ack's system - end of round 1

[ack]

On the 810LP, see this http://www.whatsbestforum.com/showt...-Spectral-Gear&p=205362&viewfull=1#post205362

 

[audioarcher]

Thank you. Strange there was more noise at 60 db gain than 66 db gain.

 

[ack]

The A90's output is just too low for it?!?

 

[awsmone]

Thanks Ack for a great thread

Reading through your set up, it sounds like you have had a very similar journey to me

Also your listening priorities sound similar

I have owned Prodigies and now own CLXs

I have not gone down the panel mod route but could clearly see the potential benefits

As a timbre freak, concert goer and musician, I share your interest in finding great electronics for the CLX

I have had an interest in the spectral amplifiers, but have never heard them on stats

Not many in Australia

I recently heard the Big Goldmund with CLX, which have similar priorites of speed, and was mightly impressed, though I felt they lacked a bit in timbral density, though their delicacy, high frequencies and dynamics were extra ordinary

I am currently using a small Japanese firms, current mod amplifiers, which like spectral have no Zobel network, no feedback, and Megahertz bandish

Since they are current mod input preferred, I have been working to reach their potential, but recently found the use of a SUT work

The timbral quality is getting very close to what I hear live

Strings always seems the let down, but recently I seem to be overcoming this to

I am intrigued by your panel mods

I am wondering where you thought you got the most improvement, was it in changing Caps in power supply or cross over

Thanks again for your post

On another matter, I am like you searching for a great phono

Any updates on xp 25?

I have my eye on a Zanden 1200 III, after reading Roy Gregory's review, which area of greatest ability seems timbral realism especially for large scale classic records, of which i have 6000

It's people like yourself's contributions which makes me love this site

Your passionate... but not self deluding....and experienced

Thanks again, and keep posting

Warmest regards

Andrew

 

[ack]

Hi Andrew, thanks for your kind comments. So a few things:

1) Yes, timbre is of utmost importance to me; anything but, and I am not really reproducing music in its most fundamental form; surely, there are plenty of other factors too (body, image size, resolution, etc), they just come in behind timbre

2) Related to that, the modified XP-25 (not only the line filters & shields, but also the removal of the loading capacitors), along with the MIT MA-X cable, additional shielding on the cable (not shown in the pictures) and arm, result in exceptional timbre fidelity. Thus, when tamed, the XP-25 is an exceptional phono; but, not for the timid. I must emphasize that it was only after installing the MA-X phono cable that the entire phono chain went in the direction I wanted it; therefore, it feels like that this bridge/interface is extremely critical, meaning that there can be significant signal losses and noise pick-up by a not-so-good phono cable

3) Still related to timbre, the DMA-400RS monos with the updated driver board, plus a new (2014) version of the 30SS S2 preamp I got recently, are also responsible for said timbre qualities (and more) - while keeping in mind that nothing is really perfect. Therefore, this is really testament to the XP-25's sound quality *potential* as well

4) "not self deluding" - yes, all of this stuff is just "things" to me; nice things, but things nonetheless. It's important to me to be able to see the good and the bad attributes of a design, in order to help form an opinion and potentially determine direction. I am really only loyal to my money and Symphony Hall

5) I have high hopes for the upcoming Spectral phono, due out before I turn 90, I assume But at the moment, I am not clamoring for it

6) These modified Logans have very little to do with what came out of the factory. The biggest gain came after replacing the crossover caps (panel and woofer - they are two different crossovers, like your ex Prodigies); I have not touched the power supply. But it's also true that the Mundorf foil inductors brought in much lower series impedance (at the very least) than the originals. At one point I thought about completing just one speaker in order to easily compare with the other, but just the cap replacement in the panel in one was so dramatic (especially with overtone decay) that it was pointless to do any further A/B testing. And between the two crossovers, the most dramatic gain eventually came in the bass section - truly night and day

7) I have heard your CLX a couple of times and I wish I could fit them in my room; I am not really familiar with its crossover, but from pictures I have seen, I would probably be looking to modify it too. The support frame would also be an issue for me. Also curious about your ribbon supertweeter - years ago I was looking at using one as well; it turned out everything but the panels were responsible for the darker system character back then

8) Apparently, Spectral with stats isn't all that unusual - I have sold two amplifiers in the past to Logan owners, who claimed they got the idea from other friends of theirs

I am curious about your Japanese tube amps - what are they? I love the tube device for its linearity and extremely wide bandwidth...

