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

[dodog]

Pics as promised. Here it is. Not too shabby for my first ever build. I recycled an old ABC switchbox (I think it was for connecting old-school printers) and everything just fit. I cut a piece of plexiglass to use as a mounting plate to place risers for the PCB as well as the 9-volt holders. I had to cut another small one to place the RCA jacks through as well and just used the hardware that was holding on the old connectors. It worked out pretty slick. Anyhoo, enough babbling. Here's the pics:

 

[jason12]

I am sorry if this question was already asked/answered - do not have time to go through all 27 pages. I have not noticed either decoupling caps or servo in schematics on 2 first pages. I just wonder how much DC offset is at the output? From my experience it would be easily in the range of Volts - due to high DC gain and use of OpAmps with BJT transistors in the input stage (1028). Even with FET input it will be quite high.

 

[redjr]

Just curious why many of these builds don't use shielded phono cable for input and output to/from the RCA jacks? I would have thot it would be the best cabling option for a MM phono stage - to minimize any hum and interference. Is using twisted pair (and, no that's not the name of a band) a better choice here?

I've got my board together, but haven't decided on a case or PS yet. I'm not thinking batteries, but realize they provide pure DC power. Are there some small, low-voltage DC supplies available as kits anywhere? Recommendations?

 

[HypnoToad]

Just curious why many of these builds don't use shielded phono cable for input and output to/from the RCA jacks? I would have thot it would be the best cabling option for a MM phono stage - to minimize any hum and interference. Is using twisted pair (and, no that's not the name of a band) a better choice here?

I've got my board together, but haven't decided on a case or PS yet. I'm not thinking batteries, but realize they provide pure DC power. Are there some small, low-voltage DC supplies available as kits anywhere? Recommendations?

It's not necessary for the distances involved and the case is grounded which shields it from emf, anyway. I have mine in a plastic case and don't have any noise or hum.

If you go to Rod Elliot Sound products, he has a good linear supply that is very easy to build:

http://sound.westhost.com/project05b.htm

I am sorry if this question was already asked/answered - do not have time to go through all 27 pages. I have not noticed either decoupling caps or servo in schematics on 2 first pages. I just wonder how much DC offset is at the output? From my experience it would be easily in the range of Volts - due to high DC gain and use of OpAmps with BJT transistors in the input stage (1028). Even with FET input it will be quite high.

The schematic posted from the National Semiconductor data sheet does not have any, but they are included in the final design.:yes:

 

[redjr]

HypnoToad -

Thanks for the cable tip and PS link.

 

[sachu888]

HypnoToad -

Thanks for the cable tip and PS link.

Hi,
I have installed twisted pair of CAT5 Ethernet cable.Earlier I was getting hum/buzz with ordinary cables.Phono RCA cables are two stiff for this purpose,An AK member suggested me twisted pair of Ethernet cable and it solved my purpose.

Regards,
Sachin

 

[FrankPA]

Good idea on the twisted pair. I have some shielded twisted pair microphone cable left over from wiring the ABS sensors into my race car, think I'll use that.

 

[DougMac]

About to build, found a tool to help

Well, I've ordered the parts from Digikey and I'm anxiously awaiting their arrival.

I want to give you a head's up to those who may not have started the project. I went to Parts Express to order a box and RCA connectors that I forgot to order from Digikey. There I ran into the Grip Tools Helping Hand. I has two alligator clips to hold the board, a built in magnifier with an LED light and a soldering iron holder. The best part is that it's only $10! I'm willing to take a chance for that money. I've seen better/fancier helping hands, but they cost a lot more. For such a small circuit board, this should work fine.

 

[vincei]

Well, I've ordered the parts from Digikey and I'm anxiously awaiting their arrival.

I want to give you a head's up to those who may not have started the project. I went to Parts Express to order a box and RCA connectors that I forgot to order from Digikey. There I ran into the Grip Tools Helping Hand. I has two alligator clips to hold the board, a built in magnifier with an LED light and a soldering iron holder. The best part is that it's only $10! I'm willing to take a chance for that money. I've seen better/fancier helping hands, but they cost a lot more. For such a small circuit board, this should work fine.

Looking forward to your build.

 

[redjr]

Well, I've ordered the parts from Digikey and I'm anxiously awaiting their arrival.

I want to give you a head's up to those who may not have started the project. I went to Parts Express to order a box and RCA connectors that I forgot to order from Digikey. There I ran into the Grip Tools Helping Hand. I has two alligator clips to hold the board, a built in magnifier with an LED light and a soldering iron holder. The best part is that it's only $10! I'm willing to take a chance for that money. I've seen better/fancier helping hands, but they cost a lot more. For such a small circuit board, this should work fine.

Doug -

Thanks for the tip on the Grip Tool thingy. I could use one of those myself. Should have had one for years, but never got around to buying one. The magnifying lens will help a lot now that my eyesight isn't what it use to be. It's not clear from the product description how it attaches (if it does) to your work space table top. Does it use just a heavy base, or is there some kind of suction cup on the bottom? Any AK'ers have one of these that can offer an opinion on its effectiveness in particular how it's secured, or an alternative product that works well? Thx.

 

[DougMac]

Doug -

It's not clear from the product description how it attaches (if it does) to your work space table top.

Don't know. The shipping charges indicates it must be heavy. I'll post a review when it arrives.

