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Marantz Transistor/Diode/Trimmer Sub Guide

Steven Tate

Steven Tate

CEO Flat Forehead Soc.
Well, I did another data dive and compiled a fairly comprehensive list of 99% of the transistors and diodes used in 70's era Marantz stereo integrated amps and receivers. I scanned threads until I was blue in the face, and scanned the internet for specs. I searched every Service Manual to pull a list of transistors and diodes. I looked for recommended subs throughout the threads, and collected the ones that were repeated often, or that someone had successfully used. I can't be sure of the appropriateness of any of the listed subs, but these are the ones I would start with if I were looking for a sub. I tried to search for availability, and only use subs I could find. Many recommendations that I came across turned out to be obsolete. I'm hoping the gurus will take a little time to scan for obvious problem suggestions, or to fill in blanks where I couldn't find any info. Please let me know if you find errors or have better suggestions for any sub. So, here is a link to the Excel spreadsheet on my Google Drive and I am attaching a PDF for those that don't have Excel handy. Give me suggestions on how to improve my list! Search for your transistor or diode in the left column (alpha order), and look for subs in the columns to the right.
Spreadsheet: Transistor, Diode and Trimmer Sub Guide
 

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Wow again, only more so. This list just replaced 20 pages of various lists and notes. It's hard to overstate the value of this to the Marantz community.

Over time I've bought nearly every substitute transistor and diode I've read mentioned in Marantz forum posts. But now I don't know what all of them are replacements for. I can cross-reference with this list to find out. Cool!
 
runningdog said:
Wow again, only more so. This list just replaced 20 pages of various lists and notes. It's hard to overstate the value of this to the Marantz community.

Over time I've bought nearly every substitute transistor and diode I've read mentioned in Marantz forum posts. But now I don't know what all of them are replacements for. I can cross-reference with this list to find out. Cool!
Click to expand...
Great! I was hoping it would be helpful. I know I will use it.:thumbsup:
 
Thanks again for this! I'm already trying to put it to good use :thumbsup:

In trying to understand the SM, in regards to replacement of the 2SC458's in a 2215, I have different types listed in the manual:
slaznuF.png


D42vf53.jpg


These are all still the same replacement part though? I would replace all of the listed above, with https://www.mouser.com/ProductDetail/512-KSC1845FTA ?
 
Yes, many transistors come with different gain codes. While they are often important factors, I decided trying to report all of the versions of each transistor was just too much to deal with. The most common replacement for the 2SC458 is KSC1845FTA. But in the 2270, there are lots of reports of a “motorboating” sounds with that sub. I’m using KSC1815 in that spot on the phono amp board, and it seems to work better. For one thing, the max collector current of the 458 is 0.1A. For the 1845, it is half that, and for the 1815, it is 0.15A.
 
Is there anywhere that states what the (B)(C)(D) codes translate to specifically, in terms of gain, or hfe?

Would you recommend to go with KSC1845FTA for everywhere but the phono board? Or should I do all 1815's?

Thanks again!
 
MarantzRefrb said:
Is there anywhere that states what the (B)(C)(D) codes translate to specifically, in terms of gain, or hfe?

Would you recommend to go with KSC1845FTA for everywhere but the phono board? Or should I do all 1815's?

Thanks again!
Click to expand...

I usually do the 4 2sc1344 or 2sc1000s as KSA1845 and then the 458s as 1815s, seems to be more reliable.
 
goldswimmerb said:
I usually do the 4 2sc1344 or 2sc1000s as KSA1845 and then the 458s as 1815s, seems to be more reliable.
Click to expand...

Thanks! I'll get the 1815's and then attempt to gain match them.

MBuras said:
Found this in an old 2012 AK post.

2SC458 B = 100 to 200
2SC458 C = 160 to 320
2SC458 D = 250 to 500
Click to expand...

Very cool! Thanks so much for that! I'll pull the original 458's and measure them, will be interesting to see how they line up to the guide above.


EDIT: This really should be a Sticky thread, too much good info in here to let it slip to the bottom.
 
Yes, many transistors come with different gain codes. While they are often important factors, I decided trying to report all of the versions of each transistor was just too much to deal with. But here are the hFE ranges for the subs in discussion.
KSC1815. “Y” class — 120-240
KSC1845. “F” class — 300-600
 
Are there more ranges of gain available to an 1815, or an 1845, besides Y and F? Where would I find that information?

Thanks again!
 
Gain options are listed on page 2 of the data sheet. Unfortunately all others than the ones you mentioned are obsolete and gone (at least from Mouser and DigiKey). Maybe find some at a smaller electronics business or third party market.
 
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