^Well, it does seem as though he's been shopping this thread for advice on amplification for his CS 2.4 SE's for over a year now.
Showing 50 responses by unsound
Shubert, Thiel's don't really favor any genre of music, but as Thiel's are less colored and closer to laboratory grade instruments than most other speakers, they will reveal the truths (more on this later) before them. Thiel's aren't necessarily better than other speakers in any specific audiophile ways, but completive with all of those audiophile speakers in all the various characteristics (with proper equipment and set up) without the downsides of those speakers that are one and two trick ponies. They are extremely balanced in everything they do. The only limiting factors are room and what precedes them. IME, classical music tends to be better recorded than most popular music. With proper room size and dimensions, and ancillary equipment (especially amplification) the larger Thiels they can excel at symphonic music. If the recordings had microphones placed deep within pianos or immediately above the violins, the lack of time for the sound to bloom can lead to perceived hardness. Sometimes to truth isn't so pretty. But I for one prefer that over the syrupy, rose colored glasses perception that other speakers seem to gloss over everything that comes through them, whether they need the it or not. All Thiels need to be at least 8' from speaker directly to listener for proper driver integration, and the time coherence that is such an integral part of the Thiel designs. |
I know nothing about this particular unit, or of the feedbackless seller, but if one could get an in house audition and pick up directly, this looks like a potential killer bargain, even if by chance it might need some maintenance, for some Thiel owner.: https://www.audiogon.com/listings/amplifiers-threshold-s500-a-ab-amplifier-2017-04-10-vintage-equipm... FWIW, it has more Class A output than Nelson Pass's later similarly powered Pass Labs X250's. Will work with many ss and tube pres (Audio Research is often cited). |
Prof, you raise an interesting point about listener's height and seating distance; one that I raised to Jim Thiel many years ago (back when the CS 5's were released). Jim told me that at distances of 8' or greater that the sonic waves were so large that critical distance became realistically less important. He also said (surprisingly enough, to me at least) that studies demonstrated that most listeners regardless of height had their ears measured to within relatively similar distances to the floor (I seem to remember approximately 3"(?) variance and typically 37-39"(?) ear to floor distance, but I'm really not certain of either). In that the vast majority of Jim Thiel's work (and amongst those of perhaps a very, very small number of other speaker designers) appears to have been towards mastering time, it seems quite rational to me, to do as much as possible to allow those efforts to flourish. I seem to recall that Stereophile apologized in almost every Thiel review for not being able to test them at appropriate distances, and at appropriate distances they expected the measurements to demonstrate superior performance. John Dunlavy was so irked (he told me so himself) with Stereophile's measurements that even he invited Stereophile to independently test his time aligned designs at his facilities. With the proper distances, measurements were much improved, with Stereophile offering the blame of small glitches perhaps to reflections from the fork lift that was used to move those large cabinets. That is not to say that without such considerations, one couldn't enjoy Thiels (heck, most people enjoy their speakers regardless of the fact that their speakers are never in time alignment). Thiels will make music even if underpowered, but again they won't be able to provide the strain free dynamics, linear frequency response and bass integration that appropriate power can. One can enjoy Thiels without proper driver integration, or even power, but they won't be enjoying the full potential of those Thiels. |
^I believe the most critical distance for time and phase coherence (an attribute that can only be found with classic Thiel's beginning with the CS series and a handful of other loudspeakers) is the 8' minimum recommended distance from loudspeakers to listener. The recommendation to start with an equilateral triangle has led many to perhaps over generalize that listener to speaker distance of 8' to a strict minimum distance between speakers. IMHO, still a good baseline from which to start. As rooms, and room nodes and reflections vary from room to room, other considerations might weight more heavily. Have you considered long wall placement? IME, (and in a room not too different than yours) such placement, with absorptive room treatment directly behind the listener, has been the preferred placement. |
