I started refurbishing a Citation 16 that I got for a song because it was in bad shape. I removed the driver boards and cleaned them and then started looking through the circuit diagram. These boards use a lot of ceramic disk caps. Could these ceramic disk caps be replaced with silver mica caps? Also I think that all of the 1/8 watt resistors on the boards are carbon film resistors. Would replacing these with metal film resistors be acceptable or would it compromise that warm HK sound?
G
G
So, you want to replace bad capacitors with
not-quite-so-bad capacitors.
May I suggest Polypropylene. Also, if you
can get the needed voltage rating and
capacitance, you can try C0G ceramics.
(not other types of ceramic)
My preference is metal film resistors. Start
with the most significant ones -- feedback loop
and anything else directly connected to the inputs
and outputs. Though if you're going to go to the
trouble, you might as well do them all!
not-quite-so-bad capacitors.
May I suggest Polypropylene. Also, if you
can get the needed voltage rating and
capacitance, you can try C0G ceramics.
(not other types of ceramic)
My preference is metal film resistors. Start
with the most significant ones -- feedback loop
and anything else directly connected to the inputs
and outputs. Though if you're going to go to the
trouble, you might as well do them all!
Nelson Pass had this amp "boosted"
http://www.passdiy.com/pdf/citation.pdf
When the design is a little bit poor and the semiconductors are tired (compared to new devises), the use of changing resistors is little. Sorry. If you still want to change into metal film, it can't hurt.
http://www.passdiy.com/pdf/citation.pdf
When the design is a little bit poor and the semiconductors are tired (compared to new devises), the use of changing resistors is little. Sorry. If you still want to change into metal film, it can't hurt.
Ceramic vs. Silver Mica caps
Hi,
Just look here what the Bongoman does:
http://groups.yahoo.com/group/SAE_Talk/message/4647
(Replaces all ceramics by dipped silver mica's)
Hi,
Just look here what the Bongoman does:
http://groups.yahoo.com/group/SAE_Talk/message/4647
(Replaces all ceramics by dipped silver mica's)
Hi All,
I plan to totally stripping the driver board and replacing all of the components. Including the UA739. So you see I have my choice of resistors and caps . The new BJT's will be MJE182s and 172s and MJE350s and 40s. There are a couple of general purpose BJT's in there but I'm waiting on the service manual before I decide what to use in their place.
G
I plan to totally stripping the driver board and replacing all of the components. Including the UA739. So you see I have my choice of resistors and caps . The new BJT's will be MJE182s and 172s and MJE350s and 40s. There are a couple of general purpose BJT's in there but I'm waiting on the service manual before I decide what to use in their place.
G
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