C28 mods

Tia

Tia

Did you say birds?
Was running this unit for the last year or so until I found a C33. Sent the C28 off to my tech about 6 months ago who gave it a clean bill of health. Sold it on BT a couple weeks ago and the buyer pointed out some mods have been done. I never looked under the hood. Even if I did, I'm not sure I would have recognized any mods. I offered a full refund upon return and the unit is back in my possession. Before it gets posted up again, I would like to get the mods sorted out. There are 2 caps wire tied to the can caps, outside of that obvious observation I'm at a loss. Can anyone tell me why that was done and if anything else is amiss? BTW, the unit sounds good IMO and everything works.
IMG_3326.jpg IMG_3327.jpg IMG_3328.jpg
 
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Everything looks original except the replacement cap and it is not a mod.
Whoever did the work is very smart. Leave the original in place so the next picky one can re-stuff and that is a mod.
 
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The tacked on caps are for the 2.5 watt classA headphone amp.....does look tacky.

The second picture top LH quadrant shows a number of ground drains repaired or at least new shrink tubing installed, this is good.

Not replacing the axial caps in the last picture is questionable. This is the final filtering stage for the phono gain and tone circuit gain...these should have been replaced.

The single rail power supply these early SS units used is their weak point for the best S/N.......upgrading the supplies really should be done in this day and age.

They built thousands and thousands of these preamps,(actually 21,764) pretending they are some kind of "collectors item" is silly.

I prefer to build a separate circuit board with a upgraded supply and leave the original multicaps inplace unattached.

I would suggest with the 10dB improvement that can be achieved via a better supply, not having it done should be the deal breaker.
 
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There supposed to be a piece of vertical metal that divides the low level circuit board in half to reduce the cross talk, especially on the phono inputs.
 
Adiosted earlier I see no real "mods" just the needed ground " Repair" and a realy ugly typically not needed capacitor add on that calls into question other hidden work that could have been done. Truly a sloppy added on cap job.

The ground repair could have been done decades at the request of DOB at a amp clinic for all that is known....but a ugly cap job ruinss everything.

Those pictured two blue and single silver axial caps should have been replaced long ago but someone chose to tack on headphone amp output caps........crazy.
 
To the OP,
If you plan to keep it then send to Terry. Or just fully disclose to the prospective buyer with pictures and sell it.
 
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