@wingding611 Excellent! Be sure to let me know if you notice any improvements to the sound quality from those speakers after you've made the mods.
You can use my pictures to guide you in the placement of the caps. You have to be careful of the placement in order to be able to re-insert the crossover/terminal post assembly back into the cabinet. Notice how in the second picture there's a short red wire I inserted to reach one of the leads on the 12 uF cap. Both of those caps are hot glued onto the underside of the X-over PCB. As you can see in the first pic, I hot-glued the 1.5 uF cap onto the resistor on the topside of the PCB and if you look closely at that pic you can see where I insulated/protected the lead coming out of the top of the 1.5uF cap with some yellow heat shrink. I can't remember if it was highly necessary to do that or if I just did it out of an abundance of caution but I just wanted to make sure you noticed it in the picture.
You can use my pictures to guide you in the placement of the caps. You have to be careful of the placement in order to be able to re-insert the crossover/terminal post assembly back into the cabinet. Notice how in the second picture there's a short red wire I inserted to reach one of the leads on the 12 uF cap. Both of those caps are hot glued onto the underside of the X-over PCB. As you can see in the first pic, I hot-glued the 1.5 uF cap onto the resistor on the topside of the PCB and if you look closely at that pic you can see where I insulated/protected the lead coming out of the top of the 1.5uF cap with some yellow heat shrink. I can't remember if it was highly necessary to do that or if I just did it out of an abundance of caution but I just wanted to make sure you noticed it in the picture.
Trust me, you're not going to want to revert but that would be a good way to physically compare a modified speaker to an unmodified one. Put one on the right the other on the left, play a mono recording and switch rapidly from one to the other simply by moving the balance control all the way from one side to the other. I'll be interested to hear what you have to say at the end of your head-to-head test.
I’ve done this tweeter replacement, with and without a 2 ohm resistor (make sure it’s rated for wattage). If you calculate out the potential crossover value change you might be scared, in my 5Ts i preferred the sound without the resister. If your rebuilding the crossover anyway you can compensate for the impedance change.
My 5Ts where free (because they had blown tweeters) so I can’t comment on how they sounded with the original tweeters but they sound wonderful with the peerless replacements.
My 5Ts where free (because they had blown tweeters) so I can’t comment on how they sounded with the original tweeters but they sound wonderful with the peerless replacements.
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I’ve done this tweeter replacement, with and without a 2 ohm resistor (make sure it’s rated for wattage). If you calculate out the potential crossover value change you might be scared, in my 5Ts i preferred the sound without the resister. If your rebuilding the crossover anyway you can compensate for the impedance change.
My 5Ts where free (because they had blown tweeters) so I can’t comment on how they sounded with the original tweeters but wonderful with the peerless replacements.
My 5Ts where free (because they had blown tweeters) so I can’t comment on how they sounded with the original tweeters but wonderful with the peerless replacements.
@Indigent Audio I know I talked about maybe replacing/upgrading the tweeters earlier on in this thread but I was talked out of it owing to the unusual 6 ohm impedance of the original tweeter and the 4 ohm impedance of the replacement tweeter. Didn't want to redesign the crossovers to accommodate the change. All I ended up doing was replacing the cheap electrolytic caps in the crossovers with some inexpensive audio grade Dayton caps and I was quite happy with the result.
I am still curious to know how much, if any, improvement I would've seen had I done the tweeter upgrade. Just out of curiosity, are there any good on-line tools that could help me figure out what changes I'd need to make to the crossovers to compensate for the impedance change of the tweeter if I did decide to try the swap?
@wingdings611 any progress/results to report on your crossover upgrade?
I am still curious to know how much, if any, improvement I would've seen had I done the tweeter upgrade. Just out of curiosity, are there any good on-line tools that could help me figure out what changes I'd need to make to the crossovers to compensate for the impedance change of the tweeter if I did decide to try the swap?
@wingdings611 any progress/results to report on your crossover upgrade?
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Indigent Audio, do you know for sure what the impedance of the original PSB (Vifa) tweeter used in the Image 1B, 2B, 4T, 5T, etc., was? That information seems not to be published and I'm not convinced that it wasn't 4-ohms. Read through my post on the top of page 3 on this thread to see why.
Did you ever make that tweeter change on a pair of Image 2Bs? If so, were you pleased with the results/ Did you have to add a resistor?
Did you ever make that tweeter change on a pair of Image 2Bs? If so, were you pleased with the results/ Did you have to add a resistor?
Indigent Audio, I have seen no documentation that states what the actual impedance of either driver in those Image 2B speakers was and believe me, I have looked hard for it. It's only the loudspeaker itself that has a 'Nominal" impedance rating of 6 ohms. It also has a minimum impedance rating of 4 ohms. The nominal impedance rating does not mean the drivers in the speaker are both rated at 6 ohms impedance. It only means that for the majority of the useful frequency range, the speaker has an impedance of 6 or more ohms. It's a rather meaningless statistic and it doesn't mean that the drivers themselves are rated at 6 ohms.
When you look at the overall impedance of a speaker at any given frequency, that impedance includes not only the impedance of the drivers, it also includes the impedance of the crossover too. Below is the impedance curve for the Image 2B speaker
You can see that at 40 - 50 Hz and from 150 - 200 Hz, the impedance is about 4 - 5 ohms. That impedance includes the impedance of the woofer and the portion of the crossover that feeds the woofer. The curve implies the impedance of the woofer is probably 4-ohms. It doesn't suggest 6 ohms at all for the woofer.
If you look at the impedance in the 5 KHz - 20 KHz range, you can see it's about 7 ohms and by 20 Khz it has slowly increased to 8-ohms. For that part of the crossover, there are likely 2 capacitors, 1 or maybe 2 inductors and likely a 3.3 ohm resistor. That will all add a fair bit of extra inductance to the tweeter circuit so it's quite possible and maybe even likely that the impedance contributed by the tweeter is only 4-ish ohms and the remaining few ohms in that range is due to the various components in the tweeter circuit.
I wish I had a schematic for that crossover but I couldn't find one anywhere on the Internet and PSB says they don't provide them to the public because they're proprietary and confidential. If I had a schematic it would be possible to deduce what the actual impedance of the OEM PSB tweeter was. If I had access to the speakers, I could examine the XOs to try to figure out what the schematic is but I don't have access to them right now.
There's another reason why I think it's more likely the OEM PSB tweeter was a 4-ohm and not a 6-ohm and it is this: AFAIK, speaker driver manufacturers pretty much stick to making drivers to either the 4 or 8 ohm standard. I don't think I've ever seen a driver for sale on PE or the other places that wasn't rated at either 4-ohms or 8-ohms. PSB sourced these tweeters from Vifa. I think it's far more likely that they bought a standard 4-ohm tweeter that Vifa was making or could easily make from existing components rather than have Vifa make special for them an oddball/non-standard 6-ohm tweeter because that would be far more costly.
So if the original tweeter was actually 4-ohms and the replacement Tymphany tweeter alternatives were also 4-ohms, why were people having to add resistors to tone them down? I think it's because the Tymphany tweeters were more sensitive/louder than the original tweeters were so a resistor was needed to attenuate them down to where they were better balanced with the woofer.
If anybody can provide me with hard evidence that the impedance rating of the original PSB TW1-2AN/P tweeter was 6-ohms, I'd like to see it. Based on all the evidence I've seen, I think the actual impedance rating of that tweeter was 4-ohms.
When you look at the overall impedance of a speaker at any given frequency, that impedance includes not only the impedance of the drivers, it also includes the impedance of the crossover too. Below is the impedance curve for the Image 2B speaker
You can see that at 40 - 50 Hz and from 150 - 200 Hz, the impedance is about 4 - 5 ohms. That impedance includes the impedance of the woofer and the portion of the crossover that feeds the woofer. The curve implies the impedance of the woofer is probably 4-ohms. It doesn't suggest 6 ohms at all for the woofer.
If you look at the impedance in the 5 KHz - 20 KHz range, you can see it's about 7 ohms and by 20 Khz it has slowly increased to 8-ohms. For that part of the crossover, there are likely 2 capacitors, 1 or maybe 2 inductors and likely a 3.3 ohm resistor. That will all add a fair bit of extra inductance to the tweeter circuit so it's quite possible and maybe even likely that the impedance contributed by the tweeter is only 4-ish ohms and the remaining few ohms in that range is due to the various components in the tweeter circuit.
I wish I had a schematic for that crossover but I couldn't find one anywhere on the Internet and PSB says they don't provide them to the public because they're proprietary and confidential. If I had a schematic it would be possible to deduce what the actual impedance of the OEM PSB tweeter was. If I had access to the speakers, I could examine the XOs to try to figure out what the schematic is but I don't have access to them right now.
There's another reason why I think it's more likely the OEM PSB tweeter was a 4-ohm and not a 6-ohm and it is this: AFAIK, speaker driver manufacturers pretty much stick to making drivers to either the 4 or 8 ohm standard. I don't think I've ever seen a driver for sale on PE or the other places that wasn't rated at either 4-ohms or 8-ohms. PSB sourced these tweeters from Vifa. I think it's far more likely that they bought a standard 4-ohm tweeter that Vifa was making or could easily make from existing components rather than have Vifa make special for them an oddball/non-standard 6-ohm tweeter because that would be far more costly.
So if the original tweeter was actually 4-ohms and the replacement Tymphany tweeter alternatives were also 4-ohms, why were people having to add resistors to tone them down? I think it's because the Tymphany tweeters were more sensitive/louder than the original tweeters were so a resistor was needed to attenuate them down to where they were better balanced with the woofer.
If anybody can provide me with hard evidence that the impedance rating of the original PSB TW1-2AN/P tweeter was 6-ohms, I'd like to see it. Based on all the evidence I've seen, I think the actual impedance rating of that tweeter was 4-ohms.
Finally, I've gotten around to installing the new capacitors on my spare crossover! Job and family life have kept me from completing this project for quite a while now...
I haven't boxed it up to do a comparison of speakers with the old/new crossovers though, because I'm debugging. There's a low hiss - a bit like the sound of holding a seashell to your ear - in the woofer and quiet, but obvious hiss in the tweeter too. Neither vary with volume on my amp, and the stock crossover (and the other speaker) are both dead silent. I'm convinced the issue was introduced by the recapping project.
I think it could be bad caps from Parts Express (seems unlikely, but I don't have the equipment to test), issues with the small differences in part values, or maybe I need to shield some of long leads on the 1.5uf cap that's near the crossover's inductors.
I can probably find a way to shield the leads, so I think that's where I'll start. If need be, I could definitely put that cap on the underside of the PCB too.
I haven't boxed it up to do a comparison of speakers with the old/new crossovers though, because I'm debugging. There's a low hiss - a bit like the sound of holding a seashell to your ear - in the woofer and quiet, but obvious hiss in the tweeter too. Neither vary with volume on my amp, and the stock crossover (and the other speaker) are both dead silent. I'm convinced the issue was introduced by the recapping project.
I think it could be bad caps from Parts Express (seems unlikely, but I don't have the equipment to test), issues with the small differences in part values, or maybe I need to shield some of long leads on the 1.5uf cap that's near the crossover's inductors.
I can probably find a way to shield the leads, so I think that's where I'll start. If need be, I could definitely put that cap on the underside of the PCB too.
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That's odd that would happen after that modification. That crossover you modified was a different unit than the original one that was in the speaker, correct? If so, did you test it before modifying it? If not, it might be that it had that problem before you made the modifications.
If you look at the pictures I provided you'll see I protected that one capacitor lead on the 1.5 uF cap that goes near that inductor coil with heat shrink which I just left on loose over the lead. It looks like you've shielded both leads on that cap with wire insulation which should be sufficient.
