SDA 2b tl's too bright. What am I missing?
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vintage dad
Posts: 57
I am a long time stalker of this forum. I am a die hard vintage Polk fan and over the years I have been able to find everything I needed to know and then some. After years of enjoying my modified SDA1c's I wanted to try a tl mod. I found a minty pair of SDA 2b's, an early pair in the 2a studio cabinets. I upgraded the crossovers with Sonicaps and Mills for the tweets and Clairity caps for the mw's. I did the extra cap for the Rdo198 tweeters. Dynamat Xtreme on the baskets and Hurricane nuts. I let them play in my garage for about 10 days, and have been listening to them in my home for a while. So I would estimate I am near the 300 hour burn in mark. They are overly bright, and a bit grainy in the highs. I pulled them apart to verify that the crossovers were correct, which they appear to be. My 1C's with sonicaps and rdo194's have a wonderful, warm sound but have always been rather laid back in the highs, even with a jumper in the polyswitch location.I love the increased detail in the 2b tl's but they feel cold and harsh, even with the 0.5 in resistor in the polyswitch spot. From everything I have read this shouldn't be the case. Am I missing something? Can the sound really change much after more than 250 hours of burn in? I want to love them, but after less than an hour of listening my ears are fatigued.
Comments
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Are you using gimpod boards?I know there is a jumper that has to be installed near the cap that is easily overlooked- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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Gear?
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Adcom GFP 555II preamp, Hafler DH500 amp, rotel CD11 tribute. I actually discovered the jumper question earlier today. I originally had the resistor and the 5.8 capacitor piggybacked using the original resistor holes. When I pulled the crossovers earlier today I followed another post's advice. I removed the resistor and cap, re mounted the resistor under the board in its original holes and mounted the cap on top of the board and used the "H" hole on the crossover board. Sadly, no change in sound.
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Post a few good pics of your crossover.
Why mix Sonicap and Clarity?
Never cared for the sound of Rotel CDP's, too bright.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Here's one pic of the crossover I took upon completion, I can pull one out of the speaker if more pics are needed. This pic has the 5.8 inline with the resistor. Yesterday I moved the resistor to the bottom of the board and the cap on there top, a solution I found in another post. It looks better but yielded no chane. I have always used Dayton caps in the lower section and wanted to try something different. The Clairity PX caps were recommended elsewhere on this site so I gave them a try. I have te agree about the Rotel, to me it seems bright. I read tons of reviews which all say the opposite, supposed to sound warm and close to analog but that is not what I am experiencing. I previously had an Adcom. I thikk it was GCD650, and a GCD 575 before that. I really liked the sound of those. I got the Rotrel from Crutchfield and can still return it, which I may do. My limitation is my budget, which the Rotel was at the top of at $600. As a side note it sounds much better on my 1C's, which can be a tad too laid back. I know that a 1C tl mod is not possible or it would already be done.[]
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I am technologically challenged, didn't mean to post the picture of my grandson. Why do we need to have graduation cerimonies from Pre K anyway?
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You can still remove it if you like.vintage dad wrote: »Here's one pic of the crossover I took upon completion, I can pull one out of the speaker if more pics are needed. This pic has the 5.8 inline with the resistor. Yesterday I moved the resistor to the bottom of the board and the cap on there top, a solution I found in another post. It looks better but yielded no chane. I have always used Dayton caps in the lower section and wanted to try something different. The Clairity PX caps were recommended elsewhere on this site so I gave them a try. I have te agree about the Rotel, to me it seems bright. I read tons of reviews which all say the opposite, supposed to sound warm and close to analog but that is not what I am experiencing. I previously had an Adcom. I thikk it was GCD650, and a GCD 575 before that. I really liked the sound of those. I got the Rotrel from Crutchfield and can still return it, which I may do. My limitation is my budget, which the Rotel was at the top of at $600. As a side note it sounds much better on my 1C's, which can be a tad too laid back. I know that a 1C tl mod is not possible or it would already be done.
Remove the first[img][/img]
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Thanks! This is why I have searched the forum for years but resisted posting.....
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What is the value of the Clarity Cap in the bottom left of your photo? Maybe it's the angle of the pic, but it looks smaller than the 40uF I used on mine.
