Just wanted to ask if anyone has tried using the lantern batteries that Sachu mentioned earlier in the thread? I listen to a lot of vinyl, so i find myself changing batteries probably once every 10 days or do. My main worry is that while changing batteries, i might snap a wire or do some damage. Also, I'd prefer not to have to unscrew the casing every 10 days. I guess ideally it would be great to have a separate box to house the batteries so I can remove and change those without opening the casing for the CNC phono itself. One thing is for sure, batteries are the way to go as you get a very noise free sound.
Batery powered DIY CNC phono stage
- Thread starter sachu888
- Start date
What about this PS? I am using this. I find no notable difference in battery or this.
Please explain this more. I have orthodox thinking of avoiding external interferences by means of conductive shielding techniques aka metallic boxes.
^^Possible. That's why we get either inferior or so called musical records.
The power supply you show is wonderful for a digital system. The problem with the 317 and his pals is that there is 80 mV of hash on the output (non-mains frequency ripple.) In a digital realm anything below 0.7 volts is "off." The microvolt signal from your cartridge can lose some sound in that hash. Worse, the quiet passages that reveal the delightful musicianship of Yo Yo Ma can be distorted to sound like Yo Mama.
As to the package, unless your building's use of electricity is restricted to battery operated torches (flashlights) there is interference flying through the air and through the earth. A metal box is effective against electrostatic noise, but does nothing for magnetic interference. Yes .250" steel or mu-metal can shield magnetics, but who can lift it or afford it? A metal enclosure will act as antenna for signal destroyers from mains frequency to radio stations to cell phones if not properly earthed. When properly earthed, the circuit needs to be properly bonded to the earth connection. Done properly, the preamp would sit in a nice LOUD ground loop. This is one reason to use battery power for the amp, and to carry signal commons on wires twisted with the output signal and covered with a braid (sometimes called a screen or shield) connected at only one end.
Rechargeable batteries like Yuasa NP 12 volt series are more economical than single use cells. The bump in voltage also slightly increases the ability of the amp to react to larger signal changes.
At the end of the day, what is nicer than a needle drop to announce the music to come?
sachu888
Well-Known Member
Great info Moviela.I am having exact same problem at very high volume.I think I need to play with ground.I am running it on cheap 9 V batteries.It would be good to try 9V rechargeable or four 6V Lantern batteries(2per side).I like the battery placement in Korora PS firestone korora
Regards,
Sachin
Regards,
Sachin
Thanks for detail information.
Datasheet of those regulator mentions THD 0.003% /V of output. For 500mA current drawn, noise figure remains 60dB while output impedance always <1 ohm (0-20KHz). We are using only 20mA max current. On impedance, the effect of DCR added by inline output coils, is nullified by smoothing caps. PASS B1 has 2 X 15000uF (current 17mA) and CNC has 10uF, 0.1uF combination at each pin (considering very low current, ~6-7mA).
Along with impedance stability, these caps also remove extra few mV noise and ripple if any. With 10uF at adjust pin of regulators not only output impedance is improved but ripple rejection ratio by 80dB. LCL filter cuts off any noise above 1.3KHz (practically considering DCR of coils anything above 120Hz)
Regarding 80mV noise, with above consideration and practical experience, I beg to differ here. Practically, at any point no phono stage could digest 80mV noise in PS. But CNC Phono Stage is happy and silent as if it was on battery. Here we are not getting ripple more that 0.9mV which is rejected by OP AMP.
I appreciate your concerns and thanks for your considerations. You hold good catch in the subject. :clapping:
There was fair thought given while choosing this PS.
Datasheet of those regulator mentions THD 0.003% /V of output. For 500mA current drawn, noise figure remains 60dB while output impedance always <1 ohm (0-20KHz). We are using only 20mA max current. On impedance, the effect of DCR added by inline output coils, is nullified by smoothing caps. PASS B1 has 2 X 15000uF (current 17mA) and CNC has 10uF, 0.1uF combination at each pin (considering very low current, ~6-7mA).
