Threshold T-100 60W Class A Power Amp

falconcry72
falconcry72 Posts: 3,580
edited January 2012 in 2 Channel Audio
Anybody have any experience the Threshold T-100? It's a 2-channel power amp, rated at 60W per channel in pure class A. Evidently a Nelson Pass design. Looks interesting.

Know what it'd be worth?

Thanks, gents.:biggrin:


Ben
2-Channel: PC > Schiit Eitr > Audio Research DAC-8 > Audio Research LS-26 > Pass Labs X-250.5 > Magnepan 3.7's

Living Room: PC > Marantz AV-7703 > Emotiva XPA-5 > Sonus Faber Liuto Towers, Sonus Faber Liuto Center, Sonus Faber Liuto Bookshelves > Dual SVS PC12-Pluses

Office: Phone/Tablet > AudioEngine B1 > McIntosh D100 > Bryston 4B-ST > Polk Audio LSiM-703's
Post edited by falconcry72 on
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  • heiney9
    heiney9 Posts: 25,165
    edited January 2012
    The T-100 was made long after Nelson left so I doubt very much it's a NP design, although it may have some NP tendencies. Those were made during the last gasp of the original Threshold Co. 1994-1998. I'm sure they are decent, but not sure they are what could be termed "from the best years of Threshold".

    If the price is right then probably worth a try, even a later Threshold is a pretty nice piece.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • heiney9
    heiney9 Posts: 25,165
    edited January 2012
    It seems based on internet comments they are prone to break down and it seems one user claims the transistors are no longer available. Certainly something to check into.

    When I heard it years ago it was very good, but if it breaks down the transistors for the T series are no longer made. Someone from Threshold has taken over the repair, but I understand they totally replace the output sections with other tranistors and it may be a little expensive. The older Threshold units before the T- series use standard parts and can more ealily be repaired. The -e series were excellent sounding true class A amps

    I believe Jon Soderberg is doing repairs/upgrades for Forte and Threshold these days, maybe contact him.

    I'm running T200's as monoblocks and run them for hrs at a
    time with no problems. This was there last reference set-up
    used at shows untill the new company opened. Vintage Amp Repair Jon Soderberg has plenty of parts for the T series

    The posts I quoted are from 2003

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • heiney9
    heiney9 Posts: 25,165
    edited January 2012
    It looks as though the T series used IGBT's (Insulated Gate Bi-Polar Transistor's) like some of the Forte stuff, I'd stay far away. If that's the case there is no Nelson Pass lineage at all. He wrote a white paper as to why IGBT's should never be used in audio equipment.

    As far as I know IGBT's are unobtanium and there likely isn't a suitable substitute.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • falconcry72
    falconcry72 Posts: 3,580
    edited January 2012
    Thanks for the info, H9.

    I looked around for a while and couldn't find hardly anything.

    There's one on my local CL, but it appears he's asking too much, 1100, so that, coupled with repair issues, plus it's an almost 20 year old amp... I think I've lost interest.


    I am still interested in Class A designs, though.
    2-Channel: PC > Schiit Eitr > Audio Research DAC-8 > Audio Research LS-26 > Pass Labs X-250.5 > Magnepan 3.7's

    Living Room: PC > Marantz AV-7703 > Emotiva XPA-5 > Sonus Faber Liuto Towers, Sonus Faber Liuto Center, Sonus Faber Liuto Bookshelves > Dual SVS PC12-Pluses

    Office: Phone/Tablet > AudioEngine B1 > McIntosh D100 > Bryston 4B-ST > Polk Audio LSiM-703's
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  • heiney9
    heiney9 Posts: 25,165
    edited January 2012
    Aleph 30 if you want to spend around $1K

    The thing with Threshold is the amp is going to be a little older and most likely use sliding bias, so it's not single ended class A. Either they have been refreshed or you will need to spend so money to get them refreshed.

    The Stasis amps are nice, but again not really class A.

    There are a couple of early Forte's that are class A, not too bad but again they are older so either they've been refreshed or you may need to have it done.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • FTGV
    FTGV Posts: 3,649
    edited January 2012
    Never mind I didn't see previous post indicating same.
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  • FTGV
    FTGV Posts: 3,649
    edited January 2012
    heiney9 wrote: »
    The thing with Threshold is the amp is going to be a little older and most likely use sliding bias, so it's not single ended class A.
    I believe the dynamic (or sliding) bias scheme was abandoned somewhat before Nelson's depature.
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  • heiney9
    heiney9 Posts: 25,165
    edited January 2012
    FTGV wrote: »
    I believe the dynamic (or sliding) bias scheme was abandoned somewhat before Nelson's depature.

    It was, but most of the "classic" Thresholds it seems were either sliding bias or stasis designs. IMO, after Nelson sold the company they really didn't produce anything groundbreaking.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • falconcry72
    falconcry72 Posts: 3,580
    edited January 2012
    Thanks again for the good info and quick responses, guys!

    I think I'm going to try a low wattage Class A or MOSFET style power amp next. I need to expand my audio horizons!
    2-Channel: PC > Schiit Eitr > Audio Research DAC-8 > Audio Research LS-26 > Pass Labs X-250.5 > Magnepan 3.7's

    Living Room: PC > Marantz AV-7703 > Emotiva XPA-5 > Sonus Faber Liuto Towers, Sonus Faber Liuto Center, Sonus Faber Liuto Bookshelves > Dual SVS PC12-Pluses

    Office: Phone/Tablet > AudioEngine B1 > McIntosh D100 > Bryston 4B-ST > Polk Audio LSiM-703's
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  • nguyendot
    nguyendot Posts: 3,594
    edited January 2012
    What about the Threshold CAS2? I got one sitting in the living room...
    Main Surround -
    Epson 8350 Projector/ Elite Screens 120" / Pioneer Elite SC-35 / Sunfire Signature / Focal Chorus 716s / Focal Chorus CC / Polk MC80 / Polk PSW150 sub

    Bedroom - Sharp Aquos 70" 650 / Pioneer SC-1222k / Polk RT-55 / Polk CS-250

    Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD
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  • heiney9
    heiney9 Posts: 25,165
    edited January 2012
    One of Nelson's first cascode circuit designs, pretty ground breaking stuff from 1979-1981.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • nguyendot
    nguyendot Posts: 3,594
    edited January 2012
    Forgot I asked you about it some time ago..lol.
    I finally got it hooked up and it sounds pretty good.
    Main Surround -
    Epson 8350 Projector/ Elite Screens 120" / Pioneer Elite SC-35 / Sunfire Signature / Focal Chorus 716s / Focal Chorus CC / Polk MC80 / Polk PSW150 sub

    Bedroom - Sharp Aquos 70" 650 / Pioneer SC-1222k / Polk RT-55 / Polk CS-250

    Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD
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  • Joe08867
    Joe08867 Posts: 3,919
    edited January 2012
    heiney9 wrote: »
    It looks as though the T series used IGBT's (Insulated Gate Bi-Polar Transistor's) like some of the Forte stuff, I'd stay far away. If that's the case there is no Nelson Pass lineage at all. He wrote a white paper as to why IGBT's should never be used in audio equipment.

    As far as I know IGBT's are unobtanium and there likely isn't a suitable substitute.

    H9

    That first line of your post would steer me clear of that unit. I have also heard they like to go poof with age.
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