Batery powered DIY CNC phono stage

[tek]

ALso, this may sound like a silly question, but does the connection for grounding need to be wired on the pcb as well? From the pic it doesn't seem like it is... but then again i am not sure if it needs to be or not.

Thanks

 

[omishra]

Thanks buddy!

Also, is that black part on the bottom left side of the back for the grounding?

Yes that is screw terminal for grounding.

ALso, this may sound like a silly question, but does the connection for grounding need to be wired on the pcb as well?

It is connected on PCB ground where battery ground meets to circuit. There s red wire connected to it from bottom of PCB. You can see one red wire in open box going below PCB.

 

[omishra]

Both the circuits played nicely at the first power on itself.

Here are initial impressions after playing 4 songs on each -
1. Silence: No audible hiss/hum/buzz. This is terrific. Even with my TT it worked with and without ground connection at ground screw.
2. Sound is sweet, musical, not harsh, not mellow and full range.
3. Still need 30+ hrs burn-in time to feel openness for HF. Now also clear but need more bright to my taste. It will happen after usage.
4. Compared to other phono stages, this makes difference in correct audio reproduction. I assume passive RIAA equalization and quality caps making difference.

I loved the simplicity of circuit and quality of parts. I tested using Gulzar-Kishore Kumar and Michael Jackson Songs for about 30 min each. Rest respective owners can report after usage,

Thanks

 

[captrajesh]

Hi,

I got my kit yesterday. :yahoo:

All components have been neatly placed in plastic pouches and professionally packed.:thumbsup:

Will get the soldering done soon.

Thank you very much for taking the pains Sachin.

Regards


Rajesh

 

[sachu888]

Hi,
Some of my observation on CNC :
1. Absolutely silent between tracks,sometimes I have to check if its on or not.
2.Very low surface noise.
3.Very musical,correct sound reproduction.
4.Some carts/albums like different loading than 47k.I prefer 47k and 62k loading on my Shure M55e.
4.The sound stage is extremely wide and 3d with as much detail as I have heard.
5.It has a slightly mellow sound that is very pleasing to the ear.
6.It takes about 30 hours plus to break-in,it really opens up after that.

In short it is a simple but extremely effective & inexpensive phono stage, which will give you a better performance in very low budget.There is a good demand for CNC on Ak,I am sending another 10 pcbs to some Ak members,today.

Regards,
Sachin

 

[tek]

My CNC Phono arrived today! Firstly, big thanks to Sachu and Omishra for helping to make this happen! Truly are assets to this forum, and very generous and helpful! I really appreciate it

I've only listened for about 30 mins, but I can say right off the bat that the music is much CLEARER than it's been with my earlier phono stage. And, as others have pointed out, it is silent. The bass is also nice, and in fact I had to adjust my amp eq and reduce the bass once it was connected. I will wait to see how the sound changes after the break in.

Stuff I listened to : Sun Kil Moon - April, David Bowie - Alladin Sane, David Sylvian - Secrets of the Beehive and John Coltrane - A Love Supreme

 

[sachu888]

My CNC Phono arrived today! Firstly, big thanks to Sachu and Omishra for helping to make this happen! Truly are assets to this forum, and very generous and helpful! I really appreciate it

I've only listened for about 30 mins, but I can say right off the bat that the music is much CLEARER than it's been with my earlier phono stage. And, as others have pointed out, it is silent. The bass is also nice, and in fact I had to adjust my amp eq and reduce the bass once it was connected. I will wait to see how the sound changes after the break in.

Stuff I listened to : Sun Kil Moon - April, David Bowie - Alladin Sane, David Sylvian - Secrets of the Beehive and John Coltrane - A Love Supreme

Hi Tek,
Nice review,which cart are you using?Try to listen it with different impedance setting,like 62k,32k etc.It will open up more after 30hrs time.

Regards,
Sachin

 

[tek]

Hi Sachu

Am currently using an Ortofon 2M Red, thinking of upgrading to a Denon DL-110 pretty soon.

How do you change the impedance settings? No clue about this stuff

Cheers again for all the effort you and Om put in!

 

[sachu888]

Hi Sachu

Am currently using an Ortofon 2M Red, thinking of upgrading to a Denon DL-110 pretty soon.

How do you change the impedance settings? No clue about this stuff

Cheers again for all the effort you and Om put in!

For changing input impedance(cartridge loading) you will have to open its top cover,CNC board has 2 sky blue colour Dip switches.OM must have selected no.3 of Dip switch which is 47k(default for most MM cartridge) you can change this setting by select another value on both switches.Please keep your system off while doing this and select only one value at one time.This pic might help.


Uploaded with ImageShack.us
Cartridge loading is explained here:
Turntable Forum :: View topic - Cartridge Loading Explained
BTW: Very few phono stages have this option.

