Another Super High End Phono Stage! No expense spared...

[sachu888]

AD-823 Op amps

Sachin I use 4 of those 6v lantern batteries in the first link and find they are fine for my phono stage, it gives +12v, 0 , -12v.

Hope this helps.

Depending on the Op-Amps you select you could use 6 - 6V batteries for +/- 18V supplies or 4 - 9V batteries for the same voltage. The 6V batteries have a higher mAH rating. They could last the rest of your life (just joking!).

Of course if you are thinking of either a 6V or 9V supply you greater headroom with the 9V supply.

Hi Grainger,
I am using AD-823 in CNC as I like their sound very pleasing.Its maximum voltage is ±18 V,so I will use +/-12 V(4 of 6V batteries).
Any opinion on regulated power supply.

Regards,
Sachin

 

[hags]

Be prepared to use copious amounts of filter/storage capacitance when using a battery PSU lest your preamp sound dynamically constrained, uninvolving and downright unmusical.

Even with sealed lead batteries with high amp hours I did not care for the battery "sound".

Just my experience, you may love them. They are convenient and less costly upfront.

 

[sachu888]

Battery PSU

Be prepared to use copious amounts of filter/storage capacitance when using a battery PSU lest your preamp sound dynamically constrained, uninvolving and downright unmusical.

Even with sealed lead batteries with high amp hours I did not care for the battery "sound".

Just my experience, you may love them. They are convenient and less costly upfront.

Hi hags,
I am using 2 - 9V batteries in my CNC and found to be dead silent,but battery life is very less about 40hrs,that's why I am thinking of using Lantern batteries.

Regards,
Sachin

 

[hags]

Hi hags,
I am using 2 - 9V batteries in my CNC and found to be dead silent,but battery life is very less about 40hrs,that's why I am thinking of using Lantern batteries.

Regards,
Sachin

You could check the data sheet for Iq on that IC. Maybe it's a bit high, ????.

The lantern batteries will help. Get four of them and hooks them up for +12/-12.

 

[sachu888]

You could check the data sheet for Iq on that IC. Maybe it's a bit high, ????.

The lantern batteries will help. Get four of them and hooks them up for +12/-12.

Hi Hags,
Ad-823 rated ±1.5 V to ±18 V from dual supplies.Can you recommend any other power source than batteries.

Regards,
Sachin

 

[hags]

Hi Hags,
Ad-823 rated ±1.5 V to ±18 V from dual supplies.Can you recommend any other power source than batteries.

Regards,
Sachin

That's a tall order......

You could build your own with 317/337 regulators or chose from a host of kits or prebuilt PSUs.

Here are a few of varying design quality:

http://www.ebay.com/itm/PREAMPLIFIER-DAC-POWER-SUPPLY-KIT-BASED-LM317-LM337-/160655171067?pt=LH_DefaultDomain_0&hash=item2567cb5dfb

http://www.ebay.com/itm/Super-buffer-w-low-noise-regulator-Walt-Jung-/320502979366?pt=LH_DefaultDomain_0&hash=item4a9f775b26

http://www.amb.org/audio/sigma22/

http://www.hagtech.com/bugle.html

http://www.ebay.com/itm/All-FET-low-noise-super-shunt-regulator-PCB-Borbely-/320619074637?pt=LH_DefaultDomain_0&hash=item4aa662d44d

In all cases you'd have to supply the transformer.

You could also install a jack for a wallwart PSU, there are some decent regulated DC output wallwarts. Probably cost you less than $20-30. You'll have to do a search. Here's an example:

http://www.apogeekits.com/ac-dc_power_adapters.htm

 

[Grainger49]

I'm going to throw in with hags on several points. Use good storage on the board where the local storage is provided for. By good I mean Elna or Nichicon low ESR caps, not Black Gate caps. I don't see that that is necessary.

I am a fan of battery power supplies properly used. I like the lack of noise. I also am a big fan of capacitance, lots of capacitance. I once put 0.9F (no, I didn't leave out the micro) of capacitance on my tube preamp heater supply. You could turn it off and the tubes glowed for another 15 seconds.

A properly regulated, maybe in stages, power supply should have a lot of noise rejection. The neat thing about batteries is that you don't need to reject the noise that isn't there.

Edit: hags posted as I was composing. I'm not a big fan of wall warts. Most tend to be cheap and therefore noisy. They don't have much capacitance in them. They have to design to the lowest price point and can't afford to have more capacitance than is necessary to get fair, not good flat DC, not what you want in a Phono Preamp. But they are a start. You can add filtering and maybe regulation downstream from the WW. Just start with more voltage than you need.

