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

[Apesbrain]

Hi, I'm coming late to this thread but I do have the appropriate pages from the FET/9e operator's manual. The switch operation is NOT the same as the FET/10.

[a.wayne]

^^^^ Thanks ...............

[clintalloy]

Originally Posted by GaryB

I've built yet another power supply for my Threshold FET 10/hl. I've incorporated suggested from Zenmod and Eric Juaneda by moving the position of the inductor for the negative supply and also increasing the size of the power transformer from 28VA to 160VA. I used a transformer that I got from ApexJr. Attached is a copy of the new schematic. In addition to what I've drawn, there is also a snubber across the transformer secondary (324ohm + 22nf) and bypass caps across the 10kuf electrolytics (10uF 63v (type K73-16) and 1uF 200v (type K40Y-9) and 0.1uf 630v (type K42Y-2)).

As Eric suggested, the bigger transformer is a worthwhile improvement giving better soundstage and a more natural and musical bass line.
Definitely worthwhile - if you're going to the trouble to build a new supply then go for a big transformer.
---Gary

Gary B, would this PS work on a Threshold 9/e? Or would I need to change anything? I am a bit of a noob

thanks

[nguy14]

Hi I am new to the forum and am trying to update the power supply and preamp cap replacement when I noticed 3-4 of the small silver painted transistors? are cracked. Anyone know if the exact replacements are still available?

Any recommendations on what is best to use for the 1uf 63v and 10uf uf along with the 4 4.7uf capacitors in terms of brand and sound quality? Any other caps that needs replacing?

I do have the Fet ten/hl with the green ERO MKT1813 cap.

[nguy14]

I found what I need after looking that the thread...

[GaryB]

Originally Posted by clintalloy

Gary B, would this PS work on a Threshold 9/e? Or would I need to change anything? I am a bit of a noob

thanks

Sorry for not noticing this message earlier.

You should be able to use the same power supply for the 9/e preamp. It use an on board regulator, so any voltage in the range of +-24v will be fine. The connectors on a 10/hl power supply and a 10/e or 9/e supply are different, so it's hard to swap the stock power supplies from one version to another. But that isn't a problem if you're building your own power supply.

---Gary

[tfender]

Originally Posted by GaryB

Sorry for not noticing this message earlier.

You should be able to use the same power supply for the 9/e preamp. It use an on board regulator, so any voltage in the range of +-24v will be fine. The connectors on a 10/hl power supply and a 10/e or 9/e supply are different, so it's hard to swap the stock power supplies from one version to another. But that isn't a problem if you're building your own power supply.

---Gary

Hi Gary

I need to Threshold FET -10hl Power supply SCHEMATICS , My power supply 15-0-15 AC.

Thanks
tfender

[GaryB]

The original power supply is very basic. It uses a small transformer (6VA), standard diodes, and modest capacity electrolytic capacitors. If you're building your own power supply from scratch then you want to improve each part. Use an 18v/18v transformer but increase the capacity to >200V. Use better quality diodes. And increase the electrolytic capacitors to >10Kuf. Other things that I would do include adding snubbers to the transformer to kill off any remnants of the diode reverse recovery and adding some film capacitor bypasses to the big electrolytic.
Or if you want to try something different, take a look at the power supply that I built in post 66 New (to me) Threshold FET-10 HL (What to refurbish?)
But the biggest benefit comes from using a bigger power transformer.
---Gary

[treuben]

I have posted in a few threads in the past asking about the differences between the line stages of these designs. I wonder if anyone here (since there seem to be some quite familiar with the circuits here) would be able to enlighten me as to the differences? I know the 10 HL/e were servo, balanced. The nine/e didn't seem balanced output though from pictures. Is the old nine and 10HL the same line stage? (wondercap coupled?)

Kind regards, from Australia.

"I love what you've done with the place, but this place is a prison, essentially, as much as you all like to deny it. I've seen insects with kneepads and you live approximately three quarters of a mile away from the sun." - Dylan Moran, On Australia

[treuben]

I did succeed in finding a schematic for a fet nine. The plain old non-e version. It looks very similar to the fet 10HL (non-e) though it uses only one 2N5566 in the input versus the 2 paralleled in the fet 10HL. I've heard it said that the psu's are the same between the two. Also, there seems to be a slightly different arrangement for the resistors and caps in the feedback loop with the nine having an extra set in series vs the ten. Would the paralleled 2N5566 in the 10HL be for lower noise or something else? It seems odd to my limited knowledge to need that in a line stage. Perhaps someone here will know more!

All the best!