I/V resistor for TDA1541 Vishay Bulk Foil

Magnet wire resistors, enough to make any engineer scream.
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mseddon
Posts: 35
Joined: Thu May 05, 2005 12:04 pm
Location: perth australia

I/V resistor for TDA1541 Vishay Bulk Foil

Post by mseddon »

I recently direct wired the audio out from the TDA1541A chip in my old Kinergetics CD player to a simple choke loaded valve stage using a 100 Ohm grid resistor for I/V. (In fact the 2nd stage of my LCR phono designed here on Intact. Thanks guys). Great improvemnt on the stock discrete transistors (inc 'hysteresis cancelling' whatever that was...)

But when we swapped the cheap 0.5w metal film for a Vishay Bulk Foil the difference was not subtle, clarity and dynamics in abundance - has made me rethink the whole thing about resistors (not to mention DACs!) - not that there are many in there what with auto vol control and ITs. What is it that hte Visha BF do so right that metal films do wrong? Presumably accuracy of value is of no importance (unless we are in a filter).

Is it the low value and I/V job it is doing that makes the difference so pronounced - what about higher values eg a 100K on a grid? Or R in a phono stage. Guess going to have to try and order some and try.

any thoughts?

martin
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reVintage
Posts: 364
Joined: Fri Sep 07, 2007 9:54 am
Location: Sweden

Post by reVintage »

Hey Martin,
In fact the 100ohm you used is the upper limit. Try from 25 to 100ohm. AFAIK Dave has an application in where lots of parallelled 1543 where used together with an input transformer.
Brgds
Lars
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