HT MC Phono Stage AD797

[sachu888]

Yes, the LME adapter that I have is the dual one. So I guess this version of the HT MC PS is different from the Mark I, then?

@Sachin: Going by this, I guess I have the wrong LME adapter.

@Hypnotoad: does the single SOIC adapter use pin 4 for V- and pin 7 for V+? I am asking this because the V- and V+ voltages are available on pins 4 and 7 respectively on the board.

Hi Joshua,
Your LMe49990 were from older version of HTMCPS which uses 2SOIC to DIP adapters like this(single to dual).This will no work here.You need only SOIC opamps here.AD797 are also single channel opamps.Dual Opamps will not work.

Regards,
Sachin

 

[jls001]

Now I hope that I have not fried the LME49990s that I had been experimenting on. I didn't see no smoke, nor any spark:lol:

 

[sachu888]

Now I hope that I have not fried the LME49990s that I had been experimenting on. I didn't see no smoke, nor any spark:lol:

They shotld be ok won't go bad so easily.

Regards
Sachin

 

[sachu888]

Offtopic


Hi Quad,
nice to see your name here http://www.audiokarma.org/forums/showthread.php?t=506745

Regards,
Sachin

 

[quad]

Re: Offtopic

Hi Quad,
nice to see your name here The Audiokarma.org Member of the Year for 2012 is... - AudioKarma.org Home Audio Stereo Discussion Forums

Regards,
Sachin

wow, I would never have found that. Thanks!

 

[kanwar]

That looks awesome Kanwar.

I notice that the extra mounting holes for the DC blocking caps at the outputs are missing, some people use the Panasonics with the 15mm spacing, some use the 22.5mm and the recommended Wima's are 27mm.

Just updated the mounting holes for capacitors with different footprints, along with PCB mounting holes.

Gerbers emailed.

Anyone else want Gerbers, let me know.

Cheers,
Kanwar

 

[malvai]

Kanwar! Build this na? It could be a great thing for us analogue philes!

 

[kanwar]

Kanwar! Build this na? It could be a great thing for us analogue philes!

Would love to do, if enough interest is generated among forum members. We can start group buy.

 

[malvai]

Would love to do, if enough interest is generated among forum members. We can start group buy.

figure out a price and the numbers... am sure there will be enuff of us for it!

 

[sachu888]

I am already having components for this.Total cost would be Rs 6000(approx).
BTW: Omishra still holding PCbs for Pearl Phono2.I was waiting from a confirmation from members.



Regards,
Sachin

 

[malvai]

sachu... which of the two is better phono?

 

[sachu888]

sachu... which of the two is better phono?

I can't say but reviews are very good for both.Pearl could cost twice as it is a dual mono design and total no of parts are almost double than AD797.

Regards,
Sachin

 

[jls001]

I can't say but reviews are very good for both.Pearl could cost twice as it is a dual mono design and total no of parts are almost double than AD797.

Regards,
Sachin

Do consider the cost of two cabinets in Pearl 2. It is designed to be built the purist way - power supply in a different enclosure, the dual mono preamps in another, joined by an umbilical.

@Sachin: I already received the Pearl 2 boards from Om and I am ready for the components from you

@the Rest who had bought the Pearl 2 boards from Om: I hope we all are ready for a mini GB for the parts through Sachin since he has vast knowledge of the best components and where to source them from. I'm already in.

 

[sachu888]

Do consider the cost of two cabinets in Pearl 2. It is designed to be built the purist way - power supply in a different enclosure, the dual mono preamps in another, joined by an umbilical.

@Sachin: I already received the Pearl 2 boards from Om and I am ready for the components from you

@the Rest who had bought the Pearl 2 boards from Om: I hope we all are ready for a mini GB for the parts through Sachin since he has vast knowledge of the best components and where to source them from. I'm already in.

thanks Joshua,
Pearl2 phono has very high gain as compare to other phonostages and requirs Power supply to be built in another cab.AD797 and Pearl 2 should sound identical.Pearl2 isa Pass design so it should be good.AD797 is Hypnotoad design and I have very high regards for him.
I would wait few more days for other members to respond and order parts.

Regards,
Sachin

 

[anilva]

thanks Joshua,
Pearl2 phono has very high gain as compare to other phonostages and requirs Power supply to be built in another cab.AD797 and Pearl 2 should sound identical.Pearl2 isa Pass design so it should be good.AD797 is Hypnotoad design and I have very high regards for him.
I would wait few more days for other members to respond and order parts.

Regards,
Sachin

Sachin,

Count me in for the parts.

Cheers.

 

[jls001]

Finally I received the correct opamp adapter and two LME49990 from Sachin. I spent today evening in soldering the opamps to the adapter. On fitting them to the circuit, it worked fine. I could barely listen to one track as I had to go out for some engagement. I will be able to give initial listening impressions after some four-five record sides. For now, I can say that the gain setting I had for the Denon DL 103 needs a drastic revision (need to increase gain by about 10 odd dBs).

It surely is problem with the wrong opamp - this one doesn't heat up at all.

Thanks, Sachin for sending the correct opamp adapter.

I guess I will finally be able to populate Bibin's cabinet with this phono pre, the B1 buffer and the source selector, and of course the OPS. I'm not sure if I can squeeze in the SSP.

 

[jls001]

For those inclined, here are some pictorial guides on how to correctly solder the opamp LME49990 to the single SOIC adapter

1) The notch A1 on the adapter must be aligned to the notch A2 on the chip

Notch B marked on the adapter is for aligning to the 8-pin opamp slot on the circuit board.


2) A simple contraption to secure the opamp to the adapter for soldering. You need a pointed solder bit to solder this opamp. A magnifying glass and good lighting are very helpful as the legs of the opamp are tiny. Make sure you do not short the legs while soldering.

3) The finished product. Now solder the legs.

 

[Hiten]

Paper Clip tip is useful. Superb micro soldering and nice macro photography Joshua. Which camera ?
Regards

 

[omishra]

For those inclined, here are some pictorial guides on how to correctly solder the opamp LME49990 to the single SOIC adapter

1) The notch A1 on the adapter must be aligned to the notch A2 on the chip

Notch B marked on the adapter is for aligning to the 8-pin opamp slot on the circuit board.

In other words -
On Adapter PCB, below "notch A1" there is a solid white dot. That dot needs to matched for SMD IC's dot at pin #1. If SMD IC has notch at side w/o pins then match notch at side w/o pins.

General convention is that -
"U" shaped Notch is between Pin #1 and 8 of IC
Or solid dot at pin #1 of IC.

You can have either marking on PCB or part.

 

[jls001]

Which camera ?

A beat up HTC Desire HD android phone:lol: