Neurochrome Differential preamp build

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Another Diff Pre build

As usual, my projects always take longer to complete than I originally expect them to. This project was no exception, and it also falls in to a category that is all too familiar to me: If I had known how good it would be, I would have done it sooner. It is pleasant to get back to clarity again!

Some details:

- The raw casework is 14-19102 from Par-Metal

- All in one input/fuse/filter modules are too physically large for this application. I had two Schaffner FN2020-3-06 available, along with an IEC connector, a DPST power switch, and some fuse holders.

- The motorized 48 step attenuator is from High Quality Audio & Industrial Attenuators and Passive Preamplifiers

- The motorized attenuator is powered from a Meanwell IRM-20-12, which very nicely snaps in to a size D battery holder (the holder is fastened to the chassis using contact cement).

There is one special trick here. There is a small circuit board that is at the side of the attenuator and in front of the main board. This is something that I commissioned from Tom. It is a signal polarity inverting circuit, that can be selected or deselected from the small switch on the front panel, and with invert selected indicated by a green LED.

I WAS GOING TO ADD THREE PHOTOS, BUT THE SIZE AND FILE SIZE OF EACH IS LARGER THAN THIS SITE ALLOWS. PHOTOS TO BE ADDED IF AND WHEN I LEARN HOW TO WORK ON JPG FILES!!
 
I WAS GOING TO ADD THREE PHOTOS, BUT THE SIZE AND FILE SIZE OF EACH IS LARGER THAN THIS SITE ALLOWS. PHOTOS TO BE ADDED IF AND WHEN I LEARN HOW TO WORK ON JPG FILES!!
Look at these programs, those you need, Resizer and Viewer, are freeware and wonderfully easy to use :

FastStone Image Viewer, Screen Capture, Photo Resizer ...

Everybody I recommended them to have adopted them.

With Resizer, look carefully at Advanced options, you can get nice images of only a few kB in PNG format with a low but sufficient color depth. Width of 800 pixels is well fitted for publications on the net.

Shareware Capture is a marvel. You can try it for a month for free.

I also used Irfanview which is another very nice tool and has some functions not present in Faststone products. But it is not as handy to change sizes and formats.
 

Attachments

  • DSCN0013_opt.jpg
    DSCN0013_opt.jpg
    183.8 KB · Views: 635
  • DSCN0011_opt.jpg
    DSCN0011_opt.jpg
    166.1 KB · Views: 631
  • DSCN0012_opt.jpg
    DSCN0012_opt.jpg
    190.2 KB · Views: 626
that driver

hi how does that driver used as a pre amp with a volume control and this pre amp compair in sound quality the smaller package would be more attractive to me as i dont need and so many inputs and i would have way more case work options
 
Last edited:
A THAT Receiver + volume pot + THAT Driver powered by a clean supply would be sonically identical to the DIFF PRE.

My Power-86 with a small mains transformer would provide plenty of power. My SMPS-86 is a nice package. A bit overkill for preamp service, but it would certainly work.

Tom
hi tom thanks for speedy reply what if i am using a single ended source do i still need THAT receiver?
or would a better option be to use THAT receiver as well as THAT driver and mod a phono lead to a Pseudo-Differential Cable
 
Tom, what if you have a multi-channel setup with 3 or 4 THAT driver boards. Is there a way to control the volume on all the boards simultaneously in sync with each other?

Sure. Just take the output of the volume pot to multiple THAT Drivers.

what if i am using a single ended source do i still need THAT receiver?

Nope. Just take your input straight to the volume control (through a selector switch if you want multiple inputs).

Tom
 
My build

I used a SlimLine 1U 170mm case from ModuShop and sent the front and rear panels to Schaeffer for processing. Not cheap, but an excellent service and their Front Panel Designer application is easy to use.

I used Rivet Nuts to mount the PCBs

41668439054_29014151ba_c.jpg


I included one of Tom's THAT Drivers to provide an output for a headphone amp and a board from CustomWorks to provide remote power on/off, volume control and trigger out to the power amp.

41419192725_12cc8f29cc_b.jpg


Here it is partnered with my Mod-286 dual mono power amp. I'm really pleased with how it sounds fed from a RaspTouch player with an IQAudio Pi-DAC Pro.

41419192095_1fff8a95cf_b.jpg

28447639688_2318f3e23e_b.jpg
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.