The AI-1 Dreadnought Project Pt.1

thsmith

DarqueKnight, you have improved the sound of your speakers and most people here's beyond belief.

You have certainly left your mark and thank you for all that you have done and will do for audio at Club Polk !

DarqueKnight

thsmith wrote: »

DarqueKnight, you have improved the sound of your speakers and most people here's beyond belief.

I, and other SDA enthusiasts, continue to be surprised at the ever-increasing performce we are able to extract from a decades-old speaker design. I think SDA's were about 20 years ahead of their time. It took that long for low noise designs for amplifiers, wire, capacitors, inductors, and resistors to "catch up". One thing I have learned is that the spatial properties of loudspeakers, particularly SDA's, are significantly affected by the noise characteristics of wiring, crossover components and associated electronics.

Moose68Bash

In july 2012 (Post # 291 above) I described my experience with the installation of Perreaux Prisma 750 monoblocks to drive SDA SRS1.2a speakers. The monoblocks are not common- ground amps, and the experience of "firing them Up" for the first time with the SDA SRSs was not fun. The Perreaux folks steered me to this thread and advised me to build a Dreadnought using a Toroid Corporation of Maryland 600VA isolation transformer.

I built the Dreadnought, and not knowing that eventually I would be able to purchase one of Larry's enclosures, I designed an enclosure, ordered pre-cut 3/8" aluminum plates, 1" x 1" x 3/16" aluminum angle irons, Cardas CCGR binding posts, and brass spikes to fabricate the enclosure. My goal was to have the aluminum components black, hard-anodized and to chamfer the face plate to resemble the face plates on my Perreaux equipment. While designing the enclosure, I assembled a prototype enclosure from 11/32" plywood, which I have been using for the last seven months with great satisfaction. (While the crossovers and binding post cups for the SAD SRS were being upgraded by Vr3 Mods -- that is, Trey -- I also used it with great success with my 1Cs and a common ground amp in a second system).

After several months -- involving work with a local machine shop and a not-so-local anodizer -- I have finally completed the assembly, and I installed it in my system last night. In the new enclosure, I installed the A-L 1000VA toroidal transformer I acquired in the recent group purchase nspindel orchestrated.

My first listening experience with the new Dreadnought v. the plywood-enclosed TCM 600VA AI was as follows:
1. The most obvious difference was that to hear the music at the same level required a significantly higher volume setting.
2. The soundstage was dramatically expanded horizontally and vertically -- about 4-6 feet beyond the speakers on horizontally and about 3 feet vertically. (As I recall, this is consistent with Darqueknight's experience with the A-L 1000VA transformer.)
3. The geometry of the sound stage was altered. Darqueknight described his experience as a "crescent" or "m" shape that is thicker in the middle. His description is as good as I can come up with. In the center of the sound stage, instruments and vocals appeared to have a deeper space to perform in.
4. Vocals sounded veiled; instruments sounded more prominent in the music. This effect was so pronounced that my wife almost immediately experienced what she described as "listener fatigue." She did not enjoy listening to the music unless I lowered the volume to a level that did not satisfactorily render the sound for me.
5. Bass was emphasized, but was not as tight or well defined as with the plywood-enclosed TCM 600VA AI.
6. Overall, the initial impression -- I expect it to change with playing time -- was that the very good sound we were getting from the plywood-enclosed 600VA TCM transformer was much better than the sound from the heavy aluminum-enclosed 1000VA A-L transformer.

Attached are some pictures of the process of fabricating the new Dreadnought. In case anybody is curious the assembly weighs about 45 pounds! (More pictures in the following post.)

Moose68Bash

I have additional pictures of my Dreadnought enclosure that I could not include in my prior post. As soon as I figure out how to reduce the size of each image (about 3.5 MB), I'll post them.

Sorry for this glitch.

nspindel

I have not noticed any fatigue or veiled vocals with my 1000VA vs. my AL 800VA. My guess is that you either have something not wired correctly or you just need to give the transformer more time to break in.

Moose68Bash

Neil, thanks for your comments. I agree that these initial observations will likely give way to very different ones as we get more time on this transformer. After I installed Trey' modified crossovers and binding post cups on the SDA SRSs, it took a good 200 hours till we heard the profound improvements that we finally realized. I expect similar dramatic changes with the 1000VA transformer.