The thing about regulating the AC power supply is that you could start with 22V, regulate to 18V then to 15V and if you want then to 12V. That is just an example I would have to look at the specs on a regulator to see what the voltage drop across a specific regulator is.

I looked at the data sheet on your Op-Amp and it has a quiescent current of 5mA. Assuming you get all the mAH current from your batteries that gives you 1480 hours of service. Of course you won't get that much in reality as the voltage starts to droop and the CNC will start to sound different.

Cheers!

 

[hags]

I'm not a fan of wallwarts either. Just a suggestion to get him started. There are a few regulated DC warts that aren't all bad.

You could always add more capacitance and/or drop the voltage with CRC or CLC circuits after the wallwart, kinda like Sutherland has in their 20/20 phono stage, $2200 msrp.

 

[sachu888]

Thanks Hags and Grainger,

I think I should buy 4- 6V Lantern batteries as I am getting clean sound from my 9V.Does it need to upgrade caps for better results.I am using stock caps as mentioned in CNC BOM.

Regards,
Sachin

 

[ghazzer]

Nice summary Grainger! Good points.

Question: Can anyone speak to the quality of a decent P/S from a computer? I think they supply +/-12vdc, but have to idea if this is "clean" enough for this application. I have 2 older PCs downstairs and there is not much else I can salvage out of them.

.

 

[shelly_d]

Nice summary Grainger! Good points.

Question: Can anyone speak to the quality of a decent P/S from a computer? I think they supply +/-12vdc, but have to idea if this is "clean" enough for this application. I have 2 older PCs downstairs and there is not much else I can salvage out of them.

.

I believe that computer supplies use a switching supply to get the amount of power out them that they need. That produces a lot of high frequency noise that could possible induct into the phono stage. I would advise both good filtering with low ESR caps and RFI shielding if you go that route.

Shelly_D

 

[hags]

Nice summary Grainger! Good points.

Question: Can anyone speak to the quality of a decent P/S from a computer? I think they supply +/-12vdc, but have to idea if this is "clean" enough for this application. I have 2 older PCs downstairs and there is not much else I can salvage out of them.

.

I wouldn't touch a switching power supply for audio use with a 10' pole.

Avoid!

 

[hags]

Thanks Hags and Grainger,

I think I should buy 4- 6V Lantern batteries as I am getting clean sound from my 9V.Does it need to upgrade caps for better results.I am using stock caps as mentioned in CNC BOM.

Regards,
Sachin

The stock caps should be fine. I don't know if you have the room or not but I would add more capacitance after the batteries. More is better.

 

[Pio1980]

Nice summary Grainger! Good points.

Question: Can anyone speak to the quality of a decent P/S from a computer? I think they supply +/-12vdc, but have to idea if this is "clean" enough for this application. I have 2 older PCs downstairs and there is not much else I can salvage out of them.

.

Definitely avoid pulse PS for DIY audio projects, linear supplies are just too easy to find like the fore-mentioned Elliott Audio Products preamp PS board or the e-Bay kit line preamp with servo-silenced PS of which I am fond for it's PS. Look up "servo preamp", you get a clean and neat simple single-chip DIY line stage and a really nice +/-15V PS for ca $20-$30 shipped. Just add a suitable power xformer and housing and "Bob's your uncle".

 

[ghazzer]

Yield! And thanks for the quick reply.

I will stick with the 9v batteries (if I can get my CNC fixed) as 45 - 50 hours will last me many weeks. I'd guess that two 12v SLA batteries and a re-charging circuit would be a better way to go if one listens to vinyl ~ 10 hours a week.

I have no idea how to quantify any performance improvement you would get by moving from a 18v R2R to a 24v R2R. Having a charging circuit would prevent performance degradation as the batteries drain down.

The attached file shows one scheme to connect the batteries and a charger. The DPDT switch should have 3 positions (on/off/on). I have added a relay that is activated by the +20vdc control voltage in my TT. The batteries are not connected to the CNC unless the tone arm is off the rest and the motor is running.

.

 

[Pio1980]

Higher voltages=more voltage swing capability out until input overload takes over. 5VP/P is twice what any line input is spec'd, including most power amps, +/- 9V rails should get you there with plenty of margin. +/- 12V rail voltage is about all anyone ever needs in practice if so.
What say you hands-on dudes?

 

[HypnoToad]

Hi Phillip,
I am seriously considering using 4 of these 6v batteries,does this come with any type of connector or I will have to solder on spring.

Regards,
Sachin

I just solder to the spring.

On the topic of batteries, newer rail to rail op amps can run at much lower voltages and don't suffer from head room problems like there predecessors.

