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

Here is a MC phono stage that I have mapped out ready to make a PCB for. It's the most sophisticated one I have attempted, it has two stage RIAA compensation like the P06. But has a output Mosfet. It's supposed to outgun many really high end MC stages, we will see.

phono_sp.jpg
 
Hypno, if that design works out as it promises to, I'd sign up for a group buy (or the likes of it) in a snap. :thmbsp:
 
catman said:
G'day all, this circuit is is interesting as I'm not sure where the bass eq network is :scratch2: Ok I see it now but my feeling is that it may need tweaking a little perhaps.
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Please elucidate-
Which components are involved and what changes should we experiment with?
 
Could one of these designs be easily modded for variable output or would doing so degrade the sound? I would love to have something that I can scale back for dropping hot albums?
 
markshan said:
Could one of these designs be easily modded for variable output or would doing so degrade the sound? I would love to have something that I can scale back for dropping hot albums?
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The gain of each stage is controlled by the 3320 ohm and 150 ohm resistors, you can simply insert a variable resistor of say 5k in place of a 3320 ohm and set it to what you want.
 
Fasterdamnit said:
Sign me up! seriously- I would love to build and test it. Please don't make me beg...
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voltcontrol said:
Hypno, if that design works out as it promises to, I'd sign up for a group buy (or the likes of it) in a snap. :thmbsp:
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I have the artwork already and both channels fit on a 5" x 4" pcb. I just need to print it out on the laser printer at work and we are on the way. It's not going to be that cheap as it has six single circuit op amps, I envisage AD797's in the input stages and AD843's in the others, op amp prices have shot up lately, the BOM is going to be over $100.00.

I already have the power supply done.

Let's not too excited though, the designer said it accounts for some very high end stages, so like I said we will see.
 
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HypnoToad said:
The gain of each stage is controlled by the 3320 ohm and 150 ohm resistors, you can simply insert a variable resistor of say 5k in place of a 3320 ohm and set it to what you want.
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Cool. I hear about different caps sounding better or worse. Is the same true for resistors? If so, what would be recommended?
 
Some say carbon/carbon film resistors are noisy in current-carrying circuits and metal film preferred, while the opposite stands for signal-only circuits where carbon film is preferred. Copper leads are preferred to plated steel and silver bearing solder for signal circuits. Of course there are 'boutique' resistors of ever-ascending cost, I don't comment on them without knowledge.
 
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I etched the PCB board today for the "high end" MC phono stage and drilled about half the holes so it's on the way. I just wish Comet Supply would come through with my Denon DL-301 Mk 2.

I am going to make a PCB of the OP's stage once I get some more copper clad, which seems pretty cheap through PCB Depot on that auction site.
 
Excellent! We will be doing some critical listening this week to "El Cheapo" and will report what we hear.

You will like what you hear once you have that Denon... ;)
 
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:
Switched2opamp.jpg
 
Hold on there, Sparky. Where's the FET?? :dunno:

Oooooh! I get it, you made a board for the the National Semiconductor recommended circuit. Well done!
 
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Fasterdamnit said:
Hold on there, Sparky. Where's the FET?? :dunno:

Oooooh! I get it, you made a board for the the National Semiconductor recommended circuit. Well done!
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I have finished the board for the high end MC stage but STILL don't have the Denon DL-301 Mk2. So there is no point in going any further (parts are just over $100.00) as I can't test it out.

I put dip switches for four different cart loadings on the simple cheap MM stage from the National Semiconductor page, it has 18k, 33k, 47k and 62k. I use 18k for my Grado Gold.
 
mo_feezy said:
If someone did a run of those PCB's I would buy one to give it a shot.
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If it sounds as good as I think it will maybe we can make a group buy of say ten PCB's. I would make them myself but I HATE the hole drilling, it takes a lot of work.

The board is only 4" x 3".

2OpAmp.jpg
 
Here is the phono section of a Mcintosh C34V.
 
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