I am pretty sure the wiring is correct: I confirmed the wiring I planned to do with DarqueKnight before I soldered the wires to the binding posts, and the connections to the speakers are the same as with the prior Dreadnought.

I'm still working on converting more picture files to smaller file sizes so that I can upload them.

Moose68Bash

Here are some more pictures of the Dreadnought enclosure in various stages of assembly and as finally assembled.

drumminman

I thought a little sound quality was lost when I first connected the 1000VA AI-1 (compared to the 800VA AI-1). With time everything that was there before returned, and then it really blossomed.

I second giving it burn in time.

Moose68Bash

Well, we now have about 12 hours of listening time in, and this rig has truly blossomed!

We're listening to Ray Charles's "Ray Charles: Genius Loves Company." It is magnificent! The sound stage is about six feet wider on both sides and very deep -- Ray and his piano are about three feet in front of the plane of the speaker fronts and the orchestra is arrayed across the entire soundstage behind him and the individuals with whom he sings successive duets.

The instrumentals are deep and clear. The vocals are beautifully precise, clear and warm! The transients are fast and detailed. I don't know what more to say other than I hope things just keep getting better -- but I don't know where they can go from here. I'll just sit back and enjoy the ride. (Current duet is with Willie Nelson singing "It Was a Very Good Year," and Willie just sang the "when I was 35" segment!) Beautiful.

Close my eyes and it sounds like they're all in the room with me.

Trey, DarqueKnight, Toolfan66, nspindel, drumminman and all those who helped me along the way with these mods, a mighty big thanks!

Toolfan66

nspindel wrote: »

I have not noticed any fatigue or veiled vocals with my 1000VA vs. my AL 800VA. My guess is that you either have something not wired correctly or you just need to give the transformer more time to break in.

Agreed!! Are you sure none of your binding posts are not touching the aluminum case you built? BTW that thing is a tank...

Toolfan66

nspindel wrote: »

I have not noticed any fatigue or veiled vocals with my 1000VA vs. my AL 800VA. My guess is that you either have something not wired correctly or you just need to give the transformer more time to break in.

Agreed!! Are you sure none of your binding posts are not touching the aluminum case you built? BTW that thing is a tank...

DarqueKnight

Moose68Bash wrote: »

I don't know what more to say other than I hope things just keep getting better -- but I don't know where they can go from here.

You would be quite shocked at the difference driver rings and upgraded internal wiring would make.

It appears from your signature you have 1.2's (with RD0194 tweeters). Since you were upgrading the crossovers, why didn't you do a 1.2TL conversion?

Moose68Bash

Thanks for the comments.

Toolfan, it is a tank -- 46 pounds with the transformer installed. The binding posts are well isolated from the aluminum. The nylon (I think) spacers and washers shipped with the Cardas binding posts are properly seated in the holes in the rear plate.

Darqueknight, I have installed Larry's rings, but I didn't do the tl upgrade because somebody (I don't remember who) on the Forum said in one thread that it was not a good idea to start swapping out the inductors to do the tl upgrade. Does that particular upgrade -- to the RD0198s -- make a big difference?

I read your write-up about your upgraded internal wiring, and if I had or can acquire the skills to do it properly, I would likely take it on one day soon. Right now, however, I have to finish the upgrades on my 1Cs before I start on any new projects. Trey told me today that he expects the inductors soon, and he is going to ship out the new binding post plates he is having fabricated in a couple of weeks or so. I also have to install my 600 VA toroidal transformer in Larry's enclosure to use with the 1Cs (I'm almost finished -- Dynamatted it this evening). When I used it in a plywood box with the 1Cs for a while, even with a common ground amp (Perreaux PMF3150), it made a very big improvement in the sound.

Then, I have to get an electrician to run dedicated lines to power the Perreaux monoblocks, and I have to build new power cords for the monoblocks. I purchased Furutech 9 AWG cable from Sonicraft and Furutech Edison and IEC plugs with which to build them. I would also like to find a solution to the problem of eliminating line noise. I still haven't decided what is best for me to do.

I have a few projects to complete before I'll be ready to open up the SRSs again!

Once again, thanks to you and all the others who have helped make these improvements in my set up possible for me.

DarqueKnight

Moose68Bash wrote: »

Darqueknight, I have installed Larry's rings, but I didn't do the tl upgrade because somebody (I don't remember who) on the Forum said in one thread that it was not a good idea to start swapping out the inductors to do the tl upgrade.

