What next for my SDA 2a's

try1256

First off, thanks to all of the folks on here who have been sharing their knowledge and experience. I have been a member of this board for quite a while but haven't posted much. Primarily because there is so much excellent info already here, I just search and usually find the answer to my question. As it is, I have far more questions than I have answers.

That being said, I am at somewhat of a crossroads with the SDA 2a's.

A little back ground. I have re-capped the crossovers with Sonicap on the tweeter, Solen on the 20uf and Mundorf NP electrolytics for the dual 130uf caps on the SDA board. I have replaced the SDA inductor with an Erse. Mills resistors. RDO-194 tweeters. Black Hole 5 behind the mid/bass drivers. Damping on the speaker and PR baskets. Speakon/10ga SDA cable. Spikes. I have the hurricane nuts but haven't put them in yet, I planned to veneer the cabinets and was going to install them then.

I am driving the speakers with an Odyssey Khartago amp. It is a high current 110 wpc into 8 ohms. Will go down to 2 ohms no problem. Speaker cables are DIY using Cat 5 cable and Audioquest bananas. My preamp is a Balanced Audio Technology VK-3i and phono stage is a VK-P5 upgraded to a VK-10 output and 6 pak plus. Table is a restored Thorens TD-160 with an SME M2-9 arm, Audio Technica OC9 ML II cart into a K&K SUT. Cables are Audioquest and Neotech. Standard power cords to each unit.

My listening room is 10 x 13 and the speakers are on the long wall. The speakers are spaced about 6 feet apart with 3 feet to the side walls. I have Acoustimac bass traps in the corners. The 2a's are probably the largest SDA I could use in this room.

I get a very good SDA effect as far as the imaging goes. The speakers disappear and the image is spread across the entire room. It was a little out of focus on the edges but a new 10 ga SDA cable seems to have taken care of that. The problem I am having is the midrange, especially noticable with piano's. There is a glare at about 800 to 1k hz. It muddies up the piano in selections where piano is dominant. Vocals are fine. Clear and centered. I have a pair of Yamaha NS-1000m's also. I put them in just to get a comparison. Mids are clear with no glare, but a much narrower sound stage. I had thought it might just be a room acoustics problem but I am not sure.

The only thing that I haven't done as far as mods is the binding posts and hurricane nuts. The cabinets seem to be sealed well though as I have plenty of low end. I am sure binding posts would help but I am not sure they would solve this particular problem.

For those who have been down this path, is this something that you have encountered? I absolutely love the SDA's but the midrange mud is driving me nuts. I know my room arrangement is not optimum but it is what I have to work with. Any input would be greatly appreciated.
Thanks,
Tim

F1nut

Tim, an excellent crystal clear post.

Chasing down issues like you are having is trying to say the least. I'll throw out a few suggestions starting with installing the Hurricane nuts or waiting for a set of Larry's rings. Replace the Cat 5 with MIT Shotgun speaker cable. Install a dedicated 20 amp line or two.

westmassguy

On my 2As, I replaced the smaller, board level inductors with Jantzens, and the shunt caps in the Low-Pass are also Sonicaps. The Sub-Bass Drives use the Erse SuperQ, and Dayton 5% MP cap in place of the NP Electrolytics.
Everything is cumulative.

pitdogg2

Replace the cat5. I've played with that stuff, no matter how i made the cable there are frequencies that the cable itself fudges. My understanding is its the resistance common to cat cables.

Get some film caps where the lytics and Solens are. The Solens can be very fatiguing imho.

HzTweaker

try1256 wrote: »

Speaker cables are DIY using Cat 5 cable and Audioquest bananas.
Thanks,
Tim

try1256

Thanks for the replies. The plan was always to eventually replace the electrolytic in the SDA board. Looks like I should do it sooner rather than latter. I will try some new speaker cables as well. The cat 5 was actually pretty big improvement over the zip cord type speaker wire I was using before. No doubt a high quality cable will be an even bigger improvement. I will probably have to pass on the MIT Jesse, it is a little above my pay grade. I am sure I can find something to fit the bill in my budget though.

leftwinger57

Being a former alarm installer we had a lot of Cat-5 on hand. While the single gu is 22 and while you bundle the solids and stripes to think it comes down to a 14 or so that I'm not sure of. In a pinch or for a temp test I used it because it was free and available. If you thought you heard a difference between H/D clear and the Cat-5 your using you would be well better off going for some raw 12gu. gu footage from BLUE Jean Cable or Signal Cable used by many here, for inches per foot rather than the uber expensive M.I.T. In getting your feet wet and seems like all the the mechanical mods have been taken care of. Next also on the cheap is replacing the original cable w/ Neutrik/Speakon i/c and binding posts which make a huge difference as also mentioned.

tonyb

I'd go along with changing out the Cat 5 speaker cables. Lots of options on the used markets too that won't break the bank. Sometimes, it's NOT the speakers fault in what your hearing.

try1256

Update: I changed speaker cables from the Cat 5 to conventional speaker cable and put a higher quality power cord on my preamp and power conditioner and the midrange mud is all but gone. Much better. There are still a few suggestions in this thread that I will do that will probably finish it off. Thanks for all the input. Now to the next challenge. I have what seems to be a ground loop hum that I am chasing. Audible enough to be a pain but doesn't interfere when music is playing. It is affected by removing the SDA cable. Almost gone when out. Audible when in. I have done all the typical trouble shooting for hum and that is the only thing that seems to affect it. Any ideas? Thanks.

try1256

Well, it appears it isn't a ground loop. Cheater plug didn't work. Transformer inline between preamp and amp made it worst. I have a new set of tubes on the way for the preamp. If that isn't it. I'm out of ideas. Could mean a trip back to Delaware for the preamp.

Jon1511

Maybe wrong thread but you guys know who does crossover upgrades without breaking the bank? Thanks

TennMan

I used westmassguy to do my crossovers. I was very satisfied with the price and the work he did. Look him up here on the forum.