What is a fair price to offer for a PV12 preamp today ?

[pani]

Folks,
I am new to the CJ world. I have just acquired a Premier 11a amp. Now I need a good matching preamp and PV12 seems to be the natural partner.
I am getting one online but I am not sure whats the fair price to offer to the seller. I have a couple of elementary questions:

1. I have read that there is a later version called PV12a. Is it worth waiting for it to come up online for sale or should I just grab the PV12 ?
2. Whats a fair price to offer for a excellent condition PV12 with phono ? It comes with Jan Philips tubes.

Thanks for your guidance.

[admin]

Hi Pani,

Welcome for CJO. Nice to have you with us.

As for the PV12 variations, you probably want to read this thread: https://www.conradjohnsonowners.com/vie ... php?t=1511

It's hard to give a "fair price" estimate as this will vary depending on the condition of the unit, included tubes, original packaging, shipping, location, and the variations of the unit (ie phono stage or not). I'm not really sure if there is a good database of this information. I know audiogon has a database of units but I believe it is behind a paywall. If you are not sure where to start, you can always ask the seller to begin the bidding.

As an owner of the PV12AL, I can say it is a great preamp and will match well with the Premier. Let us know how it turns out.

[pani]

How easy is it to upgrade the PV12 to a PV12a ?

[admin]

I haven't heard of anybody doing it. However, we do have the PV12A schematics in our database so technically all the information is there.

[pani]

Thanks. I have located a PV12A in US. It is a 110V unit. I need to use it in Singapore where the voltages are 240V. Is it possible to convert the voltage on the PV12A ? Is it a quick conversion via some simple re-wiring or do I need to send it to the CJ factory ?

[antaresbluespirit]

Hi pani,

All CJ gears can be used both in 120 or 240v AC (for the export edition)

The shematic allows to turn into a serial or parallel connection of he wire inside at the main transformer level .

I owned many CJ units (pre or amp) coming from usa in their standard 120v connection I have to turned into 240 v .

A qualified technician can do that thanks to the schematic, it is not a big deal to operate at a reasonable service price...

A PV 12 L is not fitted with phono but the extension module can be added if you find out the spares...

Regards

Raymond (France)

[pani]

Thanks Raymond. Is the procedure or schematic available anywhere to download ? Or is it too straightforward for any good technician to figure out ?

[antaresbluespirit]

just to load the schematic as follows

http://www.drtube.com/schematics/cj/pv12.gif

in the shematic the transformer 9242 is the area where a technician can modify the wiring from parallel to serial 120v to 240 v at the primary of the transformer

If your are in trouble to understand please send me your personal email and I give you the exact position to be modified (no necesairy to send the unit to CJ service since it will be to expansive for a minor modification for any basic electronician..

raylerat@orange.fr

Regards

Raymond

[pani]

Thank you again Raymond. That helps a lot.

[pani]

One more question. I intend to use the PV12 only as a line stage. In that case, will a PV12L sound more accurate/pure than a PV12 (which has extra circuitry for phono and power supply also gets shared) ?

[admin]

I haven't heard of any audio quality reduction because of present phone stage. That stage simply won't be used. I would not "worry" about having a phono stage in the unit. I think you could also remove the phono stage if you wanted as it is modular design.

[roberto]

Hola Pani,

As Admin pointed out, the phono stage is not in use when you are using the preamp in Line stage. Also, Admin wrote: ..." The PV-12A/AL upgrade consisted of upgrading the volume control circuit and incorporationg a new biasing circuit for the input amplifier of the line stage. This new arrangement eliminates local feedback from the line stage voltage amplifier"...

The phono section is not shared, it is just a circuit for phono. Only phono audio signal goes through this circuit. Line stage does not.

Happy listening!

[pani]

Thanks everyone for responding. Any recommendations for tubes for the PV12 ?

[roberto]

Hola,
Tubedepot has a lot of different types of 12AX7. You have a 5 stars on some of them, and are use for live music power amps. You will see that there are some very expensive. I did buy one the expensive ones, and then realised that it was about the same quality as the other costing a fraction.

https://tubedepot.com/products
https://www.thetubestore.com/search?keywords=12ax7
https://www.tubesforamps.com/best-12ax7-review

Don't spend a lot of money, but read the reviews and choose three or four, and do the tests. Let your ears decide...my liking could be different than yours.

Happy listening!