It is not a good idea to swap inductors for ones with different wire gauges and DCR's (except for the 16 mH SDA inductor). It is a good idea to replace the inductors with higher quality inductors with the same wire gauge and DCR.

Upgrade-High-Frequency-Inductors-For-The-SDA-SRS-1.2TL

Upgrade-Low-Frequency-Inductors-For-the-SDA-SRS-1.2TL

Moose68Bash wrote: »

Does that particular upgrade -- to the RD0198s -- make a big difference?

Polk thought it did, hence the introduction of the SDA SRS 1.2TL and the 1.2 --> 1.2TL conversion kit. Toolfan66 can provide first-hand insight since he converted his 1.2's to 1/2TL's.

Moose68Bash wrote: »

I read your write-up about your upgraded internal wiring, and if I had or can acquire the skills to do it properly, I would likely take it on one day soon. Right now, however, I have to finish the upgrades on my 1Cs before I start on any new projects. Trey told me today that he expects the inductors soon, and he is going to ship out the new binding post plates he is having fabricated in a couple of weeks or so. I also have to install my 600 VA toroidal transformer in Larry's enclosure to use with the 1Cs (I'm almost finished -- Dynamatted it this evening). When I used it in a plywood box with the 1Cs for a while, even with a common ground amp (Perreaux PMF3150), it made a very big improvement in the sound.

Moose68Bash wrote: »

Then, I have to get an electrician to run dedicated lines to power the Perreaux monoblocks, and I have to build new power cords for the monoblocks. I purchased Furutech 9 AWG cable from Sonicraft and Furutech Edison and IEC plugs with which to build them. I would also like to find a solution to the problem of eliminating line noise. I still haven't decided what is best for me to do.

1. AC Regenerator for your preamp and source components.
2. Passive line filter (Shunyata Hydra, PS Audio Solist, or similar) for the power amps.

Moose68Bash wrote: »

Once again, thanks to you and all the others who have helped make these improvements in my set up possible for me.

Congrats on the Dreadnought build and your sonic results.

nspindel

Moose68Bash wrote: »

Well, we now have about 12 hours of listening time in, and this rig has truly blossomed!

We're listening to Ray Charles's "Ray Charles: Genius Loves Company." It is magnificent! The sound stage is about six feet wider on both sides and very deep -- Ray and his piano are about three feet in front of the plane of the speaker fronts and the orchestra is arrayed across the entire soundstage behind him and the individuals with whom he sings successive duets.

The instrumentals are deep and clear. The vocals are beautifully precise, clear and warm! The transients are fast and detailed. I don't know what more to say other than I hope things just keep getting better -- but I don't know where they can go from here. I'll just sit back and enjoy the ride. (Current duet is with Willie Nelson singing "It Was a Very Good Year," and Willie just sang the "when I was 35" segment!) Beautiful.

Close my eyes and it sounds like they're all in the room with me.

Trey, DarqueKnight, Toolfan66, nspindel, drumminman and all those who helped me along the way with these mods, a mighty big thanks!

Now we're talkin'! Ah, the difference a little break-in can make. I see we have another believer. Still amazes me how many people argue that break-in is nonsense.

parnold

DarqueKnight wrote: »

There were small, but easily heard, improvements with the xStream cables. I did listening tests with an xStream cable first on the right and then on the left, then on both sides. Quantitatively there was a little more detail, moreso at the sides of the sound stage. Spatially there was a little more image height overall and a little more depth at the sides of the sound stage.

And we lost another one to the cable companies..

DarqueKnight

parnold wrote: »

And we lost another one to the cable companies..

If I were going to be lost, I would much rather it be to an audio cable company than to a casino, recreational drug dealer, cigarette company, or diamond dealer.

nspindel

parnold wrote: »

And we lost another one to the cable companies..

And we found another one. A newbie to debate cables. Great....

EndersShadow

Raife, as long as you're more lost than me I am ok with it, your blazing the trail for me ....

LOL, nothing like a troll

DarqueKnight

nspindel wrote: »

And we found another one. A newbie to debate cables.....

...with the typical lack of knowedge about electrical noise, dielectric effects and conductor quality and how they affect the spatial properties of stereophonic music.

