New (to me) Threshold FET-10 HL (What to refurbish?) - Page 3 - diyAudio
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Old 14th June 2010, 12:48 PM   #21
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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.
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Old 14th June 2010, 01:55 PM   #22
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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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Old 14th June 2010, 04:56 PM   #23
gk7 is offline gk7
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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.
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Old 14th June 2010, 06:11 PM   #24
a.wayne is offline a.wayne  United States
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Quote:
Originally Posted by jacco vermeulen View Post
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.

Will do when we get back in .......
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Old 14th June 2010, 07:37 PM   #25
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Quote:
Originally Posted by gk7 View Post
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 : threshold sl10
=> 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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Last edited by jacco vermeulen; 14th June 2010 at 07:41 PM.
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Old 22nd June 2010, 07:15 PM   #26
a.wayne is offline a.wayne  United States
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Jacco ,

Tried to open the lid today on the FET 9/E , all but 2 of the micro allen screws came out, 2 are being basturd's arggggghhhhh




Time to get evil ..........................
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Old 23rd June 2010, 12:48 AM   #27
a.wayne is offline a.wayne  United States
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Fet9/E

Got the cover off finally ... Phone cam is crap , i will post more from a real cam..
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Old 23rd June 2010, 02:38 AM   #28
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Bigger external power supply can really help. I have heard the difference.
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Old 23rd June 2010, 07:43 PM   #29
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Oh My, you're as big a fuzzy digipic taker as me.

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.
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Old 23rd June 2010, 09:00 PM   #30
a.wayne is offline a.wayne  United States
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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



.

Daddy cool is just watching at the moment .....

Last edited by a.wayne; 23rd June 2010 at 09:02 PM.
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