Marantz 2270 phono board caps

[Douglie]

I’m redoing a 2270 phono board. It has some odd looking C701-2 coupling caps. They are 2.2uF 16v electrolytic. The little blue things at the top of the picture. The schematics I’ve seen say they ought to be 0.47 50v film. My serial number is 40937 so it’s a later build one; 1975 date on the frame. Planning to put a 2.2 wima there. Any input? Thanks!

 

[rBuckner]

Yeah, do it!

 

[Ray Gianelli]

I’m redoing a 2270 phono board. It has some odd looking C701-2 coupling caps. They are 2.2uF 16v electrolytic. The little blue things at the top of the picture. The schematics I’ve seen say they ought to be 0.47 50v film. My serial number is 40937 so it’s a later build one; 1975 date on the frame. Planning to put a 2.2 wima there. Any input? Thanks!

Those are tantalum capacitors. Should be fine in a low voltage application like this. Their main fault is that they tend to fail shorted.

 

[EastPoint]

C701/702 should be replaced with 1 uf caps from what I have generally seen on AK. If you google "2270 C701" there are a lot of posts.

 

[Douglie]

Thanks! Nice consensus to use the 1uf film caps on the in and out couplers
Why would this 2270 end up with 2.2uf tantalum caps when 0.47 or 1uf film caps were used in earlier 2270s? Seems like a step backwards.

 

[rBuckner]

Thanks! Nice consensus to use the 1uf film caps on the in and out couplers
Why would this 2270 end up with 2.2uf tantalum caps when 0.47 or 1uf film caps were used in earlier 2270s? Seems like a step backwards.

Without doing a study, perhaps the surrounding resistors were changed and so these needed to as well to maintain bandwidth.

 

[Douglie]

Well I did a quick study. All components (res, cap, and semis) are the same on the board as the schematic except for C701-2 and C714-5 which were 2.2uf 6V polar on the board and 0.47 50V film on the schematic. Must have been a sale on the 2.2….. would the 2.2 just serve to lower the low freq cutoff coming to and going from the phono amp?