I can tell you my opinion.I owned a Threshold ( new purchase)a S/300 sereis 2 for many years of trouble free operation. Great peice no hassles.Very non-solid state sound.One of the best of the best! I would definately recommend the S-series.In my opinion this was the best of the Nelson Pass efforts.They were also built to last a lifetime.....Hope that helps
The stasis design as implemented by Nakamichi is an lower budgeted implementation of the Threshold. I owned the Nak PA5A MKII which was the upgraded 150wpc stasis version with huge heat sinks - very 'cool' looking and operating. I was very happy with it driving my hybrid ribbon speakers. Yet, it was completely unable to drive my estats. So, like any other component, it depends what you match it with.
Threshold SA/1 mono block (pure class A) power amps are the best sounding poer amps that Nelson Pass had designed, period.
Personally owned just about every Threshold amp that was ever made, and still have about two dozen Threshold pieces.
The SA/1's standout alone on top.
I believe that the SA series, made in the mid 80's were the best amps made by Threshold when Nelson Pass was in control. Pure Class A. The SA3 a 50 watt model was outstanding and the SA1 mono's are a classic. They still cost 3K+ if you can even find them on the used market. The S500 was a great AB amp if you needed a lot of power.
As good as many Threshold amps are, they can all benefit from component upgrades / internal modifications.
One of my friends has a very highly modified Stasis 2. He swapped out many of the caps, diodes, etc... of the existing circuitry, increased the filter capacitance of the power supply and then had Jon Soderberg of Vintage Amp go through and align it. While this was the most heavily modified amp that Jon has ever worked on, he also said that it was probably the best sounding Threshold amp that he had ever heard. Given that Jon used to work for Threshold and has probably repaired / modified hundreds upon hundreds of Threshold based products, even after they went out of business, i think that his comments should say something about how much parts quality equates to what we hear. This is just another reason why i encourage others to upgrade / modify what they already have, if they are basically happy with it.
With that in mind, i don't think that you can go wrong with any of the mid to later series Threshold pieces, even in stock form. Some are better than others, but all of them have the potential to sound very nice. While I can't say that i've even come close to hearing or examining every amplifier or design out there, Nelson Pass is my favourite amplifier designer at this point in time. He has been for several years now. Sean
For class AB, the S500e and 550e are the best I have heard. For class A, I prefer the T400 driven balanced by the T2 preamp. I think this is the best I have heard period. The T400 is basically dual mono unlike the lower power amps in the T series. John S mentioned that the bridge rectifier can fail on the T200 when driven hard over long periods. He has a simple fix and can update the bridge to the fast recovery type. Please note that most preamps cannot handle the low impedance on the balanced inputs very well.
Why don't you pose the question to hime or others at the DIY.com BB which he posts at .
Not trying to say you will not get an adequate answer here,but it just stands to reason that there you might get some more or different feedback.NP might answer your question himself.
Another point that should be made is that synergy is everything and you should match your speakers with a particular amp that is known to work good.
The opinions I have heard favor the SA series and T series. I would much rather use a ClassA than AB amp ,but watch the electric bill. NP says his amps should be left on 24\7.
The T series of amps were not designed by Nelson Pass. These are amps that were designed after he had sold Threshold. This is NOT to say that they are bad amps, they just aren't of Nelson's "bloodline". The Forte' 4, 5, 6, 7 & 55's were also post-Pass products. Sean
Any word if Jon is still in business, the www.vintageamp.com site has been down for a week now, though I did find an old cached site on google:
Sean, I would love to "pick your brain" and see what mods you recommend on the Threshold/Forte line.
I have a THRESHOLD SA/20M power without pre but unfortunatly I dont know anything about it. I would be pleased if you help me to find out the answer of some questions:
1-general information about it.
2-which pre is better to match with this power.
The Best Threshold amps designed are the SA Series amps.
These are Pure Class A Designs. And are the top designs of Nelson Pass.
Here are the top 3 Best Sounding and Quality made Threshold power amps. I have had every Threshold amp in the last 25 years.
1) Threshold SA/1 mono blocks with e mod in balance mode.Also love those Big Analog meters !
2)Threshold SA/4E stereo amp in balance mode.
3)Threshold SA/12E (as you know these amps) in balance mode.
I'll buy your Threshold SA/1's. I own a Threshold SA/4e and love it ! I prefer it over Nelson Pass's new stuff from Pass Labs. Had a Pass X350 and even tried the Pass XA100 and still prefer my Threshold SA/4e / But I am serious Mfslgoldcd, I will buy your Threshold SA/1's if willing to part with.
Lawyerman, I'm very interested in why you still prefer the older SA/4e amp. In what ways do you feel it's better than the newer Pass amp designs?
The Threshold SA/4e power amp is more refined than the newer Pass amps. I found has a better midrange and imaging than the PASS amps. The PASS X350 had more bass but the drawback was not as smooth , or natural in the mids as the Threshold SA/4e amp.
True the Threshold SA/4e is a pure class A sound verse the Pass X350 is Class A/AB sound.
Now when compared to the Pass XA100 amp I still prefered my Threshold SA/4e. Better dynamics and still smoother in the mids and top end with the Threshold SA/4e amp.
