Hiten's CNC Phono Build - Courtesy Sachin :-)

[Hiten]

Hello Everyone,
First I must apologize to Sachin who gave me free CNC Phono Kit long back but I couldn't finish it. I have built it now and must say what a wonderfull sounding this Phono Preamp is. Thanks Sachin . Following is the build process.
I am a bachcha (Kid) in Audio HiFi world so pardon me for not so High quality build process. (Pictures videos are from my Mobile)

There are ready made Resistor lead pitch bending tools available for professionals. But I am not that prolific buildier so made one temporary one for myself. Just a small piece of Aluminum thin plate bend to exact PCB hole pitch. One advantage of Sachin's Kit was all resistors values were marked. It was so easy to just place them and solder. Appreciate this very much Sachin.



Resistors placed and soldered


Capacitor placed and soldered


Op-amps, DIP Switchs and Connectors soldered. There is no case/enclosure for this as in future I am planning to have integrated case (Probably a SET Tube Amp or AmpCamp ) where all things will be in single case. So I bought cheap chinese RCA Cables, A pair of speakers etc. just for testing purpose.


All things in place I connected the Preamp to the system. No Sound !? One 9V Battery was drained. Bought one new and the Preamp started working. A working electronic circuit is a rare achievement for a clumsy audio enthusiast like me; who has stepped on hot soldering iron, Blown transistors by shorting speaker wires, Broken few styluses....

Here is a video of Preamp working. Song that had intermittent silent passages was chosen to display how good this Preamp is. Absolutely No hum, Lowest Possible noise I have ever seen. Even on loose speakers it sounds fantastic. Kudos and thanks to FasterDamnit, Hypnotoad of Audiokarma. Thanks very very much to our own Omishra and Sachin. you guys are wonderful people.

Thanks for watching and Best Regards.
Hiten

 

[frend2001]

Neat Job Hiten.

It is always thrilling to DIY electronics.

Soldering is almost meditating for me.

I am also a content user of CNC Phono. Omishra and Sachin have done a fab job and they are such supportive and humble people.

Ek thanks banta hai.

 

[Hiten]

Omishra and Sachin have done a fab job and they are such supportive and humble people.

Indeed. Would not have been possible without them.
Regds.

 

[sachu888]

Wow !! Hiten bhai soldering looks very neat. I am happy , you build this.

Regards
Sachin

 

[Kannan]

neat work. Congrats

 

[sadik]

Congrats Bro... Very neat work.

 

[Hiten]

Hi all,
Finally assembled power supply for this Phono Preamplifier. Some pictures. What a beautiful PCB design and circuit. I am turning in to big fan of Sachin and Oms work. I hope someday they make SE tube amp kit.
The Power supply is half finished (I envy those who work 'fatafat' and make beautiful amps, speakers etc.(In other words I am Lazy ) I need 12-0-12 transformer for this. I did visited Lamington Road and transformer was well made (Rs. 250) But total negative marks for finishing. Need good finish like this. The metal casing will be good (Though it doesn't sheild magnetic flux from spreading) OR will go for R Core transformer. Any pointers are welcome for R Core OR Well made + finished EI transformer.
Thanks and regards.

 

[Hiten]

...will reorient 3 pin preset soon. symmetry looks good.

 

[jls001]

Great photos, Hiten.

Try using an R-Core transformer.

 

[Hiten]

Joshua this will be put in casing with SE tube amp, and I guess 750mA will also do (Low foot print is what I am looking for). Kindly tell where can I get 12-0-12 R Core transformer ?
Thanks and regards.

 

[jls001]

Joshua this will be put in casing with SE tube amp, and I guess 750mA will also do (Low foot print is what I am looking for). Kindly tell where can I get 12-0-12 R Core transformer ?
Thanks and regards.

where can I get 12-0-12 R Core transformer ?

