[ARN]

Hi again

Thougt I better post some piqtures of the wires in question.
The wires are in contact some places where the insulation is removed.








Best regards
Arild

[John Chapman]

Hello!

I get that question about insulation quite often! It is no problem at all - the wires look bare but are in fact insulated with an enamel coating. It is OCC copper wire and is the same type of wire used inside the transformers - but in a bigger gauge on the leadout. My guess is that the switch contacts are a bit dirty. Give it a good fast spin 10 or 20 times back and forth to clean them up and if you can spray a little contact cleaner on there that will likely quiet it right down. If not let me know and we'll dig a bit more and fix it up for you.

Thansk!

John

[ARN]

Thank you very much for quick answer

I like the sound of the NOH very much.
It is more dynamic than my Audio Syntheses Pro Passion (passiv pre).
Is there a big leap in sound quality with the new Bent Audio transformer based preamps?

Another question: I am using Nordost Red Dawn ballanced signal cables.
Are they a good or bad choice on the NOH? I am not sure if they are made for passiv preamps?

Best regards
Arild 

[John Chapman]

Hello!

Glad you like the sound! I no longer make the newer units as finished pre-amps - I stopped that to avoid conflicts with my OEM customers. I'd say if you like the NOH just enjoy it and put the $ into more music rather than changing gear.

Same thing for the interconnects - if they are working well just enjoy. With any of the AVC/TVC based pre-amps the cable from pre-amp to amp is not as sensitive to capacitance / length as it would be with a higher output impedance resistor based passive. This is due to the lowering of output impedance as you turn the level down and the lower output impedance does a better job of driving the downstream cable and amp. It is not an audio voodoo thing - it is very easy to measure here on the test gear. It could be that a particular cable would work especially well for you but I would not focus on cables 'made for passive pre-amps' since they would likely be optimized with resistor passives in mind. Feel free to play though if it is easy and not too expensive to do that.

Thansk!

John

[jazzyboy]

Hi everybody

I have the opportunity to buy a NOH preamp, but i'm new in the subject.
What do you think about this one ?
I think the wiring between the RCA and the selector is not adapted : too large diameter.
What do you preconise for rewire this one if i decide to buy it ?

[John Chapman]

Hello!

That red wire looks like the audience OHNO wire I used in all my later builds. It's really good stuff.

Have fun!

John

[jazzyboy]

Thanks for reassuring me.

Is it easy to rewire XLR connector on this preamp ?
What should check on my amp for compatibility with passive preamp ? Some forum evoke compatibility risk with some equipment ?
I just uploaded the electric scheme and the caracteristics of my mono amps.

Input sensibility 2v/100W
Gain : asymetric 20dB / symetric 26 dB

[John Chapman]

Hello!

Amp specs look fine. To convert to xlr outputs we must first confirm the rev of the transformers used.

If the primary leads are marked "++" and "+" and "--" and "-" then it can use xlr with good results.

Rewiring is not too hard if you have done some DIY work before.

Thanks!

John

[jazzyboy]

Thanks.
I will question the actual owner.
Where could he read the REV number of the transformer ?

What are theese parts on the back of the housing ?

[John Chapman]

Hello,

The marking on the primary ( input side ) wires tells us the rev. The owner might know the rev but for xlr operation we have to be certain so it's best to check the wires.

These were kits and so customers built them or had them built for their specific systems. Once and a while someone wanted the output interconnects hardwired not the preamp. Those connectors are not connectors but special parts made to hold the cables as they exited the preamp.

Thanks!

John

[glynnw]

Time flies.  About 15 years ago or so I looked into cables for passives and found the Red Dawn was considered an excellent choice due to, I seem to recall, it's low capacitance.

[jazzyboy]

HI John

Unfornately, there is only + and -.
It is a 2006 model.
I managed to negotiate with the current owner to make me try it for 15 days against a deposit. It will be the best way to discover the quality of sound from the preamp .

Today my preamp is only a DAC/headphone amplifier who give very good results : MATRIX Mini i Pro DSD (look like a Bel Canto case).

[Ed Sawyer]

that NOH pictured looks like a nice one. Note it has the Seiden switch, what I and many consider the best switch available at any price.  That volume control switch alone is  $150-200, and only available directly from Japan.

This looks like a nice unit and more than likely worth getting.

-Ed