The XA100 had a slight edge in depth . It seems that the newer PASS amps emphasize more on bass- boom sound than being more dynamic and smooth. In my opinion the Threshold SA/4e is overll a better sound than the Pass X350 . And it's a matter of taste if you want more boom in your bass with the Pass XA100.
I also own a pair of Pass X600 amps which I use in anothe system. Again a lot of bass and depth but misses on the
Mids and TReble smoothness when compared to the Threshold SA/4e. I still like the Pass X600 amps for my application needing bass.
In summary the Threshold SA/4e is a finesse sounding amp. Very smooth, articulate and natural sounding. Still has plenty of power to drive just about any speaker out there even though it's a modest 100 watts pure class A sound. In fact when I had the Pass X350 verse the Threshold SA/4e listening levels were almost the same on my preamp.
Lawyerman great analysis of the Threshold amps.
The Threshold SA/4e is a great amp. I also prefer the Threshold SA series over the Pass Labs new stuff.
Sorry my beautiful silver Threshold SA/1's are not for sale. Will probably take them to my grave.
They are doing a S/350e reissue. Any comments on this product?
The original was made in the USA. The re-issue is made in China.
I own an original S350e. Pretty much all Threshold amps are great sounding especially the S and SA series, last of the Nelson Pass designs. I would assume that the new Chinese reissue of the S350e should sound as good as the originals if the same parts are used, the only issue may be possibly one of quality control and reliability. The original designs were built like tanks and designed to last a lifetime. That being said though there are some pretty decent designs comming out of China these days. As far as comparing the Threshold sound to Pass Labs I haven't had the oportunity to listen to as many Pass Lab amps as I have Threshold as there is no Pass dealer in my area. I will say though that even though the Pass amps may be newer much more expensive designs, the older Threshold designs can hold their own quite well against the Pass designs OR most any of the newer designs of any other manufacture. I'm sure we can all agree on one thing though, Nelson Pass has got to be one of the top few great amp designers.
Greatb to see this thread keep on keepin' on.Would like to know about mods or basic service if anybody has the tip there.Obviously the build quality was there in fisrt place (unlike Adcom who justI think were too big a company to keep quality control reasonable with their (excellent) NP designed "Gold Badge Series".Might have kept the rack if Adcom with it's swell head reviews of it's 41K D/A processor got cute and had a digital INPUT with no output for the CD player.Otherwise a nice inexpensive balanced stack but while i sold them so contatcs for pre go all the time and small issues come up.Nakamichi's 7 and 5 series stuff still seems to be working 20 years down the line.But with the quality and price of the "real" Stasis gear one would want to knwo if any can't be repaired for lack of parts and even if not the case who to send them to.Leads?Still may end up with a Sonic Frontiers pre and Threshold yet though as time goe on with good digital like Bel Canto and PS Audio and companies like Plinius,Nuforce,and current darling Parasound are out there.Not to mention high quality hybrids like Pathos and Unico though these maybe the bedroom set and not worthy of comparison with large hi-current amps.Choices like freedom can be a bitch but you'd rather have them than not.But repair and upkeep tips fopr anybody still reading post would be appreciated.
Lawyerman I agree with you on the Threshold SA/4e amp. By the way I will be selling some of my personal Threshold gear to downsize a bit.
Including Threshold SA/4e and Threshold SA/1's if interested.
mrchips i own a threshold sa/3.9e amp. Can you tell me how this amp fits into the threshold family. The rest of my gear fet/10, dac1/e. I'm looking now at upgrading my speakers. Polk SL70 is what i have now.
Also if i was looking to purchase the sa/1's what would be a fair market price. Thanks for sharing your knowledge on threshold.
I believe everyone on this thread would be in total agreement that Mr. Nelson Pass has to be one of the greatest designers in the history of modern high end audio.
I now power my bi-amped system with a pair of Pass Labs XA-100 monoblocks and a pair of Threshold SA-1 monoblocks. I do believe that both pairs of amps are the best sounding designs in either the history of Threshold or Pass Labs. I used to have a pair of Pass Labs Aleph 1's, which are a classic design also, but believe the new XA amps have surpassed the sonic performance of the Aleph and SA series amps.
Unlike Lawyerman, I find the XA-100's to be a better sounding amp then my SA-1's in my system, however they are both great and its amazing that the SA-1's are still almost as good as any SS amps on todays market considering that that they are twenty years old!
Can someone tell me how much of an upgrade a SA/4e would be from an 6.9e? I know there would be some power difference but how much difference in sound if any?
Sorry guys, that'a Threshold 3.9e not a 6.9.
a threshold s300 recently came into my possesion and i was wondering what thresholds are for. i am a bassist and was going to try to hook it up to amp a home-made cab (using 2 JBL 12's) i have never heard dof threshold before now and im sure u guys could tell me a little more about it
I have a Jon Soderberg upgraded S/150 sereis II. It is the lower powered one of the S sereis, but many thought it to be very Musical. It was rated at 90 watts but performs like much more.
Here is the proper website for Jon Soderberg.
I don't know if this is the right to ask this, but maybe someone can help.I'm looking for the schematics for a S500 series II.If anybody can knows where to obtain them it would be of a great help, thanks, Randy