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Here It Is: The All Singing All Dancing HTMCPS

dodog said:
I'm confused as well. For the CNC build, the power grounds to the PCB which shares a ground-out wire with the binding post/chassis. Is there something different about the HTMCPS that you wouldn't do this as well?
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I don't know. That's kind of what I thought it would be, but Sachin said to keep the tt ground separate from chassis ground.
 
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AARRGGGHH! Sorry, the ground points on the pcb are all linked with the neg outputs on both boards. I have a hard time following the traces...
 
This is what I do, I connect the ground point on the PCB to the screw on the chassis where the Turntable ground goes. So the chassis is connected to the PCB ground.

If you look at the latest HTMCPS PCB's there are two ground points, one for the virtual ground from the batteries or PSU and one close by for the chassis/turntable.

If you have the older PCB just use the virtual ground point for the batteries or PSU for everything.

Hope this clears things up.
 
So where do we stand on op amp rolling?

Hypnotoad - have you tried the LME 49990 which Sachin liked a lot?
Or is the OPA2134 still the prefered choice?

Thank you Sachin, for pointing me in the direction of this project.

Starting to pull my parts together for the build. :zoom:
 
It is for rme.

Qwin said:
So where do we stand on op amp rolling?

Hypnotoad - have you tried the LME 49990 which Sachin liked a lot?
Or is the OPA2134 still the prefered choice?

Thank you Sachin, for pointing me in the direction of this project.

Starting to pull my parts together for the build. :zoom:
Click to expand...

I tried the LM4562, 49720, AD823, 49990, and a couple of others. In this pre-amp the 2134 is the best all-rounder (so far!) Detail, bass, transients, vocals all are excellent and balance very well. The 4562 and 49990 have greater emphasis on detail but they have a hard edge to my ears. YMMV.
 
Qwin said:
So where do we stand on op amp rolling?

Hypnotoad - have you tried the LME 49990 which Sachin liked a lot?
Or is the OPA2134 still the prefered choice?

Thank you Sachin, for pointing me in the direction of this project.

Starting to pull my parts together for the build. :zoom:
Click to expand...

Yesterday I tried OPA2107 and Opa2132 in CNC.They both were good.2132 was even laid back than Opa2134 and 2107 was great in every dept than 2134.I have even tried LM4562 which was very detailed,no harshness was present in my system,bass was little less than BB chips.It performed nearly 90% like LME49990.My preferences are
1.LME49990
2.LM4562
3.OPa2107
4.Opa2134
5.Opa2132
6.Ad823

Regards,
Sachin
 
A lot of it depends on the rest of your system, if your system is laid back then detailed op amps will bring it to life, if it's detailed to start with you may prefer the BB sound.

It's horses for courses IMO.
 
Has anyone stacked opamps?
Sorry if it's been discussed. But' shouldn't it yield a lower noise floor. And if mixed properly possibly mix the best of two different worlds.
 
If you connect the positive and gnd you have a lopsided supply.

The 8.2k resistor drops the current across the LED, without it the LED will burn out.
 
HypnoToad said:
If you connect the positive and gnd you have a lopsided supply.

The 8.2k resistor drops the current across the LED, without it the LED will burn out.
Click to expand...

Thanks, got it.

Re your first post on this thread...I was listening to the Carpenters album "Singles," and Karen's voice sounded a bit harsh/hard in places. I'm looking forward to seeing if the HTMCPS can smooth it out on my system as well. It's a really well-recorded album otherwise -- seems like a good candidate for a high-end vinyl reissue. They did the K2 CD thing with their greatest hits, but no vinyl yet...
 
I was thinking of getting the Audio Technica AT OC9II -- on the spec sheet I can find, it doesn't have the coil resistance, but only says "recommended load impedance: more than 20 ohms." Any idea what resistor value to use?

FWIW, the newer model, the OC9III, lists the coil impedance/DC resistance as 12 ohms.
 
GreatTone said:
I was thinking of getting the Audio Technica AT OC9II -- on the spec sheet I can find, it doesn't have the coil resistance, but only says "recommended load impedance: more than 20 ohms." Any idea what resistor value to use?

FWIW, the newer model, the OC9III, lists the coil impedance/DC resistance as 12 ohms.
Click to expand...

I found the AT-OC9 which was 12 ohms also so I would go with that.
 
HypnoToad said:
A lot of it depends on the rest of your system, if your system is laid back then detailed op amps will bring it to life, if it's detailed to start with you may prefer the BB sound.

It's horses for courses IMO.
Click to expand...

I think choice of opamps for HTMCPS & CNC is like icing on the cake. Not everyone favors the same type of icing, but all will enjoy a good cake regardless of the icing.

Some opamps will require break in time to sound best. From my experience, very slight harshness of LME49990 does go away after 10 to 15+ hours of use. Also, LME49990 used with OPA2134 will make it sound even less balanced, worst then paired OPA2134. In my set up, the balanced performance of LME49990 is only achieved when used as pair.

Unlike other opamps, LME49990 seems to be very sensitive to supplied voltage on the input socket end of the board. Try swapping two LME49990 on sockets, place the one used at the input and place it in the output socket and vice versa, if you're not getting the detailed, fuller & balanced vinyl playback.
 
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