I've been looking some at a few classic Threshold amps lately, wondering what would work well on the original RS series, more specifically my RS1Bs but really anything that has EMIMs. Anyone have experience driving Infinities with them? I imagine that a lot of the bigger Thresholds have killer bass, but I'm wondering about their character throughout the frequency range. Any Thresholds that have less than stellar bass or lackluster highs, ones that should be avoided?

The 400A looks intriguing: 100wpc class A @ 8 Ohms, but capable of up to something like 500wpc dynamically due to some auto-biasing circuit. That sounds like it would keep the planar drivers from getting fried, right? Maybe not... I'm going to try out tubes too, like most people suggest, but I've read that the woofer/EMIM transition is smoother with S.S. on top and I want to hear the difference for myself.

I had good luck with SS on my IRS. I will say tubes take them in a different direction. A direction that I prefer. I will not argue SS vs. Tubes, as it is personal choice, and until you hear your speakers on both, the point is moot. There are great SS and great tube amps out there. It's a bit easier to pair the emit/emim with tubes, as less SS amps are up to the task but there certainly are enough great SS amps that can do it.

There, that is out of the way...

I always wanted to try a Threshold class A on mine. The biggest problem was after reading about them, I found they tend to cook many of the components as they run so damn hot. So; buy a nice Threshold or Pass Lab class A for boku-bucks, then end up spending a bunch more to get it into spec? So I stayed away. But I wanted to. I remeber there is a website of a guy that specializes in the Nelson Pass Class A amps (upgrades, rebuilds, repairs).

Chris, if you have a bit of patience, my new preamp will be here next week, and my buddy that is selling the IRS Betas, also picked up a Krell class A amp on his road trip. Since I've always wanted to hear a great big class A SS, I can do some comparison listening between the Baron and the Krell and get back to you. Things are a bit tight till after next weeked (not this weekend), as a nephew is getting married and we're hosting some parties over here.

I was running a S-500II on my 2b's at first.I then tried the tube route and I'm bi-amping now with the S-500 on the bottom and a Mac275V on top.I have tried going back to the Threshold to compare and although the S-500 sounds very good,for me the Mac needs to be on top.Lately even I've been feeling that I'm waisting the Thresh on just running the bottom and just getting a "bass amp" because the Thresh is too good just bass duty!
Someday I would like to try out a Pass XA.5 series amp, when funds permit.

Randy

This is probably of little help, but the only guy I know that has RS-1bs runs them on Threshold amps. I've never had the pleasure to hear them, so I can't relate anything beyond that.

I'm running a set of Modulus with a 400A. Seems like a good combo, nice sound, but hard to compare because they're in my office and the room is an acoustic nightmare. My only major complaint is that it runs hotter than Hades and I worry about cooking the equipment adjacent to it.

David

I was running a S-500II on my 2b's at first.I then tried the tube route and I'm bi-amping now with the S-500 on the bottom and a Mac275V on top.I have tried going back to the Threshold to compare and although the S-500 sounds very good,for me the Mac needs to be on top.Lately even I've been feeling that I'm waisting the Thresh on just running the bottom and just getting a "bass amp" because the Thresh is too good just bass duty!
Someday I would like to try out a Pass XA.5 series amp, when funds permit.

Randy

I put Randy onto the McIntosh MC275 some time ago, and he is a believer. I also had excellent results with a MC275IV on RS1b's.

Around my area I have numerous long-time audiophile friends still with big Infinities from days past, myself included. You will not find even one SS amp on the topside amongst us all. LOL been there, done that. SS will work, but the magic is reduced quite a bit.

Paul

I have a variety of Threshold Amps running various Infinity speakers. First off if you are considering 400A's or early Stasis amps including the first S series and S-II then the best sound will be achieved after the amps have been refurbished.

Currently I use a 400A to drive my Ren 90's to great satisfaction. The tube like sound of the 400A mates well with the Rens.
I have a pair of rebuilt S500 II's driving my Kappa 9's. I have tried various other amps both single and biamped and cannot find a better combination.
I have a set of Kappa 6's being driven by a Threshold S300-II and a set of Kappa 7's driven with a Threshold Cas1. I would reverse these in a perfect world but the Cas1 is far more tube-like then the S300 and the Kappa7's are a stand alone system where the K6's are the surrounds for the K9's in my home theater.

I can recommend any Threshold amp to drive vintage Infinities, they where in my opinion the best there was then.

I have a variety of Threshold Amps running various Infinity speakers. First off if you are considering 400A's or early Stasis amps including the first S series and S-II then the best sound will be achieved after the amps have been refurbished.

by refurbishment do you primarily mean new electrolytic caps?

My Treshold S/300 drives a pair of Apogee Scintilla's if required to do so, so I'd imagine they'll also drive Infinity's.

My Treshold S/300 drives a pair of Apogee Scintilla's if required to do so, so I'd imagine they'll also drive Infinity's.

The thing most people don't get is yes, your Thresh will drive them. So will an old receiver. :D

You could "drive" them with a pair of SET amps.

Quality of sound from the big dog Infinities is based on a whole lot more than driving them. Some will never know what these are fully capable of.

Threshold made some wonderful amps, don't get me wrong. However based on my years of experience and the quantity of different amps I have tried on large Infinities over the years, I would not consider the Threshold for anything but bass duty on any large Infinity that requires biamplification.
The Threshold would also be a far better choice on the woofers than any mid-fi amp. One of my buddies who has Betas one time decided "it's just bass, any old amp should do it". The Hafler 9505 he bought for short money lasted about a week in this role what with my friend's love of large-scale classical.:scratch2: Myself, I have been running an elderly and well maintained Levinson ML-3 on Betas for years now, with never a glitch. Current and power go hand in hand with multiple woofer Infinitys, RS1b, Beta, Deltas, Gammas......

I prefer amps with fairly high damping factor for use on woofers. Some say high damping factor can make an amp sound "dry", others say DF matters not at all. I say I like high DF, but you try for yourself. No recommendation can please all ears.

What I intend to do soon is try one of my QSC PLX 3402's on the Beta woofers. These have been outstanding most everywhere I've tried them, and most excellent on a pair of Polk SRS-SDA 1.2tl's.

Best,

Paul

The thing most people don't get is yes, your Thresh will drive them. So will a an old receiver. :D

You could "drive" them with a pair of SET amps.

Quality of sound from the big dog Infinities is based on a whole lot more than driving them. Some will never know what these are fully capable of.

Threshold made some wonderful amps, don't get me wrong. However based on my years of experience and the quantity of different amps I have tried on large Infinities over the years, I would not consider the Threshold for anything but bass duty on any large Infinity that requires biamplification.
The Threshold would also be a far better choice on the woofers than most mid-fi amps. One of my buddies who has Betas one time decided "it's just bass, any old amp should do it". The Hafler 9505 he bought for short money lasted about a week in this role what with my friend's love of large-scale classical.:scratch2: Myself, I have been running an elderly and well maintained Levinson ML-3 on Betas for years now, with never a glitch. Current and power go hand in hand with multiple woofer Infinitys, RS1b, Beta, Deltas, Gammas......

Best,

Paul

From what I've heard and read (yeah, second hand I know) the big, real class A super amps (Krell, TH, Pass...) are supposed to be THE BOMB on the low-end. Maybe an amp guru can chime in and explain in greater detail why class A holds onto the woofers so well. Whatever the reason (assuming it's true), I'll be trying my buddy's Krell out on my IRS and hopefully talking him out of it, if indeed it does improve the bass over my Adcom 565 monos.

I've run both an SA3.9e and an SA4 with the 2.5's, and both were major disappointments, to say the least. While these amps sound very good with other products, they were so bad with the 2.5's that listening was downright painful.

I love the two S/500 II with the Kappa 9's. Unwavering control over the woofers like no other amp I've used. Very fast tight bass, that is deeep. Having the current capabilities that this amp does makes audibly significant differences.
I use two though and it is more so for the the high pass side that I so highly recommend these amps with Infinity speakers. Detail, staging effortlessness. Sonic Truth, which is what have attempted to achieve in my system, is most prevalent with a Nelson Pass design amp and a Arnie Nudell speaker. Moreso I feel than with the Audio Research gear that these speakers were voiced with.
We each have our own truth though, and that is what makes our hobbies so entertaining for us.

The thing most people don't get is yes, your Thresh will drive them. So will an old receiver. :D

You could "drive" them with a pair of SET amps.

Quality of sound from the big dog Infinities is based on a whole lot more than driving them. Some will never know what these are fully capable of.

Threshold made some wonderful amps, don't get me wrong. However based on my years of experience and the quantity of different amps I have tried on large Infinities over the years, I would not consider the Threshold for anything but bass duty on any large Infinity that requires biamplification.
The Threshold would also be a far better choice on the woofers than any mid-fi amp. One of my buddies who has Betas one time decided "it's just bass, any old amp should do it". The Hafler 9505 he bought for short money lasted about a week in this role what with my friend's love of large-scale classical.:scratch2: Myself, I have been running an elderly and well maintained Levinson ML-3 on Betas for years now, with never a glitch. Current and power go hand in hand with multiple woofer Infinitys, RS1b, Beta, Deltas, Gammas......

