5C5 Pro amp schematic puzzle.

[zapped]

The fender Pro amp (5C5) layout shows the 3 preamp tubes as 6sc7's but also lists them as 12ay7 for V1 & V2 and 12ax7 for the V3. Can I assume the components on the circuit board stay the same with either tube selection?? I'm aware of the difference in the tube bases. Is there an big difference in sound or reliability between tube types?? Thanks  Ed

[HotBluePlates]

The fender Pro amp (5C5) layout shows the 3 preamp tubes as 6sc7's but also lists them as 12ay7 for V1 & V2 and 12ax7 for the V3. Can I assume the components on the circuit board stay the same with either tube selection?? ...

Yes. Fender switched to 12AY7 & 12AX7 but didn't change the on-board parts until the 5D5 Pro version.

... Is there an big difference in sound or reliability between tube types?? ...

Some folks feel they get a thicker, rounder sound from octal based preamp tube like the 6SC7. Other folks feel the octal based preamp tubes more often have microphonic issues. The 6SC7 isn't readily available everywhere, and I'm uncertain what Russian type is being sold as a 6SC7GT so I can't comment on how closely its specs match the vintage original. However, old production tubes are out there if you seek them out.

[drgonzonm]

Its my guess you can get 9 pin to octal adapters, assuming that you don't have clearance problems, you could have the best of both worlds. 

[zapped]

Thanks for the replies. I have been trying to recycle an old Conn organ power amp with many octal tube sockets into a fender all octal 6G11 or something similar.

[DummyLoad]

russian 6n10s (6h10c) is the equivalent to the 6sc7.


--pete

[kagliostro]

Thanks Pete

I was looking just yesterday for a russian equivalent tube for the 6SC7 without finding one (the 6SC7 has no russian correspondence on my tables)



http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6SC7.pdf

Franco

[HotBluePlates]

russian 6n10s (6h10c) is the equivalent to the 6sc7.

Thanks for this! The Russian 6H10 data sheet gives exactly equivalent info the the 6SC7; so new production tubes ought to be a good fit.

[DummyLoad]

YW HBP & franco.


--pete

[TubeGeek]

Good info to know. Thanks from me too.


A few years back I built a 5c3 deluxe to hear for myself what octal preamp tubes sounded like.


I had troubles finding a good 6sc7 that wasn't microphonic so I converted them to use 6sl7's.  It was very easy to re-wire the sockets. 


When I finished the amp and was testing it out, one of my paying customers dropped by for a visit.  He ended up taking the amp home because he had to have it that badly.  It has been going strong since, been on several tours and the octals are holding strong.  Reliability with new production tung-sol 6sl7's seems to be good.  Maybe in the end you'd find it easier to convert to a tube you can readily get.  That 5c3 was the nicest sounding deluxe I have ever built, the octal preamp tubes played a role in its thick creamy, blooming distortion characteristics I am positive.