[mocenigo]

I could still use my rogue?
Two pre-amps are too much for me YMMV.
More cables, more connectors, more transfer losses.

I agree. Also, if one has sufficient gain and no turntable, why use a preamp?

[JackD]

That Rogue Magnum has 23 db of gain which is entirely too much for the Nuforce but that should show up as tube rush not as a hum.  Since you said the hum was there with another amp also there is nothing wrong with the Nuforce amp.  You either have a grounding issue or DC on your lines.  The Schitt Sys or the like will let you reduce the gain but it will not resolve the electrical hum issue.  I have used multiple preamps over the last couple of years with my STA-200 and while some of them had too much gain resulting in tube noise or reduced volume control travel none of them have caused a hum in two different systems in two different rooms.  While the Rogue is in fact an inappropriate match for the Nuforce gain wise the noise is coming from somewhere else. Did you try the cheater plug on both the amp and the preamp or just one of them? The preamp that Nuforce sells as a match to the amp has no gain and the one Job sold to match their version of the amp had 3 db of gain.

[flavo]

I agree. Also, if one has sufficient gain and no turntable, why use a preamp?

Are you saying I should be using an integrated? I'm confused by your question.

It is a nice little thing but the potentiometer is really poor. I would rather go for something like this which costs a bit more but is based only on resistors, no moving parts, and has a remote (my wife complains that changing the volume is a bit to clickety-clackety)

Thank you, I had a Schiit pre previously and clickity clack of the volume adjustment drove me batty. I used it for a day and back in the box it went.

I could still use my rogue?
Two pre-amps are too much for me YMMV.
More cables, more connectors, more transfer losses.

I agree, if I go this route rather replace the amp I will get a dedicated quality passive pre.

[flavo]

That Rogue Magnum has 23 db of gain which is entirely too much for the Nuforce but that should show up as tube rush not as a hum.  Since you said the hum was there with another amp also there is nothing wrong with the Nuforce amp.  You either have a grounding issue or DC on your lines.  The Schitt Sys or the like will let you reduce the gain but it will not resolve the electrical hum issue.  I have used multiple preamps over the last couple of years with my STA-200 and while some of them had too much gain resulting in tube noise or reduced volume control travel none of them have caused a hum in two different systems in two different rooms.  While the Rogue is in fact an inappropriate match for the Nuforce gain wise the noise is coming from somewhere else. Did you try the cheater plug on both the amp and the preamp or just one of them? The preamp that Nuforce sells as a match to the amp has no gain and the one Job sold to match their version of the amp had 3 db of gain.

I tried the cheater plug on both with no change to either. But only one at a time.
I don't know if that makes a difference?
I also shut the entire house off except for the 1 circuit that powers my stereo.   PC>Bluesound node>Pre>power.
Are you sure from my description that it's not an issue with the pre causing the hum?  The other DIY amp that I have hums on this system too, but not near as loud.
My Decware Torii previous to the STA did not hum. But you never when somethings going to have an issue.

In the search for a passive pre, since your familiar with the STA-200. Do you know what resistor value I should be requesting?
Thank you

[JackD]

It could very well be that the Magnum is the source of the hum but you can't really know unless you have the ability to test it in another system. Hums from Rogue gear is not all that un-common.  I had to send a Rogue amp back for service under warranty due to a hum.  As to the passive the only one I have used is the W4S STP-SE and it is a full service preamp.  If you just want something to put in between then the SYS will do fine but won't solve the hum.  If you think you have checked everything you can then I would call Nick at Rogue and talk to him.

[flavo]

I'm running out of amps! 
I took my integrated DDA120 https://www.optoma.com/hk-nuforce/product/dda-120/
and hooked it up in place of the STA200. Turned the volume on the DDA all the way up and used the volume control on the Rogue preamp.
Dead quiet. Even with the music off and the both volume controls all the way up.
So I'm assuming that it is strictly a matter of the gain of the 2 units combined is just way too high and there is nothing wrong with either of them?
Please correct me if I'm wrong.

Now I don't know whether to replace the pre or the amp.

I also have the nobsound passive on its way thanks to the generous offer of chrshanl to test the passive theory in place of the Rogue.

If it's the amp I replace, I'm considering the Akitika GT102 - https://www.akitika.com/GT102.html
Does this look like a good fit?

[JackD]

You would still have to much gain from the Rogue.

[flavo]

As an update.
I got the Nobsound pre in the chain and it is now dead quite when it's supposed to be.
I'm sure it's not audiophile approved, but for my listening style I can't tell it's in the chain.
I will still likely buy a Tortuga considering the new price drop and why not??

[tdinut]

I'm running out of amps! 
I took my integrated DDA120 https://www.optoma.com/hk-nuforce/product/dda-120/
and hooked it up in place of the STA200. Turned the volume on the DDA all the way up and used the volume control on the Rogue preamp.
Dead quiet. Even with the music off and the both volume controls all the way up.
So I'm assuming that it is strictly a matter of the gain of the 2 units combined is just way too high and there is nothing wrong with either of them?
Please correct me if I'm wrong.

Now I don't know whether to replace the pre or the amp.

I also have the nobsound passive on its way thanks to the generous offer of chrshanl to test the passive theory in place of the Rogue.

If it's the amp I replace, I'm considering the Akitika GT102 - https://www.akitika.com/GT102.html
Does this look like a good fit?

I know this thread is a little old, but I have the Akitika GT-102 amps and it's absolutely amazing, especially for the money. It is DEAD QUIET, smooth - especially on top, 3D, no hum, no hiss, nothing but wonderful music. I bought the amp assembled and tested. It's a screaming bargain. Please don't hesitate to purchase this wonderful piece.