Norge 1000's Modded Avatar Lands!

[Audiodoc]

This is the first few mods to my Norge 1000 Gold:

1. Speaker Protection Circuit: Removes the irritable turn on "pop" sound and provides instant turn off and DC protection.

2. Default preamplifier Mod: Removed on board TL072 opamps. Replaced with IC bases. Tried NE5532 with subtle improvement followed by Burr Brown OPA2134s with significant improvement.

3. Installed a separate preamplifier based on the well known Burr Brown OPA627s with fixed gain jumpers bypassing volume control (volume controlled by DAC) with instant switching between the two pre amplifiers. Both sound different. Tired right now to compare will do it later.

4. Forthcoming mod will be the replacement of supply capicitors by 4x10000 microfarad Nichicons.

Hope you like the pics.

 

[gopib]

Audiodoc,

Good initiative. It also looks like there was enough real-estate inside
the amp. Just out of curiosity, did you decide to do the mod after seeing
that there was enough space and so on, or did you decide to do the
mod any which way since there are better components available?

TIA

 

[josephjohnt]

Goodone Audiodoc. Its nice to see that your efforts was worth it.

 

[omishra]

Nice! any DIY guy can't be satisfied with ready made product unless puts his/her own hands into it.

BTW, we are waiting for audition result.

 

[quad]

Great work, doc!
What about the motorized volume control? Is that your add on too?

 

[murali_n]

Hi audiodoc,

Pl go thro this:

Hi-Fi Preamplifier

The Norge pre-amp is based on this ckt. I had earlier done the same mod in 2060, the results were not very encouraging, the mids remained the same, so thats why I am asking you to go thro this article.

N.Murali

 

[quad]

Hi audiodoc,

Pl go thro this:

Hi-Fi Preamplifier

The Norge pre-amp is based on this ckt. I had earlier done the same mod in 2060, the results were not very encouraging, the mids remained the same, so thats why I am asking you to go thro this article.

N.Murali

OMG, it's a complete rip off of the ESP board. Absolute copy.
Hope it's an authorized one.

 

[Audiodoc]

The motorized volume control was already upgraded by Norge since I found the 1500 buck upgrade to be cheaper than a DIY upgrade. Motorized volume knobs are not preferred by audiophiles! The DIY preamp bypasses the motorized remote.

Upgraded the opamps just to notice any significant audible changes though the differences in noise between TL072, NE5532 and OPA2134 are in inaudible ranges. Searching someone with golden ears to do a blind comparison.

And yes all that empty space and the high cost of enclosures tempted me to use the real estate inside the Norge 1000.

Planning to make a tube based preamplifier tonight. Will be a good comparison with respect to TL072, NE5532, OPA2134 and OPA627 semiconductor ones.

 

[sudhishkv]

What about adding a USB DAC circuit?

 

[Audiodoc]

I am planning an external DAC:

Many DIY options don't know which one to build:

Buffalo and Gamma 2 are the most loved ones on Head Fi.

Want something great (but not a $1800 Benchmark). Presently using the FiiO E7 as DAC.

 

[gurubhai]

I am interested in gamma 2......
we can build it our self by getting the parts....

 

[Audiodoc]

Then we should buy them. Can you arrange for the PCBs and parts. How much moolah will it cost? I already have so many amplifiers:

2 x DAP
2 x Potable headphone amplifiers
2 x Desktop headphone amplifiers
2 x Desktop Preamplifiers
2 x Power Amplifiers (Plus Parts for a 5.1 multichannel Amp)

and just 1 DAC. Sarasar na insafi!:lol:

 

[Audiodoc]

The final upgrade has been done to complete this project for the time being. 4 x Nichicon 10000 MFD, 50V capacitors.

Instant low end grunt could be felt. These replace (previously as 'relapse' typo error) the 4 x 6400 Samwha capacitors.

 

[gopib]

Good job Audiodoc!:clapping:

"relapse"?? i guess you meant "replace" ...profession taking over???

 

[Audiodoc]

You are right gopib. It was replace and I do a lot of oncology reporting during the day lots of cancer relapses today. Seems the brain has got rewired :lol: in writing these bad words!

 

[omishra]

Now those 4 diodes in the PS need attention. e.g. something ultra fast diodes like MUR3020 or MUR860 ..etc

 

[Audiodoc]

Good Suggestion Mr. Omishra will do the same soon.

Am upgrading the aesthetics by using 4 solid aluminum knobs for the same. and possibly a small headphone amplifier.

What about the filter caps for the balanced 15-0-15 supply. Will upgrading them make any significant difference

 

[quad]

What about the filter caps for the balanced 15-0-15 supply. Will upgrading them make any significant difference

I believe that is the power for the tone control section. Better caps
should help here too.
BTW, Is there a way to bypass the tone controls on this amp?

 

[Audiodoc]

There is a default tone defeat switch which suppresses the effect of the tone controls however the same has not been implemented in the models with motorized volume control because Mr. Bajaj uses the hole in the front fascia for the infrared receiver. I could have implemented the same by drilling a new hole preferably in the rare panel however I can shutoff the inbuilt preamplifier by a single DPDT switch to a OPA 627 preamplifier with fixed 6x and 12x gains which bypasses the selector switch and preamp going directly to the power amp inputs for something like a direct switch of AV receivers. At the same time have shifted the line out of the amp to the new preamp so I get to use the OPA627 preamplifier for my other devices.

 

[Audiodoc]

@ gurubhai

How does the buffalo DAC compare to this

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