Regards,
Sachin

 

[tek]

Hi Sachu

Thanks for the explanation. Yes, I opened it and figured it out right after posting that! I set both switches to the 4th one (62k) and it's become a bit louder now.. will play around some more.

Cheers

 

[tek]

for my cart it says the recommended load resistance is 47k... what happens if I set it higher at 62k? Can it damage the cartridge or system in anyway?

Thanks

 

[sachu888]

for my cart it says the recommended load resistance is 47k... what happens if I set it higher at 62k? Can it damage the cartridge or system in anyway?

Thanks

No,
I don't think so,47k is recommended setting for almost all mm carts,but for safer side you can continue using 47k.
I am running my Shure M55e on 32k setting.

Regards,
Sachin

 

[sachu888]

for my cart it says the recommended load resistance is 47k... what happens if I set it higher at 62k? Can it damage the cartridge or system in anyway?

Thanks

Hi Tek,
Let me put this question on Audiokarma/Vinylengine.

Regards,
Sachin

 

[omishra]

for my cart it says the recommended load resistance is 47k... what happens if I set it higher at 62k? Can it damage the cartridge or system in anyway?

Thanks

No it won't damage anything. Input impedance should be maximum and output impedance should be minimum. Matching exact impedance enables source (cartridge) to transfer maximum current in load (phono pre) and minimize noise. Here as we are using OP AMP which has very large input impedance, it won't matter 47K or 62K. Even 62K is better as input shunt because impedance of op amp is much greater than 47K.

 

[sachu888]

No it won't damage anything. Input impedance should be maximum and output impedance should be minimum. Matching exact impedance enables source (cartridge) to transfer maximum current in load (phono pre) and minimize noise. Here as we are using OP AMP which has very large input impedance, it won't matter 47K or 62K. Even 62K is better as input impedance of op amp is much greater than 47K.

Here are some findings on Vinylengine regarding cartridge loading,I find it very informative.
Turntable Forum :: View topic - Cartridge Loading Explained

Regards,
Sachin

 

[sachu888]

for my cart it says the recommended load resistance is 47k... what happens if I set it higher at 62k? Can it damage the cartridge or system in anyway?

Thanks

Nope, you won't damage anything, you'll change the frequency response.I have got this reply from both forums.
Regards,
Sachin

 

[spacemonkey]

Guys, i received my Phono Stage today.
First off, let me just say how grateful I am to the two of you, Sachin and Mr. Mishra. You guys are an absolute Godsend and are so helpful and generous. Thank you ever so much for organising all of this and making it one of the best Group Buys I have ever been a part of. Spectacular experience that I cant stop talking to my friends about and its all credit to the two of you.

Having said that, I am a first time TT user. I have never owned a TT before sparing one Technics that i bought from Salvation Army store at a bargain only cause I wanted to listen to something at home. Now that I have my Phono Stage, to start listening to some of my records, i decided i'd buy an old refurb turntable. I ended up getting a Yamaha TT (dont quite have the specifics yet, but I'll have them tomorrow) from Mr. Anand from Nova Audio. He was nice enough to find me one and i got it for a stellar price. My whole logic of buying some old and refurb for the price that I picked it up was cause I wanted to see how much I would end up listening to my vinyls. I do have the passion for them, but time, I am not so sure about. I wanted to do a dry run before buying something more professional and built well and Mr. Anand seemed to share the same opinion on my decision to buy a TT.

So let me just tell you how excited I am to hook that baby up. Its old, a little dusty and has a quaint charm that I seem to enjoy. Unfortunately its lying at my girlfriends house and I'll be bringing her (both of them) home tomorrow. Cant wait to listen to the Phono Stage hooked up to it and then to my Denon 1612 going to my Wharfe's. I am excited as hell and cant wait to begin this journey.

Thanks again to Mr. Mishra and Sachin for making this happen. I feel blessed

 

[tek]

Yes, this was my first group buy as well! I'm gonna keep burning this baby at both ends until the 30 hrs is up

Spacemonkey - enjoy! Hope your vinyls sound great! Mr Anand is who I bought my first TT from, and I'm glad you're happy with your purchase! If you ever want to come over and do a listening session, just PM me.

Om and Sachu - hats off to you gentlemen!

Listening to some Leonard Cohen right now and it sounds great!

 

[sachu888]

Yes, this was my first group buy as well! I'm gonna keep burning this baby at both ends until the 30 hrs is up

Spacemonkey - enjoy! Hope your vinyls sound great! Mr Anand is who I bought my first TT from, and I'm glad you're happy with your purchase! If you ever want to come over and do a listening session, just PM me.

Om and Sachu - hats off to you gentlemen!

Listening to some Leonard Cohen right now and it sounds great!

Hi Tek
You are really enjoying,I can see your posting time @2:38 AM.:clapping:

Regards,
Sachin

 

[jls001]

Hi Tek,
Let me put this question on Audiokarma/Vinylengine.

Even Sachin doesn't know so this must be a tough one:lol: