Modifications to the RTA 15TL

Fanatic · September 2016

So the modifications continue.

Now it's time to give the estetics of the speakers an upgrade. It seems to me like the grilles look a bit to much 90's

, so i started making new ones. Hopefully they will end up looking a bit more 20-th century. The original design does actually have a design flaw, which is when the fabric covering the frame is mounted, it tends to make the sides of the grille bend towards the center of the speaker (looking like a banan), so i added some extra bracing to the new ones.

The new ones wont be having any angle cut sides/bottoms/tops, just rounded right/left edges and they will be mounted flush with the sides and top of the speaker. This modification won't show any of the veneer when you are standing/sitting right in front.
I'm also thinking about adding a newer badge/emblem, prefferably aluminium colored, or the black/white/red one.

And well, i swapped the 90's looking feet to new black aluminium ones (44x17mm round with a rubber insert)

westmassguy · September 2016

Nice work!

RandyCroissant · September 2016

Nice to see some serious effort going in to those Polks

boston1450 · September 2016

+++ Very nice work

boston1450 · September 2016

Are those SPIKED yet

tonyp063 · September 2016

Nicely done. Very pleasing to the eye.
What does the ear say?

F1nut · September 2016

And well, i swapped the 90's looking feet to new black aluminium ones (44x17mm round with a rubber insert)

Spikes are a much better idea than the amplifier feet.

Fanatic · September 2016

Needless to say, i like the sound they poduce, else i wouldn't put all this effort in making new grilles!

About the spikes, its not really an option at the moment, since one of the speakers are placed on tiles/wooden floor. If i'll be using spikes it will be when they're placed in another room with "proper" flooring.

At the moment im running a DSPeaker Anti-Mode 2.0 Dual Core in the system, and the Anti-Mode probably produces more wonders than the spikes would have done in my room.

leesonic · September 2016

I wish I still had my RTA-15TLs. I never got a chance to fully listen to them. I bought them after we sold our house, and so that sat in a storage unit for a while, along with a pair of AR9LSi. I had to sell them because I needed the money, now they never seem to come up for sale around the South Jersey/Philly area. I would buy them back given the chance, I'm buying the ARs back.

I always wondered, what would happen if you "boarded up" the rear facing passive radiator? Maybe with a piece of 3/4" MDF screwed into the same holes as the passive, and will a gasket to stop air leaks. I find that speakers without rear ports (or passives) are easier to place in my room.

Lee.

Fanatic · September 2016

leesonic wrote: »

I wish I still had my RTA-15TLs. I never got a chance to fully listen to them. I bought them after we sold our house, and so that sat in a storage unit for a while, along with a pair of AR9LSi. I had to sell them because I needed the money, now they never seem to come up for sale around the South Jersey/Philly area. I would buy them back given the chance, I'm buying the ARs back.

I always wondered, what would happen if you "boarded up" the rear facing passive radiator? Maybe with a piece of 3/4" MDF screwed into the same holes as the passive, and will a gasket to stop air leaks. I find that speakers without rear ports (or passives) are easier to place in my room.

Lee.

Removing the rear radiator is not a good idea, since it's needed to reproduce lowest frequenceys. You could probably remove both passives and compensate with ports (carefully calculated and tested). But my guess is you'll suffer from distorsion when trying to reproduce the same SPL levels as with the passives.

This is just why i'm using the Anti-Mode,i cant't place any speaker in my room without placing them really close to the wall. The Anti-Mode removes all the boomyness and excessive bass, if i'm not wrong it does also compensate frequenceys with time, so the result is just tight,heavy and articulated bass! Well worth the money if you have limited placement options for your speakers.

Fanatic · September 2016

So i finished the new grills yesterday evening.

So the next question, which emblem/badge should i add to the grills? and where?
I was thinking top center or bottom, not like the original ones (just above the pr).

boston1450 · September 2016

Excellen work. That shiny top look sweet

leesonic · July 2017

I finally managed to get another pair of these a few weeks ago. They had one Peerless and one SL-3000 tweeter, which I replaced with RD0198s when I did the crossover mods over the weekend.

Here is a shot of the original crossovers, with a production date of 12/10/90 :

Here they are restored with Solen caps, and Dayton Audio Grade resistors. I went with the Dayton resistors because I wanted to get all the parts from the same source to save on shipping, Parts Express matched the Madisound price on the Solen caps. Some people have used additional boards for the larger caps, but I found with some deft positioning of the components, I was able to get them all on one board, and more importantly to fit back through the hole. I used the original woofer inductor, but used the a Dayton one for the tweeter.

There was an unused solder pad on the board that I was able to use to fit the 0.5R resistor. Those wires might look a bit tight in that area from the 0.5R resistor, the 2.7R, and the 12uF cap, but they are all going down to the same pad anyway.

Here they are going back in. Notice I swapped the tweeter polarity on the board, not at the tweeter. I meant to take pictures of the new RD0198 tweeters, but forgot.

Lee.

boston1450 · July 2017

Excellent job. I think youll enjoy the tweeters much better then the way it was. Cant imagine why someone would mismatch tweeters

pitdogg2 · July 2017

Get back to us after they play for about 300hrs. I will be curious as to your thoughts on the Solens in the tweeter section. Can i ask why you didn't use mills or mundorf non inductive resistors?

leesonic · July 2017

I used Dayton non inductive resistors instead. As I mentioned above, I wanted to get all the parts from one source, as shipping costs start to add up. I don't mind if it's for more expensive parts (like the parts I just ordered for a NAD 2700 power amp), but for just a few caps and resistors? Parts Express was nice enough to match Madisounds price on the Solens. If you hear the difference between Dayton and Mills resistors, you've got better ears than me.

Lee.

K_M · July 2017

leesonic wrote: »

I used Dayton non inductive resistors instead. As I mentioned above, I wanted to get all the parts from one source, as shipping costs start to add up. I don't mind if it's for more expensive parts (like the parts I just ordered for a NAD 2700 power amp), but for just a few caps and resistors? Parts Express was nice enough to match Madisounds price on the Solens. If you hear the difference between Dayton and Mills resistors, you've got better ears than me.

Lee.

In the DIY community, Dayton stuff is used very regularly with spectacular results.

F1nut · July 2017

K_M wrote: »

leesonic wrote: »

I used Dayton non inductive resistors instead. As I mentioned above, I wanted to get all the parts from one source, as shipping costs start to add up. I don't mind if it's for more expensive parts (like the parts I just ordered for a NAD 2700 power amp), but for just a few caps and resistors? Parts Express was nice enough to match Madisounds price on the Solens. If you hear the difference between Dayton and Mills resistors, you've got better ears than me.

Lee.

In the DIY community, Dayton stuff is used very regularly with spectacular results.

That's only because they haven't used better components to know that Dayton stuff isn't spectacular.

pitdogg2 · July 2017

Yes agree shipping can be a deal breaker at times.

leesonic · July 2017

I knew there would be people on here that would whine and moan if I didn't use the Solen caps. Usually, I would have used PEX caps from Erse Audio, or Dayton caps. I've done plenty of crossover restorations using these caps, and have had no complaints, both on my own stuff and speakers I've restored for others. You can see my threads over on AudioKarma, same user ID as this one.

Caps are a subject that people have strong but very misguided opinions on. Some people with unlimited funds prefer caps with 24ct gold foil, using the finest snake oil as the electrolyte, soaked in pure silk sheets from free range (not battery) silkworms, and hand-rolled on the thighs of dusky maidens. Me, I've already said what I use. The fact is, a Dayton, Erse, or Solen cap is going to be miles better than a 20 year old electrolytic, so don't lose any sleep over it, just listen to the music.

F1nut · July 2017

Sorry, there are people here with more experience using caps you haven't used that know how much better they are. Since you've never tried any your comments mean nothing.

pitdogg2 · July 2017

leesonic wrote: »

I knew there would be people on here that would whine and moan if I didn't use the Solen caps. Usually, I would have used PEX caps from Erse Audio, or Dayton caps. I've done plenty of crossover restorations using these caps, and have had no complaints, both on my own stuff and speakers I've restored for others. You can see my threads over on AudioKarma, same user ID as this one.

Caps are a subject that people have strong but very misguided opinions on. Some people with unlimited funds prefer caps with 24ct gold foil, using the finest snake oil as the electrolyte, soaked in pure silk sheets from free range (not battery) silkworms, and hand-rolled on the thighs of dusky maidens. Me, I've already said what I use. The fact is, a Dayton, Erse, or Solen cap is going to be miles better than a 20 year old electrolytic, so don't lose any sleep over it, just listen to the music.

I asked that you report back only because I would of liked your impression. I've used Solen in the low pass but in the high pass they for me can be very fatiguing and or shrill.
Forgive me for trying to get another point of view.

Sea · January 2018

Good Morning All. After spending several years accumulating and restoring Carver Amazings, I have found mayself back dabbling with Polks again. I still think my fully modded SDA 1C are the best speakers I own,

Anyway, I have just acquired a pair 15tl's in great shape from the original owner. I am trying to decide whter to go down this update path. Great work by Decato.

My first question for all of the experts here is are these supposed sealed cabinets like my RTA 12c's and other models with passives. I do not get any movement of the passive cones when I press on the drivers.

Sea · January 2018

Thank you to decato for his great work.

I have just acquired a pair of 15tl's. Quick,question. I assume these are supposed to be sealed cabinets since they have passive radiators. I do not get the expected defection of the drivers when I press and hold one of the cones.

FestYboy · January 2018

You shouldn't press on the driver, you SHOULD press on the passive. A single MW won't displace enough air to significantly move the passive. Think of it like a hydraulic circuit.

pitdogg2 · January 2018

Sea wrote: »

I do not get any movement of the passive cones when I press on the drivers.

You should be pushing the passive not the drivers. Since these have 2 passives it might not work the same

Sea · January 2018

Yes. I found a post suggesting to push on both passives at the same time. My enclosures are sealed well. Thanks.

pitdogg2 · January 2018

Excellent

Sea · January 2018

My postings were delayed for some reason. Maybe because it has been so long since I posted. I think the meantime I found d a post somewhere suggesting that both the front and rear passive should be pressed at the same time. The cabinet is indeed sealed. Thanks.

Sea · January 2018

My postings were delayed for some reason. Maybe because it has been so long since I posted. I think the meantime I found d a post somewhere suggesting that both the front and rear passive should be pressed at the same time. The cabinet is indeed sealed. Thanks.

Modifications to the RTA 15TL

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