Mpp

[Ghianni]

Phantastic photos by the way

Yes indeed! he used a x.xxx $ pro-camera...But the reason is that your gear is great.

[Morfeus]

Originally Posted by Joachim Gerhard

I will come to the Frickelfest.

Great, Joachim!

I am following this thread from the beginning and I am very curious to hear your pre.

Looking forward to see you there.

Heinz

[Joachim Gerhard]

I am working on the Balanced-In, Balanced-Out, Instrumentation, Inductive RIAA for several days now. It is quite a complex beast and much more delicate work than i thought. For my own use i am building a Low Z version because i simply like the slam and drahma circuits like that provide. The input stage of one channel is ready. I have not closed the feedback loop yet. I wait unil tomorrow and will chek everythig double.
I hate to see smoke or OPamps with red ears. I will post some photos later and will stop to build today. I need a rest.
P.S.: I am looking forward to see you Heinz. I hope to bring a complete DIY system.
What is still missing is a poweramp. I am collecting ideas. Maybe something single ended Cass A or let´s see what Brianco is getting together.

[Joachim Gerhard]

Here are some photos of the input stage. Sorry for the poor quality. My camera is not very good at night in the nearfield.

[Audiofanatic]

Hi Joachim,

It seems like a tube amp kind of circuit the way you put things together

I'm curious about the sound, I'm still busy rebuilding my home, otherwise I'd make a copy of your amp to try it out

I'm going to bed now, it's late again.

Cheers,


Audiofanatic (José)

[Joachim Gerhard]

It´s a novel topology with advantages i hope. Needs only one coil for balanced.
I will publish the circuit when it works. To do this with tubes whould be imposible but i use this "dead bug" groudplane style all the time now. No problem with hum and easy to change and repair.
Somebody is now also working on PCB´s for some circuits i consider finished.
I hope they turn out well and make building easier.

[Joachim Gerhard]

I have now 130 Ohm and 300 Ohm resistors from Simon that measured well ( see Blowtorch thread) and i got 138 Ohm ( recommended by David Wilson for the Lyra Olypos
i have in house) and 300 Ohm naked Z Foils from Sigurt.
I am just building the latest version of the High Z MPP with transimpedance 75usec and capacitive RIAA to make the listening test. I will build that in a proper cabinet.
Dear Salas, i am still not finished with your Shunt but i have all parts now.

[Joachim Gerhard]

Today i did the first round of listening to loading resistors. I am using the latest version of the High Z MPP Transimpedance, Capacitive RIAA. The culmination of 1 year of hard work. It sounds just w........
Picture and circuit included. I use a current and voltage buffer to drive my 5m long cable to my high speed ( 25MHz -3dB) reference preamp. I use my MPL speakers.
The reference resistor is a Dale NS-2B 300 Ohm wirewound. That resistor sounds better then a 1kOhm TX2352 naked foil in my system but i will try a 300 Ohm naked foil tomorrow. So let the cat out of the sack as we say here. The resistor i listened to for comparison is a Dale Mil.Spec. RS65E i got from Simon.
i comfortably trampled the NS-2B. The soundfield with this resistor is much more populated in the midle and tonality is much more homogenious like listening to a full range speaker. There is no doubt any more what kind of instrument is playing. a Flugelhorn is a Flugelhorn and not a trumpet. Distortion is subjectively very low. I know that beacause i can play louder as usual without my right ear starts to distort. Distortion always starts in my right ear first. I think i have to go to the doctor to blow some dirt out. I did that ones and the gain in sound quality was amasing. Voices are magically 3 dimensionally delineated. This resistor is highly recommended and not so expensive. Ceveat : It is BIG. It has a 1/2 watt military rating but it looks more like a 2 watt.

[bocka]

Originally Posted by Joachim Gerhard

i comfortably trampled the NS-2B.

...

Ceveat : It is BIG. It has a 1/2 watt military rating but it looks more like a 2 watt.

Hi Gerhard,

I just took a look into the vishay datasheet. To me it seems this resistor (Vishay NS02B) is rated at 3 watts. I think this is the reason why it is such a big one. I've been gone for quite a long time here from diyaudio. Really a nice, straight forward design.

[Joachim Gerhard]

Thanks. Yes, in the commercial world this whould be a 2W or 3W resistor but Mil.Spec.
parts are rated more critical.
This resistor (RS65E) may be good for speakers too. 3W is just enough for a tweeter but we could parallel some for higher wattage.
By the way the NS02B is slightly smaller.