First impression of The RD 0198 "TL" MOD SDA 2B's

VSAT88

Just completed the mod. Used Gen.1 Sonicap 5.8uF in the added capacitor position. I like them already. I know they need time to break however not too bad so far. This may sound like a strange way to explain the way they sound to me but it is the best I can come up with right now so here goes. It seems as if something is missing, but it is as if that something should not have been there to start with. Does that make sense to anyone else who had done this mod. ? Need to thank @F1nut, @VR3, @westmassguy @pitdogg2 for help on this as well as many other projects I have attempted while here at CP.

pitdogg2

the RD-0198 is a great tweeter FAR FAR better than the SL3000 which are not all that bad per say BUT holy hey suess they bring out the shiznit....

you can quote that

VR3

I could be mistaken but I believe a jumper has to be inserted or removed when converting to the rd0198, would double check that

VR3

Yep, this one

VSAT88

pitdogg2 wrote: »

the RD-0198 is a great tweeter FAR FAR better than the SL3000 which are not all that bad per say BUT holy hey suess they bring out the shiznit....

you can quote that

Just did !

VSAT88

VR3 wrote: »

Yep, this one

Went by this schematic, Did I not do this correctly because I did not put a jumper there.

VR3

I honestly haven't used a sda circuit board in 5 years but I would just double check your connections and make sure everything is 100% right

pitdogg2

this also shows a jumper in that place. Tony's site is pretty legit he spent a lot of time researching and many of us use it for reference.

http://gimpod.com/pdfs/SDA_2B_CRS+_1987+_PB_Schematic.pdf

http://gimpod.com/partsp2b.html

Hover over this link ^^^ and it is full of instructions.

VSAT88

Used that schematic but not the same holes as it shows so I guess there is no way to make sure I have it jumped out as it shows in the schematic. I really wish I had taken some pictures or I could see the back side of that board at "http://gimpod.com/partsp2b.html" The holes I used should not matter (I do not guess) as long as I follow that schematic with my actual wiring is that not correct ?

pitdogg2 wrote: »

this also shows a jumper in that place. Tony's site is pretty legit he spent a lot of time researching and many of us use it for reference.

http://gimpod.com/pdfs/SDA_2B_CRS+_1987+_PB_Schematic.pdf

http://gimpod.com/partsp2b.html

Hover over this link ^^^ and it is full of instructions.

VR3 wrote: »

I honestly haven't used a sda circuit board in 5 years but I would just double check your connections and make sure everything is 100% right

VSAT88

This is how it is wired. I did not use the lettered holes as my resistor leads were too short. I piggybacked my resistor on top of the 5.8uF cap.


And I know I cant draw or write worth a $hit..

heiney9

Also, evaluation really can't be accurate until they break in. The entire speaker will change A LOT, so trying to trouble shoot now, is probably not the best.

Get 250-300 hours on them and if they still are lacking, then start trouble shooting.

But, it's always prudent to check, recheck and then recheck your work to make sure nothing was missed when doing the upgrades.

Rock on

H9

VSAT88

heiney9 wrote: »

Also, evaluation really can't be accurate until they break in. The entire speaker will change A LOT, so trying to trouble shoot now, is probably not the best.

Get 250-300 hours on them and if they still are lacking, then start trouble shooting.

But, it's always prudent to check, recheck and then recheck your work to make sure nothing was missed when doing the upgrades.

Rock on

H9

I totally agree. When I originally restored the crossovers it took quite a while for everything to settle in. It will not take all that long for me to get the 200-300 + on them as I play them more than any of the others. Elton, Sabbath, Floyd and The Grateful Dead say they sound better already.

VSAT88

So, today they sound like they splatter the sound. Sound a little fuzzy I suppose. After only 48 hours though...Keep in mind these descriptions are 1. Just my opinion. 2. described best I can, I am sure some of the words I use are not accurate audio descriptions.

TennMan

I have some 2BTLs. During break in they never whet through a splatter phase or anything that sounded really bad. I think you need to add the jumper VR3 suggested if you used gimpod boards and check the work you did.

westmassguy

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

VSAT88

westmassguy wrote: »

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

I used the original boards. As far as I can see it I did exactly the same as you. Only difference being my resistor leads were short so I stacked/piggybacked the resistor (2.7 ohm) on top of my capacitor. They do not touch but that was the only way to use the mills resistors that I had without extending the leads. That puts the resistor and the capacitor in parallel. If the resistor and the capacitor are supposed to be in series I have it wrong but the schematic does not call for a series run. It shows the two in parallel. far as I read it anyhow. You guys are the experts. Tell me different and I will pull them back out right now.



I still intend to go back in and check what I did. I am not going to pull them again till some break in occurs. So far, Fleetwood Mac, Three dog Night and Cheap Trick concur.

westmassguy

@VSAT88 you're good to go then.

VSAT88

@westmassguy , Thank you Sir. I finally put two and two together after all this time and see that you are DHS. I am glad to know that now. I may get in touch about an EQ I have here made in January 1968. Unsure if I want to tackle it myself just yet.

westmassguy

VSAT88 wrote: »

@westmassguy , Thank you Sir. I finally put two and two together after all this time and see that you are DHS. I am glad to know that now. I may get in touch about an EQ I have here made in January 1968. Unsure if I want to tackle it myself just yet.

Looks like a first production unit.

VSAT88

I do think so. He had all the cables, booklets EQ, tulip stands. Got them from a retired fellow moving to Florida. He said he wanted someone to enjoy them as much as he did all those years. He found him. January 1968 is the date on the owners manual up top right. That was the first month/year the 901's were sold from what I have read anyway.

westmassguy

VSAT88 wrote: »

I do think so. He had all the cables, booklets EQ, tulip stands. Got them from a retired fellow moving to Florida. He said he wanted someone to enjoy them as much as he did all those years. He found him. January 1968 is the date on the owners manual up top right. That was the first month/year the 901's were sold from what I have read anyway.

