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CAV50 triode connection

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Andresound
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CAV50 triode connection

Post by Andresound » Mon Aug 18, 2014 7:22 am

Hi Guys,
Please can someone provide details (maybe pics) to change my CAV50 for triode connection
Thanks, Andresound

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Joe Appierto
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Re: CAV50 triode connection

Post by Joe Appierto » Mon Aug 18, 2014 9:40 am

Found this old post from 2002. It may be of some help. I've highlighted the specific part although please take note of his comment regarding the change in sound. Also, your speakers are going to need to be pretty efficient to run on about 20wpc.

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Re: CJ response for tech advice - Capt. Z 15:24:36 06/28/02 (1)
In Reply to: CJ response for tech advice posted by Lep on June 27, 2002 at 17:35:04:
Hi;
I have the CAV 50, which is very similar to your amp. The CAV 50 can also be converted from pentode to triode, by simply resoldering a piece of wire (bridge) under each output socket. The needed resistor is already on the PCB board. If you open the bottom of your amp, you will see a bridge next to the output socket. At this time it will be diagonal in front of you. To convert to triode they need to be perfectly vertical on the PCB board.

That said, you may loose your warranty by doing so.

$ 64 for a small solder job. Hmmmmmmmmmmmmm

I asked CJ to have my CAV 50 converted from 120 to 240 Volts. They asked $ 100. All it takes is on bridge needs to be resoldered.

But now to the sound.

I had my CAV 50 converted into triode mode. Nice full and warm sound. However, the sound becomes also more boring and eventless. EHIEN has written about this before on the Tube Asylum in more detail. You should find it in the archieves.

However, you could change it yourself, if you dare and judge for yourself. If you like it you can leave it or return it to Pendoe mode.

Enjoy.
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Musictek
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Re: CAV50 triode connection

Post by Musictek » Mon Aug 18, 2014 11:50 am

Yes, there are jumpers (4 of them) that connect the output tube screen grids to either the screen grid taps of the output transformesr OR the plates. Those jumpers are factory set for ultralinear (connected to the.
taps). Just change those jumpers to connect the SG's to the plates and you'll be all done. Bias shouldn't change much, but you should recheck that. Power will be roughly half that at the ultralinear setting.
Hope this helps.
Best Regards,

Martin
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Re: CAV50 triode connection

Post by Martin » Mon Aug 18, 2014 12:11 pm

Hi,
i added 4 pictures that show the jumpers in Triode and in Pentode Mode
Regards, Martin
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CAV50 1 Pentode.jpg
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CAV50 1 Triode.jpg
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CAV50 2 Pentode.jpg
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CAV50 2 Triode.jpg
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Re: CAV50 triode connection

Post by admin » Tue Aug 19, 2014 10:06 am

Martin wrote:Hi,
i added 4 pictures that show the jumpers in Triode and in Pentode Mode
Regards, Martin
I think this is really useful info for our CAV50 owners. I'll add this to our schematics database. Thanks for the post.
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Andresound
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Re: CAV50 triode connection

Post by Andresound » Thu Oct 23, 2014 6:52 am

Hi Martin,
Thank you so much. Will do mod and then revert.
Regards :D

Billy Budapest
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Re: CAV50 triode connection

Post by Billy Budapest » Wed Jan 20, 2016 1:55 am

I've been thinking about a pretty cool mod--repurposing the epl button (which I do not use) into a switch so that I can convert from triode to ultra linear on the fly. Well, not exactly on the fly, because I would power off the unit before doing the switch--I don't think it would be a good idea to switch between the two while the tubes are energized. Thoughts?

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Re: CAV50 triode connection

Post by Zink » Sun Aug 13, 2017 10:11 pm

Good Day,

just bought a CAV50, did your switch work well?

Billy Budapest
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Re: CAV50 triode connection

Post by Billy Budapest » Mon Aug 14, 2017 9:41 am

I never implemented the switch although I still think it would be a good idea. Instead, I actually used it as an epl loop and set it up as a stereo to mono converter using this:

http://www.juno.co.uk/products/monacor- ... 432335-01/

I went this route rather than using y-cables because this little box has resistors which attenuate the signal so that when you choose mono it's not louder than stereo.

ronenash
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Re: CAV50 triode connection

Post by ronenash » Mon Aug 14, 2017 11:32 pm

Just a note, you also need to adjust the bias point when converting the amplifier to triode.
ronenash
----
Power:CJ LP125m SE, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura

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