I think the job you did of insulating the leads on all the capacitors is excellent and better than the job I did. Yet I didn't end up with the hiss you did which baffles me unless that crossover had the problem to begin with. I bet that if you made those same mods to one of your crossovers that tests good before modification you will get the desired results.
If you look at the pictures I provided you'll see I protected that one capacitor lead on the 1.5 uF cap that goes near that inductor coil with heat shrink which I just left on loose over the lead. It looks like you've shielded both leads on that cap with wire insulation which should be sufficient.
I think the job you did of insulating the leads on all the capacitors is excellent and better than the job I did. Yet I didn't end up with the hiss you did which baffles me unless that crossover had the problem to begin with. I bet that if you made those same mods to one of your crossovers that tests good before modification you will get the desired results.
I've made more modifications/upgrades to the PSB Image 2B speakers. I replaced the stock PSB/Vifa tweeter with a Peerless BC25SC08-04 (4 ohm) tweeter. The tweeters made a VERY noticeable improvement over and in top of the VERY noticeable improvement that was made by replacing the electrolytic caps in the PSB Image 2B XO with audio grade caps. I'm very pleased with the difference the tweeter upgrade made and very, VERY pleased with the improvements both upgrades have made together.
I first started with just swapping the stock PSB/Vifa tweeter for the Peerless BC25SC08-04 (4 ohm) tweeter with no other changes being made to the XO. I did the swap on one speaker and left the other one with the old tweeter and then listened to both carefully to hear the differences.
I could hear right off that the Peerless sounded much more clear, crisp and airy. Much more detail in the high end and clearer mids than the stock tweeter. The stock tweeter sounded a bit muffled in comparison, especially in the female vocals. With the Peerless having much higher sensitivity than the original tweeter, it needed to be "pulled back" a little to keep it in balance with the woofer so I needed to add a resistor ahead of and in series with the tweeter circuit.
On a suggestion made by @Lozjek on a different thread where he made some calculations based on the crossover schematic and the stock response curve for the speaker and the response data for the Peerless replacement tweeter, I tried a 4.7 Ohm resistor ahead of the tweeter circuit for the first trial. I could've added some smaller resistors to tone the tweeter down a bit more or put in smaller resistors to kick it up a bit with the extra resistors I ordered but I decided to leave it at 4.7 ohm and be done with it.
I don't have test equipment or a well trained ear but I thought that the tweeter seemed in good balance with the woofer with 4.7 ohms added. It definitely didn't need to be made any brighter by reducing the resistance ahead of the circuit and I couldn't imagine the sound could be improved by subduing the tweeter further with added resistance so I just left well and good enough alone and went with the 4.7. I still have the other resistors I bought so I can always change it later on if I ever get access to some test equipment to give those speakers a proper response test.
Attached is the final schematic for the upgraded PSB Image 2B crossovers. The red components are what were added in the tweeter upgrade. While I was adding the 4.7 Ohm Lynx resistor to the tweeter circuit I also replaced the original 5W 3.3 Ohm wire wound resistor with a 10W 3.3 ohm Lynx resistor.
Aside from deadening the cabinets (which I intend to do still) the only other simple upgrade that's possible would be to upgrade the Inductors to better ones, especially I1 which is a laminated iron core inductor. Unfortunately, the Inductances of the three inductors are not marked or known and I lack the knowledge and equipment necessary to measure the inductance of the inductors.
A warm heartfelt thanks goes out to @Lozjek and others who contributed to the other thread and helped me figure out which of the two upgrade tweeter options I should go with. I'm very pleased with the improvements I was able to make to those speakers on a low budget.
I first started with just swapping the stock PSB/Vifa tweeter for the Peerless BC25SC08-04 (4 ohm) tweeter with no other changes being made to the XO. I did the swap on one speaker and left the other one with the old tweeter and then listened to both carefully to hear the differences.