The best Equalizer for the Series I & II, is the Series II. Many improvements were made.
The 1st production model you have will be fine.

VSAT88

OK, took out the network and could not understand why my board was exactly like the board you posted but without an "H" on the board next to "E". The reason was revealed when I decided to pull the inductor. "H" was completely hidden under it. I understand totally the reason to jump out "E" and "H" now. If not the circuit would not be complete and the capacitor would do nothing. Using "B" and "G" for the resistor, standing it up on the board, jumping out "H" and "E" and placing the "TL MOD" 5.8uF capacitor across C5 looks like how most are doing this. With your help I do see a much better way by placing the capacitor across "R2=C5" on the top tweeter + and the "H" hole on the bottom with the resistor still at "G" and "B" is much better to me anyway. The way I did it is totally unorthodox. I used "R2"="C5" at the top tweeter + and placed the other capacitor lead in "G" with the resistor in parallel mounted on top of the capacitor because my resistor leads were too short and since I intend to re work these networks on wood one day I was not about to order new resistors twice. I suppose what I am trying to clear up is no matter what hole I use as long as the actual schematic is followed for the "TL MOD" for the SDA 2B Blade/Pin there should be no question It is right, right ? I am sorry if I was unclear in my ^ posts and thank each of you for your help and comments.

westmassguy wrote: »

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

F1nut

I just got a headache

VSAT88

LOL. ^ I keep one. Anyhow, above I had written that they had a sound that sounded sort of splattered or fuzzy. I now think that 1. some of the music I was listening was poorly recorded 2. That there were sounds in some of my music were starting to reveal themselves that I had never heard before. Like far in the background. The new tweeters are bringing out those those sounds. Everything seems very nice now. It has been 7 days of burn in at 24 hours a day now.

F1nut wrote: »

I just got a headache

westmassguy

VSAT88 wrote: »

OK, took out the network and could not understand why my board was exactly like the board you posted but without an "H" on the board next to "E". The reason was revealed when I decided to pull the inductor. "H" was completely hidden under it. I understand totally the reason to jump out "E" and "H" now. If not the circuit would not be complete and the capacitor would do nothing. Using "B" and "G" for the resistor, standing it up on the board, jumping out "H" and "E" and placing the "TL MOD" 5.8uF capacitor across C5 looks like how most are doing this. With your help I do see a much better way by placing the capacitor across "R2=C5" on the top tweeter + and the "H" hole on the bottom with the resistor still at "G" and "B" is much better to me anyway. The way I did it is totally unorthodox. I used "R2"="C5" at the top tweeter + and placed the other capacitor lead in "G" with the resistor in parallel mounted on top of the capacitor because my resistor leads were too short and since I intend to re work these networks on wood one day I was not about to order new resistors twice. I suppose what I am trying to clear up is no matter what hole I use as long as the actual schematic is followed for the "TL MOD" for the SDA 2B Blade/Pin there should be no question It is right, right ? I am sorry if I was unclear in my ^ posts and thank each of you for your help and comments.

westmassguy wrote: »

Did you use the original boards, or Tony's?
I prefer to use the original boards on the CRS+s due to lack of space.
On the original boards, you can forgo the jumper and just run the lead from the 5.8uf over to "H"

As long as the circuit is the same, regardless of the marking on the printed side, you're good. I frequently get creative, when trying to stuff large caps and resistors onto the old boards. That's why Tony's (@gimpod) boards are so much easier to work with.

TennMan

Maybe a view of how westmassguy installed the caps and resistors on my stock boards will help. I like the way he dealt with the problem you had with the resistor. He added it to the bottom of the board.

VSAT88

Verified. Its correct and the tweeters sound nice. I like them so, more mods.

VSAT88

There is no doubt now after around 225 hours or so these tweeters are brilliant. I spoke above about a splattering or fuzzy like sound. I am almost 100% that what I heard was detail starting to come in that I had never heard before. I am listening to music that I have listened to many times before and hearing sounds that I have not heard before. I have heard others say that they wish they had done the mod to start with I am in that camp now. They sound excellent !

mccarty250

Resurrecting an ancient thread here but am hoping to solicit some help. I have a pair of SDA 2b's whose values seem to be spot on except for the single resistor which shows 2.2 ohms instead of 2.7 ohms.

Any ideas on why I have some weird variant that has a resistor value that doesn't match the schematic?

Per the SDA handbook my SDA 2 appears to be a B because:
1. Has horrible side panels covered in speaker cloth that vibrate because the glue adhesion is poor (removed)
2. Crossover matches 2b with the exception of the resistor.
3. Serial numbers:
Left: 18740
Right: 16449
Strange that they are non-consecutive but they are marked left and right and both crossovers are exactly the same from a capacitor and resistor perspective.

Should I just forklift the 2.2 ohm resistor and replace it with a 2.7 ohm resistor or do you believe there is a reason for these values?

Photo of said resistor below:



Second question. Do folks typically reglue/refabric the MDF side panels or discard them to prevent potential future rattles? Are they critical from a front baffle width perspective?

VSAT88

@mccarty250 there could be a few different reasons that resistor is off a bit. All its going to do is make one speaker a tiny bit louder than the other. It probably came that way from the factory. How much do you like the speakers ? If you really dig them then start a thread and see what others here say. A new thread may get more attention. I would be willing to bet if you pull that resistor and put in a brand new one you will not hear any difference. If you really like them then decide what mods you want. Those can be some flat out amazing speakers for little cash or giant killers for more cash.

pitdogg2

+/- 5% one resistor may have measured low the other high therefore they may actually match pretty closely.