Author Topic: How to Build a killer Amp  (Read 44254 times)

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #120 on: October 31, 2012, 10:54:17 PM »
Steve, the output from these amps is only 40 watts class A.  The HT voltage is 1250 volts.  14 volts dc at 6 amps on the heaters.  

Peter
Peter. Well they are only tiny then.  Only 37 watts more than mine, amazing amps.  Can you give more info on them.
« Last Edit: October 31, 2012, 10:56:47 PM by stevenvalve »

Offline kajak12

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Re: How to Build a killer Amp
« Reply #121 on: November 01, 2012, 12:30:12 AM »
Steve, the output from these amps is only 40 watts class A.  The HT voltage is 1250 volts.  14 volts dc at 6 amps on the heaters. 

Peter
1250v  life insurance recommended to work on them
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline Peter A

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Re: How to Build a killer Amp
« Reply #122 on: November 01, 2012, 09:29:39 PM »
The STC 4212E amp tube complement:  Mullard E80CC for the input tubes, TT21 GEC tube for the interstage tube and STC 4212E tube for the output tube.  There are four RCA 5R5GY tubes as a bridge rectifier for supplying HT of the 4212E tube.  These is also one 5R4GY tube supplying rectification for the TT21 and E80CC tubes.  See attached picture for the amplifier circuit.  Donald Tan from Brisbane helped me with drawing up the circuit. 

Lucas Cant from Blackart Audio in Melbourne made the two mono STC 4212E amps.  All Power, Choke, Interstage and Output Transformers were designed and manufactured by Lucas.  It was a labour of love or hate for Lucas to design and build.  This is an original tube design for the 4212E tube. 

Steve, Graham and Craig have all listened to my system and they can describe the sound they heard when I changed the tube in the DIYHIFI Supply Tram2 Pre-amp to a RCA 45 tube.  Over to you Steve.

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #123 on: November 02, 2012, 02:34:22 PM »
Listening to these unique power amps, was one of the highlights of my Queensland visit. What do you get from amps like this, A single ended sound with all the benefits of power. These amps have a lot of power and you can hear it in its relaxed presentation, so liquid you can cut it with a knife, a huge sound stage with max body and warmth that envelopes you in the music without a hint of strain, a wall of sound that you really can immerse yourself in. I think that a great plus for this type of amp is that you can drive most speakers on the planet and do not have to worry about efficient drivers. One draw back is the price of these tubes (STC4212Es) I wonder how expensive the western electric (212E) versions are.
« Last Edit: November 02, 2012, 02:49:13 PM by stevenvalve »

tuyen

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Re: How to Build a killer Amp
« Reply #124 on: November 02, 2012, 02:49:10 PM »
Awesome looking units. Thanks for sharing Peter and Steve.

Your experience mimics how I felt when listened to amps at Feastrex that use the Telefunken RV25 tubes.   Photos below for you tube lovers















« Last Edit: November 02, 2012, 05:44:42 PM by tuyen »

Offline Peter A

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Re: How to Build a killer Amp
« Reply #125 on: November 02, 2012, 06:05:24 PM »
Very nice amps.  A top cap to boot.  My top capped NOS GEC TT21 tetrode sounds so much better than the NOS GEC KT88 tube in the 4212E amp.   

For Steve, have a look at:

http://www.ebay.com/itm/Western-Electric-212D-Power-Triode-Tube-/150933327772?pt=Vintage_Electronics_R2&hash=item232453cf9c

Steve, have you contacted David Crittle regarding the STC 4212E tubes.  If so, what is his price for this mighty tube.

Steve, thanks for the glowing opinion of my audio system.    It's a step up from my old 45 tube amp. 

Peter

Offline Peter A

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Re: How to Build a killer Amp
« Reply #126 on: November 02, 2012, 06:15:32 PM »
I forgot to mention, the interconnects and speaker cables used when Steve auditioned my STC 4212E system comes from the Keith Eichmann Innovations and not ETI-research.  Keith has released a range of interconnects and speaker cables.  Keith was very kind to lend them to me for my audio afternoon a few months ago and when Steve, Graham and Craig heard my system.

Peter

tuyen

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Re: How to Build a killer Amp
« Reply #127 on: November 02, 2012, 06:54:30 PM »
Very kind of you for sharing info and schematics of amp to all Peter.   Any photos of amp innards? As I'm sure you know that stuff is what gets some of us excited around here :)

Also what speakers are those that you are using? Look really nice and the extra subwoofers are active?
« Last Edit: November 02, 2012, 06:56:02 PM by tuyen »

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #128 on: November 02, 2012, 07:37:38 PM »
I forgot to mention, the interconnects and speaker cables used when Steve auditioned my STC 4212E system comes from the Keith Eichmann Innovations and not ETI-research.  Keith has released a range of interconnects and speaker cables.  Keith was very kind to lend them to me for my audio afternoon a few months ago and when Steve, Graham and Craig heard my system.

