Samsung audio foolery Fake Tubes - Page 1
Forum section: electronics / general

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 03:12:27 am
content: Check this out guys. Did you know the Tubes on a Samsung home theater system don't actually do anything

author: Ampera
author_rank: Super Contributor
timestamp: November 14, 2016, 03:19:48 am
content: Samsung, what are you doing?This is not how you business, this is how you bankrupt.You release a phone that catches fireYou release explosive washersand now you lie about your products.RIP Samsung.

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 03:22:59 am
content: It's audio foolery at its best .

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 03:44:44 am
content: There very big as a company , but I didn't expect this kind of foolery from Samsung

author: Brumby
author_rank: Unknown
timestamp: November 14, 2016, 04:03:54 am
content: It's a gimmick - but not one I would have expected from Samsung.Does any of the promotional material makespecificclaims related to valve performance? ... or is it just the (rather fundamental) misleading presence of the valves?

author: Cubdriver
author_rank: Unknown
timestamp: November 14, 2016, 04:12:11 am
content: It would be interesting to get a look at the bases of the tubes and see if there's actually anything connected to them and if they're truly in the circuit in some way. I'm not quite sure how a pair of dual triodes would be used in a 5+1 amplifier, either. The fact that it seems to output audio without the tubes installed does kind of call into question what exactly they do in the unit...-Pat

author: Cubdriver
author_rank: Unknown
timestamp: November 14, 2016, 04:16:51 am
content: It's a shame that in the video he didn't get a close enough shot of the tubes to determine whether their heaters were actually lit or if the glow was simply coming from the LEDs shining up through the bases. Additionally, if theyareactually operational, it's gonna get mighty hot in that little tiny compartment!-Pat

author: Brumby
author_rank: Unknown
timestamp: November 14, 2016, 04:22:21 am
content: Quote from: Cubdriver on November 14, 2016, 04:12:11 amQuote from: Cubdriver on November 14, 2016, 04:16:51 amThese are two questions I had as well.

author: zipob
author_rank: Newbie
timestamp: November 14, 2016, 04:30:59 am
content: Service manual for similar model:http://download.samygo.tv/Documents/SM-HTE6730W.pdfIt seems there's a bypass circuit if valves go dead.

author: Cubdriver
author_rank: Unknown
timestamp: November 14, 2016, 04:32:51 am
content: I'm alsoVERYimpressed that they can get 165W x 6 ('front', 'front top' and 'surround'; 2/ea) and 170W x 2 (center channel and subwoofer) into 3 ohms out of that tiny device - which has a dataplate on the back that says it draws 127W from the wall.I need to look into this class D stuff - perhaps I could make one that could amplify at 60 Hz and run all the lights in my house on 5W!-Pat

author: Brumby
author_rank: Unknown
timestamp: November 14, 2016, 04:33:11 am
content: So ... in a multi-channel system, which channels are they in?... and would not the other channels suffer with 'non-valve' artefacts?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 14, 2016, 04:33:25 am
content: These guys did it right

author: Brumby
author_rank: Unknown
timestamp: November 14, 2016, 04:35:25 am
content: Quote from: Cubdriver on November 14, 2016, 04:32:51 amOld school marketing BS. Hardly rates a facepalm from me these days.I don't believe a word of it - and always wonder what therealspecs are.

author: BradC
author_rank: Super Contributor
timestamp: November 14, 2016, 04:56:58 am
content: Quote from: blueskull on November 14, 2016, 04:35:03 amFunny, PMPO is how I refer to Chinese CCTV camera specs. It's not a term I hear in common usage anymore, but I saw this a couple of weeks ago in a garage and it made me laugh :Digging the light bulbs inside the "tweeters".

author: Brumby
author_rank: Unknown
timestamp: November 14, 2016, 05:03:30 am
content: Lightbulb tweeters...?Aside from their emissions being electromagnetic - I think the frequency might be a few orders of magnitude too high for my ears.

author: BradC
author_rank: Super Contributor
timestamp: November 14, 2016, 05:11:41 am
content: Quote from: Brumby on November 14, 2016, 05:03:30 amActually, now I think about it I've heard light bulbs sing before. Get the right modulation on the AC and the filament will vibrate. I can only guess against the earths magnetic field. Somehow I don't quite think this was the effect they were after though.On topic, my old man has one of those Samsung amps. We both laughed when he pulled it out of the box. There is no heat generated around the plastic window, so I assume they are just LED backlit. Next time I'm down there I'll see if he'll let me pop the top off. It's out of warranty by now.

author: wraper
author_rank: Unknown
timestamp: November 14, 2016, 06:14:53 am
content: Quote from: BradC on November 14, 2016, 05:11:41 amThose tubes are in audio path and are really working. The other question is if there is any good in them.

author: bobaruni
author_rank: Regular Contributor
timestamp: November 14, 2016, 06:33:27 am
content: Ahhhm Errrrr, the guy doing the reveal on you tube was using the HDMI output for the audio, the valves are in the path of the analog L R (2CH) output only.

