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Friday, December 16, 2022

Some Work in Progress

Hi!

Here a peek into the workshop showing some work in progress.



Above the connector plates of a 10Y preamplifier and 300B single ended mono blocks combo in the works. On the left the back plate of the monos which wi have both RCA and XLR inputs. Speaker connections for 4, 8 and 16 Ohms. Next the back side of the preamplifier power supply and the back plate of the preamp itself with 3 RCA inputs, 2 XLR inputs and both RCA and XLR outputs.




The front plates of preamplifier and its PSU. As always the lien stage is transformer volume controlled. The AVCs are directly mounted behind the front plate and hand wired to the volume control switch. 




The preamp section is already assembled and can be mounted into the chassis and hooked up to the front plate.






The power supply:





The power amps will be built into tower chassis with several modules stacked in 3D fashion and only tubes on the top. 




Above the power supply modules with B+ transformer and separate filament supplies for the output and driver tubes. These will be placed on the bottom, then some stabilising plates, one of them carries a choke.




And then a module with output and interstage transformers as well as some high voltage filtering.




Some more parts will be directly mounted to the top plates which are not finished yet. As soon as those are made work will commence.

Best regards

Thomas





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2 comments:

  1. AnonymousDecember 17, 2022 at 8:17 PM

    Hi Thomas, Love the various 10y and 300B builds you have showcased. I also commented on AA yesterday (re: Elrog 300B vs. WE 300B thread), about the 421a tube.
    While I can only comment anecdotally, Don Garber told me that it was used as a voltage regulator in front of a 274 and 300B in WE theater equipment. A very linear 5 watts, as Don set it up, indirectly (AC) heated and capacitor coupled, (all his other amps were directly coupled, no capacitor). He built mine in 2008.
    Keep doing your wonderful builds, great eye and ear candy,
    Regards,
    Mike in Palm Springs, CA.

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  2. AnonymousDecember 17, 2022 at 9:00 PM

    Hi! I like to use indirectly heated tube myself as output tubes. But to be fair, they are not as linear as directly heated triodes and the 421a also shows some non linearity in the plate curves. Pass tubes were not designed for linearity as that was not required in their intended application.

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