New (to me) Threshold FET-10 HL (What to refurbish?)

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The stretched blind front panel of the 90s series is much prettier than the earlier model, imo.

Besides swapping out the few lytic caps inside the preamp case you could consider a power supply upgrade.
It's just a raw power supply with umbilical connectors and Papa's philosophy towards auxialliary cases is likely the same as for opamps : ACAP

The power supply with cap multipliers of the stuffed T2 model is a step up, or go multi-stage regulation, for example a Shunty.
The two posh commercial line stage preamps i have are complete opposites, one follows the wabi sabi jiggy simplicity of the FET 9/10 series and the other is twice the complexity of the T2.
Both suck on multi-stage series and parallel voltage regulation, downside is that it requires a PS case as big as that of the preamp.
Upside of doing a PS upgrade for a FET nine/e is not ravishing a benchmark preamp classic.

You're welcome to post some pics of the guts of your 9/e. :clown:
 
While i'm in the picture party mood, example of an oval shaped polypropylene foil cap i just ran across.
My parts storage may be rather vast, but not exactly well organised.

(auxialliary ? WTFrolic ?)
 

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Jacco, in your picture I can´t see any (except for the electrolytics) caps that are bigger than 0.1 uF - so it seems unlikely that these are coupling caps. The 10 uF from the schematic in post #9 are nowhere to be seen. Is the schematic correct ? Or probably the 10/e is DC coupled.
 
The stretched blind front panel of the 90s series is much prettier than the earlier model, imo.

Besides swapping out the few lytic caps inside the preamp case you could consider a power supply upgrade.
It's just a raw power supply with umbilical connectors and Papa's philosophy towards auxialliary cases is likely the same as for opamps : ACAP

The power supply with cap multipliers of the stuffed T2 model is a step up, or go multi-stage regulation, for example a Shunty.
The two posh commercial line stage preamps i have are complete opposites, one follows the wabi sabi jiggy simplicity of the FET 9/10 series and the other is twice the complexity of the T2.
Both suck on multi-stage series and parallel voltage regulation, downside is that it requires a PS case as big as that of the preamp.
Upside of doing a PS upgrade for a FET nine/e is not ravishing a benchmark preamp classic.

You're welcome to post some pics of the guts of your 9/e. :clown:


Will do when we get back in ....... :cool:
 
Is the schematic correct ? Or probably the 10/e is DC coupled.

The schematic is of the FET ten/hl, what i linked to is the successor model FET ten/e.

Balanced : 4 identical amp boards, 8 blue Siemens B32520 style polyester rail decoupling caps, 8 Wondercaps.
Ergo, the 0.1uF caps also decouple the rails, they are too large to place on the boards.

The amp boards show Papa's favorite crappy opamp, the LF351.
For big daddy's opamp philosophy : http://www.diyaudio.com/forums/pass-labs/71525-threshold-sl10-3.html#post827152 :clown:
=> DC-servo => DC-coupled (e-series style)

You can figure out for yourself what the other two boards are.

(change of the amp boards is zener based ccs, means two less of the MPSA TO92)
 
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Oh My, you're as big a fuzzy digipic taker as me. :eek:

I second Mr Big John C on that.
The powersupply of my serial production preamp has a 150VA toroid per channel for the amp boards, swapping connectors to 50VA specimens is noticeable.
The PS of the boosted version has a total of 4 R-cores of +200VA (less than 10 dollah each from Taiwan), connected to the preamp above even seems to make a difference.
Not measurable anymore though.

Makes me wonder which anabolic pointers Daddy cool may have. :clown:
 
Jacco you mean 50 or 500 VA transformer, What about storage (capacitance)
I will have better detail pics with my digital cam later , the phone cam sucks and is suppose to be one of the Best :rolleyes:



.

Daddy cool is just watching at the moment .....;)
 
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Well, I send out my FET-10 for a refurb. All the caps were replaced, and after looking at how wimpy the original power supply was, my buddy made a new and much beefier power supply for the unit. Got rid of a small hum problem with the old power supply.

I'll post pics this weekend when I get it back. First impreessions are that the unit has improved bass, image depth, and smoother sounding.
 
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