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Marantz Transistor/Diode/Trimmer Sub Guide

I've got a question about KSA992's, what's the difference between a KAS992FTA and a KSA992FBU? the Data sheet links to the same document for both...
 
Leestereo said:
Small clarification: the KSA992 is currently still available with a minimum hFE of 430, i.e., KSA992FBTA is the taped variant with hFE classification of 430-600. This option is useful to select transistors for differential pair duty.
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Well, there you go. I learn something new every day. Thanks for the clarification!
 
Leestereo said:
Small clarification: the KSA992 is currently still available with a minimum hFE of 430, i.e., KSA992FBTA is the taped variant with hFE classification of 430-600. This option is useful to select transistors for differential pair duty.
Click to expand...
Correct. They divided the gain group into another "B" range to keep them closer. Earlier they varied a lot more within the entire "F" group. I still buy just the "F" since I grade all of them anyways 100 at a time all at the same temperature. I have gotten some nice high gain pairs that way for "special occasions". :beatnik: But averages were always in the 400 to 550 ranges, except for the few "special :angel:" ones.
 
So what is the replacement for the KSA1220AY going to be?
"End of Life: Scheduled for obsolescence and will be discontinued by the manufacturer. "
 
I guess it depends on where it is used
Did Marantz ever use a NEC 2sa1220A? In what model?
Toshiba has tta004c? parts that are close iirc
I do not use ksa1220 in power amps I use ksa1381 and its complement ksc3503 but it depends if you need that current spec in your design. For a 3ef design the a1381/c3503 work well as vas and pre-drivers
 
I would like to add an important note when replacing some of the 2SA, 2SC transistors for 2N3904 or 2N3906. They have different pinouts. For example the 2SA562 and 2SC735 are ECB while the replacements 2N3904, 2N3906 are EBC.
The replacement BC337 for 2SC735 has pinout CBE rather than ECB.

Thank you
 
Roger_88_K said:
I would like to add an important note when replacing some of the 2SA, 2SC transistors for 2N3904 or 2N3906. They have different pinouts. For example the 2SA562 and 2SC735 are ECB while the replacements 2N3904, 2N3906 are EBC.
The replacement BC337 for 2SC735 has pinout CBE rather than ECB.

Thank you
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Thanks. I've added those notes to the spreadsheet.
 
Hey girls & boys,

I have a question regarding changing (installing new) single or multi-turn trimmer pots in Marantz 1060. Finally I have compiled complete inventory, ordered and received all components BUT trimmer pots.

Service Manual calls for 100 kOhm (2 pots) and 470 kOhm (2 pots). My question is which are best (best, optimal, most used, taper material etc.). I guess multi-turns are in order just because of fine adjustment. I can't figure out which to order when it comes to Wattage. Multi-turn pots (and single turn) comes in 1/2W and 1/4W.

Can you fine people provide some guidance. Or even which manufacturer and type (material used etc.) is the way to go? I am far from being an expert so please have patience with me. ;-)

Thank you in advance!

Take care & stay safe everyone,

Krešo
 
The current is usually very low and 1/4w will do in most instances. But I always get 1/2 watt Bourns Cermet trimpots and use them in everything. Some units that have high BIAS current always get 1/2w.
 
The current is usually very low and 1/4w will do in most instances. But I always get 1/2 watt Bourns Cermet trimpots and use them in everything. Some units that have high BIAS current always get 1/2w.
 
I know a lot of people prefer the multiturn trimmers. They are fine if you like them, but a new single turn trimmer usually works just fine, and, being new, is very smooth in its adjustment. I really don't find the multiturn trimmers to be much easier than a single turn to dial in.
 
Steven Tate said:
I know a lot of people prefer the multiturn trimmers. They are fine if you like them, but a new single turn trimmer usually works just fine, and, being new, is very smooth in its adjustment. I really don't find the multiturn trimmers to be much easier than a single turn to dial in.
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Agreed. Most important is their "staying power".
 
Dear @Skywatcher @Steven Tate @ocdecio ,

thanks for the tips. Especially on wattage specs on trimmers. Well, regarding single- or multi-turns I guess it is all the same to me but my thinking was multis were better because of resolution and fine tuning. After hearing your thoughts and experiences I see I can go either way as long as I find both resistance and wattagae specs.

Thanks again for all the info!
 
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