Along with impedance stability, these caps also remove extra few mV noise and ripple if any. With 10uF at adjust pin of regulators not only output impedance is improved but ripple rejection ratio by 80dB. LCL filter cuts off any noise above 1.3KHz (practically considering DCR of coils anything above 120Hz)
Regarding 80mV noise, with above consideration and practical experience, I beg to differ here. Practically, at any point no phono stage could digest 80mV noise in PS. But CNC Phono Stage is happy and silent as if it was on battery. Here we are not getting ripple more that 0.9mV which is rejected by OP AMP.
I appreciate your concerns and thanks for your considerations. You hold good catch in the subject. :clapping:
Last edited:
"Never use a non ferrous chassi. Using an aluminum chassis lets the EMF from the power transformer bleed right through. A toroid transformer will radiate up to 20 Miligauss. A steel chassis reduces that to below 7mG, aluminum however lets all 20mG pass right through. If you must use an aluminum box either internally shield the transformer or, mount the PS at least 1-2 feet from the turntable."
I can see this is quite true. Been experimenting with various materials for both
the phono preamp as well as another valve radio restoration project that I am working with. In the case of the phono preamp, I find that encasing the powersupply in a perforated metal casing reduces a certain amount of hum/noise that I can hear. This noise is heard when the turntable is spinning but the cartridge is off. I can hear it even with the tt disconnected. I did not notice it with my legacy integrated amp. The integrated amp was housed in a metallic chassis which is definitely not aluminium. When I opened out the integrated amp and used it, I got the same hum/noise.
Note that currently I am running the phono preamp with a toroid which I had. I have not yet integrated the r-core I got with the PASS B1 group buy.
Thanks Om for this note. I did not know the science behind this....
I can see this is quite true. Been experimenting with various materials for both
the phono preamp as well as another valve radio restoration project that I am working with. In the case of the phono preamp, I find that encasing the powersupply in a perforated metal casing reduces a certain amount of hum/noise that I can hear. This noise is heard when the turntable is spinning but the cartridge is off. I can hear it even with the tt disconnected. I did not notice it with my legacy integrated amp. The integrated amp was housed in a metallic chassis which is definitely not aluminium. When I opened out the integrated amp and used it, I got the same hum/noise.
Note that currently I am running the phono preamp with a toroid which I had. I have not yet integrated the r-core I got with the PASS B1 group buy.
Thanks Om for this note. I did not know the science behind this....
Yes, that's why I enclosed my CNC in perforated iron metal partition and same for PS as well. I am literally getting absolute peace. No hum and no hiss.
shaizada
Active Member
I want to give a heartfelt thanks to Sachin for making those PCB's and answering my never ending questions. This setup wouldn't have happened without him. :clapping:
A small update:
So after building the CNC phonostage, I decided one very late night to get it up and running on lantern batteries. I buy them from the 24 hour open Walmart, bring them home and wire them up. I was a little sleepy and wired the battery circuit perfectly opposite so my CNC opamps saw a -ve voltage drop on the +ve leg. Nice! Opamps and electrolytic caps blown! So I order replacement parts and got them in today and wired them in. It's alive and well finally.
Well, in other news, I had recently sent out my VPI HRX motor for some upgrades and thats when I had realized I cannot be without vinyl like this. That had got me thinking of getting a quick turntable setup on the side using Sachin's CNC and some Moving Magnet cartridge as I didn't have any. Just to change things up a bit. I ordered the $50 amazon deal on the Shure M97xe.
Next, I needed a turntable...a NOS Micro Seiki BL-21 belt drive turntable showed up locally. I met the guy and picked up a brand new, 30 year old table. Great, except it still needed an arm as it comes with a blank armboard.
So I look around and come into a Graham Robin tonearm. I win the auction and the arm arrives. I didn't want to make holes in the original armboard, so I got 2 made using the original as a template. Finally mounted the tonearm in today, loaded. aligned the Shure m97xe and hooked it up to the CNC phonostage. Before I forget, I even made my own DIN to RCA cable using cardas 4x24 awg cable, Cardas S Din connector and Vampire 800 RCA connectors all using some Cardas quad eutectic solder I picked up.
FINALLY, everything came together and I've been listening to a few things this evening though a Ray Samuels Protector running a pair of Sennheiser HD-650 balanced (with Stefan Arts Equinox Cable).