Oblgny, I would have to nominate the CS 2's as the easiest Thiel's to power (and most reliable): https://www.stereophile.com/content/thiel-cs2-loudspeaker-measurements Most of the earlier CS 1 series were amongst Thiel's easiest to drive as well. Though the 3.5's impedance does climb just where the eq does it's stuff to help mitigate the eq's 12 dB's boost at the 20 Hz setting, well, that's still demanding of an amplifier. |
jonandfamily, It's been a long time since I've heard the CS 1's. I believe they were a very steady 4 Ohm load of moderate sensitivity. All in all a pretty easy load for most amps, providing of course they are suitable into 4 Ohm loads. If one plans on using tubes, it's suggested to double the power rating. As I recall, they were of typical Thiel sound, but due to the limited bass, could sound more tilted up. |
@oblgny , Have you ever considered Thiel CS 2's? I'm not trying to tell you what to do, just offering an option for consideration. I know you're a fan of the 3.5's, but circumstances might be keeping you from those. I see CS 2's regularly listed for a few hundred bucks. Somewhat similar to the 3.5's in sonic signature, but also somewhat easier to drive. Other than perhaps for some amplifiers and to a lesser extant some speaker cables, upstream components would suit both equally well. If and when considering, do make sure to inspect the drivers. Though the CS 2's might have been Thiel's most durable models, I've seen examples of unscrupulous sellers passing off other drivers as OEM. The CS 2's somewhat unique grills, which perhaps more so than any other Thiel model needs to be in place when used, have additional and rather sturdy double sided tape attached to the baffle. At first it might seem as though the grills can't be removed, but they can. Be sure to inspect that the drivers are genuine Thiel's. All in all the CS 2's might make transitioning back to 3.5's when circumstances permit rather easy. |
I haven't made such an experiment of comparing separated cables compared to those of close proximity. It's interesting that so many manufacturer's use close proximity for their speaker cables, whether they use twisted, braided, co-axially, compressed or layered approaches as in Jim Thiel's later preferred Goertz Alpha-Cores; that probably have the maximum close proximity possible. |
@vari66robert, It seems as though many manufacturers of speaker cables have taken to additional effort to bring conductors as close as possible, going beyond merely efficiency of packaging. Brands like Vandersteen suggest separate bi-wire runs of speaker cable, not that much different than separate conductors for single terminal runs. |
David, welcome! In answer to your question as to why more Thiel users don't use pure Class A amplification: cost. And heat. To my ears, though typically advantageous, Class A is not the only criterion of the many upon which an amplifier's sound is determined. Jim Thiel's power recommendations were based upon standard solid state 8 Ohm ratings (with a level of quality expected), where it could be assumed that the power doubled down as impedance halved, not the impedance load of the specific speaker. Let's take your 3.7's https://www.stereophile.com/content/thiel-cs37-loudspeaker-specifications for example: with power recommendations given as 100 - 600 Watts per channel. Of course actual power needs will vary with rooms and desired volume levels amongst other things. But, for the sake of this post, let's fall on the old audiophile axiom that one should first consider starting with double the minimum power recommendation, which in the case of the 3.7's would be 200 Watts per channel. 200 Watts per channel of pure Class A amplification comes with some expense. Many high quality amps runs their bias towards Class A before sliding into Class AB. For example I run my 3.5's with their recommend power of 50 Watts minimum 250 Watts maximum (with hints of 300 Watts max). My Threshold amplifier is rated at 250 Watts (8 Ohm) per channel. The first 20% (50 Watts) biased towards Class A, then sliding into Class AB. Now into my 3.5's 4 Ohm minimum impedance; as the impedance is halved, the power doubles to 500 Watts per channel, but the Class A bias output is halved to 25 Watts per channel. This not only true for some Class AB amps. Some amps that claim pure Class A output really only do so in their standard 8 Ohm rating, but as the impedance halves and the power levels double; their Class A outputs halve as well, with the increased power correspondingly sliding into Class AB. https://www.stereophile.com/content/threshold-stasis-sa12e-power-amplifier-page-2 