The SRS 1.2TL ..should I buy them?? :-O

westmassguy

hauxon wrote: »

I will probably be able to find a way to fit the single 12uF 250V CSA (38mm length ) onto the original board just to get the speakers up and running. I will however order Gimpods for the new crossovers.

Right now I'm looking into what parts to order and how much I'm willing to spend. Lot's of options to agonize over.

I've also been wondering how the Gimpods mount to the crossover plate in my 1.2TL's.

They mount the same way as the original boards Hrannar, on top of the large Sub-Bass Drive Spool Inductor. Tony duplicated the four original mounting holes, and also added mounts at the corners.

pkquat

hauxon wrote: »

I wont sell them unless I get the SRS 1.2TL working properly. And I would preferably sell them to someone in my family. ...or just let my oldest daughter (16) have them in her room. ..but I'll keep 'em at least until the 1.2TL are good.

One thing I really noticed with the 1C's and I gather would be the same for 2B's vs. any of the SRS line is they seem to work better in smaller rooms than the SRS. The SRS line had a larger spacing between the MW's. This works great for larger rooms. I question the 3ft from a wall with these. More than 3ft may be better. My 1C's worked really well in a smaller and narrower room. The SRS 2.3TL and 1.2TL in the same room have not sounded as good. I think it is because of reflections. I have heard SRS speakers in a larger room and they sounded better than my current setup. I had thought I was going to sell the 1C's on after SRS speakers, but that has changed. I would for sure keep them in the family with a buy back or gift back clause.

hauxon

The SRS 1.2TL are in my living room with about 7 feet of open space to each side. I'm pretty sure they will sound fantastic when I have replaced the bad cap. Right now I'm waiting for my order to arrive. Hopefully I can solder the new caps in next weekend.

audioluvr

Those gold plated binding posts appear to be Klipsch factory stock items.

hauxon

Little update on my little 1.2TL babies. As I reported earlier in this thread I found one of the the crossover caps lying on the bottom of the right speaker. I managed to solder it back but didn't trust it 100%. I also had the tweeters in my left speaker going silent for some reason. At first I thought it was a connectivity issue since I put a single RD0-198 tweeter in but troubleshooting led me to believe the problem was with the crossover.

I did make an order from HiFiCollective of two Claritycap CSA 12uF caps to replace the broken one and the corresponding cap (C5) on the left crossover. The caps arrived yesterday so last night was soldering night. Since I was having trouble with the tweeters on the left speaker I decided to remove the polyswitches in the hope that the polyswitch was the problem with my tweeter array. My plan is to build new crossovers using Gimpod boards and will reuse the new caps so I left the cap wires a little longer to be safe. I then used the cutoff wires as jumpers in place of the polyswitch. I had used Claritycap ESA before on my SDA 2B TL mod. Seems like the wires of the CSA caps are thicker, almost too thick for the crossover board holes. You need to clean every bit of solder off before being able to pass through. I might add a 0.2 ohm resistor n place of the jumper when I assemble the new crossovers but I'll leave the jumpers in for now.

I didn't have much time for listening after installing the updated crossovers again last night but the tweeters on the left speaker came back and the third tweeter on the right seems to emit normal amount of sound. The sounded good with the song I used for testing. More listening hopefully after work today.

The (left) crossover before modification.


That small brown circular thing is the (faulty) polyswitch


The poly is out!


The jumper in place (located by S1 on board)


The crossover after replacing the cap and poly. Plent of space for the little bit larger Claritycap capacitor at C5.

pitdogg2

.5 ohm resistors are the normal replacement for the polyswitch. The tweeter array is of a progressive point source with top playing full and lower tweeters less so as you go down towards the bottom tweeter.

hauxon

pitdogg2 wrote: »

.5 ohm resistors are the normal replacement for the polyswitch. The tweeter array is of a progressive point source with top playing full and lower tweeters less so as you go down towards the bottom tweeter.

I read somewhere that the initial resistance of the 1.2TL polyswitch was 0.2ohm and 0.3ohm after tripping so I figured 0.2ohm would be the way to go. I might be wrong however.

RXE135, initial resistance range 0.12-0.19 ohm, post trip maximum resistance of 0.3 ohm.

source: https://forum.polkaudio.com/discussion/128258/resistor-replacement-for-the-sda-srs-1-2tl-polyswitch

hauxon

..and : https://datasheet.octopart.com/RXEF135-Tyco-Electronics-datasheet-7576646.pdf

hauxon

I think older models might have a polyswitch with 0.5ohm resistance the "newer" ones 0.2ohm polyswitches. The 2B have 0.2ohm polys from '89 and 0.5ohm before that. I googled the poly I took out and the correct replacement part is the RXE135 (0.12-0.19 ohm). So I doubt that one would even hear a difference that small compared to a jumper.

hauxon

When I came home yesterday the left tweeter array was out again. This left me a bit puzzled. I was pretty confident that the crossover was ok. I had taken a closer look at all the other solder points and did not find anything broken broken or out of the ordinary.