RickTfromAZ

DarqueKnight wrote: »

...with the typical lack of knowedge about electrical noise, dielectric effects and conductor quality and how they affect the spatial properties of stereophonic music.

Agreed.

parnold

DarqueKnight wrote: »

If I were going to be lost, I would much rather it be to an audio cable company than to a casino, recreational drug dealer, cigarette company, or diamond dealer.

This is a sentiment I agree with

nspindel wrote: »

And we found another one. A newbie to debate cables. Great....

This is one that needs some re-evaluation. Have you ever tried blind testing cables? Although there may be some minor differences people tell you such as

DarqueKnight wrote: »

electrical noise, dielectric effects and conductor quality and how they affect the spatial properties of stereophonic music.

Which cable companies want you to believe in will make an audible difference, its a old trick thats been tested many times over which shows it's just a subjective effect.

Don't get me wrong guys I love the sound of my Polks just as much as you guys do, yet cables should be the last thing on everyone's mind when upgrading their Polks to make an audible difference. They do look cool though, I'll give them that.

nspindel

GlennDog

^^^^ That really doesn't warrant a response, but I'll give it a shot . . . I recently went from 12 awg Tributaries to MIT AVT2 . . . .

NIGHT AND DAY DIFF



G

Edit: Neil beat me to it . . .

nspindel

Seriously, parnold. No joke. This is one of the best threads in the entire Polk forum. Please, just go away. Do not drag this thread down to a cable debate. We're more than aware of the fact that many people do not believe cables make a difference. Been down this road too many times. Just let it go.

parnold

I'm letting it go, and I do admire DK's work, don't want to derail the thread too much. Just didn't want people thinking that cables are the end all solution to audio nirvana. /thread back on rails.

DarqueKnight

parnold wrote: »

Have you ever tried blind testing cables?

Of course I have tried blind testing cables. Have you ever tried reading as opposed to jumping to erroneous conclusions? The reason I ask is that my first comment in the post you quoted from (#308) said this:

DarqueKnight wrote:

I did not hear a difference between the [Monster Cable] Z2 Reference and Volcano cables, even though the Volcanoes had a lower average noise spectrum density and magnitude. This seems to indicate that either there is an upper bound on improvement in sound quality with improvement in SDA cable quality or my equipment could not convey the difference or that my ears could not discern the difference.

While I did not hear a difference or improvement with the use of a pair of $3300 cables on the Dreadnought, I did hear a moderate improvement when the Dreadnought was placed in its $200 aluminium enclosure.

However, in spite of the above, you just zeroed in on the very last comment where I reported a small audible improvement with a cable upgrade.

DarqueKnight wrote:

Don't get me wrong guys I love the sound of my Polks just as much as you guys do, yet cables should be the last thing on everyone's mind when upgrading their Polks to make an audible difference.

Yeah, maybe that's why so many of us focused on upgrading tweeters, modifying drivers, upgrading crossover components, modifying cabinets...and other things. We are not as naive as you seem to need to believe.

parnold wrote: »

I'm letting it go, and I do admire DK's work, don't want to derail the thread too much. Just didn't want people thinking that cables are the end all solution to audio nirvana.

Thanks for the "enlightenment".

ZLTFUL

Oh how I wish I had oscilloscope plots to show how much cables DO make a difference.
Basic electrical theory still applies. Path of least resistance and all of that.

Sort of like saying a house having a 100 amp service is just as good as having a 200 amp service when the home owner runs 3 phase table saws and drill presses and lathes, oh my.

Pretty sure that this shows how wrong you are parnold: http://www.cirris.com/testing/resistance/wire.html

Or how about just taking the exact same length and diameter of wire and simply seeing the resistance of various materials: http://chemandy.com/calculators/round-wire-resistance-calculator.htm

DarqueKnight

ZLTFUL wrote: »

Pretty sure that this shows how wrong you are parnold: http://www.cirris.com/testing/resistance/wire.html

Or how about just taking the exact same length and diameter of wire and simply seeing the resistance of various materials: http://chemandy.com/calculators/round-wire-resistance-calculator.htm

I'm sure parnold meant well. He just didn't want us to get ensnared by the diabolical schemes of the snakeoil audio cable companies. If parnold, and others, wish to discuss the evils if the the audio cable industry, I hope they will take it to another thread.

Thank you for your consideration.

ZLTFUL

Whoa...there's snake oil?!? Where do I sign up??!!