I did a test with my latest creation, I hooked it up to a Rod Elliot P05b and then to batteries, the sound was smoother and less edgy with batteries YMMV.

 

[bobrown14]

Power Supply ?

Hi all, since we are on the topic of power supplies ... I've built my P05b power supply (14.9V out) from ESP and am housing my CNC in a seperate box. I've just built my umbilical cable using 3 pin din sockets (1 female on the power supply and one female in the CNC box with a 3 wire cable and male 2 male 3 pin dins on the cable). My question is regarding chassis/earth ground. I built my umbilical cable WITHOUT a chassis ground going from my power supply to the 3 pin din female and no connection from the shield on the cable (3 wire shielded cable from a computer power supply). The female socket looks like it would pick up the chassis ground on both ends (if I connected the shield to ground on the male din plug). I'm installing these in metal cases. My question is: is it correct to NOT pass the chassis ground thru to the preamp box? I don't want to have to re-do the umbilical cable. My thoughts are IF I passed the chassis earth ground thru to the preamp box I "might" enduce hum. So erring on the side of caution, I did not hook up the shield on the cable to anything. Good bad or ugly? All I have is Ve+ Ve- and (circuit) ground going from power supply to preamp box.


The cable with the din sockets "looks" almost like a balanced connection! Same look to the male plugs without the lock. I think it looks pretty cool .. hope it sounds good.
Dang it, I forgot to turn off my (battery powered) CNC again last night... FYI - sounds pretty good with batteries. If it would sound any better with a regulated supply I'm going to be VERY happy.

My only expectation is same sound but no turn off... thats what my power filter is for, one switch off and it all turns off. My SO has one of those switches and I'll be damned if I can figure out where that is.. seems to be in a different place every day.

Cheers,
Bob

 

[redjr]

Hi all, since we are on the topic of power supplies ... I've built my P05b power supply (14.9V out) from ESP and am housing my CNC in a seperate box. I've just built my umbilical cable using 3 pin din sockets (1 female on the power supply and one female in the CNC box with a 3 wire cable and male 2 male 3 pin dins on the cable). My question is regarding chassis/earth ground. I built my umbilical cable WITHOUT a chassis ground going from my power supply to the 3 pin din female and no connection from the shield on the cable (3 wire shielded cable from a computer power supply). The female socket looks like it would pick up the chassis ground on both ends (if I connected the shield to ground on the male din plug). I'm installing these in metal cases. My question is: is it correct to NOT pass the chassis ground thru to the preamp box? I don't want to have to re-do the umbilical cable. My thoughts are IF I passed the chassis earth ground thru to the preamp box I "might" enduce hum. So erring on the side of caution, I did not hook up the shield on the cable to anything. Good bad or ugly? All I have is Ve+ Ve- and (circuit) ground going from power supply to preamp box.


The cable with the din sockets "looks" almost like a balanced connection! Same look to the male plugs without the lock. I think it looks pretty cool .. hope it sounds good.
Dang it, I forgot to turn off my (battery powered) CNC again last night... FYI - sounds pretty good with batteries. If it would sound any better with a regulated supply I'm going to be VERY happy.

My only expectation is same sound but no turn off... thats what my power filter is for, one switch off and it all turns off. My SO has one of those switches and I'll be damned if I can figure out where that is.. seems to be in a different place every day.

Cheers,
Bob

Bob -
Where did you source the filter caps (C1-C4) for your P05b? I got some from Parts-Express, but sadly the leads are spaced to wide, as are the caps themselves to fit on the board.

Also, did you use the 15-0-15 center-tap x-former, or 16v? Source for the x-former?

Thx,

 

[bobrown14]

Bob -
Where did you source the filter caps (C1-C4) for your P05b? I got some from Parts-Express, but sadly the leads are spaced to wide, as are the caps themselves to fit on the board.

Also, did you use the 15-0-15 center-tap x-former, or 16v? Source for the x-former?

Thx,

Mouser for C1-4 and Antek for the Toroidal tranny - 15-0-15. My caps are tight but they fit and look ok. Mouser was out of the taller thinner ones I wanted when I odered my parts. Spacing is critical on the ESP boards as they are very small. When ordering I always look at the spacing on the leads and size of the can for caps. I lernt that one the hard way. You will have to keep to the 1/4 watt resistors or mount them standing up if you get larger ones. They are tight with 1/4 watt RN/CMF Vishay resistors I used.

C1-C4 - I used 667-EEU-FR1E222S Mouser - those are at the absolute max size that will fit. They are even tighter than I like but worked.

Cheers,
Bob