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5842 and 5842 WA for 300B

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dear all,
i drive a 300b with 5842-Haltron in cathode commeon config. and Rplate of 9k on it.
I can drive directly the ampli directly from CDPly and have 6.3 W rms output.
5842 has Vg=-2.15V, Vp=175V and Ip=18mA. 300B has -70Vg trimmerable and 355Vp. opt is 3k/8ohm. Rk of 120ohm bypassed by a 470 uF.
Before a changing (and I hope have better sound) a new driver load (es.a CCS or a IT) I would like to sove my dubt.

My dubt is:
the 5842 datasheet from web told me on anodic curves until Vg=-3V and so on paper I can draw the escursion, THD of h2 etc. At contrary the oscilloscope confirm me a good wave witout clipping with 2.15V input or bit more.
I found the Raytheon 5842 WA version (I think with cuves extended) but I can not find the datasheet.
Someone know the really diffrencies between 5842 and 5842 WA?, and can pass me the datasheet of 5842WA? The glass on my Haltron there is written 5842/417A but on web I can find 5842WA=417A. Which equiv.is correct? Note: the WE417 datasheet has on it plate curve to -3Vg only.
Hoping in a help, bye.
massimiliano:D
 
I can't help you. But my Ericsson 5842s say 5842/417A as well. So that's probably what they are.

"Western Electric was one of the earliest commerical tube manufacturers, and made many classic designs that are still very much in demand today, especially in the audio world. Some tubes, like the 101 and 417A remain literal standards for high quality, low noise tube design. WE production in Canada was via their subsidiary, Northern Electric, and in Europe, was licensed via Ericsson in Sweden."
 
for Bhn or whoever want help me

...thanks Bhn for your reply.
I can see on web that the schemas that use a 5842/471A to drive a 300b (all SE) use always an interstage IT or a choke-plate.
Do you use an Rplate, an IT, an choke or a CCS on plate of 5842?
Actually I use a Rplate and would like to change it with a IT or a CCS. What do you suggest me to have more quality?

ciao, massimiliano
 
thanks for replies,
>did you test a Rplate too, and know the differencies using the other kind of load?
However I can think to change the Rplate with them but please could you suggest me data for choke, IT or CCS to use in this case?

The 5842/300b circuits I found on web use:
as IT a LL1660 Lundhal,
as choke a LL1667Lundhal,
as ccs the IXCP10M45S.

...suggestions well accepted.....!!!!!!!!!!

>Franlky speaking I don't know in general on a Driver (and appreciate to know your thinking/experience) when is convenient use a IT or a choke or a ccs instead an Rplate. It's a black hole for me!
I know that with a IT (and with choke should be the same) you have to think it with a little opt. The vantage is that you can use a Point of work with high voltage very next to Vb+ and use the "magnetic voltage" to extend the laod line (=less Vb+ value and so more efficiency!).
But in my case I have Vb+=350V and the Vak fixed at 175V and so I don't understand the advantages. Peraphs only a better sound ? Should I only try without understand, or exist a reason?

ciao, massimiliano
:bawling:
 
Hi,

I used to have both of my 5842 drivers running at 10mA, 10K Rp. Like you, I have always wondered how other types of loading will sound like, and that's the reason why I tried both. Both of which also progressed to LED biasing, instead of bypassed Rk.

Whether you will like the sonic result from either choke or CCS load is something I won't know. But for me, I like the combination that I have- choke loaded 5842 for the 45, CCS loaded 5842 for the 300B.

Cheers!
 
I probably know less about tubes than you. I haven't even heard the 417A. I'm talking about my limited experience of ITs. I know nothing about the whys. My experience with trafo-coupling can be compared to how people describe the sound of trafo attenuators. It's a sort of uncanny naturalness you cannot really put your finger on. I cannot see why this should not be the same for all tubes, as long as they are suitable for ITs.

As for Lundahl, I don't understand a much on their site. I'm trying to understand how to use trafos in LTSpice. All I know about the LL1660 is that it will work with the C3m as well, which, as you most likely know, is another great driver for the 300B.

As for the rest of your questions, somebody else will have to chip in.
 
thank to both.
Arnold, what type of ccs do you use?
I think to have 2 step: 1° ccs(lower cost).

2°step, eventually I will try an IT and listen the uncanny naturaless decritted by dhn.

A good explanation of the use of Lundhal trafos is on www.diyparadiso.com, Benny Glass' website. He is not a commercial person, he is a technician with own web-shop.

In future I am going to try to change the Rk (of 5842) with 2 x 1,2V NiMh batteries or led.

massi
 
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