Of course some amps that tout pure Class A output, really don't. https://www.stereophile.com/content/krell-ksa-250-power-amplifier-when-class-class We know that power consumption is not linear but rather exponential, and musical content can demand many, many times it's nominal power requirements. I haven't measured the bias output, but I suspect that much of the time my amp is behaving towards Class A bias. But now with the capability to cruise at 500 Watts per channel all day long (with short term headroom doubling that to 1000 Watts per channel). Now some might suggest that some of these power recommendations into actual impedances are outrageously high. To those may I remind them that with Thiel's and most typical speakers for that matter, that as impedances drop and power output increases that speaker sensitivity decreases correspondingly. So for general comparisons one might see the wisdom of the standard 8 Ohm ratings. Or not? Would I prefer more Class A output? Probably, double that would be dandy. All 500 Watts per channel into 4 Ohms Class A? Sure! But, for my money I'd probably move up the line in speakers first, and settle on less Class A output with Thiel CS 5i's. Thiel's weren't made as cost no object super premium products, though in their time the CS 5's were knocking on the door. Given the cost of pure Class A with enough power to drive most Thiel's, some of which approach 2 Ohms (and some with challenging phase angles), I think many might find the money might be better off spent elsewhere. For example with the 3.7's, and given enough room, I can easily see someone spending the money on Thiel's own subwoofers before committing the funds towards up to 600 Watts of pure Class A amplification (if you could find it). As a general guide (and with adequate funds available), perhaps a reasonable starting point might be amplification meeting the minimum power recommendation with Class A and the maximum into power recommendation sliding into Class AB. If one could afford to provide the maximum power recommendation all in pure Class A output into actual minimum impedance load, perhaps all the better. But be prepared to pay! |
Hi David, please accept my apologies if I wasn't clear in my previous post. As for the Pass Lab users not using Pass Labs X amps instead of Pass Labs XA amps, every Thiel user I know that asked for guidance directly from Pass Labs has reported that Pass Labs has suggested that the X's would better serve Thiel's, with X250 and X350 with their various "." derivations most commonly recommended. Yes, there are truly pure Class A amps that can double down while maintaining Class A all the while (the early Mark Levinson ML2 w/ 25 Watts output certainly jumps to mind). I was merely trying to make a generalized comment to a larger audience that might mistakenly believe that all amps that tout Class A, don't necessarily do so all the time. If I recall correctly the Aragon mono's dropped all Class A output below 8 Ohms despite being touted as pure Class A. I remember another manufacturer of a very highly regarded amp admitted when pressed that despite claims to the contrary, that his amps weren't really Class A and argued that it made no difference except in the market place perception. The current Pass Labs XA's aren't really pure Class A, as they provide extra Class AB Watts when power demands require it. To their their credit they only advertise the true Class A output, but unfortunately some leave thinking that these (advertised) relatively low output amps prove that extra power isn't necessary and/or that Class A is more powerful than Class AB. Doubling the minimum recommended power is not my axiom. I've been at this for a few decades and it existed long before I became involved. Which is why I chose to use it previously. It is merely a long used generally accepted starting guide. I do believe that time has been kind to this guide, and though one might find less or more power might be required, and as difficult as it is find any specific guide I've found this one to be especially helpful as a general starting point. Heck, I can remember a time when 200 Watts was a broad brushed minimum recommendation for a serious system. That I think is an over simplification. As for an amp being able to handle a 2 Ohm load, keep in mind this is more of a prerequisite with some Thiel's (especially at lower power outputs) if one cares a whit for frequency and amplitude linearity. Despite what might appear to be technically true, the 200 Watts that your Accuphase puts out at 2 Ohms is really not so different than 50 Watts into 8 Ohms. Which really isn't all that much. Now in a smaller rooms playing music without much in the way of dynamic contrast such as much small choral works or chamber