When Jon Soderberg of vintageampair.net (the guy for all your Threshold/Forte' maintenance needs) refreshes these amps; one of the things he routinely suggests is the replacement of the power switch (circuit breaker).
Threshold S300 Power Amp
QUESTION PLEASE:
Who might be using this amplifier in their 2 channel audio system? What do you like about this amp? And please share speaker cables and interconnects that work well with this amp. I have recently purchased this amp used and would also like to learn anything else I might need to know to take great care of this unit. Finally, where would I get a manual? Thank you so much for your responses.
Who might be using this amplifier in their 2 channel audio system? What do you like about this amp? And please share speaker cables and interconnects that work well with this amp. I have recently purchased this amp used and would also like to learn anything else I might need to know to take great care of this unit. Finally, where would I get a manual? Thank you so much for your responses.
20 responses Add your response
| Post removed |
Unfortunately it suffered from a very wicked turn-off transient, about a minute or so after the power switch was turned off. I had the S300 Stasis MkII with optical bias, it never had this problem, a few others dry caps and such, but I fixed all those and gave it all most double the uf’s in the power supply, tightened the bass it was a nice amp. Nelson said to me over at DiyAudio to bias it up higher so on a 30c-35c day you can just keep your palms on the heatsinks for 6 sec then have to remove, bricklayers need not apply. If anyone needs I still have all the circuit diagrams and adjustments for it. First to get them has to spread them around. Here’s an old shots of him when he was into esl’s I posted at diyaudio he got a kick out of, I believe this was a Plasma and not an ESL. http://airspeaker.co.uk/Nelson%20Cover.jpg http://airspeaker.co.uk/9108CMTHR-IMG-JS-Ionic.jpg I have a pair of these from 10khz up on my ESL’s https://www.ebay.com/itm/Magnat-Plasma-MP-02-ion-tweeter-massless-air-plasma-speaker-Plasmahochtoner... Cheers George |
I had an S300 in the mid 80s that sounded decent but kept popping fuses so I got rid of it for a Classe 25 that had much more oomph. Eventually traded that guy for a CA200 with side heatsink (basically a CA201) that sounded even better along with a McCormack 225. With amps like Classe and McCormack that can be had for 1000 - 1500 there’s really no reason to buy a used Threshold of that era. |
I just sent my S500 to Jon to have it upgraded. Jon said he could turn it from a class A/AB to class A up to 160 watts that would make it like a stereo SA1. I can't wait to hear just how the upgrade will sound. New caps, fast recovery rectifiers, cardas binding posts, new power switch and I should have a new amp. I owned an SA/4e when they first came out and like an idiot sold it about 15 years ago, I hope these upgrades get me close to that sound! I will be using a CJ PV 14L preamp so I should have a pretty good tube sounding powerhouse. |
I own a S/300, partnered wit an Audio Research LS-2 pre and Apogee loudspeakers. The Apogees are demanding and revealing - and the Threshold drives them very well. I like all kinds of music, from death metal to classical. The Threshold is a musical omnivore as well. I'd love to hear them with your Maggies, IMHO the Threshold is well suited to drive planar loudspeakers. So you have the start of a very good setup, which will give you many hours of pleasure. |
I owned one briefly about 15 years ago. Unfortunately it suffered from a very wicked turn-off transient, about a minute or so after the power switch was turned off. I have no idea if that was a defect in the particular unit or characteristic of the design. It was as if when the energy stored in its filter capacitors dissipated, the driver stages lost power before the output stages, resulting in an uncontrolled seemingly full-power bass transient. Hopefully your unit doesn't do that. Regards, -- Al |
Thank you all for taking the time to comment here. This is awesome information especially regarding speaker and interconnect cables. Thank you and thank you very much all. I will welcome any other comments as well. I will be using the S300 to drive Magnapan 1.6 speakers. I will now be looking for a pre-amp to support the S300. I will need a pre-amp that can accomodate 2 reel to reel tape decks to include a Tascam 32-2B and Technic 1506. From time to time I will also use the Otari MTR-15.I will of course listen to music via a turntable and CD player. My primary listening pleasure is classical and jazz music to include large and small scale choral works, big band and small group jazz. I love the human voice. While I can't afford to purchase new audio stuff I am trying to put together the best system I can afford at this present time. With the great assistance I am getting from you guys I can't go wrong putting together a wonderful music system that will satisfy me into the future. Thanks again. |
The amp is way ahead of its time even though it was designed in the eighties. Very refined, transparent and powerful. By todays standards it still is extremely good sounding, Nelson Pass is a genius but also takes pride in his designs and workmanship. Recommending interconnects is hit & miss and you should experiment yourself since you have to take in consideration your other associated gear & personal tastes. |
An amp as old as the Threshold S300 might need new caps and rebiasing. You have a fine amp and the costs to do the above would be well worth it. It would probably cost much more to find a newer amp that could compare to your Threshold. I like many others have found the Alpha-Core Goertz speaker cables to work particularly well with Threshold amps. The Threshold amps will absolutley require the RC networks that Alpha-Core can provide. Of course I don't know the rest of your system or your individual preferences, but Alpha-Core offers a generous free trial period. You'll probably want to consider Alpha-Core's Goertz MI2's. The above mentioned Jon Soderberg, though not cheap, truly knows Threshold gear and does excellent work, highly recommended. |
