PL36 (triode) SE

[Dumortier-us]

Hi Peter:
What type and where did you source the output transformers for your SE PL36?
Thanks - Joe
Dumortier Tube Audio and more – Vintage Tube and Classic Audio

 

[Dumortier-us]

European PL36

I have a number of New In Box vintage European PL36's in my "hoard". I purchased these for use in my Sansui 1000 (not 1000A) and they sound wonderful. I too will be building a PL36 based mono-block set using output transformers from a 1000, but I have more PL36's then I will use in my lifetime.

Regards - Joe
dumortier-us

 

[Tubes4e4]

Hi folks,

for sure you can get excellent results with triode strapped single ended EL36 / PL36 / 6CM5 / 25E5 and you can expect about 5 Watt Po using a decent OPT. I used a really cheap OPT and got about 4,5W Po

Loadline and schematic are excerpts from my (not yet published) book.

Kind regards, Tom

 

[Ryssen]

I`m at the moment listening to my 6E6P - 6S31P SE amp,very open sound with good details.I use James OPT.
I think you won´t be dissapointed,what driver are you going to use?

 

[Alastair E]

this is a working amplifier build exactly as as illustrated in the diagram...still on breadboard though.

The negative bias is generated by a voltage doubler circuit and stabilized with Z-diodes.

cheers
Peter

Hmm, just my opinion....

Shouldnt voltage stabilise the bias supply unless +B is also stabilised...

Line voltage variations will make bias drift if you have the bias supply stabilised, and not +B as well...

 

[TonyTecson]

that is the Russian 6P13S, i ordered 6N13's and received those tubes instead....

i am looking to build an SE using the same op as the 2A3 at 250 volts plate and 60mA cathode......
it will be interesting to find out how it compares to the real 2A3.....

 

[211hojbjerg]

Hi Tom,
I have been running my MTA SE PL36 connected in pentode at 20W since the EFT16.
330@60mA over the PL36, g2 is 150V regulated. OPT 5,2k
The setup is very stable and sounds great on Tannoy Berkeley.
btw looks like the PL36 glass tube is larger than the EL36? both quite low rated 12W

see you at the ETF in Denmark.

best regards
Karsten

 

[LAZAROIU]

I do not understand where the 8W on the task?

 

[Ketje]

I do not understand where the 8W on the task?

Nothing to understand as i allready mentioned in post #5 it's impossible.
And using a EF183 for audio is wrong too, it has a long Vg1-Ia tail.
Mona

 

[LAZAROIU]

Nothing to understand as i allready mentioned in post #5 it's impossible.
And using a EF183 for audio is wrong too, it has a long Vg1-Ia tail.
Mona

I think it's EL183 not EF183, (#1) !
The EF183 is a tube with a variable slope (S), so it is not recommended in audio applications, but my opinion is, but the EL183 tube is very good in such projects.

 

[pieroh]

Hi Joe,
the output transformers are from ebay seller wambo2002, he (she?) sells transformers regularly. But...I believe a transformer with 5K Ra, as Tom points out, will be more suitable.
Cheers
Peter

 

[pieroh]

Hi folks,

for sure you can get excellent results with triode strapped single ended EL36 / PL36 / 6CM5 / 25E5 and you can expect about 5 Watt Po using a decent OPT. I used a really cheap OPT and got about 4,5W Po

Loadline and schematic are excerpts from my (not yet published) book.

Kind regards, Tom

Dear Tom,

when will your book be published?

Regards
Peter

 

[v4lve lover]

Isnt 360V in triode mode exceeding the maximum screen grid voltage on the EL36?

By the way, i think the E235L was a repacked EL36 sold as a SQ tube. The telefunken datasheet shows triode curves, and pentode curves that show a striking resemblance to those of the EL36

 

[pieroh]

Isnt 360V in triode mode exceeding the maximum screen grid voltage on the EL36?

By the way, i think the E235L was a repacked EL36 sold as a SQ tube. The telefunken datasheet shows triode curves, and pentode curves that show a striking resemblance to those of the EL36

..in fact, the E235L is the longlife(?) version of the EL36 without an anode cap. Unfortunately no bargain like the PL36, which is the same tube with a 0,3 A filament.

regards
Peter

 

[Parafeed813]

The EL360 and E235L both have higher voltage specs than the EL36, 400V for g2 instead of 250V.
Triode connected I wouldn't worry about 300V between a/g2 and kathode.

 

[v4lve lover]

Perhaps, measure the G2 current on your proto to make sure the PL36 isnt exceeding its G2 specs. Furthermore you could drive the PL36 with a mosfet or BJT source follower?


The telefunken datasheet shows 300V UG2 for the E235L.

 

[pieroh]

A lot of very useful information can be found here:

2323-triode-integrated-6cm5

regards
Peter

 

[ToddD]

Bumping an old thread

Questions for Tom (or anyone else who can answer) regarding post #23

• On your schematic, you show feedback from the output tube plate to the G2 on the driver. What are the benefits of this method for this schematic?
• zoebel network on OPT; what are the benefits? How to calculate?
• Was this amplifier built? Or just modeled?
• Is your book available? I did a quick search but I was not able to find it.

thanks

 

[Ketje]

Bumping an old thread

Questions for Tom (or anyone else who can answer) regarding post #23

• On your schematic, you show feedback from the output tube plate to the G2 on the driver. What are the benefits of this method for this schematic?
• zoebel network on OPT; what are the benefits? How to calculate?
• Was this amplifier built? Or just modeled?
• Is your book available? I did a quick search but I was not able to find it.

thanks

The feedback to the screen grid is not what it looks.The screen is decoupled to the cathode so it's feedback to the cathode, the voltage screen-cathode doesn't change.
Mona

 

[artosalo]

What are the benefits of this method for this schematic?

The phase shift of the output transformer is eliminated from the NFB signal (since it is taken before the OPT). This improves the stability of the amplifier.