47000$ Headphone amp with no resistors or capacitors - Page 1
Forum section: electronics / general

author: iampoor
author_rank: Frequent Contributor
timestamp: April 11, 2014, 04:08:07 am
content: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=231198367845&ssPageName=ADME:X:AAQ:US:1123Could this even work?Class A with no bias resistor?

author: TheBorg
author_rank: Frequent Contributor
timestamp: April 11, 2014, 04:14:42 am
content: Don't worry, you can buy theschematicfor only $47!!!

author: pickle9000
author_rank: Super Contributor
timestamp: April 11, 2014, 04:20:38 am
content: Quote from: iampoor on April 11, 2014, 04:08:07 amIt does not come with a resistor, you need lick two fingers a place them in the appropriate locations.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 11, 2014, 04:25:18 am
content: S. Bench did a few:http://www.jacmusic.com/techcorner/SBENCH-PAGES/sbench101/#PowerAmpsNothing wrong with it, just a matter of arranging it so the bias range is okay. Also takes a shitload of transformers to do rightTim

author: pickle9000
author_rank: Super Contributor
timestamp: April 11, 2014, 04:46:37 am
content: To be honest I haven't touched a tube in over 40 years. It is interesting.I still think the finger touching would be funny / potentially deadly of course.That price is amazing.

author: GreyWoolfe
author_rank: Unknown
timestamp: April 11, 2014, 02:36:44 pm
content: Forget the amazing price, there are actually 2 watchers!!!!!!!!!!! For that price, it should come with a couple of the ladies of the evening to clean your tubes for a year!

author: linux-works
author_rank: Super Contributor
timestamp: April 11, 2014, 02:51:56 pm
content: inside those tubes are hidden lm741's and silver band carbon resistors.lol

author: kolbep
author_rank: Frequent Contributor
timestamp: April 11, 2014, 03:07:22 pm
content: Maybe it is a Unity gain amplifier. The Battery connection is just to make the filaments glow, giving that warm feeling. but then the In and Outs are probably just tied together.But for the price, maybe they cut open the tubes, and put an Opamp in each of them, and an orange LED for the same effect.

author: wraper
author_rank: Unknown
timestamp: April 11, 2014, 03:52:00 pm
content: Quote from: kolbep on April 11, 2014, 03:07:22 pmSeems to be. Two filaments in series connected to the 12 V battery as there are no other power connections. He also wrote that it works only with high resistance headphones, no wonder why. I think this guy is trolling audiophools.

author: linux-works
author_rank: Super Contributor
timestamp: April 11, 2014, 03:55:42 pm
content: if the phones are high-z, then they will need a higher voltage across them to make the same volume. I have high-z phones (sennheiser) and I need a good dual 15 or even dual 24 (one of my amps is dual 30) to get enough volts across them to drive them properly.mostly, you don't need voltage gain for phones, though; you need current gain (drive). but still, 12v (if that's all he has) is a bit absurd if you are talking about high-z phones.

author: wraper
author_rank: Unknown
timestamp: April 11, 2014, 04:58:17 pm
content: Wrote him a message:Are you trolling audiophools? Seems that input and output is directly connected and battery is for glowing filaments.Reply:Hello,Forget what you think and please read feedback on eBay's profile.You are right. It sounds like a wire connected from input to output but with power gain. But when fillaments start to fade away, music fades too. And when you switch on and they begin to glow, music happens, and there's magic in music, and you feel beauty...Best regards,Aetoulis

author: linux-works
author_rank: Super Contributor
timestamp: April 11, 2014, 05:07:21 pm
content: you 'feel beauty'?for $47k, I would hope this includes a free 'happy ending'. yeah, feelin' some beauty there, lol!

author: miguelvp
author_rank: Super Contributor
timestamp: April 11, 2014, 05:40:13 pm
content: Well, when I saw the comments on the auction he says that the prices is and is not a typo and that he will sell the schematic for $49.So it seems the auction is the hook, making the user check the profile (the line) and the schematic is the sinker

author: eliocor
author_rank: Unknown
timestamp: April 11, 2014, 06:31:02 pm
content: Just a question (I do not know how to check it)...Was the auction started on the first of April?

author: Aldobrandi
author_rank: Regular Contributor
timestamp: April 11, 2014, 06:35:07 pm
content: Oh wait, I think I recognize this guy, it is one of these class B.S. amplifier. They supposedly have high chromatic rendition achieved by sub-quantum charging of the "inventor's" dead brain. The only problem with them (which can actually be a bonus for some) is that they make your entire house smell like bacon

author: linux-works
author_rank: Super Contributor
timestamp: April 11, 2014, 06:37:13 pm
content: aha! its BDA based (bacon-defined amplification).I can smell theswine-wavesall the way from here!hahaha

author: Aldobrandi
author_rank: Regular Contributor
timestamp: April 11, 2014, 06:38:53 pm
content: Quote from: linux-works on April 11, 2014, 06:37:13 pm

author: The Electrician
author_rank: Frequent Contributor
timestamp: April 11, 2014, 07:02:46 pm
content: Holy crap!!!Look at his "other items" on eBay!!

author: wraper
author_rank: Unknown
timestamp: April 11, 2014, 07:15:28 pm
content: http://www.ebay.com/itm/Tube-600-Ohm-Headphone-Amplifier-for-Sennheiser-HD-580-650-AKG-K240-Beyer-DT-990-/331174282190?pt=US_Pro_Audio_Amplifiers&hash=item4d1b8683ceOne more listing. The same "amp" but with one pot. Driven by ipod

author: GreyWoolfe
author_rank: Unknown
timestamp: April 11, 2014, 10:16:18 pm
content: Quote from: Aldobrandi on April 11, 2014, 06:35:07 pmMmmmmmmmmmmmmmmmmmm, greasy pork products!

author: tom66
author_rank: Super Contributor
timestamp: April 11, 2014, 10:45:16 pm
content: I don't understand the point of this. Virtually any source is going to be full of icky resistors, capacitors and "gasp" transistors... so how the hell does two tubes matter? Even to the stupid audiophile do they think their iPod or CD player exclusively uses tubes only??

author: N2IXK
author_rank: Frequent Contributor
timestamp: April 11, 2014, 10:52:59 pm
content: Quote from: tom66 on April 11, 2014, 10:45:16 pmYou mean they don't? Guess they save the tubes for more important jobs, like running supercomputers....http://www.ominous-valve.com/vtsc.htmlTake the virtual tour--- great stuff. Maybe Dave can visit for a teardown video?

author: iampoor
author_rank: Frequent Contributor
timestamp: April 12, 2014, 12:05:46 am
content: Quote from: tom66 on April 11, 2014, 10:45:16 pmOr the fact that the must was recorded through a signal path with hundreds of opamps.