Peter
I can only imagine what they sounded like when you where using Craigs Wadia transport plus killerdac.
« Last Edit: November 02, 2012, 07:39:50 PM by stevenvalve »

Offline Peter A

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Re: How to Build a killer Amp
« Reply #129 on: November 02, 2012, 08:17:11 PM »
With Craig's Wadia and Killerdac the sound was a lot better an what you heard with the Njoe Tjoeb CD Player.  I loved the sound of the Wadia and Killerdac over my Njoe Tjoeb CD player.  Everyone at my audio meeting listened to the music.  That is a very good indication of the very good sound of a system.

Craig, what are your thoughts.

Peter

Offline gamve

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Re: How to Build a killer Amp
« Reply #130 on: November 02, 2012, 09:20:35 PM »
Hi Peter,
Thanks again for having us around to listen to your very individual system. I can only add to Steve's comments about the experience. I enjoyed the powerful effortless and liquid delivery these huge amps provide. Your speaker choice worked very well and seemed well suited to the amps. I thought your tube output CD player acquitted itself very well but I can only imagine how the system sounded with Craig's Wadia and Killerdac in the system. It's a pity there was a noise with the 2A3 monoplates but the Tram 2 fitted with the RCA 45's brought the system even more alive regardless. It's been some journey for you getting these monsters up and running and I admire your dedication with the project. Thanks again for the chance to hear your system.
Cheers
Graham

Offline Peter A

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Re: How to Build a killer Amp
« Reply #131 on: November 02, 2012, 09:50:20 PM »
The speakers I am using are from New Zealand.  They are: http://www.imageloudspeakers.com/products/revelation.asp

For Tuyen.  Some pictures of the internals of my amp.

Thanks Graham for you review response.  

Offline Peter A

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Re: How to Build a killer Amp
« Reply #132 on: November 02, 2012, 09:57:41 PM »
More pictures

tuyen

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Re: How to Build a killer Amp
« Reply #133 on: November 03, 2012, 10:01:28 AM »
Cheers for sharing Peter!   Speakers and amp look great.  I can picture those amps doubling as excellent room heaters for the winter season :)

Offline Peter A

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Re: How to Build a killer Amp
« Reply #134 on: November 03, 2012, 11:17:38 AM »
Tuyen, surprisingly, the amps don't produce alot of heat.  At 14 volts 6 amps equals 74 watt bulb for each STC 4212E tube.  There is only a 2 amp 240 volt slow blow fuse at each power socket for the amps.

Peter

Offline rab

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Re: How to Build a killer Amp
« Reply #135 on: November 03, 2012, 10:11:05 PM »
What beautiful amplifiers! ... Indeed, I recall seeing a pair of similar monoblocks at Lucas' place a few years ago (still being built at the time), and can't help wondering these might be the very same ones...?

- r.

Offline flemo

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Re: How to Build a killer Amp
« Reply #136 on: November 03, 2012, 11:17:31 PM »
Wow, those amps look serious!  Big tubes, big sound!  8)

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #137 on: November 04, 2012, 12:09:52 AM »
What beautiful amplifiers! ... Indeed, I recall seeing a pair of similar monoblocks at Lucas' place a few years ago (still being built at the time), and can't help wondering these might be the very same ones...?

- r.
They most likely are the same. He built them for peter.

Offline Peter A

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Re: How to Build a killer Amp
« Reply #138 on: November 04, 2012, 04:18:36 PM »
These are the same amps.  It took about 10 years for Lucas to build the amps in his spare time.  Lucas said there was a lot of experimentation with getting the interstage and output transformers right. 

I sent two STC 4212E tubes to Lucas, but only one made it in tacked.  The insurance did not cover the tube because I packed it.   Lucas could not listen two them both in stereo.

Lucas did a fantastic job as he had to build them from scatch.  No web plans and previous circuits to copy from.  Lucas rang me indicating he was coming up to Brisbane and he dropped them off.  Not bad for service. 

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #139 on: September 09, 2017, 10:18:18 PM »
Well I am 90% there to getting my ux250 killer amp bits together and feeling very excited.
Thanks Steve for all of your help and wisdom so far.