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There is a 20uf on top of the board and a 20uf mounted under it run parallel.
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Vintage dad, the 5.8uF is not connected properly. One lead has to go into the hole closest to R2. I can't see where you've made the other connections.
Never cover a resistor in hot glue. It's best to have as much free air space around one as possible.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
This pic may help you.
Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
The picture you posted is what I found yesterday and I did the same thing. The bottom of the 5.8 now makes a bend to the right and is soldered into the H hole. I will pull the passive and take a picture to verify that I have done it correctly.
I think you may be right about the Rotel. I have pulled out some vinyl and am pleased with what I am hearing. -
The top of 5.8 has to go into the hole cloest to R2.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
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So one pair of my speakers is not right, just not sure which pair. The 1c's sound great with the CD player and half dead on vinyl. That 2b's soung great with vinyl and harsh with the CD. I think I will pull my stock Monitor 5's and see what they sound like.
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I did clean the hot glue off of the resistors before I re mounted them.
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The firs pic also does not show the 0.5 Mills in the polyswitch spot. I had originally jumped it like I did in the 1c's, but I immediately knew the 2b's were to bright without it.
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Just a suggestion, your crossovers are a bit of a mess, so consider removing everything and start over being methodical in placement and neat application. You can remove the hot glue with denatured alcohol. Use a Q-tip to apply it to the glue keeping the glue wet. After a few minutes or so the glue will peel off. Also, make sure your solder joints are clean and shiny. A cold solder joint will cause problems. Do not bend the leads of a resistor right at the body.
The SDA 2BTL is not a bright speaker, but it is definitely livelier than the 1C.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Thanks for the feedback. I am definitely not the most gifted solderer, but I may give them another shot. I didn't know not to bend the resistor leads close to the resistor. If I were to redo them I assume I would solder additional lead wire to the existing leads as I have already cut them. Or should I just get new resistors?
After a day of vinyl I know that the CD player is very bright. I was also considering the NAD C538 and the Cambridge ACX 35. Both have a Wolfson Dac. There is also an inexpensive Yamaha. I had some Yamaha players years ago and liked the sound but don't know what they sound like now. Any recommendations? -
Never mind. Just hooked up my old Mirage 1090i's and they sound more like the SDA 1. So the 2btl is definitely too bright, like the tweeters are a few db louder than they should be. I guess I will pull the crossovers and start over. Is there a better resistor to use than the Mills? Can't get the Vishay Mills anymore, they now say made in Mexico on them. Also, should I use a different value resistor in the polyswitch position?
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I am feeling a little bipolar today.
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Get your crossovers sorted out first. The 2BTL is not a bright speaker, so something isn't right.
Vishay bought out Mills years ago and yes, they are made in Mexico.
Sure, you can bump up the .5 ohm resistor, but I wouldn't go higher than .75 ohm as higher than that kills the top end. Try a .67 ohm.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Did you verify that you have resistors that actually measure out at 2.7 Ohm and not 0.27 or some other lower value by mistake?
Are all the driver polarities correct?
George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Also for verification the 2 20uf caps are in parallel for the 40uf value, not in series. I feel Sur I read that but now I am doubting myself. I know just enough to be dangerous.
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vintage dad wrote: »Also for verification the 2 20uf caps are in parallel for the 40uf value, not in series. I feel Sur I read that but now I am doubting myself. I know just enough to be dangerous.
Well you're in the right place to learn
Yes, parallel capacitors add so that is correct. A nice primer on Crossovers below. The 2.7 Ohm resistor in parallel with the 5.8uF capacitor creates what is known as a contour network. In this case it would help to flatten out the falling response that you would get with the RDO-198 tweeter otherwise.
https://download.phoenixphorum.com/TechSupport/X-Over Chart.pdf
George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Thanks gardenstater. I will check all the values when I take the crossovers apart.
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VR3 mentioned the gimpod boards above. I tried to track some down a while back. If memory serves he sold his remaining stock to another vendor. I emailed them and the boards had all been sold. Are any available anywhere or have they gone away like Larry's rings?
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Long gone.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
What is the best type if solder to useon a crossover? I used silver, does it make a diffetence?
