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Old 11th May 2010, 01:19 PM   #1311
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The PSG buffer is my version of your B1 symetrical buffer. It is DC coupled and uses the LSK389C for good matching and higher class A. I also designed a balanced to unbalanced converter with two of this buffers and a diffential amp based on the AD797.
I put the PSG buffer in a system of a friend for example that has an Audio Aero player.
We cranked the volume control of the CD player full and added the buffer. The sound gained in emotional quality much. It had a bigger and better focussed soudstage, dynamics got up, tonal colours where much more fleshed out. Many people that heard before and after the modification where extemely pleased with the result.
First one ceveat : when i talk about " carefully designed distortion" i do not mean drastic measures that are taken for example in the recording studio. I talk about harmonic distortion that is less then -60dB in level. 0.1% second harmonic does not sound like distortion, listening tests done as early as the 50th have proven that. Rather
what i hear is a kind of fleshing out of tonal colours, especially if CD is the source.
Salas and i have speculated before about what could be the reason. Could distortion cancelation be at work ? Could the overtones created by the buffer extent the frequency response sujectively by adding artificial but natural sounding information that is lost in the recording and playback chain ? Could we interpret harmonic distortion as a kind of DC shift that makes the loudspeaker more easy to moove out of it´s zerro position ? Anyway, the word we coined is "Analog Dither" and more research is needed to understand what is going on. In the meantime i enjoy the positive effect it can have to the sound. Do not understand me wrong, i hate distortion and fumbling around with a delicate signal. I just whould like to throw into the discussion the notion that we do not life in an ideal world. Recordings are not ideal, so are rooms and speakers. As far as amplifiers go, they can be made vitually perfect.
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Old 11th May 2010, 01:35 PM   #1312
Salas is online now Salas  Greece
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This kind of buffer ups its (very small) distortion little by little with input level. Mainly even. The JLH type compound JFET BJT follower holds better THD with level but ups odd harmonics. Has 2 more elements and a trimmer in signal line. Which one you prefer in a situation like after Aero? Did you actually test? I think you had one like JLH in a phones amp at least.
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Old 11th May 2010, 02:01 PM   #1313
Salas is online now Salas  Greece
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P.S. I got DCB1 in two builds. One with series regs (two small plastic boxes one just has the trafo), and one with shunt regs. It listens a lot to supply intrinsic quality.
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File Type: jpg DCB1Mezmerize.jpg (261.5 KB, 315 views)
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Old 11th May 2010, 04:10 PM   #1314
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I am using the JLH now most of the time and use the PSG buffer only when i need it, soundwise that is. I have rebuild my HeadPhone Amp with my version of the JLH and the sound difference was smaller then i expected. Maybe the JLH is slightly more tranparent and it is cheaper to build. A PSG could of cause be build with selected 2SK170.
In our JOSI discrete OPamp we use a modified version of the buffer that has more current drive and is even faster and has lower distortion. The trimmer has been ommitted because we use a servo.
I will put more information about the JOSI on this thread when the layout is ready and we have build it. Simulation looks very good. Thanks to Sigurd Ruschkowski that did the simulation and added some important improvements.
Layout will be done by the one and only Janneman, he also designed the servo.
The Josi is diffential and is not designed for the lowest voltage noise posible.
We focussed more on speed and low distortion. It´s 2nV/QHz is fine for MM but for a low output MC it can be bettered. That is the reason i designed an ultra low noise version. It is parallel symmetric and has around 0.3nV/QHz,
the limit of what i can design at room temperature. It should work even better then the High Z MPP because it has better PSU rejection, a buffer that can drive heavy loads and better silicon. A servo can be added and i am also working on a NFB version. The version shown is open loop and uses my older JLH design because it will not drive heavy loads.
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Old 11th May 2010, 05:59 PM   #1315
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I forgot the PSU. It can be from +-12V to +-15V. I use a battery with decoupling.
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Old 11th May 2010, 08:24 PM   #1316
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Quote:
Originally Posted by Joachim Gerhard View Post
I forgot the PSU. It can be from +-12V to +-15V. I use a battery with decoupling.
Hello Joachim

Thanks for clearing up the the thing about solid state amplifiers , your main issue is trying to improve the sound quality of poorly recorded material through the use of outboard hardware with a particular THD profile.

I cant find out anything about the Berentzen amplifier on the net.

What is your CD source namely CD player , DAC setup.

Your battery power supply uses decoupling may I ask what value decoupling you use and brand and type of capacitor.

Regards
Arthur
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Old 11th May 2010, 08:35 PM   #1317
Salas is online now Salas  Greece
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Blue LEDs without a filter for base voltage of the first stage cascodes? Blue are much more noisier than IR and red. Second stage's red LEDs with PSU tied RC filter, couldn't be the case for 1st stage too? Also what are Is1, Is2, something like LM334s?
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Old 11th May 2010, 09:12 PM   #1318
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My CD player is a Forsell Air Reference with the latest Hörwege DAC. I listened a lot to cables, mechanical decoupling etc. so the setup is a bit hard to describe. It brings out the best on CD namely speed, stability, raw dynamics etc. I did not find much time to listen to CD the last 6 month because i focussed on phonostages.
Berentzen has a webpage. Maybe you could try www.berentzenaudio.de or try Berentzen Audio in google.
Salas, this is more of a concept. I am dicussing this issue with Sigurd all the time and he hates elcaps. Lets see what works best. The current sources are J511 or something like that. I heard they are now obsolete because of ROHS.
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Old 11th May 2010, 09:15 PM   #1319
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Here i have it, i spelled the name wrong, i get old.

Berendsen Audio
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Old 11th May 2010, 10:04 PM   #1320
PHEONIX is offline PHEONIX  Australia
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Originally Posted by Joachim Gerhard View Post
Here i have it, i spelled the name wrong, i get old.

Berendsen Audio
Thank you for link.

Your battery power supply uses decoupling may I ask what value decoupling you use and brand and type of capacitor. or is this a secret .

Regards
Arthur
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