[Edwood]

Well, I've warmed it up and fired it up.

It sounds weird. Almost like the soundstage is inverted. Left and Right are correct, but sounds like vocals which normally sound like they are a bit in front of my head, sound like they are coming more towards the back of my head, imaging wise.

Here are pics, is this correct?

(1) --->Left?
(2) --->Right?
(3) --->What is this? Sounds like a loudness switch.

My Setup

Do I have the Left and Right hooked up correctly? I checked the left and right with my reference songs, so I have the left and right setup correctly.

-Ed

 

[Orpheus]

well, there are two potential problems:

it says xlr pin 1 is ground. that's fine. pin 2: "inverting?" hmm.... now that might be a problem. normally pin 2 is referred to as "+"... i think they're implying that pin 2 is the "-" instead. it says pin 3 is "non-inverting." so, maybe that's the "+". usually most equipment is 1: ground, 2: +, 3: -. so, that's what those adators you're using assumes too. i dunno. it's really a matter of reference. however, like i said, i understand that normally it's the "-" that's inverted then added to the "+."

secondly, there have been reports that some SAC K1000 amps had one channel's polarity reversed. do a search on it. it's possible that the previous owner already corrected for such problems though.

dean

 

[lan]

The monster cables are the problem. I recommend you wear your headphones backwards

j/k

Um where are the cables going? To 1/4" TRS? Does that work with balanced? I dunno.....

 

[Orpheus]

those are RCA to XLR adaptors he's using. but anyway, just for your information, 1/4" TRS are balanced (3 connections via tip/ring/sleeve), 1/4" TS is unbalanced (2 connections via tip/sleeve.)

 

[Edwood]

Yes, I have read kwkarth's thread about this. I am not sure how I would test for this.

The previous owner claims to not have done any modifications to it. I believe him as the unit looks immaculate. I'm going to crack the SAC open tomorrow (LOL, that just sounds funny). I'll post pics.

Quote:

Originally posted by Orpheus secondly, there have been reports that some SAC K1000 amps had one channel's polarity reversed. do a search on it. it's possible that the previous owner already corrected for such problems though. dean

 

[Edwood]

Quote:

Originally posted by lan The monster cables are the problem. I recommend you wear your headphones backwards j/k Um where are the cables going? To 1/4" TRS? Does that work with balanced? I dunno.....

Yeah, there's nothing wrong with the adapters. I tried them out on my Grace (see it in the second pic above?) and they work fine.

As for the crappy old Monster Cable, It's the longest cable I have (My PC is too far away). And Orpheus is helping me out in the getting rid of the crap Monster Cables.

I used a Hosa YPR-102 6" Shielded "Y" Cable 1/4" Stereo Phone Plug (M) to Two RCA Jacks (F) plugged into my RME PAD.

I had asked RME and they say thr digi96/8 PAD does not output balanced analog.

-Ed

 

[grinch]

doesn't grace 901 have xlr output?

i suggest you buy a set of balanced interconnects and use that as a source. probably sound better too. then you could use your soundcard's digital out for computer audio. that's what i do, at least.

 

[Edwood]

Yes, I have done that. Unless the RME digi96/8 PAD really does have balanced analog outputs, I'll be unbalanced until I end up getting a better DAC. So far, the analog unbalanced output from the RME PAD beat my Muse 2 Plus DAC with balanced outputs to my Grace.

Iron_Dreamer and I did some good A/B testing with the Muse 2 Plus DAC, smART DI/O, DAC in the Grace, and the RME PAD. The RME PAD won hands down. We even used the SPDIF output from the RME PAD to use it as a transport. Alas, the Muse does not have optical inputs, as I hear the RME PAD's optical output is better.

Well, I'm rambling on away from this thread's topic.

Gotta dig up my allen wrenches tomorrow.

-Ed

 

[Edwood]

OK, how do I open this thing up?

Should I start with the front panel?

Should I take off the Volume Knob off first?

Woot, I just noticed that the voltage rating on the brick says 110V. One less thing to mod.

Oh, kwkarth, gerG, Jan, anyone please impart your wisdom!

-Ed

 

[gerG]

Boy does this sound familiar.

The issue is probably not on the signal side, but on the output side. My SAC and my headphones were wired differently, such that the 2 sides are driven out of phase. Hey, it's a "feature".

2 options:

1) Remove the jacks from the amp (you don't need to open it up) and rewire to match headphones. I did not like this route, because the pin out on the amp made so much sense. The 2 close pins are ground, and the wide spaced pins are the L & R outputs. I can remember this! btw the outputs are not balanced, and the ground is common to both channels. Internal wiring goes to one jack, then jumpers to the other.

-or-

2) Open the plug on the headphones and swap 2 wires. Very easy if you can work a soldering iron. Even if you mess up you can just re-do it until you run out of cable. That should give about 50 tries

The SAC does invert phase. On the input side the unbalanced signal goes to the + terminal, while the - is grounded along with the shield. This is pretty standard. I checked phase through the whole system using a low voltage DC source and observing driver displacement.

The button is an input sensitivity switch. Pro gear all seems to have this, but I am not sure why. My guess would be that there are 2 standards out there, and gear is configured to work with both. Call it a "gain switch" if you like.

btw, isn't it nice to have an amp with the power switch on the front, where it belongs?


gerG

 

[gerG]

...and another thing...

If you have a balanced source, some long balanced xlr cables work great. I used the white Canare cable. Most elegant!


gerG

 

[Edwood]

Option #1 is my only choice. I'd like to use my K1000's on other amps too, like my Grace. (Which has a better power button that actually shuts the amp off.)

So, I should swap the wide spaced ones (#1 and 4, I believe) which would be LT ans RT signals?

Did the K1000 get different pin outs later on? Why would an Amp designed specifically for the K1000's be wired incorrectly?

Sorry, I thought I'd beat that rotten horse corpse there.
-Ed

 

[gerG]

You have other amps with 4 pin xlr outputs? If not, option 2 works fine as long as you remember to swap the leads on the adapter cable. If you have an adapter that goes from xlr4 to 1/4", the same applies. The only other issue is if you try another pair of K1000 on your SAC.

I don't know where the error happened. Personally I think that the amp is correct and there are a lot of K1000 owners listening to their cans out of phase, but that is just a hunch

I don't know which wire is which in the amp anymore. I will look for the email from Jan that tells which to switch. I would use a meter and check to be sure.


gerG

 

[Edwood]

Jan was kind enough to provide me with the following info:

Quote:

The simplest method to check the polarity is to measure the impedance between pins 2 and 4 of the output connector (the amp should be turned off!). The value should be smaller than 1 Ohm. If the value is higher just let me know and I'll provide you with instructions on how to solve the problem. Cheers, Jan

Going to check it tonight.
Even if everything else is wrong and the SAC amp is right, It's easier just to change the SAC amp. Only one thing for me to change.

Plus, if every K1000 and Adapter Cable is wrong, then wouldn't they be right by default?

Granted, two wrongs don't make a right, but three lefts make a right.

-Ed

 

[Edwood]

I do not get any readings with the power supply plugged and power switch off. (I am using a Fluke 110 Auto Ranging DMM) With power switch on and pot turned all the way down I get 22.1 ohms

Now what?

-Ed