Bryston: THX for 2 ch - a good thing or not?

Several Bryston amps are available with THX certification and badging at extra cost. Is this a good thing for 2 ch setups?
I recently had an email exchange with an Audiogon seller of a Bryston 8B ST amp. I told him I was also looking at two Bryston 8B ST THXs on eBay. He related to me an opinion he had heard that the ST THX versions were somehow inferior to the ST versions. Was he just hyping his amp or is there something to this allegation?
I googled this issue every which way without much satisfaction. One source mentioned that the THX stardard required expanded dynamic headroom, which sounds like a good thing, but doesn't the ST version also meet this requirement?
I spoke to a Bryston designer at the factory in Peterborough some months ago, before the current question became an issue for me. I got the impression from him that the THX versions were just the ST/SST versions with THX certification and badging, for which Bryston had to pay Lucas for the priviledge. Therefore, amps were certificed as THX compliant more for marketing reasons than due to any design modifications, except perhaps for some features (like a different input gain for the THXs).
Bottom line, is there any reason I should avoid THX versions for 2 ch listening? Are they better, worse, or just about the same?
I'd be anxious to see if this is even worth worrying about. Buying used, shouldn't age, condition, model, proximity of seller etc. be much more important then if it has a THX logo on it? I see Monster selling really cheap cables badged THX and believe they're junk. But sure enough, the big box retailer's salesperson is quick to point that THX certification a reason for spending a little more on them.

Hope you don't miss a perfect Bryston amp for you worrying about this.
They are the same amps. Whether THX or not, a 3B ST is a 3B ST from all I have known. They meet the standard easily in stock form. Try the Bryston owners circle at for more clarity. In fact James Tanner (VP at Bryston)may have already answered this question.
THX is simply a licensing certification that an amp meets certain operating conditions, and has nothing to do with the design of the amp. As the previous two posts indicate, the "ST" and "SST" amps comply with the THX certification requirements, and Bryston had to pay for right to use the logo. I own a Bryston pre-pro and two of their amps, and find them excellent for both music and home theater. Don't worry about the THX version -- the "regular" Bryston amps work just fine.
I agree with Sailfishben, Mcfavre4 & Sdcampbell. Whether THX or not, it's not worth worrying about if ST/SST versions are in fact exactly the same as the THXs.
However, have a look at the following from an item currently for sale as "Bryston 4BST - Thx
RE: THX certification taken from Bryston website....

New Standards of Accuracy:The Bryston THX amplifiers incorporate the use of an innovative gain stage topology, which yields the quietest possible noise floor through the use of low-impedance pathways within the amplifier. This approach also has strong advantages in improving overall distortion performance. Bryston's computer-controlled distortion analyzers confirm intermodulation distortion levels less than 10 parts per million (below 0.0009%) are typical for this new circuitry."
Doesn't that imply that this THX amp is superior to a 4BST without THX? It's totally misleading if everything claimed for the THX also applies to the 4BST. So why would, or should, anyone pay a premium price to get the THX badge on their amp? I agree that they shouldn't, but I still have an open mind on the topic if anyone out there has evidence to the contrary.
BTW Mcfavre4 I tried but it doesn't seem to be an active site.
Mcfavre4: I found the site at (w/o the plural "s" and certainly not my mispelled "audiocirles"), but haven't found Tanner's comments on THX. Thanks for the suggestion. I am very impressed that Bryston and Tanner are so supportive of the Bryston owners' community.
Sorry for the bad address. I think the same statements above could be made for the ST version as the ST version is the same THX version. They are just promoting the THX badge. I don't think the versions had a price difference though I'm not sure. I am pretty confident there is no difference other than the badge. I have a 3B ST THX, have owned the B100 SST and still have a B60R. All are great amps. I'm certain the 8BST in both incarnations is the same great design. Everyones source, speakers and pre have lot more to do with the ultimate sonics vs a THX badge. To add confusion, some NRB versions also came badged as THX certified. Therefore you cannot assume a THX version of a Bryston is superior or inferior. Its the NRB, ST or SST that makes a difference.
I am very hazy on what I remember having read before about this. I thought the difference was that the THX had an extra connection on the back of it so it could be turned on by relay when a home theater preamp was turned on. feel free to correct me. i have a regular st series, but check to see if you can find pics of the back of both as ST and ST THX and see if there are any connection differences.
Bryston's online manual for the 3/4/5/7/8B STs includes drawings of the rear of the units, which indicate that the 5/8B STs have the power on/off function, whereas the 3/4/7B STs don't, and the 8B ST THX does.
The manual also refers to this function as being optional, so I suspect you could order it on a non-THX ST version.
A Bryston brochure also says "All ST amplifiers are available in THX version, include remote power on/off function."
The implication of this to me, as someone searching eBay, Audiogon, etc. for a Bryston power amp, is to make sure I ask the seller of non-THX versions if this feature is present or not. I have a Bryston pre-amp with it, so I would definitely want it.
The upshot is it seems I don't have to be concerned that the THX versions contain any design trade offs to comply with the THX standard that would effect my listening experience in 2 ch listening.
BTW I recall a posting on one of the forums where Tanner (Bryston VP) was commenting on a similar issue: the difference between base and pro versions. He said (in my own words from memory, since I can't find that posting right now) there was no fundamental difference, other than the pro version having a feature to attenuate the incoming signals to facilitate matching amp gains. He cautioned those who prefer a purer signal path (w/o attenuation electronics/switches) should stay with the non-pro version.
Remember the "Gold Record Award" label that was stuck on high selling LPs many years ago? These met the marketing ctiteria for units sold. Here we have amp specs that meet minimum criteria; same thing. Another stupid marketing sticker just like "digital ready" headphones and speakers.
10 years late but I feel like contributing my 2 cents to this thread.

I have owned the 7B ST's, 7B THX's, 7B SST2's, a 4B THX and a couple of very old 4B pros.

In short, I found that the Bryston THX amps performed noticeably differently than the non THX versions and is more than just a marketing scheme. 

To my musical tastes I would say the THX's sounded better. More dynamic, more weight in the bass, lots of midrange presence and I would even dare say a tad on the warm side. The 7B THX's drove my big subs way better than the 7B ST's. They had some serious punch.

Currently I have a 4B THX in my system and it is substituting for my Threshold T-400 which is in the shop for some repairs. Before I "Pass" my final judgement in the Threshold I will wait for it to return to my rig with a clean bill of health but for half the price the 4B THX could very well become my preferred amp.