I could hear right off that the Peerless sounded much more clear, crisp and airy. Much more detail in the high end and clearer mids than the stock tweeter. The stock tweeter sounded a bit muffled in comparison, especially in the female vocals. With the Peerless having much higher sensitivity than the original tweeter, it needed to be "pulled back" a little to keep it in balance with the woofer so I needed to add a resistor ahead of and in series with the tweeter circuit.
On a suggestion made by @Lozjek on a different thread where he made some calculations based on the crossover schematic and the stock response curve for the speaker and the response data for the Peerless replacement tweeter, I tried a 4.7 Ohm resistor ahead of the tweeter circuit for the first trial. I could've added some smaller resistors to tone the tweeter down a bit more or put in smaller resistors to kick it up a bit with the extra resistors I ordered but I decided to leave it at 4.7 ohm and be done with it.
I don't have test equipment or a well trained ear but I thought that the tweeter seemed in good balance with the woofer with 4.7 ohms added. It definitely didn't need to be made any brighter by reducing the resistance ahead of the circuit and I couldn't imagine the sound could be improved by subduing the tweeter further with added resistance so I just left well and good enough alone and went with the 4.7. I still have the other resistors I bought so I can always change it later on if I ever get access to some test equipment to give those speakers a proper response test.
Attached is the final schematic for the upgraded PSB Image 2B crossovers. The red components are what were added in the tweeter upgrade. While I was adding the 4.7 Ohm Lynx resistor to the tweeter circuit I also replaced the original 5W 3.3 Ohm wire wound resistor with a 10W 3.3 ohm Lynx resistor.
Aside from deadening the cabinets (which I intend to do still) the only other simple upgrade that's possible would be to upgrade the Inductors to better ones, especially I1 which is a laminated iron core inductor. Unfortunately, the Inductances of the three inductors are not marked or known and I lack the knowledge and equipment necessary to measure the inductance of the inductors.
A warm heartfelt thanks goes out to @Lozjek and others who contributed to the other thread and helped me figure out which of the two upgrade tweeter options I should go with. I'm very pleased with the improvements I was able to make to those speakers on a low budget.
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I final got my image 5T out of storage and gave a more expanded listen and learned some good and bad things
I noticed a buzz at LF after the tweeter swap, so first I went back and checked the original tweeters and you were right DangerBoy not only were they 4.6ohms, they were not blown. Will keep the upgraded peerless anyway, they sound nice and I prefer soft domes. The LF buzz seems to be coming from both woofers so I am hoping crossover or connection? Maybe wishful thinking?..I might have time for a small procedure to have a look tomorrow
The buzz or hiss is not unlike the one wingding611 described, my crossovers are original
I noticed a buzz at LF after the tweeter swap, so first I went back and checked the original tweeters and you were right DangerBoy not only were they 4.6ohms, they were not blown. Will keep the upgraded peerless anyway, they sound nice and I prefer soft domes. The LF buzz seems to be coming from both woofers so I am hoping crossover or connection? Maybe wishful thinking?..I might have time for a small procedure to have a look tomorrow
The buzz or hiss is not unlike the one wingding611 described, my crossovers are original
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Hello @DangerBoy! I was very surprised to discover this thread. I also happen to own a pair of PSB Image 2B that I bought back in 2005. I've had them in store for fifteen years and last year I've put them back to work. Although I bought new speakers, I still love them and I also felt that they've lost their sparkle on the tweeter (I accidentally pushed one dome) and would like to mod them like you did, replacing the tweeters and upgrading the caps and resistor. Do you still use them?
For the tweeter's original impedance, according to your reasoning above, its impedance curve and the speaker being 6Ω, it makes sense that the stock PSB/Vifa was 6Ω. Furthermore, an owner of a Image 1B (which looks the same as the 2B) reports the stock tweeter's part number being TW1-3AN-G and that it is 6Ω:
PSB Image 1 and 2 are the same in different color:
https://www.psbspeakers.com/product/image-2b/
https://www.psbspeakers.com/product/image-1b/
It happens to be two 6Ω Vifa/Peerless tweeters on the market now, 91.8 and 90.3 dB respectively. You can see their impedance curves and frequency responses:
D27TG35-06 - 6Ω, 91.8 dB
DA25BG08-06 - 6Ω , 90.3 dB
I would choose a 6Ω to replicate the stock crossover frequency as @Galu said, as a 4Ω or 8Ω will skew it.
