lofiharvest
Member
Cool!
Another Super High End Phono Stage! No expense spared...
- Thread starter Fasterdamnit
- Start date
lofiharvest
Member
I actually may be interested in participating in the group buy for the PCB. Let us know!
Last evening my wife and I did some critical listening on the Super Cheap Phono Stage that Fasterdamnit and Big Bill built. The only difference with the one I did was it has AD823's in both stages and I added some DC blocking and loading components. I also found I could get very close to the RIAA values with less components than the original schematic. So close so as not to matter which makes things easier.
I must say we were both surprised at how good this thing sounds, this evening I am going to compare it to my modded 640P and Rod Elliot P06. From what we heard it's going to be very close and I am not sure at this stage who the winner will be.
Fasterdamnit and Big Bill are onto something really good here especially when you consider the cost of this thing, the components coming to around $30.00.:thmbsp:
I must say we were both surprised at how good this thing sounds, this evening I am going to compare it to my modded 640P and Rod Elliot P06. From what we heard it's going to be very close and I am not sure at this stage who the winner will be.
Fasterdamnit and Big Bill are onto something really good here especially when you consider the cost of this thing, the components coming to around $30.00.:thmbsp:
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voltcontrol
Fizheuer Zieheuer
Thanks for sharing all of this effort guys!
Still on the lookout for that first soldering project.
If you'll (Hypno?) offer PCB + BOM im up for it.
Also NEED an MC stage for my Dynavector.
Very much looking forward to your listening impressions Hypno.
Still on the lookout for that first soldering project.
If you'll (Hypno?) offer PCB + BOM im up for it.
Also NEED an MC stage for my Dynavector.
Very much looking forward to your listening impressions Hypno.
voltcontrol
Fizheuer Zieheuer
Wondering what the thought behind posting this is?
(Really am wondering, quite new to 'this')
shelly_d
Not An Audiophool
I'm not the poster but I took it as a comparison. An inexpensive, 2 dual opamp circuit using passive equalization (that is passive filters nestled between flat gain stages) as opposed to a 1 opamp stage using active (read feedback loop) equalization used in a very expensive name brand device.
Just my take on it.
Incidentally, in case my opinion is not really clear, I like the idea of the passive eq. circuit better then the feedback eq.
Shelly_D
Fasterdamnit
Super Member
And the cheap Audio Technica ATPEQ3 phonostage is a single op-amp, active EQ. Interesting what you find when you look under the hood...
dodog
Addicted Member
I finally made the PCB of the super cheap phono stage. I did an oops with it as I had quickly scribbled the component values onto a piece of paper and had a 2.7k resistor instead of a 27k. When I first tried it I couldn't work out why there was no bass.
Once that was fixed all was well, it needs burning in and I added some components, a dc blocking resistor in the inputs and a blocking cap and loading resistor to the outputs. As well as bypass caps on the op amp supply lines.
It sounds remarkably good, I will do some critical listening once it's burned in, but for less than $30.00 it's a bargain.
Here's the PCB design:
Does this have to run off of 9V or could it be adjusted for 10V? I have two of these guys (Nakamichi PS100) that are getting no action otherwise:
https://www.naks.com/products/nakamichi_ps100.html
If it could be used, would I need more than one?
Fasterdamnit
Super Member
It can run up to +18V/-18VDC. You just need a pair of power supplies to provide for both the positive and negative rails. 1 pair of 9V batteries are cheap and easy. 2 pair could be run for 18v. As long as you have the dual supply, it will work.
Aerobat
Class A all the way
The Hagerman PS would be ideal.
I am going to purchase 4 x 6v lantern batteries, this gives +12V, Gnd, -12v and will last well over a year for less than $15.00. The power drain on these things is very low. And anything of 9volts or higher is fine. The op amps are designed to run on low voltages.
I have a couple of filtered linear supplies but I found once I switched to batteries everything became much clearer.:thmbsp:
The PCB's with silkscreen and solder mask would cost around ten dollars each for ten, and they get slightly cheaper the more you order.
For the PCB, components, switch and RCA Jacks around $55.00 and then you just need a case. A LED would be mandatory and easy to incorporate.
I also like the fact that we can adjust the gain by replacing the 150 ohm resistors with higher or lower values without disturbing the RIAA equalization.
I guess National Semiconductor knew what they were doing.
Fasterdamnit
Super Member
I would gladly go for at least two boards, maybe more. Count me in.
PS- what happened to the 33nf cap that parallels the 47nf on your built board?
I also see you went with one cap for 27nf instead of three in parallel to hit 27.2.
PS- what happened to the 33nf cap that parallels the 47nf on your built board?
I also see you went with one cap for 27nf instead of three in parallel to hit 27.2.
airframer85
Active Member
I'm down
Don't tell anyone but I tried one 82nf as they were out or 33nf caps when I ordered, but the boards that we will have made will have slots for 33nf & 47nf, and I used one 27nf cap like you saw. It makes very little difference IMO.
At the moment I'm experimenting with the 150 ohm gain resistors as the output is a bit lower than my other phono stages, 100 ohms should give it the necessary boost. The AD823's are a little lower in the output.
Have you done anymore critical listening and how do you find it compares with other stages?
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Fasterdamnit
Super Member
Not really. We need to crack it open so we can roll op-amps. At the moment it has a pair of LM4562's and the one time we compared to the Bugle, it was a bit harsh. The op-amps were put in during a troubleshooting session and I meant to change back before the first listening test.
Arkay
Lunatic Member
Count me in, too!
If you're going through with the group buy, please include me. Just PM me with details, and I'll send the cash. I'll follow with rapt fascination your experiments, and once you've worked out what works best, I'll populate my board accordingly. (Love this place, too!
) I have visions of being REALLY extravagant with it, and actually mounting it (gasp!) inside of a nice little BOX --if that doesn't destroy the whole spirit of the thing!
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