So I started thinking that maybe there was a connectivity issue with the bi-wire jumpers or even somewhere inside the cabinet on from the connectors to the crossover. I disconnected the bi-wire jumper and connected the amp to the tweeter posts ..and no sound from the tweeters but still something from the woofers, hmmmm. Ohh the SDA cable was still connected, I unplugged and silence. I plugged into the lower (bass/midrange) post and silent too. The sound that I heard from the left speaker was just through the SDA cable. The problem was not with the speakers, it was the power amp!!

After short investigation I found out that there is a input selector switch on the back of my power amplifier to choose if it operates with fixed gain or if you control the volume/gain by a small rotary knob at the back. This button was the problem. Switching it back and forth few times made the problem go away, at least for now. So I must dig up the contact spray and take a closer look at the amp this weekend. The good news are that the speakers are in good shape

hauxon

I've had few days now with the speakers and they do sound impressive especially when listening to content with acoustic instruments and good stereo. ...but they sound a little thin on bass. This makes most rock music sound a bit thin. This is not the case with the much smaller 2B's I have, they sound great with rock music. So there must be something I need to sort out. I've ruled out room acoustics since the 2Bs stood in the same spot and all testing of phase seem alright. I found a thread on SRS 2.3 with weak bass output. Plenty of replies but no fix.

I however made a strange discovery today. I was on Tidal and searched for "bass test" and found two different playlists with test notes from very low to mid-range. I began with 50hz and good level from the speakers. Then I tested a 45Hz tone, also fine to my ears. Next up 40Hz ...and no sound at all!! What!! No wonder the sound like a bookshelf I thought to myself. I decided to test 35Hz and to my wonder the speakers were not silent!! 30Hz also fine and 25Hz a little weaker but still there. I did another test with a different recording and same result, no sound at 40Hz. Here we have an answer to why bass drum sounds thin on the speakers and rock music in general. I remember from the thread about the 2.3 that electronic music often sounded fine. So music with ultra low bass below 40Hz maybe sounded fine?

What's happening here? Seems to be the same with both speakers. Something in the crossover? Have you heard of something like this before?

nooshinjohn

Replace the amp...

hauxon

I have an old Pioneer 40wpc amp at home I can use to check if the problem still occurs to eliminate either amp or speakers. Should be ok to use at moderate levels. I will also use a different source and dac. I will also try to see if it might be some sort of acoustic cancellation even if I find that rather unlikely.

Maybe I'll ask too at the diyaudio forum to see if someone has encountered something like it.

@nooshinjohn why do you think it's the amp? Have you seen a problem like that before, or maybe an educated guess?

nooshinjohn

The amp is already giving you problems... if you are going to test the speakers properly, you need to eliminate known problems in order to find solutions. You can't diagnose a problem if you are testing with stuff you know has issues.

And 40 watts is not enough juice. You need high current amplification and at least 300wpc to get where you are trying to go. I suspect the amps you are using, while good for the smaller 2b's, is nowhere near enough for the 1.2TL's. The bass you are missing could be because your amp is simply not up to pushing the speaker to deliver it.

hauxon

My current NAD C272 power amp is 2x150W continuous into 8ohms and plenty for most speakers but might be at the lower end of the spectrum for the SRS 1.2TL. It should not have a problem at moderate listening levels. I always felt that the NAD power amp + SDA 2B combo sounded great. The idea was to add a second NAD C272 later for 2x300W (bridged) but not until I had finished upgrading the speakers. I'll check if I can get someone to lend me a proper amp for testing.

honestaquarian

The NAD is a high current amplifier and you are correct @hauxon. It is at the lower end of what you SHOULD be using for these loudspeakers (the 1.2's) However @nooshinjohn is right, if you know the amp is giving you problems, then it should be removed from the loop. How can you properly diagnose anything with the loudspeakers when you have a known issue with the amplifier?? You have no way of knowing if the speakers are at fault or if the amp is at fault.

hauxon

Status update. It's not silent at 40Hz. Heard it better when not seated. Probably room acoustics...

nooshinjohn

You have too many oars in the water. Solve your first known problem, the amp, and move on to the next, which would be the room and speaker placement.

hauxon

Affirmative!

honestaquarian

It's a phenomenon called Standing Waves.

hauxon

Just ordered the Gimpod boards from David. Next up is getting the parts. Will most likely use ClarityCaps CSA for the tweeter part and ESA for the bass, or CSA for all, haven't decided yet. Probably Mills resistors, or possibly PathAudio, or Duelunds. Opinions/recommendations are welcome.

Maybe I should start a new thread for the restoration?

Hrannar

VR3

You will have a hard time installing duelund on the gimpod boards due to size.

I would recommend Jantzen Superes or mundorf mox over mills.

Path audio is a great resistor, may be a little difficult to get them installed plus incorporating the ground wire shield.

F1nut

hauxon wrote: »

Just ordered the Gimpod boards from David. Next up is getting the parts. Will most likely use ClarityCaps CSA for the tweeter part and ESA for the bass, or CSA for all, haven't decided yet. Probably Mills resistors, or possibly PathAudio, or Duelunds. Opinions/recommendations are welcome.

Maybe I should start a new thread for the restoration?

Hrannar

Sonicap, Mills and SDA's are a match made in heaven.