[Zombie_X]

LOL my thread shifted from a review about the amp to a general discussion topic...

 

[realmassy]

I know I'm OT, but again on the bias voltage: I have this multimeter
and I'm not sure if I'm getting the right measurement. Just below the display there's a switch with 4 position, I guess the last two are resistance (ohm) and current, but what about the first two? Which should I use? I have no experience, sorry

 

[Mad Dude]

Quote:

What about Hi/Lo gain switch? Any preliminary comments on that?

 
Well, it does exactly what it should do, changing the gain. Other than that, I didn't notice any difference in the sound.
However, I must say that the positioning of the switch is a bit unfortunate. It is located between the inputs of the amp - this means the cables on both sides of the switch will obstruct access to the switch. If someone has both efficient and very power-hungry (Orthos) headphones and wants to change the gain for the headphones, this could be a little problem.
When using the RS1 out of the balanced output, I have to be very careful with the volume control, even the lowest settings result in a moderate listening level. Switching to High gain would intensify this even more...

 
Quote:

I hear the volume control wears in with use and works better after time. Not certain of this though.

Unlikely, since the volume is controlled by relays and not the potentiometer itself. But the issues are really not worth worrying about, as long as you don't change the volume very often.
 
 
I've also tried the ROC SA with bookshelf speakers today, with quite good results. It has more than enough power for an efficient pair, even with the low gain setting.
 
 
Quote:

Originally Posted by realmassy
 
I have this multimeter
and I'm not sure if I'm getting the right measurement. Just below the display there's a switch with 4 position, I guess the last two are resistance (ohm) and current, but what about the first two? Which should I use? I have no experience, sorry

 
 
One is for DC voltage (V=) and the other for AC (V~). Use DC for the measurement.

 

[FauDrei]

Put the upper slider to position 2; position which points to V with something like = above it (DC voltage symbol).
 
Turn the dot on the knob to 20V position.
 

 

[realmassy]

Thanks FauDrei!
Phewwww...I did the right move then!
Yesterday I set the bias to 12, and listened to the Roc for a couple of hours, but the sound was too dark.
Then this morning I set it to 13, and was unbelievably better! So I thought I did something wrong because the sound was very different...but I set the slider to the first switch, and I could get any measurement :-O

 

[TigzStudio]

Quote:

Thanks FauDrei!
Phewwww...I did the right move then!
Yesterday I set the bias to 12, and listened to the Roc for a couple of hours, but the sound was too dark.
Then this morning I set it to 13, and was unbelievably better! So I thought I did something wrong because the sound was very different...but I set the slider to the first switch, and I could get any measurement :-O

Im telling you 13.4 to 14 is where its at I bet you! I had same impression at 12v.

 

[realmassy]

OK, I set the bias first to 13.75 then to 13, and I think (I would emphasize 'think') 13 is the right choice in my case.
I need to spend some time with this setting, as I've only used a single track as reference, and it was a bit of a pain
Thank you again Tigz and FauDrei for this suggestion.

 

[TigzStudio]

Yeah I am actually comparing it to my reference for musicality (Stacker II).  Im listening to a full album on the ROC and then switching to the warmed up Stacker II and listening to the same full album.  I am going to try 13 now.  13.4-14v is missing a bit of that musicality still and naturalness in the vocals....however it might have an advantage in the detail over Stacker II.  For example Violin on Stacker II just feels like the real thing, where as the Roc at 13.4 feels a bit dryer or something.  I think you could say the Roc is more analytical at that voltage.  
 
I find it fun trying to tweak it

 

[realmassy]

Yes, exactly my feeling!
Since I own the HE-5LE I felt the violins were a bit dry, compared to the K702 (the AKGs really excel with strings)
With a 13v setting they sound warmer and less sharp, though they're still not perfect.
I mean, a solo violin is close to perfection, you can easily feel the bow touching the cords, the sound is actually 'physical', but the strings in the orchestra...well they still sound 'digitalized', if you know what I mean
I can't blame the source for it, I just tried a cheap Rega Ear and, while the sound is compressed, the soundstage is narrow, the instruments have more body. 
I'd like to try the XLR or the RCA connection over the ACSS, but I don't want to spend a fortune for cables :-D
Or try a tube amp, but a good tube amp for this orthos would cost even more.