 

[bobrown14]

Don't know. The shipping charges indicates it must be heavy. I'll post a review when it arrives.

Does it look like this? I use one all the time holds the PCB or wires etc when soldering .. keeps me outta trouble asking my SO to hold wire while I solder... :thmbsp:

Cheers,
Bob

 

[redjr]

Does it look like this? I use one all the time holds the PCB or wires etc when soldering .. keeps me outta trouble asking my SO to hold wire while I solder... :thmbsp:

Cheers,
Bob

Yes. It's very similar to that one, but I believe it is different. From the looks in the ad, it appears to have a heavy base, and does not look like there's a suction cup.

 

[redjr]

For $9.95 I decided to take a chance on the Grip Tool thingy. I had some other parts I was ordering, so decided to try it. My biggest concern - sight unseen - was if and how it secured to the work space tabletop. It does not. This is NOT a review, but just my first impressions of unboxing and looking and feeling the Grip Tool.

It has a very small weighted base that may not be sufficient to keep it from moving around when using it. Since it is rather small, it appears you will only be able to handle small circuit boards with it, or hold a component and wire while you solder. The magnifying glass seems okay and does have a light in to help. I'm a little skeptical of its effectiveness, but will keep it and give a try. There's generally always a reason something is on sale!

 

[aabottom]

For $9.95 I decided to take a chance on the Grip Tool thingy. I had some other parts I was ordering, so decided to try it. My biggest concern - sight unseen - was if and how it secured to the work space tabletop. It does not. This is NOT a review, but just my first impressions of unboxing and looking and feeling the Grip Tool.

It has a very small weighted base that may not be sufficient to keep it from moving around when using it. Since it is rather small, it appears you will only be able to handle small circuit boards with it, or hold a component and wire while you solder. The magnifying glass seems okay and does have a light in to help. I'm a little skeptical of its effectiveness, but will keep it and give a try. There's generally always a reason something is on sale!

Hey, for $9.95, glue it to a big weight.

 

[redjr]

Hey, for $9.95, glue it to a big weight.

Yeah, a 2.5 lb barbell weight just might just do the trick.

 

[DougMac]

For $9.95 I decided to take a chance on the Grip Tool thingy. I had some other parts I was ordering, so decided to try it. My biggest concern - sight unseen - was if and how it secured to the work space tabletop. It does not. This is NOT a review, but just my first impressions of unboxing and looking and feeling the Grip Tool.

It has a very small weighted base that may not be sufficient to keep it from moving around when using it. Since it is rather small, it appears you will only be able to handle small circuit boards with it, or hold a component and wire while you solder. The magnifying glass seems okay and does have a light in to help. I'm a little skeptical of its effectiveness, but will keep it and give a try. There's generally always a reason something is on sale!

That's pretty much my impression as well. It will do for lightweight, once-in-a-blue-moon jobs, but if you do any amount of soldering on PCB's, spring for a real tool. The soldering iron holder seems to be in an inconvenient location, I'm going to remove it and use another holder that has a sponge tray.

 

[redjr]

That's pretty much my impression as well. It will do for lightweight, once-in-a-blue-moon jobs, but if you do any amount of soldering on PCB's, spring for a real tool. The soldering iron holder seems to be in an inconvenient location, I'm going to remove it and use another holder that has a sponge tray.

My son was using it yesterday to do some light soldering, and said the magnifying glass and light came in real handy. He said it stayed in place for what he was doing. I was not observing him at the time. I guess one benefit of it being movable is that you can easily position it right where you want it for soldering. He's new to soldering and I'm letting him do some small projects/boards to get the hang of it. His hands are steadier then his ole man's and eyesight much better!

I started with a Weller gun in the mid-60s which was easier to learn on. Of course that was before PCBs being used for home projects. I later honed my soldering skills on many a Heathkit using a soldering pencil (that I still have and use), and when I built my first computer - the SOL-20 in the mid-70s. Ah, those were the days. Now I'm building phono-stages, power supplies and DACs. Are kits coming back for us old-timers? eBay can be a wonderful thing.

 

[DougMac]

I started with a Weller gun in the mid-60s which was easier to learn on. Of course that was before PCBs being used for home projects. I later honed my soldering skills on many a Heathkit using a soldering pencil (that I still have and use), and when I built my first computer - the SOL-20 in the mid-70s. Ah, those were the days. Now I'm building phono-stages, power supplies and DACs. Are kits coming back for us old-timers? eBay can be a wonderful thing.

Me too! I had a Weller gun with two heat ranges. Pull the trigger lightly for normal heat or really squeeze it mongo heat for fat wire. The Weller was fine for point to point. Remember when Zenith advertised their TV's were hand wired? They considered it a selling point.

I also put together a Heathkit or two, including an AR-19 receiver, a photo timer and a color TV! What I miss is the ability to run down to the local electronics store like Specialty Distributing and picking up whatever you needed; hardware, resistors, capacitors, tubes(!), etc. It was fun to hobknob with all those TV repairmen, I remember when our town must have had a dozen. That was back in the day of house calls, from either your doctor or your TV repairman!

 

[sachu888]

CNC update

Hi all,

I have shielded my wooden box with aluminium foil,PCb sits on an old hard drive cover, added a banana terminal and 4 rubber feet etc.