I have an SAE XXX preamp that has a slight sizzling/crackling sound on one channel and only on one channel. It is unaffected by the volume control and is constant and only noticeable when the volume from source is at dead zero. Yes the slider pots have been cleaned with Deoxit F5. This unit was recapped a few years ago with premium caps and other than the slight noise sounds and works great. Here's the catch. When I engage Tone Defeat the sound completely disappears and all is well. The first thing I guessed was a bad bass//treble slider but don't think that's the issue. When moving the tone sliders up/down the sizzle remains very constant. Yes I have reflowed all solder points. Any ideas?
SAE Mark XXX
- Thread starter taineasy
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If whoever recapped it didn’t replace any transistors, there’s your issue.
I replace all transistors on any American gear I work on (GAS, SAE, early Marantz, etc).
Well it’s 50 years old, of course they won’t be! You have to do a little legwork…..
Here’s my thread;
Got one of these on the cheap and now I’m replacing just about everything I can for fun!
The only weak points here was the power switch was underrated and the resistor for the power light gets too hot.
The only weak points here was the power switch was underrated and the resistor for the power light gets too hot.
BC239C is NLS, BC307B may be a few around, 2n4250 is NLS, 2n5307 may be a few around, SE4010 is NLS,
I will have to tear it down somewhat to read the numbers as my inside pcb boards and layout is nothing like those in the photos. My main boards are mounted vertically not horizontally.Well it’s 50 years old, of course they won’t be! You have to do a little legwork…..
Here’s my thread;
Got one of these on the cheap and now I’m replacing just about everything I can for fun!
The only weak points here was the power switch was underrated and the resistor for the power light gets too hot.
This is what I used in the last Mark 1B I re-did.
2N4250 I used PN4250A
SE4010 I used 2N5210
2N5307 I used 2N5307 / I've heard the 2N5308 is supposed to work ?
BC239C I used BC550C, in the past I've used BC546
BC307B In the past I've used BC556
There are others you can use that will also work just fine.
2N4250 I used PN4250A
SE4010 I used 2N5210
2N5307 I used 2N5307 / I've heard the 2N5308 is supposed to work ?
BC239C I used BC550C, in the past I've used BC546
BC307B In the past I've used BC556
There are others you can use that will also work just fine.
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I've repaired/rebuilt lots of MK30s and have NEVER seen one like that, very interesting. What's the Serial # on this one? I'm thinking it's an early one since there a lot of wires, most SAE products are wire-free more or less.
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This is the second one of this type I've seen. I also have a rack model that has a different layout to yours and the one I posted photos of. I have seen at least two that have the same layout as yours. There are definitely 3 versions of this preamp. Will send serial number when I get a chance.
Got it. Well start Googling some PN’s to try and find subs.
What on earth is going on with those rear axial caps??? Your tech did a horrible job.