Thanks again

 

[audioarcher]

I found this nice little tutorial on shielding online if anyone is interested. http://www.learnemc.com/tutorials/Shielding02/Practical_Shielding.html

 

[ack]

I found this nice little tutorial on shielding online if anyone is interested. http://www.learnemc.com/tutorials/Shielding02/Practical_Shielding.html

Beautiful, thanks! Just about the perfect article for the uninitiated. I would add a couple more data points to complete the picture: materials with very high permeability, like mu-metal, are far superior for magnetic shielding, and are thus used in what we call Zero-Gauss chambers (using layers and layers of said materials; think room within a room). By contrast, low-permeability materials, like the XP-25's aluminum (permeability ~= to air's), effectively leave the circuit board totally exposed. Finally, when working with such materials, make sure they are not bent out of shape too much - i.e. avoid creases, otherwise, in order to fix those, you need to re-anneal the material in a hydrogen atmosphere within a high-temperature furnace.

 

[audioarcher]

After reading the tutorial above I decided to mess around with some 1/2 inch copper foil tape I had bought awhile back. I decided to tape the seam of the bottom plate on my Lehmann SCR. The enclosure is all billet aluminum except for the bottom plate. I also covered the dip switches on the back, and the led light on front with copper tape. About all I can do that is practical.

So what was the result? Well before I did that I would get interference from my cell phone putting noise through the system if it got too close to the phono stage. After the tape I can now put the phone right by the phono stage and tonearm and get no noise from it.

 

[LL21]

After reading the tutorial above I decided to mess around with some 1/2 inch copper foil tape I had bought awhile back. I decided to tape the seam of the bottom plate on my Lehmann SCR. The enclosure is all billet aluminum except for the bottom plate. I also covered the dip switches on the back, and the led light on front with copper tape. About all I can do that is practical.

So what was the result? Well before I did that I would get interference from my cell phone putting noise through the system if it got too close to the phono stage. After the tape I can now put the phone right by the phono stage and tonearm and get no noise from it.

very interesting...just so I get this straight...what exactly does one tape in your opinion? Any seam of the component? Why the LED light? Thanks for any guidance on this.

 

[audioarcher]

very interesting...just so I get this straight...what exactly does one tape in your opinion? Any seam of the component? Why the LED light? Thanks for any guidance on this.

Hi Lloyd, well since this is my first crack at this sort of thing, I just did what made sense to me from reading the info in that link above. It says that the seams in the equipment can act as an antenna. Also holes in the case can let RF in. It's also important to use shielded cables in and out of the equipment. I know my tonearm wires are shielded but my interconnects coming out of the phono stage are not shielded. As far as covering up the LED not sure if that was necessary but figured I could block the light from being annoying as a bonus.

I can put up some picks of what I've done if you like?

The adhesive on this foil tape is not really aggressive so I'm not too concerned about it staying on the equipment when removed. If it does I can remove it pretty easily.

 

[LL21]

Hi Lloyd, well since this is my first crack at this sort of thing, I just did what made sense to me from reading the info in that link above. It says that the seams in the equipment can act as an antenna. Also holes in the case can let RF in. It's also important to use shielded cables in and out of the equipment. I know my tonearm wires are shielded but my interconnects coming out of the phono stage are not shielded. As far as covering up the LED not sure if that was necessary but figured I could block the light from being annoying as a bonus.

I can put up some picks of what I've done if you like?

The adhesive on this foil tape is not really aggressive so I'm not too concerned about it staying on the equipment when removed. If it does I can remove it pretty easily.

Thanks! The reason I was curious was the fact that you can hold a cellphone with no effect now. That is quite something...but given that you were taping edges...I thought...do I need to tape edges, holes around tubes, and all RCA inputs that are unused as well?

