CAV50 triode connection

Do It Yourself - everything from building your own hardware to room
treatments.
Post Reply
Andresound
Regular
Regular
Posts: 6
Joined: Sun Feb 23, 2014 1:24 am

CAV50 triode connection

Post by Andresound »

Hi Guys,
Please can someone provide details (maybe pics) to change my CAV50 for triode connection
Thanks, Andresound
User avatar
Joe Appierto
Pro Master
Pro Master
Posts: 647
Joined: Fri Aug 24, 2012 5:04 pm
Location: NJ

Re: CAV50 triode connection

Post by Joe Appierto »

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.

Follow Ups:
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.
Oppo BDP-105D and PSA DS DAC
C-J CA200
Polk T50
In-Akustik Exzellenz Cat 6, Kimber IC, Q-Audio SC, Blue Circle and Acrolink power cords; PSA Juice Bar and Duet PLC
Musictek
Regular
Regular
Posts: 7
Joined: Thu Mar 27, 2014 6:17 pm

Re: CAV50 triode connection

Post by Musictek »

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
Beginner
Beginner
Posts: 2
Joined: Fri Aug 15, 2014 12:34 pm

Re: CAV50 triode connection

Post by Martin »

Hi,
i added 4 pictures that show the jumpers in Triode and in Pentode Mode
Regards, Martin
Attachments
CAV50 1 Pentode.jpg
CAV50 1 Pentode.jpg (736.74 KiB) Viewed 3557 times
CAV50 1 Triode.jpg
CAV50 1 Triode.jpg (757.35 KiB) Viewed 3557 times
CAV50 2 Pentode.jpg
CAV50 2 Pentode.jpg (586.47 KiB) Viewed 3557 times
CAV50 2 Triode.jpg
CAV50 2 Triode.jpg (651.67 KiB) Viewed 3557 times
User avatar
admin
Site Admin
Site Admin
Posts: 4565
Joined: Tue Jan 03, 2012 1:50 pm
Location: New Hampshire, USA
Contact:

Re: CAV50 triode connection

Post by admin »

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.
-admin
Home Theater in Member Gallery
Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
Andresound
Regular
Regular
Posts: 6
Joined: Sun Feb 23, 2014 1:24 am

Re: CAV50 triode connection

Post by Andresound »

Hi Martin,
Thank you so much. Will do mod and then revert.
Regards :D
Billy Budapest
Super Advanced
Super Advanced
Posts: 50
Joined: Sun Nov 22, 2015 1:17 pm

Re: CAV50 triode connection

Post by Billy Budapest »

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?
Zink
Beginner
Beginner
Posts: 2
Joined: Sun Aug 13, 2017 10:02 pm

Re: CAV50 triode connection

Post by Zink »

Good Day,

just bought a CAV50, did your switch work well?
Billy Budapest
Super Advanced
Super Advanced
Posts: 50
Joined: Sun Nov 22, 2015 1:17 pm

Re: CAV50 triode connection

Post by Billy Budapest »

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
Pro
Pro
Posts: 86
Joined: Sun Aug 05, 2012 2:19 pm

Re: CAV50 triode connection

Post by ronenash »

Just a note, you also need to adjust the bias point when converting the amplifier to triode.
ronenash
----
Power:CJ ART150, 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
Post Reply