocnet.net/sheets/164/e/EL509.pdf

there are data for the use in SE A1 class

also EL519 is near close to the PL509

Traynor used the 6KG6 (EL509) tube in the YBA-3A Custom Special

https://el34world.com/charts/Schematics/files/Traynor/Traynor_customspecial_yba3.pdf

--

Here there is an interesting thread, but it didn't give a response to your question

https://el34world.com/Forum/index.php?topic=20773.msg219508#msg219508

Franco

[Balticnoiseforge]

Thanks for reminding me about the Traynor.

That one used a quad for 300w with around ~570v into a 1.9K OT right?

So with ~700v into a 4K 150w should work?
They used a seperate winding for g2 at 100mA and a 400vac 600mA winding for the rest.

So could a
190 - 0  @ 300mA for B1 at ~700vdc
280 - 0 - 280 @ 200mA for g2/preamp
6.3vac @ 3a
20 - 0 - 20 @ 1a
60 - 0  @ 20mA

Into a 4k 150w work for two pl509 PP?
Or maybe that would just overcomplicate it compared to just one secondary for B1/Preamp and a seperate for g2?

( If iam not totally wrong about OT primary etc )

[sluckey]

190 - 0  @ 300mA for B1 at ~700vdc

How will you get 700VDC from a 190-0 winding?

[Balticnoiseforge]

Thought about something like Hiwatt does, while having the other stage centertapped to draw ~150vdc from

[kagliostro]

Assuming you connect the windings like in the Hiwatt the disposable current will be those of the lower powered winding

200mA in your case

Franco

[PRR]

> claim max watt ~30w

Tube dissipation is NOT maximum audio output.

On another forum folks were moaning about the very high price of PL509.

That strange transformer setup will also be hard to source.

[Balticnoiseforge]

Sourcing transformers would not be a issue since they will be custom if so.

And yes anode watt is another thing, but since this is just a hobby for me i havent been able to read out from the datasheets what i need, since they doesnt show information for push pull audio and such that some other tube does that are ment for audio, and how they behave in different conditions.

But iam sure that someone that is more experienced can read it out from them.

That is why i ask about how many watt a pair of PL509 gives when having a B1 at ~700vdc and a G2 at 150vdc, if a 150w OT would be enough? And if i am correct that it would work with a 4K primary?

And also how much mA the powertransformer would need to have when it comes to the PL509 tubes, if 400mA would be enough?

I wish i could view the datasheet and understand all that, but i dont.

But would be very grateful if someone with some goodwill could point me to correct values when it comes to the transformers, it is not tubes that i would use normally but the box of pl509 got abit of personal story behind them.

[kagliostro]

Isn't an exact response to your question (you talk about 700V B+) but I think that what I've find in my archive can be of your interest





Note Output Power -- B+ -- G2 voltage -- Load


Franco

[Balticnoiseforge]

Thanks for reply! Didnt know 2k5 was more suitable, but what the guy wrote about 400v+ on g2? On schematic it is 150, and the 400v+ was for B1.

But yeah maybe since i dont fully understand the datasheet i should maybe do a copy of their poweramp section, if i can find out their power transformer specifications.

Even if it would be fun to try a 700vdc.

[kagliostro]

460V B+ so around 330V AC (considering SS rectify)

120W of Power Is something like 260mA of current

A 330V AC @ 300mA PT is what I think you need

I hope that someone that Is more experienced than me can say if this Is correct

Franco

[Balticnoiseforge]

Thanks that info helped alot!
But still curious about having higher anode voltage, i find it weird that i cant find any schematics on the "transcendent Super Compact 150".

Which is the 700vdc circuit i linked on top, i have managed finding some forum post discussing using Hammond 1650T for building two monoblocks of that power amp circuit which have a spec of

"Output transformer, push-pull, 120W , primary 1,900 ct, 403 ma., secondary 4-8-16"

Which is supposed to give 150w RMS, but it maybe is better to try basing poweramp on the APX since it seems more grounded in being correct.

[Balticnoiseforge]

Someone posted this, which i found alot later than my project.

But for people interested in EL509 PL509 and such in the future it can be interesting.

Will post next two pictures which is a part list after this.

Output transformer used in this PP configuration is a Hammond 1650T with 1k9 CT 120w

[Balticnoiseforge]

Part list.

[Balticnoiseforge]

Part list 2