Some Preamp observations....

netaron · « **on:** 30 Oct 2005, 01:23 pm »

Good day all,
I have had the pleasure of owning the 55N+ for over a year now and I have tried many different falvours of preamps. Recently I went passive with a stepped attenuator, and I must say, what is in the recording is exactly what I get. I have heard of some people not liking passive, "it sounds too dull and lifeless". I have to agree, but my observation has been it is dependant on the quality of the recording. I have noticed if I go past 12 o'clock on my 24 step attenuator to reach decent listening volumes, I will need a pre-gain stage, if I can reach good levels around 10 o'clock, I am happy and the music is full of life. It has been difficult in the past to judge recordings since the preamp adds a certain quality that fools you into thinking most recordings are decent. I have been finding out that only 10-15% of the music I have was recorded well. About 60% fall somewhere in the middle and the rest just plain terrible. In my system and to my ears, the preamp has added some life into the so-so recordings and somewhat masked the true character of the original recording. I actually have been talking to Hugh about his GK-1 offerings, but if I do go the route, it will have to be wired passive/active. Has anyone tried this method? The above statements are my experiences only in my system.
Thanks

Haron

stvnharr · « **Reply #1 on:** 30 Oct 2005, 03:01 pm »

Haron,
I have two systems in two locations (at the moment anyway), I have one system w/no preamp, and one with a GK-1. The GK-1 adds more gain and a subtleness change to the music, from the output stage. The amp in both systems is a 55N+. Both systems sound great.
I have read your observations about the position of the volume control. Keep in mind that the position of the volume control knob is irrelevant for the most part. It is only a measure of the amount of signal level attenuation. It says more about the recording level of the particular recording being played and the interaction of the speaker, mostly to do with efficiency of the speaker, with the amp, than it says about "life" in the music. As long as there is no amplifier clipping and there still is some dynamic headroom, signal attenuation from the source doesn't matter. In fact, I kind of feel that the less attenuation the better.
Most popular recordings tend to be recorded at high levels as there normally is not a whole lot of dynamic range, thus they respond to gain rather quickly. And most people find the volume control never having to get much above the 10 o'clock position, and get worried if the music has to be turned up more than that to sound good.
I don't really know about "poor recordings", could be so. My personal opinion may be that it's just poor music.
If you feel the need for more gain and a preamp, you will be well served and well pleased with a GK-1. No need to really consider any others, IMO.

BTW, it should be relatively easy to configure the GK-1 so that it could be active/passive.

netaron · « **Reply #2 on:** 30 Oct 2005, 04:38 pm »

stvnharr,
I agree with your observations, my finding is that half the recordings I own do well with passive and the other half sound better with an active stage. I am trying to look at it from a purist and less is more point of view, but the media is not consistent, therefore the need for a cure is on demand (in this case a GK-1). Hopefully, one can have the best of both worlds in a case like mine. I am also curious to know if anyone here notices something similar.

Haron

ginger · « **Reply #3 on:** 30 Oct 2005, 10:18 pm »

The position of the Volume Control on a passive may well affect the sound. It changes the source impedance of the signal driving your power amp.
I have not tried my GK-1 in passive/active BUT wired it for use with and without the tube buffers stage when I built it. Mostly run it with the tube buffer in when driving the 55N+ BUT often run with it switched out when driving tube amps.
Cheers,
Ginger

stvnharr · « **Reply #4 on:** 30 Oct 2005, 10:36 pm »

Ginger,
Good point!
The impedance does change slightly with each step in a shunt attenuator. I use a shunt on my GK-1 but have never noticed any changes with the attenuator settings.
Both a series attenuator and ladder attenuator will have constant impedance.

Geoff-AU · « **Reply #5 on:** 31 Oct 2005, 08:57 am »

interesting experiences.. I'm interested in passive attenuators, and will be building one as soon as I get around to it (small diecast box, 4 RCA sockets and a double gang pot.. easy!). I am sure for the most part I'll prefer an active module because I can set it up to drive headphones, switch multiple sources and the pre-amp will act as a consistent buffer between the source and the amp and not one with varying impedance which will likely change the sonics. But it'll be interesting to compare the two

rabbitz · « **Reply #6 on:** 31 Oct 2005, 10:45 am »

I have spent over 12 months trying various pre amps, active and passive, to use with the AKSA 55N+.

Commercial pre's didn't suit and most had miles too much gain, active pre's built with LM6172, OPA2134, OPA134 and OPA627 didn't quite make the cut either, but were better. The best was a passive pre using a Alps 20K RK27 but there is a discrete buffer I'm still playing with as it sounds great (hum and buzz problems).

If you want to try a reasonably priced stepped attenuator, have a look here.
http://www.diyfidelity.com.au/product_info.php?cPath=0_33&products_id=32

Those who have built it have been very happy with the sound and is as cheap as. Just need heaps of patience to solder all those resistors on but they have a option for pre built.

Andrew Rothwell has an interesting article on passive pre's and passive pre's really need good impedance matching from my understanding.
http://www.rothwellaudioproducts.co.uk/html/passive_preamp_tech.html

All that is history now as a GK-1 has just gone into the system and beats all the other options I've tried in every area from my inititial impressions. Just need more listening time to really get a handle on it

Cylon · « **Reply #7 on:** 3 Nov 2005, 09:01 am »

Just my 2 cents worth regarding the quality of recordings... it appears to me that liking pop/rock/alternative or anything resembling mainstream means having to put up with compressed, lifeless recordings and it is PISSING ME OFF!!!! Apologies for the expletive.

Having to opt for 'unplugged' recordings just to get some subtelty or detail is not good enough. I do not care if the recording is engineered to be listened to on a cheap radio at the beach having been transmitted over fm. If the signal needs to be compressed let the radio station do it. If it doesn't sound good in your car then let the graphic equaliser/tone controls compensate.