 

[audioarcher]

Thanks! The reason I was curious was the fact that you can hold a cellphone with no effect now. That is quite something...but given that you were taping edges...I thought...do I need to tape edges, holes around tubes, and all RCA inputs that are unused as well?

I would not try to seal up a tube based phono stage with copper foil tape. Unless the tubes do not protrude and do not need the ventilation. I would ask the designer first in that case. My SS phono stage does not need ventilation. The transistors are heat sinked to the aluminum case inside.

 

[LL21]

I would not try to seal up a tube based phono stage with copper foil tape. Unless the tubes do not protrude and do not need the ventilation. I would ask the designer first in that case. My SS phono stage does not need ventilation. The transistors are heat sinked to the aluminum case inside.

Thanks...was thinking the same...glue, paper and intense heat...a very, very bad combination! I keep my tubes clear of anything except a specially designed tube damper.

 

[awsmone]

Hi ACK

Please see the link about the amplifiers

http://www.whatsbestforum.com/showthread.php?14844-Bakoon-shp-5516-100-Watt-monoblock-current-drive-
amplifier&highlight=bakoon

Subsequent to this post I am now able to interface them with the Accuphase in using current mode via Jensen transformers

This has been 100% quality improvement and timbral improvement

This has also dropped the noise floor to negligible levels

However in light of your postings of RFI shielding :- I may attend to this in my phono space...... very interesting

On cart loading I have Ortofon BLACK MM

My sony PSX9 has variable loading for this

I note a difference here with variablemc loading

Others have published on effect of loading of 2 M BLACK in terms of frequency response

I include a link

http://forums.stevehoffman.tv/threads/ortofon-2m-black-frequency-response-charts.312499/

results are self evident and consistent with listening observations and Ralph's comments

Keep up postings on your experiments

I hope to post my adventures in CLX mods soon with pics and freq responses as you have done

regards

A

 

[ack]

Nice, though couldn't find any info on the tube versions... So the other thing I wanted to mention is that noise has dropped to the point I can easily hear the faint pre-echo that some LPs have before the start of a track, from the speakers at regular listening levels - the pre-echo is usually audible when using headphones with the volume cranked up, or from CDs. This is a good noise threshold to have, and I am sure others with more capable systems reached that level years ago.

An example of such an LP with pre-echo is this Speakers Corner re-issue

 

[ack]

ack's analog rig shield

Here's a video of the completed analog rig shield I have implemented, mu-metal+copper foil throughout and routed to ground - as others have attested, the drop in noise and resulting improvement is simply staggering... a clear example of form following function.

 

[audioarcher]

Here's a video of the completed analog rig shield I have implemented, mu-metal+copper foil throughout and routed to ground - as others have attested, the drop in noise and resulting improvement is simply staggering... a clear example of function following form.

You're not messing around anymore. Perhaps the tuner on top of the XP-25 is/was bringing more RF and EMI to the party?

 

[ack]

I mean business No the tuner is dead quiet; unplugging or removing it makes no difference; it's an exceptionally well-shielded tuner. BTW, I recently added a Shunyata Defender to the same circuit with the tuner, phono and panels - and what a significant improvement that brought; e.g. there was some residual noise from the panels' power supply if you were to stick your ear on them - like hashies - with no music playing, but no more... tiny but important improvements.

 

[audioarcher]

I mean business No the tuner is dead quiet; unplugging or removing it makes no difference; it's an exceptionally well-shielded tuner. BTW, I recently added a Shunyata Defender to the same circuit with the tuner, phono and panels - and what a significant improvement that brought; e.g. there was some residual noise from the panels' power supply if you were to stick your ear on them - like hashies - with no music playing, but no more... tiny but important improvements.

Interesting. I have my panels and DAC plugged into an old PS Audio UPC 200. Not sure it does much but it is a handy 4 banger power strip. Have not really noticed any noise out of my panels with no music but it could be worth a shot.

 

[XV-1]

Hi Ack

I am looking at wrapping my xp-25 in my metal to see what it does to the noise floor.

Impossible to find in Australia. Does this mu metal in the abay link look like the right stuff?

Thanks

Shane