music 50 Watts might be more than enough, but for realistic symphonic music in larger rooms it might be lacking. There's a reason Jim Thiel allowed his loudspeakers to handle such big power inputs, Many other speaker manufactures discourage such power, as their speakers can't handle it. Sure one can get sounds out of most any Thiel with even the most low budget low powered amplifiers, but if one wants all that Thiel's are capable of, then more high quality Watts are needed. The halving of Class A output with impedance drops isn't really all that much of a problem. I just pointed it out because many attribute the sound of some amps due to their Class A output, when if fact it might be due to something else. Most of the time our speakers really don't require that much power. It's really only when things get loud do the speakers drink up copious Watts. But then the demands really ramp up. The thing is that as things get loud our ears aren't as sensitive to all the delicacies', that is until real distortions start to rear their ugliness. Personally I'd rather deal with an adequately powered Class AB amplifiers cross-over distortion than even the impending clipping of an underpowered Class A amp. Especially with solid state amplification. That is not to say I'm suggesting tubes with Thiel's, I don't. Though some do. I do think we're really much more in agreement than not. I was not specifically trying to tell you what to do, or what to use, but rather to offer a more generalized response to a larger audience for your rather good question. I used to often say that we all hear differently, but I now realize that it's probably more correct to say we all listen differently. I don't like to argue with success; if your happy, enjoy! |
Jafant, I was shopping for speakers for a while, visiting all the brick & mortars in NYC. It originally came down to Maggie III’s or Vandy 2’s. Just when I decided on the Vandy’s and went to put my money down, the dealer pulled out the Thiels. I was really torn at first, but the more I listened the more appealing the Thiel’s became. I really wanted the 3.5’s but they were really beyond my budget at the time. I was starting from scratch and needed everything else too . Happily settled on the CS 2’s. When I moved from my NYC apartment to a house with a larger dedicated room, the used market had expanded dramatically and was able to track down a pair of 3.5’s not too far away. Of course as is the want of audiophiles, I soon replaced everything else except interconnects. |
Jafant, I was shopping for speakers for a while, visiting all the brick & mortars in NYC. It originally came down to Maggie III’s or Vandy 2’s. Just when I decided on the Vandy’s and went to put my money down, the dealer pulled out the Thiels. I was really torn at first, but the more I listened the more appealing the Thiel’s became. I really wanted the 3.5’s but they were really beyond my budget at the time. I was starting from scratch and needed everything else too . Happily settled on the CS 2’s. When I moved from my NYC apartment to a house with a larger dedicated room, the used market had expanded dramatically and was able to track down a pair of 3.5’s not too far away. Of course as is the want of audiophiles, I soon replaced everything else except interconnects. |
This seemed germane to recent discussion here: https://forum.audiogon.com/discussions/speaker-cable-geometry-question |
Thiel Audio used to diplomatically recommend a few cable manufacturers. Amongst them were the OCOS. I’m curious what Thiel users experience with them might be? I believe @pops has tried them. In the past, he like myself have found the Goertz Alpha-Core and Straightwire Maestros to be amongst the best tried. I would be especially interested in comparisons of those three, as well as others to those. |
@arvincastro, Alpha-Core offers (ed?) a free trial, with only shipping costs to be incurred. There is no sound reason not to use the RC networks (zobels) and they are only used to keep some amplifiers from going into oscillation. I strongly suggest using the RC networks! The original flat MI (copper) and AG ( silver) seem to be the preferred sounding versions. The later twisted runs are reputed to be more durable. The silver spades also seem to be the preferred terminations. Alpha-Core used to recommend the series #’s 1, 2 , 3 based upon amplifier output. I seem to remember recommendations of up to 150 Watts for the 1’s, up to 250 Watts for the 2’s and the 3’s for 250 Watts and up. The MI’s due to materials used are much less expensive than the AG’s. Whether or not one prefers MI’s (copper) or AG’s (silver) will come down to personal taste and budget, The specs are quite similar. FYI, all of the above refers to the speaker cables only. |