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 06:49:55 am
content: Strange as when I spoke to Samsung they claimed the tubes work in any input . They did not say anything about only in aux mode . As I used to sell them when I worked for Joyce mayne. So I'll do a test tonight using auxAs for the heater they do glow but very very dull . They produce a little bit of heat but nothing I compared to the last tube amp I had that used ECC82 valves

author: Cubdriver
author_rank: Unknown
timestamp: November 14, 2016, 06:52:50 am
content: I tried to redraw that stage earlier, but don't recognize the topology off the top of my head...-Pat

author: David Hess
author_rank: Super Contributor
timestamp: November 14, 2016, 07:12:41 am
content: Quote from: Cubdriver on November 14, 2016, 06:52:50 amThat is a shunt feedback amplifier with a constant current load. The upper tube operates as a current source. It would have been a pretty rare configuration simply because it is a waste of one triode.

author: Cubdriver
author_rank: Unknown
timestamp: November 14, 2016, 07:17:58 am
content: That would explain it - that's not something I've ever encountered. I'm used to seeing dual triodes used as phase splitters. I prefer to have the tubes go all the way to the end of the amplifier...-Pat

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 07:41:12 am
content: That's a strange way of going about using tubes . yet they do get warm but not as hot as expect from a pair of tubes

author: David Hess
author_rank: Super Contributor
timestamp: November 14, 2016, 08:22:05 am
content: Quote from: Cubdriver on November 14, 2016, 07:17:58 amAll of the negative shunt feedback and the current source would lower the distortion sort of defeating the purpose of "tube sound" but I am no expert on that subject. I would have expected a simple class-a amplifier but maybe the signal levels were high enough that some feedback was necessary or there would have been too much distortion. One of the tube guys will know.You could duplicate this circuit with JFETs or depletion mode MOSFETs of course but they would not saturate in the same way.

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 10:15:13 am
content: What I'm considering doing is making the front 2 channels full range and actually marking the tube amp dedicated to the pre amp

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 10:25:15 am
content: Ok since some people seem to think I'm using the HDMI out for the sound I'll clarifiyI'm using the speakers that come WITH the system not HDMI digital sound going to a other form of amplification. The Technics 2 channel amp in the video is clearly off .The system sounds the same with the tubes in or out doesn't effect it in any way even using my JBL Ls60s no difference

author: daqq
author_rank: Super Contributor
timestamp: November 14, 2016, 10:25:41 am
content: It's a step in the right direction - it's not self igniting.

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 10:29:06 am
content: I would have expected removing the tubes to lower the output signal from the Samsung speakers but at the same volume levels it doesn't so either they matched the levels perfectly

author: bobaruni
author_rank: Regular Contributor
timestamp: November 14, 2016, 11:31:02 am
content: Quote from: Marinlaw on November 14, 2016, 10:25:15 amLooking at the block diagram, it looks like the VT circuit might be switched in and out of circuit, perhaps by a menu setting or maybe only when a 2ch Audio source is present or maybe it bypasses the valve if the filament is not in circuit (just speculating), if The VT amp is truly there just for looks then this is an absolute scam but psycho-acoustics may make some people feel like it sounds better because there are vacuum tubes in the circuit.

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 12:42:56 pm
content: So in AUX 2 channel mode ( not surround ) tubes in or out sounds no different and volume levels are identical

author: Zbig
author_rank: Frequent Contributor
timestamp: November 14, 2016, 12:53:48 pm
content: Quote from: bobaruni on November 14, 2016, 11:31:02 amThat's not what psychoacoustics is about.

author: Marinlaw
author_rank: Contributor
timestamp: November 14, 2016, 01:04:57 pm
content: So this is what's confusing me there in the signal path but there's a bypass . Anyone know what's going on here . Is this really just foolery

author: Alex Nikitin
author_rank: Super Contributor
timestamp: November 14, 2016, 01:27:43 pm
content: Quote from: David Hess on November 14, 2016, 07:12:41 amIt is actually a SRPP stage (Shunt Regulated Push Pull) and the top valve is not a constant current source.CheersAlex

author: @rt
author_rank: Super Contributor
timestamp: November 14, 2016, 04:16:15 pm
content: They were JJ Electronic new production valves, so can only be one of a few types.

author: David Hess
author_rank: Super Contributor
timestamp: November 14, 2016, 06:42:25 pm
content: Quote from: Marinlaw on November 14, 2016, 10:29:06 amThe voltage gain is about 2 (ratio of 270k to 120k) and with the tube removed it would be about 3/4s (the 120k, 270k, and 1M resistors make a divider) assuming a high impedance load so it is possible that even with the tube circuit inline for all modes, the user would not notice the difference in level.

author: calexanian
author_rank: Super Contributor
timestamp: November 14, 2016, 07:12:59 pm
content: That's a common fail over thing. The feedback loop now is the signal path. The phase of the signal will be reverse of what it was before. Apart from that, yet another product that really does not need tubes. Waste of money.

author: bobaruni
author_rank: Regular Contributor
timestamp: November 15, 2016, 12:09:19 pm
content: Quote from: Zbig on November 14, 2016, 12:53:48 pmWhen the brain overrides what other ears are hearing due to information from other senses such as the eyes, that's part of psychoacoustics.

author: Marinlaw
author_rank: Contributor
timestamp: November 15, 2016, 01:51:31 pm
content: I really think its a case of '' ohh look tubes it must be better '' so it is better . even if its not really doing anything .