I prefer amps with fairly high damping factor for use on woofers. Some say high damping factor can make an amp sound "dry", others say DF matters not at all. I say I like high DF, but you try for yourself. No recommendation can please all ears.

What I intend to do soon is try one of my QSC PLX 3402's on the Beta woofers. These have been outstanding most everywhere I've tried them, and most excellent on a pair of Polk SRS-SDA 1.2tl's.

Best,

Paul
Still beating that drum. :boring:

Still beating that drum. :boring:

Correct. :boring:

Please post your impressions Mark when and if you try any of the recommendations I make. I do not disrespect your choices and opinions, extend the same courtesy my way.

Paul

I am still learning from you all, it is almost to much info for me grasp, as to so many choices makes for a diffiicult decision. But I have had good luck with my crown amps. I don't know if they compare to some of the others listed in this tread but I know they are very tough and based on my work, they are very widely used in live performances that we all try to duplicate. If you ever go backstage in many of the top venues you will many times find racks of Crown Amps powering those huge Line Array EAW's. They are very stable at low impedances, built like a tank. I asked in another thread if anyone had any experince using them and no one commented. Below is a link to a pair of Reference Crown amps for sell and the Crown PDF file with the specs. Very high damping factor, Crown claims they are stable at any load I have yet to have one fail. The only failures I have occured are when a lighting strike surge hits them.

http://cgi.ebay.com/CROWN-Studio-Reference-II-Amplifier-Series-2-Amp_W0QQitemZ180393371826QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item2a004868b2&_trksid=p3286.c0.m14

I am still learning from you all, it is almost to much info for me grasp, as to so many choices makes for a diffiicult decision. But I have had good luck with my crown amps. I don't know if they compare to some of the others listed in this tread but I know they are very tough and based on my work, they are very widely used in live performances that we all try to duplicate. If you ever go backstage in many of the top venues you will many times find racks of Crown Amps powering those huge Line Array EAW's. They are very stable at low impedances, built like a tank. I asked in another thread if anyone had any experince using them and no one commented. Below is a link to a pair of Reference Crown amps for sell and the Crown PDF file with the specs. Very high damping factor, Crown claims they are stable at any load I have yet to have one fail. The only failures I have occured are when a lighting strike surge hits them.

http://cgi.ebay.com/CROWN-Studio-Reference-II-Amplifier-Series-2-Amp_W0QQitemZ180393371826QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item2a004868b2&_trksid=p3286.c0.m14

Another excellent post Ken. On another audio forum I frequent I was told that "All Pro amps suck". There is some serious misconception out there in regards to these, I believe based on many manufacturers lower end models.

The Crown Studio Reference and Macro Reference were damn good, I appreciate high DF amps myself, however some feel that they can sound a bit dry. Like any piece of equipment, synergy and system matching are everything.

I would put my pair of Crown Macro-Tech 2402's or the Macro-Tech 5000VZ up to darn near any available amp out there. They are that good.

Recently I bought a pair of QSC PLX 3402's. I have always been suspicious of these as the weight to power ratio was insane, and I remember my disappointments with the Carver Magnetic Powerfield offerings some years ago. However QSC claims stable to 2 ohms in stereo, and I have ran them balls to the wall on the DJ rig, and found no problem. I have also found great synergy with the QSC's on a pair of Polk 1.2tl's.

The difficult part is many folks believe what they want to believe, and follow the pack. Attempting to get them to consider and try a different direction is not always easy.

Best,

Paul

I have used Crowns for many applications for a long time, along with QSC's. My experiance with QSC has been mainly Distributed sound systems in commericial establishment, 70 volt systems, and I always prefered the Crowns in those applications as well. I will have to try one in my personal system to see how they sound, but the ones I have probably are not some of the best ones QSC produces. Sometimes the music companies purchase the QSC because of the price level which is less than the crowns in most cases.

I am going to set up a Macintosh Rack, as I am worried about parts for my SAE equipment, and I always wanted those big blue meters!

New to my line up of Speakers

A Pair of one owner Infinity QLS-1 Quantum Line Soures

A Pair of Kappa 9's

I am going to set up a Macintosh Rack, as I am worried about parts for my SAE equipment, and I always wanted those big blue meters!

There is something very compelling about the sound of a Mac and the look has that something that we all have a fond memory of as audiophiles. If you were to compare the Stasis S series of Thresholds with the Mac of yesterday or today with either the QLS or the Kappa's I think you would end up with the Threshold. These were the state of the art in the late 80's and early 90's.

And because of their non retro cool look they don't fetch ridiculous prices in the resale market.

I have auditioned both tube and solid state Macs on my Infinities. No chance I swap for my Stasis amps.
(Although I would like an SA-1 as the compromise to those cool meters on the Macs.