First things first, the Shure M97xe sounds MUCH better with the brush up not on the record. Tracking with the brush at 1.75 grams, the sound is good but closed in...somewhat muted. I realized that the CNC phono was at 47k so I switched to 62k. Much better but still not open enough. So I wired in a 56pf cap (after experimenting with the different cap values suggested by Omishra, THANKS GUY!!) and there it opened up nicely! That lost air was regained. BUT I still wasn't happy with the sound.
I finally locked the M97xe brush upwards and set the VTF to 1.25 (antiskating to 1.25 as well) and it was magic. Everything got dialed in, all frequencies well represented and the music came alive. It was an Aha moment
So bottom line is, the CNC is a bloody good phono stage. Sounds fantastic. Basically here is what's happening according to my ears...MM carts give you more of a birds eye perspective of the musical forest. Quality MC carts give you that and offer you the luxury of zooming into the bark of the trees in this musical forest. Giving you a chance to see the veins of the leaves while still helping you to maintain the birds eye perspective. MC's just give way more information and detail regarding the musical performance. This gives you the "you are there" feeling much more than MM's.
Here are some pics of the table, arm and cart I clicked to share here:
A small update:
So after building the CNC phonostage, I decided one very late night to get it up and running on lantern batteries. I buy them from the 24 hour open Walmart, bring them home and wire them up. I was a little sleepy and wired the battery circuit perfectly opposite so my CNC opamps saw a -ve voltage drop on the +ve leg. Nice! Opamps and electrolytic caps blown! So I order replacement parts and got them in today and wired them in. It's alive and well finally.
Well, in other news, I had recently sent out my VPI HRX motor for some upgrades and thats when I had realized I cannot be without vinyl like this. That had got me thinking of getting a quick turntable setup on the side using Sachin's CNC and some Moving Magnet cartridge as I didn't have any. Just to change things up a bit. I ordered the $50 amazon deal on the Shure M97xe.
Next, I needed a turntable...a NOS Micro Seiki BL-21 belt drive turntable showed up locally. I met the guy and picked up a brand new, 30 year old table. Great, except it still needed an arm as it comes with a blank armboard.
So I look around and come into a Graham Robin tonearm. I win the auction and the arm arrives. I didn't want to make holes in the original armboard, so I got 2 made using the original as a template. Finally mounted the tonearm in today, loaded. aligned the Shure m97xe and hooked it up to the CNC phonostage. Before I forget, I even made my own DIN to RCA cable using cardas 4x24 awg cable, Cardas S Din connector and Vampire 800 RCA connectors all using some Cardas quad eutectic solder I picked up.
FINALLY, everything came together and I've been listening to a few things this evening though a Ray Samuels Protector running a pair of Sennheiser HD-650 balanced (with Stefan Arts Equinox Cable).
First things first, the Shure M97xe sounds MUCH better with the brush up not on the record. Tracking with the brush at 1.75 grams, the sound is good but closed in...somewhat muted. I realized that the CNC phono was at 47k so I switched to 62k. Much better but still not open enough. So I wired in a 56pf cap (after experimenting with the different cap values suggested by Omishra, THANKS GUY!!) and there it opened up nicely! That lost air was regained. BUT I still wasn't happy with the sound.
I finally locked the M97xe brush upwards and set the VTF to 1.25 (antiskating to 1.25 as well) and it was magic. Everything got dialed in, all frequencies well represented and the music came alive. It was an Aha moment
So bottom line is, the CNC is a bloody good phono stage. Sounds fantastic. Basically here is what's happening according to my ears...MM carts give you more of a birds eye perspective of the musical forest. Quality MC carts give you that and offer you the luxury of zooming into the bark of the trees in this musical forest. Giving you a chance to see the veins of the leaves while still helping you to maintain the birds eye perspective. MC's just give way more information and detail regarding the musical performance. This gives you the "you are there" feeling much more than MM's.
Here are some pics of the table, arm and cart I clicked to share here:
sachu888
Well-Known Member
Thanks for your kind words Shaizada.I am glad you are like it.Your TT looks beautiful with that arm.I am also thinking of buying a budget arm like Rega Rb250/300.Yes, you are right about MC carts,no MM can match their performance IMHO.
Regards,
Sachin
Regards,
Sachin
svaze
Member
Hi Sachin,
If you are planning for another GB of the CNC phono, please count me in.
~Swapnil
If you are planning for another GB of the CNC phono, please count me in.
