Jeff Rowland

Jeff is a very nice man and makes time for less fortunate people. He is not a personal friend. I just have seen him at some dealers and have been to his company with other retailers and got to see his operations and visit with him at times. So I know of him. I am not a retailer and never have been. I have just got to enjoy others in this hobby. Jeff also has a great ear for what is natural. I think very highly of his electronics. I have been on the look out for a long time for something from him and just havn't done it because of cost. But hopefully someday.

But for Ricred. I don't know if this will help or not. I use a buffer after my passive attenuator and it does fill out the bottom end in a very nice way and does not leave anything negetive to speak of. I don't know how this would work out for you. What I have is a Burson AB160. It is made with quality discrete components. I think that may be why it seems like it doesn't have a sound signature of it own yet fills the sound out. What I think I mean is it doesn't seem to lose any transparency yet it makes everything sound more full or complete. I have always liked the less is more plan. It has always worked out well. So I was somewhat surprised that this buffer was such a benefit for my system. Chris Johnson of the Parts Conexion(former Sonic Frontiers owner)said this Burson AB 160 was the cadillac of buffers. For whatever that is worth. And that happens to be what the Burson sales stuff says it is suppose to do. And suprise it seemed to meet up to that for me.

That being said they don't make them any more. And I don't want to give mine up for almost anything I have heard(6 preamps)under 8000.00. Sometimes they have shown up used. Burson may have a better replacement for it. I don't know how it could be much better but I have been wrong before. Anyway just a thought.

03-09-15: Ricred1
Speakers are as follows:
the rear of the speakers are 4' 2" from the front wall
8' apart, 4' 8" from sidewalls, I sit 10'away, my head is 6'away from the rear wall
I have 2 GIK Soffit Bass traps in each front corner from floor to ceiling, 6 GIK 242 panels-2 each on the left and right at the first reflection points and 2 on the ceiling

OK, so rear wall reflections will result in a suckout centered at a frequency of 282/6 = 47 Hz. It's hard to say how far above and below that frequency the suckout would extend to an objectionable degree, but I wouldn't be surprised if the affected frequency range is wide enough to be a significant contributor to the issue.

For experimental purposes, just to gauge the significance of that effect, if practical you might temporily relocate the two bass traps that are in the front corners to a position such that both of them are in a line extending directly back from the listening position. Perhaps one immediately behind the listening position, and one up against the wall. And it would probably be most useful to compare sonics between having the traps in that position and having them out of the room altogether, so that the comparison wouldn't involve changing two things at once (i.e., moving the traps away from the front corners, and placing them behind the listening position).

Also, again for experimental purposes, you might try to determine how severe that effect seems to be at differing listening distances. In doing so, it might be helpful to purchase a test CD, such as this one, further described here. Track 17 would facilitate assessment of frequency response flatness in the bass region.

Bombaywalla, I agree with your comment. It would be unusual for an amp to be able to fully quadruple its max power rating into 8 ohms when bridged, much less into 4 ohms, due to the current and thermal limitations you referred to. Although for an 8 ohm load the OP's 525 comes surprisingly close to doing that, the 8 ohm ratings being 250 watts and 950 watts for stereo and bridged modes respectively.

Best regards,
-- Al

Almarg,
Thanks for taking the time to provide assistance. You are a smarter man than me!!!I moved the bass traps from out of the corner and put them behind my listening position. I promise I'm not exaggerating...my wife was downstairs and game upstairs. She said,"I knew you did something, because it sounds so powerful downstairs." I haven't move the bass traps out of the room, but I will do it tomorrow. It addition, to more powerful bass, I hear more detail. The question is why? I thought bass traps were good?

Almarg,
My other question is about the volume control on my PS Audio DSD DAC. I guess it operates as a passive preamp; consequently I need to turn the volume up to 70-80 for it to be adequate(70 normal listening, 75-80 loud). How does that affect the amplifier? Would it sound better with an analog preamp?

The output of the DirectStream DAC is transformer coupled, and in that sense can loosely be considered to be passive, but unlike resistive-based passive preamps it has an output impedance that is low enough to be comparable to that of most active preamps, both tube and solid state. That is confirmed in John Atkinson's measurements.

Given that, as well as the 40K balanced input impedance of your amp, as well as PS Audio's claim that its volume control mechanism does not lose resolution at any setting (which if it occurred at all would occur at low settings of the control, not high settings), I see no technical reason that would call for the insertion of a preamp. Which is not to rule out the possibility that you might find adding a preamp to be subjectively preferable. But FWIW my own bias is to put the burden of proof on adding anything to the signal path that is not clearly necessary, and in this case I don't see it as being clearly or technically necessary.

The reason for the relatively high settings of the volume control you are using are most likely the combination of the "full scale" (maximum) output voltage of the DAC being a bit lower than usual, and the sensitivity of your speakers being somewhat low (Stereophile measured the speakers as 86.6 db/2.83 volts/1 meter, which for their 4 ohm nominal impedance is 83.6 db/1 watt/1 meter).

So as long as you never find yourself wanting to turn the volume control up beyond the top of its range, I wouldn't attach any significance to the fact that you are using it in the upper part of its range.

A couple of things to check, though:

1)Apparently the DAC's output can be set to two different levels via the menus. Check to see that it is set for the high level, i.e., that the output attenuator that is provided is deselected.

2)Check that the unit has the latest firmware (version 1.2.1) installed. User comments as well as PS Audio indicate that that update tightens up and improves the bass. I would expect that you can determine the firmware version somewhere in the menus, or perhaps it is displayed briefly at startup. If it is an earlier version, you can easily download and install that version per the instructions at PS Audio's site.

Regarding the bass traps, it's of course sometimes possible to have too much absorption in a room as well as too little absorption, especially from a subjective standpoint, and depending on the speakers, their placement, etc. I suspect that the main reason for the more powerful bass reported in your latest posts was removal of the traps from the front corners, rather than their placement behind the listening position, in part because the change was perceivable at other than the listening position. Hopefully after doing the remaining experiment (removing the traps from the room altogether), and some further listening, you'll be able to determine which of the four possibilities is preferable (traps or no traps in front; traps or no traps in the rear).

Continued good luck. Regards,
-- Al