 

[BigMango]

Quote:

If you don't have a balanced source/DAC, don't bother with the Roc, just get the C2.

I don't agree with this.
 
The Roc is transforming SE input into balanced, so when powering your headphones in balanced mode you get the soundstage and instrument positioning improvements also with non-balanced sources (I have used my Roc with non-balanced sources during 2 months while waiting for the Ref5 to arrive). There is a slight improvement with balanced sources, but even with non-balanced sources the Roc's XLR out is definitely worth it over an SE amp.
 
 

 

[TigzStudio]

Cool man!  I actually have some DH-Labs balanced XLRs from moon audio I was selling, but now I am going to try them out again to compare to ACSS....will let you know the difference I hear.  A month or so ago when I tried XLR vs ACSS I felt I was getting more space and detail with ACSS, but I don't remember if things were less "cold" or dry" with XLR.  
Quote:

Yes, exactly my feeling!
Since I own the HE-5LE I felt the violins were a bit dry, compared to the K702 (the AKGs really excel with strings)
With a 13v setting they sound warmer and less sharp, though they're still not perfect.
I mean, a solo violin is close to perfection, you can easily feel the bow touching the cords, the sound is actually 'physical', but the strings in the orchestra...well they still sound 'digitalized', if you know what I mean
I can't blame the source for it, I just tried a cheap Rega Ear and, while the sound is compressed, the soundstage is narrow, the instruments have more body. 
I'd like to try the XLR or the RCA connection over the ACSS, but I don't want to spend a fortune for cables :-D
Or try a tube amp, but a good tube amp for this orthos would cost even more.

UPDATE:
 
Tried XLR's again and I still prefer ACSS, I admit I could not find a huge difference....but enough for me to stay with ACSS.  
 
BTW I have also gone to 13.04v output....seems to be the most natural to me
while keeping the bass controlled enough to my liking.  

 

[Zombie_X]

I agree with you as well. It does convert it to a balanced signal, it's just not "true" balanced. But it does improve the sound of single ended stuff for sure.
 
Quote:

I don't agree with this.
 
The Roc is transforming SE input into balanced, so when powering your headphones in balanced mode you get the soundstage and instrument positioning improvements also with non-balanced sources (I have used my Roc with non-balanced sources during 2 months while waiting for the Ref5 to arrive). There is a slight improvement with balanced sources, but even with non-balanced sources the Roc's XLR out is definitely worth it over an SE amp.
 
 

 

[nigeljames]

My ROC'S arrived.

Only had the chance to check it over for travel damage and check that it works OK. Haven't had the chance to re-terminate any of my phones yet so had a quick listen single ended via my ALO-780's. Definately dynamic and full sound but needs to tighten up.
Had to put the stock Audio-gd power lead on my Cyrus and use a bog standard lead on the Roc,only one long enough as I don't want to remove the copper line from the Woo.
Must upgrade the cable but space is at a premium.

 

[nigeljames]

Well I have balanced my ALO-780's.
First time I had ever picked up a soldering iron but apart from the fact that the Jena cable's gauge was a bugger to fit everything went ok.
First serious listen to the Roc on first day,still singel ended, after being powered up for 8 hours was very encouraging and very enjoyable

 
Second listen the next morning with the Roc being powered up for less than 2 hours (did not leave it on overnight) with my newly balanced 780's was a bit of a let down. Sounded better the night before.

Left on all day again and tried again in the evening. Hell yes this is more like it. Very dynamic,rich,detailed and still fast even explosive at times. I also was drawn to the greater control. Everything sounded tight,solid and exactly how it should be.
 
More details and possibly a head to head with my Woo will follow but as of now I'm a happy chappy.

 

[realmassy]

Cool Nigel (or James, I don't know!)
You're right about the warm up: when the Roc (and the Ref.5 in my experience) are cold they sound ordinary. I have mine for sale because I want to try some tubes but I'm still not sure if I'm doing the right move.