... phono stage

jonstanza

Well-Known Member
Apr 9, 2013
35
4
83
Lisbon PT
Dear Sirs

Since kid, always had a passion for vinyl. The pleasure of listening to music is something magical. I decided to design a project for my simple (denon 103R). phono stage. Follows the same philosophy of the power amplifier (thread 04-10-2013, "project... power amplifier ").

The circuit is 100% discreet, not using operational amplifiers. Each channel has two stages of amplification. The (RIAA) is passive and is located between the two stages. The first stage gain, have the selection of gains and also correction of the load Cartridge. The second stage amplifier has a gain of approximately 25 dB to compensate for losses (RIAA).

On the input board, I put a socket for a future alteration of the load value. Small signal circuitry is based on discrete circuit, multiple cascode, output stage consists of powered Mos-Fet. Accurate tracking of the RIAA equalization curve is a more difficult task than is generally appreciated. By using extremely high quality components custom made film foil capacitors (dYnamiCap) and better than 1% tolerance Welwyn, Caddock resistors in a passive network. The chassis uses a precision front panel machined of high grade aluminum and custom aluminum for the top and side.

The transformer ( power supply ) sub-enclosure is constructed from machined aluminum plates. Affixed to the top and bottom surface
are closed-cell neoprene damping sheets and mu-metal. The neoprene combines excellent damping and thermal stability, the mu-metal is excellent to isolation of magnetic fields.

I go enclose photos and then inform details of the project.

Cheers
jon
 

jonstanza

Well-Known Member
Apr 9, 2013
35
4
83
Lisbon PT
Hi

the first photos (developing the boards in Altium Designer. excellent, sophisticated and with a margin of error "null". The best that has passed through my hands).

Board´s (power supply, mother board...)


The boards (phono stage)


preparing the chassis







the elements made, ??to mounting the chassis


box to transformer


chassis



Cheers
 

jfrech

VIP/Donor
Sep 3, 2012
2,152
749
1,160
Austin
That's quite a project !
 

jonstanza

Well-Known Member
Apr 9, 2013
35
4
83
Lisbon PT
Here is the motherboard. The line of power supply is based on copper UP-OCC an optimal material to be a ideal transmission line. For the time being, UP-OCC pure copper has been considered the state-of-the-art conductor material in Hi- E nd Audio cable industry.



assembling the first components (one channel).


two channel


after many tests with capacitors (tracking of the RIAA), this manufacturer has shown excellent results positive. (DynamiCap)


Final assembly of a channel


setting gains


board of configuration loads (values ??are pre-defined, but it is possible to change these values??).


the board of power supply (lack of power transistors "lateral mosfet from exicon")


jon

Ps:my condolences to the victims of boston
 
Last edited:

jonstanza

Well-Known Member
Apr 9, 2013
35
4
83
Lisbon PT
Beautiful Jon

Is your plan to bring these to market?

Good question .... Steve I'm in a country that does not value what people do. is a hard way to go. If I were in germany, england, or even in the United States would be different. I'll do the best possible for that to happen. Only time will tell.
 

jonstanza

Well-Known Member
Apr 9, 2013
35
4
83
Lisbon PT
but .... continuing

Here is the box for the transformer (power supply), is Affixed to the top and bottom surface are closed-cell neoprene damping sheets and mu-metal.
the mu-metal is excellent to isolation of magnetic fields.



preparing transformer assembly


screen printing .....


Mounting board (power led)


Mounting rear panel


inside 1


inside 2


boards


rear/inside


jumper.... load adjustment


front "logo"


Rear panel


Cheers
jon
 

mep

Member Sponsor & WBF Founding Member
Apr 20, 2010
9,481
17
0
jon-Your work is absolutely stunning and puts lots of high-end gear to shame. If your gear sounds half as good as it looks, it should be killer.
 

rugyboogie

Well-Known Member
May 30, 2010
163
127
1,600
Vancouver, BC
Nice to be able to take on such a complex project from start to finish.
First rate in design and top notch execution.
Congrats, and please let us know how it sounds.
 

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