Write to or call:
electro magnetic devices
Factory: 225P/226P, Phase II,
IDA, Cherlapally, HCL Post
Hyderabad 500051
Ph: 040-27261513, 27262044
<[email protected]>

 

[sachu888]

Nice work Hiten bhai. Pics look so great. I have saved it on my computer. You can use Ei core without any issue, if you shield it properly. You van get the metal cover fabricated for the transformer.

Regards
Sachin

 

[keith_correa]

https://www.amazon.in/gp/aw/s/ref=nb_sb_noss?k=12-0-12

 

[Hiten]

Thanks Joshua, Sachin and Keith.
I have sent email to 'Electro Magnetic Devices' plus two other R Core manufactures at Andheri. They are big companies and may not cater to single piece requirement. Lets See. Also it is in Ansa Industrial Estate, where I used to get my printing work done. So will be easy to travel and meet old friends.
---
Power Supply Photos : Joshua, Sachin they are taken from my humble mobile phone. I took numerous and posted which were clear. Sachin as forum has restriction on resolution of images I will mail high resolution pictures to you.
Regards.

 

[Hiten]

Keith thanks for the list. I like this one. But it shows only two leads. Others are showing proper 12-0-12. Like this. Finish is also good compared to 'Soumik electrical' one. Lets see how R Core enquiry goes or will buy from the list you have provided.
Regards.

 

[Hiten]

Hello good people.
Fed up with not getting good transformer I purchased cheap Indian one (Rs. 110) for the time being to test the power supply and phono preamp. However here is one important ALERT. The pictures posted in Post #7 the diode at bottom is placed reversed. So kindly correct that if you are following pictures. The circuit (PCB) is perfect. It was my mistake. At first I was not getting and -ve DC voltages and problem was sorted to that diode. I have corrected it and now it is OK getting stable good -ve and +ve DC supply. Will test connecting with TT today or tomorrow .

As I am planning to build Single ended tube amp. I have decided to use multi tap transformer in the future. But I sincerely thank everyone who suggested the links.
Cheerios and best Regards.

 

[Hiten]

Hi all,
I tested the power supply. It is working superbly. Absolutely silent. I am posting Video of the same. Tested on cheap Creative 2.1 pc speakers which I use so I don't accidentely blow my regular speakers etc.

I have deliberately placed the phono cables on the transformer. Also the jumble of the wires are placed on intention. And I hear absolutely no hum etc. To check I shot the video after turning off (lifting the tonearm but TT on) the TT Player and got close to the speaker as much as possible. seen in the end of video.
This is one superbly regulated power supply. Thanks everyone who helped in designing and making it.
Regards.

 

[Hiten]

If anyone is interested in mad scientist experiments . please do look at my other videos. Click on the V (Vinyl turntables) in the you tube video in above post. The videos are...
1) Phono Preamplifier power supply
2) CNC Phono testing
3) Stylus test torture test (it is said that heavy platter torque helps in sound quality and speed staibility. This was to proov that for some direct drive the stylus drag doesn;t affect the speed stability. I placed a dummy nylon stylus and the whole counterweight on headshell. Checked the speed it was stable)
4) Acoustic feedback on cheap turntables (This was to demonstrate the sound travelling from speakers to 'opened" dust cover and ultimately getting amplified
5) This was my little fun flea watt amplifier made from LM317 power regulation IC.
6) This was my restoration of garrard changer (Posted in the forum somewhere)

Regards

 

[Hiten]

Hello eeryone,
as my my earlier phono preamp was fitted in Preamplifier (Link) and was sold I got new one from Sachin, Thanks very much Sachin. Sharing some pictures. This build has most quality parts, Nichicon, Vishay, Bournes etc.





Power Supply.





Text Book Soldering ...



Waiting for proper transformer. This is very easy build as Sachin provides all parts with proper lable.

Regards.

 

[amrutmhatre90]

I am using this phono too, excellent phono.
I upgraded the op amps and this sounds musical and refined, no hum buzz or anything.

Here you can view my build