As one who is not into self-centered eclectic jazz and whose classical listening is restricted to definate in-the-mood-for-it occasions I am deeply disappointed at the disdain which most engineers show the albums in their care.

10% recorded well? I'd have to agree, and maybe even then Haron is being a little generous. There are even a few albums that I no longer listen to after buliding my ASKA 100N and my speakers. Sad because I can still enjoy the songs when I hear them on the raido in my car...

andyr · « **Reply #8 on:** 3 Nov 2005, 10:23 am »

Quote from: Cylon

Just my 2 cents worth regarding the quality of recordings... it appears to me that liking pop/rock/alternative or anything resembling mainstream means having to put up with compressed, lifeless recordings and it is PISSING ME OFF!!!! Apologies for the expletive.

Having to opt for 'unplugged' recordings just to get some subtelty or detail is not good enough. I do not care if the recording is engineered to be listened to on a cheap radio at the beach having been transmitted over fm. If the signal needs to ...

Hi Cylon,

I think you need to start taking your medication again, mate

... all I can say, with my GK-1 driving my triple-AKSA active setup is that I have a heap of LPs which sound absof'inglutely fantastic! Perhaps U listen to CDs, BTW??

My listening habits extend from Pink Floyd/Bob Dylan/Bob Marley/Roy Orbison through J-M Jarre/Jeff Buckley/Dead Can Dance/Flamenco to Baroque and opera. Yes some recordings sound bad but most, I have to say, keep me listening on and on!

Maybe you need to add a GK-1 to your system?

Regards,

Andy

Cylon · « **Reply #9 on:** 8 Nov 2005, 09:28 am »

Ummm welll... yeah.

Perhaps a little strident, and to be honest most of my recent purchases have been pretty good.

As for the GK1, I had intended to have one by now, but the best laid plans and all that... Hopefully I can wrnagle one as an xmas pressie to myself.

As for the medication I think a nice central otago pinot noir might do the trick, while listenign to some pleasing tunes through my 100N that is.

andyr · « **Reply #10 on:** 8 Nov 2005, 09:38 am »

Quote from: Cylon

Ummm welll... yeah.

As for the medication I think a nice central otago pinot noir might do the trick, while listening to some pleasing tunes through my 100N that is.

Hi Cylon,

That medication sounds real nice!

Gotta save up for that GK-1, though!

Regards,

Andy

Greg Erskine · « **Reply #11 on:** 8 Nov 2005, 10:46 am »

Call me "easierly lead" (Is that the right led??)

I'm going to join you with a cheap red.

Greg Erskine · « **Reply #12 on:** 8 Nov 2005, 11:01 am »

I might just have another.

Rhythm Willie · « **Reply #13 on:** 10 Nov 2005, 05:14 am »

Netaron,

I agree with your observations, the best performance I have obtained from my setup on good recordings is no preamp at all - just run the Aksa 100N+ Monos straight from the variable outs on the Sony XA7ES CDP.

Less than good recordings(+ some classical) sounded more pleasant and bearable with the GK1 however.

My floorstanding mono amps have the RCA inputs quite accessible on the inside(centrally located)) sides of each box, so I am going to try these "piggyback" attenuators from Scott Endler right at the power amps, this may sound better again, largely eliminating any cable issues.

http://mysite.verizon.net/vze4c5pt/id2.html

netaron · « **Reply #14 on:** 11 Nov 2005, 03:01 am »

I see, this gives me an idea or two, attenuate as close to the amp as possible as not to send a weakend signal over interconnects. Makes sence to me, I was actually even thinking about installing the ladder stepped attenuater inside the amp itself, but this was due to avoiding another enclosure and not due to signal degradation.

stvnharr · « **Reply #15 on:** 11 Nov 2005, 04:37 am »

If you are going to go passive and do not require more than one input, it is quite easy to install the attenuators in the amp. Look at my recently posted pics in the gallery, and you will at least see one way of doing it. It's really quite simple, you just have to pay some attention to layout is all.

netaron · « **Reply #16 on:** 11 Nov 2005, 05:13 am »

Sorry, but I am not sure if you are attenuating the signal before or after amplification.

Geoff-AU · « **Reply #17 on:** 11 Nov 2005, 06:00 am »

passive attenuators are a bit of a mixed bag. I made one and A/B'd it with my active pre-amp and while I initially thought it sounded quite clean and nice, there was a lack of foot-tapping compared to normal. I'll have to try it again, but sometimes an active pre-amp will sound better just for its buffering capabilities (otherwise you are driving an amp with a really high impedance source - especially at low volumes).

stvnharr · « **Reply #18 on:** 11 Nov 2005, 02:54 pm »

Netaron,
I attenuated the signal upon input to the amp, essentially like a preamp. I've never heard things the other way around, with amplification and then attenuation. This would certainly call for more attenuation. However, it would be quite easy to configure the wiring to do this.

stvnharr · « **Reply #19 on:** 11 Nov 2005, 03:06 pm »

Geoff,
I have heard of this. And when I first made a passive last year, I was wondering if it indeed would be okay, because I read so much of how an active pre was so much more dynamic, etc.
However, when I first hooked up the passive and compared it to my
Bat VK-30SE I heard no loss of dynamics with the passive, and I heard more low level detail that the Bat seemed to cover up. I did a double take on this with the Bat, and it was no mistake, low level details were lost with the Bat.
I mostly listen to classical music, which is all about detail, and low level detail in particular. Pop music has little of either, IMO, and certainly not much low level detail due to the electronic nature of the music.
BTW, the person who bought the Bat thought it really did the trick and was much better than his non-preamp setup, using the variable out on his cd player.
All about personal preference, and musical tastes I suppose.