[Early B.]

So imagine if one day we can let you customise your sonic characteristic comfortably at home by flipping a few switches, everything is so smooth, so powerful, so dynamic, so perfect and yet customisable. Did I just describe audio heaven? Hopefully we will get there in less than 5 years time. And it will be affordable.

You just described tube rolling.

In the auto industry, you can go online, choose all of the features you want, and your custom car will be delivered to your door. Wouldn't it be nice to do the same thing on your website for audio gear at a reasonable price? Perhaps that's where Letitroll98 was headed -- how can a layman determine the right configuration for him based on sonic attributes? Yeah, as you mentioned, it's much more complicated than that, but the engineer's job is to un-complicate it.

A few years ago, I owned a couple of Audio GD solid state components whereby you could change the sonic character by choosing from various low cost, plug-in modules. Worked very well, IMO.     

[Eric Gustafsson]

Today I will go from two STA-9, used as mono blocks, to an MCH-K38. I will use it in a bi-wire setup with 4 channels in bridged mode. 

[mresseguie]

I look forward to your impressions. 

[Eisener Bart]

Today I will go from two STA-9, used as mono blocks, to an MCH-K38. I will use it in a bi-wire setup with 4 channels in bridged mode. 

[Eric Gustafsson]

I must say that STA-9 is a very good amp, but to compare them with K38 is ridiculously. K38 is much much better at everything.
I use K38 bridged to 4 channels. 2 channels at 400 W each to each speaker. My speakers, Magnepan 3.3/R, seems to like the power (2 x 800 W) from K38.
So far the K38 is giant killer! 

I will give you more feedback later. Now I have to listen to more music.

[John Casler]

I must say that STA-9 is a very good amp, but to compare them with K38 is ridiculously. K38 is much much better at everything.
I use K38 bridged to 4 channels. 2 channels at 400 W each to each speaker. My speakers, Magnepan 3.3/R, seems to like the power (2 x 800 W) from K38.
So far the K38 is giant killer! 

I will give you more feedback later. Now I have to listen to more music.

This is exactly true.

In a sea of wonderful amps the STA-9 is a STAND-OUT especially for it's price point.

That said, the K-38 rises to a level that made me post my glowing assessments.

While everyone knows ALL amps and impressions are based on many elements including listener's preferences, if we look at all the qualities that make a truly great amp, the K-38 will be in the CREAM of "price no object" gear.

Some will have them in their systems and NEVER even know how good they are, because just assuming that an 8 channel amp for HT is not of that quality, and never actually listen closely.

Have fun Eric!

[Eric Gustafsson]

There is a minor 50 Hz hmmmmm when K38 is connected via xlr-cables. Connected via rca-cables is silent.
Something wrong with my xlr-cables or anything else?

[Eisener Bart]

There is a minor 50 Hz hmmmmm when K38 is connected via xlr-cables. Connected via rca-cables is silent.
Something wrong with my xlr-cables or anything else?

I had same with one STA-9. Then I found that is XLR cable.

[Eric Gustafsson]

Very strange. I didn't have this problem with STA-9 with same cables.
I have to try with some other xlr-cables.

[John Casler]

Very strange. I didn't have this problem with STA-9 with same cables.
I have to try with some other xlr-cables.

What preamp are you using?

Try this:  while using the XLR cables as you are, take a single RCA cable and run it from any RCA output of your preamp to any input of the K-38.

[Eric Gustafsson]

My preamp is from Hattor Audio in Poland.
I will test the trick with the rca-cable

[Eric Gustafsson]

To connect an rca cable didn't solve the problem. I will test with som other xlr cables.

[Eisener Bart]

I will test with som other xlr cables.

Yes, it's better idea.

[Eric Gustafsson]

Now I have tested with some other xlr cables, but with the same 50 Hz hmmmmmm sound. 

What to do? 

[rustydoglim]

If your K38 has humming noise with XLR cable, please get help from our support. We can fix it. Create a Help Desk ticket on mytdss.com.
If you are not from USA or Canada, email support@nuprimeaudio.com

[Eric Gustafsson]

I have now sent an e-mail to support as I live in Sweden.

[Eric Gustafsson]

By coincidence I found this information today.

"Due to the XLR shield and ground pin specification (see https://en.wikipedia.org/wiki/XLR_connector), some manufacturers implement it differently from others, therefore there could be humming noise if a non NuPrime product is connected to MCH-K38 using XLR cables.
XLR Hum Eliminator products from http://www.ebtechaudio.com/hedes.html can be used to completely remove the noise and improve performance."

It seems to me that Nuprime has made some kind of special xlr connection in MCH-K38. It can' t the same as in STA-9. Why? This is not good at all! 

I found the information in the FAQ releated to Home Theater and not in the Power Amp section. 

Now I have to spend money on one or several "Hum Eliminators". 

[rustydoglim]

There is no need to do that anymore. We have to replace a board on the MCH-K38.
We just need to get the instruction and board for you. No soldering is needed to replace the board.

[Eric Gustafsson]

There is no need to do that anymore. We have to replace a board on the MCH-K38.
We just need to get the instruction and board for you. No soldering is needed to replace the board.

That sounds great! When will it happen?

So far I haven't heard anything from your support. Not even a notice that they have recevied my e-mail.

[loonix]

@rustydoglim

I was thinking about purchasing this from SonicUnity and wondering if they will have these new boards installed? Is there another/better source in the US to get a unit?

@Eric, thanks hoping to get a detailed review in the coming days! While you wait to test out XLR, maybe we can also get some feedback from you utilizing the unbalanced inputs.