~Swapnil
shaizada
Active Member
Me too! I'll take 2 more CNC boards whenever you do this again
sachu888
Well-Known Member
Me too! I'll take 2 more CNC boards whenever you do this again
Ok,
I will order 10 more boards this time.
Regards,
Sachin
shaizada
Active Member
sachu888
Well-Known Member
I have put XLR connection for easy swapping of batteries.
[URL=http://imageshack.us/photo/my-images/851/dsc04933m.jpg/]
Uploaded with ImageShack.us[/URL]
[URL=http://imageshack.us/photo/my-images/163/dsc04932f.jpg/]
Uploaded with ImageShack.us[/URL]
[URL=http://imageshack.us/photo/my-images/401/dsc04934e.jpg/]
Uploaded with ImageShack.us[/URL]
Regards,
Sachin
[URL=http://imageshack.us/photo/my-images/851/dsc04933m.jpg/]
Uploaded with ImageShack.us[/URL][URL=http://imageshack.us/photo/my-images/163/dsc04932f.jpg/]
Uploaded with ImageShack.us[/URL][URL=http://imageshack.us/photo/my-images/401/dsc04934e.jpg/]
Uploaded with ImageShack.us[/URL]Regards,
Sachin
cmsajith
Well-Known Member
Right Channel not working
CNC assembling is complete and connected to two rechargeable batteries. I am facing one problem. Initially the right channel was not working. After switching off all the equipment and switching on again, somehow both started working. It was working for last two days. But the issue started coming again since yesterday. The battery pack is sending 18v. Rest I am not sure. Please help.
CNC assembling is complete and connected to two rechargeable batteries. I am facing one problem. Initially the right channel was not working. After switching off all the equipment and switching on again, somehow both started working. It was working for last two days. But the issue started coming again since yesterday. The battery pack is sending 18v. Rest I am not sure. Please help.
sachu888
Well-Known Member
Re: Right Channel not working
Hi,
Batteries should be sending +/-9V only.Could you post a pic or drawing how battries are connected to PCBs.
[URL=http://imageshack.us/photo/my-images/824/cncbatteries.jpg/]
Uploaded with ImageShack.us[/URL]
Regards,
Sachin
Hi,
Batteries should be sending +/-9V only.Could you post a pic or drawing how battries are connected to PCBs.
[URL=http://imageshack.us/photo/my-images/824/cncbatteries.jpg/]
Uploaded with ImageShack.us[/URL]Regards,
Sachin
Last edited:
cmsajith
Well-Known Member
I have connected
: + from the first battery to the PCB +
: - from the second battery to the PCB -
: connected - (first battery) and + (second battery) and connected to the PCB G (phono ground is connected to this)
I will post the pics in the evening. I think this is a series connection and the effective volt should be 18v, right? As per DIY Audio it works in the range of 3v to 18v. As of now I am not using any switch. Batteries used : COWIN 9v 250mAH rechargeable
: + from the first battery to the PCB +
: - from the second battery to the PCB -
: connected - (first battery) and + (second battery) and connected to the PCB G (phono ground is connected to this)
I will post the pics in the evening. I think this is a series connection and the effective volt should be 18v, right? As per DIY Audio it works in the range of 3v to 18v. As of now I am not using any switch. Batteries used : COWIN 9v 250mAH rechargeable
Last edited:
sachu888
Well-Known Member
I have connected
: + from the first battery to the PCB +
: - from the second battery to the PCB -
: connected - (first battery) and + (second battery) and connected to the PCB G (phono ground is connected to this)
I will post the pics in the evening. I think this is a series connection and the effective volt should be 18v, right? As per DIY Audio it works in the range of 3v to 18v. As of now I am not using any switch. Batteries used : COWIN 9v 250mAH rechargeable
Yes this is a series connection,and you have connected properly,voltage should be +/-9.Your batteries must be dead as you are not using any switch.You need to use a DPDT switch,otherwise your batteries won't last long,also ground your board and case,otherwise you'll have Hum.
Regards,
Sachin
Last edited:
cmsajith
Well-Known Member
At the PCB +/- I am getting +/-18v, donno how. Also in a series connection if any of the battery or both are not working, both the channels will be off.
Will post the pics by evening, please help me in troubleshooting. Also what else can be checked?
Last edited:
Buy from India's official online dealer!
