Lorenz (RFT) v241 and other EF86 + ECC85 preamps

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ungifted

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Sep 4, 2012
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414
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Has anyone ever seen a schema of Lorenz (RFT) v241? I could find only some technical docs but no schema.  :(

I has EAG eb031 schematics - v72-style preamp from East Europe - It uses common EF86 in the first stage plus ECC85 - rather unusual choice. Output signal is taken from the cathode of ECC85.
There are no chokes, schema is clear and it seems to be easy to build a DIY version (sure, exept trafos).

v241 uses the same tubes - EF86 and ECC85 and It's interesting to take a look on its schema.

Many people say that Lorenz (RFT) v241 sounds great! Perhaps anyone have heard it, and has some info?
 
To make talk more substantive here is EAG EB031 schema - http://cruisher.digitaltrip.hu/beag/EB031/
(I've got another variant in higher resolution)
And a link on the v241 - http://www.tab-funkenwerk.com/id9.html (at the bottom is some words about v241))
 
I've redrawn the schema and binded the docs concerning v241.
Here is the bind: http://diy-tubes.com/files/v241.zip
And here is redrawn schema: http://diy-tubes.com/files/UV300.zip (some mistakes are possible, be warned)
Perhaps, anyone is interested in trying to make a clone... and will help to track the bugs in schematic.

How would you rate the chances of building a "clone" of v241?
Main question is which trafos and choke we can use? The rest is relatively clear...

PS: Found some docs about Lorenz v242 Trennverstaerker - it's build of 2x ECC85.
Curious to take a look at the schema - a rather unusual choice of tubes.
 
ungifted said:
PS: Found some docs about Lorenz v242 Trennverstaerker - it's build of 2x ECC85.

Hello,

many thanks for the compilation of the V241.

Would you please publish your V242 documents in the forum?

Regards Andreas
 
v242 is here:
http://diy-tubes.com/files/v242.zip
The document mentions V42a... Nothing else found exept of page 12 here: http://www.irt.de/IRT/publikationen/braunbuch/Geraeteverzeichnis.pdf - B-V 42 1947, Maihak

Any ideas about possible subs for v241 tranformers? In - 1:18, out - 17:1. :)  Maybe Sowter produce something like this?
Or trying standard OEPs?  :-[
 
AndreasS said:
The V241 is also known as "Übertragungsverstärker ÜV300"

(warning: this is gibberish - see below  :eek: ) Quite strange topology, isn't it - it seems that gain is controlled mostly by loading the output stage (although the two lowest gains are done by adding cathode resistance to input pentode), and no overall feedback.

How does it sound - and do we have specs on in/out levels and such?

Jakob E.
 
ungifted said:
PS: Found some docs about Lorenz v242 Trennverstaerker - it's build of 2x ECC85.
Curious to take a look at the schema - a rather unusual choice of tubes.

Hello,

the ECC85 is an usual choice: the magnetophon Telefunken M5 used this tube also.

Regards Andreas
 
AndreasS thank you for linking to M5
Found this description http://www.tonbandmuseum.info/details-magnetophon-m5.html
 
v242 is here:
http://diy-tubes.com/files/v242.zipThe document mentions V42a... Nothing else found exept of page 12 here: http://www.irt.de/IRT/publikationen/braunbuch/Geraeteverzeichnis.pdf - B-V 42 1947, Maihak

Any ideas about possible subs for v241 tranformers? In - 1:18, out - 17:1. :) Maybe Sowter produce something like this?
Or trying standard OEPs? :-[
Hi, I know this is a very old discussed theme but do someone have the “http://www.irt.de/IRT/publikationen/braunbuch/Geraeteverzeichnis.pdf - B-V 42 1947, Maihak”? look like the link is death time ago!

Thanks
opacheco
 
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