I would politely ask @Lojzek to simulate the crossover response for a 6Ω tweter to identify if I should add like you a resistor in front of the tweeter circuit, as he did here, for both 91.8 and 90.3 dB sensitivities. Note: I'd also use a 8,20μF replacement for the 8μF stock. If possible, I'd rather not add any resistor to replicate the original crossover not to add more impedance to the crossover. I must say the BC25SC08-04 you put has a 96.3 dB sensitivity, higher than the two I propose, so these above could make up for the 4.7Ω resistor you put.
So, which tweeter you propose of the two? The 90.3 or 91.8? I'd lean for the alluminium dome as stock , DA25BG08-06 (90.3 dB).
PSB Image 2B specifications:
Nominal impedance: 6Ω, minimum 4Ω at 140-200 Hz
Sensitivity: 89dB (2.83V/1m, also W/m ?) (SoundStage! measurement graph indicates 87.5dB averaged 300Hz - 3kHz, 2.83V/1m
Thank you very much for the thread and your work with the crossover schematics and documentation!
P.S: @DangerBoy, did you confirm that the tweeter is connected in reverse polarity?
For the tweeter's original impedance, according to your reasoning above, its impedance curve and the speaker being 6Ω, it makes sense that the stock PSB/Vifa was 6Ω. Furthermore, an owner of a Image 1B (which looks the same as the 2B) reports the stock tweeter's part number being TW1-3AN-G and that it is 6Ω:
PSB Image 1 and 2 are the same in different color:
https://www.psbspeakers.com/product/image-2b/
https://www.psbspeakers.com/product/image-1b/
It happens to be two 6Ω Vifa/Peerless tweeters on the market now, 91.8 and 90.3 dB respectively. You can see their impedance curves and frequency responses:
D27TG35-06 - 6Ω, 91.8 dB
DA25BG08-06 - 6Ω , 90.3 dB
I would choose a 6Ω to replicate the stock crossover frequency as @Galu said, as a 4Ω or 8Ω will skew it.
I would politely ask @Lojzek to simulate the crossover response for a 6Ω tweter to identify if I should add like you a resistor in front of the tweeter circuit, as he did here, for both 91.8 and 90.3 dB sensitivities. Note: I'd also use a 8,20μF replacement for the 8μF stock. If possible, I'd rather not add any resistor to replicate the original crossover not to add more impedance to the crossover. I must say the BC25SC08-04 you put has a 96.3 dB sensitivity, higher than the two I propose, so these above could make up for the 4.7Ω resistor you put.
So, which tweeter you propose of the two? The 90.3 or 91.8? I'd lean for the alluminium dome as stock , DA25BG08-06 (90.3 dB).
PSB Image 2B specifications:
Nominal impedance: 6Ω, minimum 4Ω at 140-200 Hz
Sensitivity: 89dB (2.83V/1m, also W/m ?) (SoundStage! measurement graph indicates 87.5dB averaged 300Hz - 3kHz, 2.83V/1m
Thank you very much for the thread and your work with the crossover schematics and documentation!
P.S: @DangerBoy, did you confirm that the tweeter is connected in reverse polarity?
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Hi, I'm thinking of upgrading my old PSB Image 2B's aswell. So you measured the stock tweeter impedance with a multimeter and it was 4.6 ohms?
Did you use DangerBoy's same tweeter Peerless BC25SC08-04 for replacement? Did you add any resistor in series with the tweeter such as the 4.7 ohm that DangerBoy used? Measured for linearity?
And lastly, did you fix your LF buzz?
I am very curious to revive this speaker, it still sounds good, but the tweeter seems a bit rolled-off.
Sorry for so many questions, hope for your news!