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Dennis Murphy Pioneer SP-BS22-LR DIY Modifications

whereshaldo said:
I realize no one has posted on this thread for 2 years now, but I just picked up a NIB set of BS22s on an auction for $38. I originally planned to wire them up as second speakers to go with my BS41s. After listening I decided the BS22s were even better than the BS41s and then I stumbled across this thread. All parts are now on order, hopefully financed by selling my BS41s. Thank you to whoever managed to keep all those images alive, the internet really can be an incredible place.

Hal
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Hi: I like my 41s quite a bit. I think they were quite a bargain. Just wondering in what ways are the 22s superior?
 
iramegdal said:
Hi: I like my 41s quite a bit. I think they were quite a bargain. Just wondering in what ways are the 22s superior?
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I liked them too but the modified 22's just sound better to my ears. Less boomy bass, better treble end of things, fuller midrange, more overall volume and projection.
H
 
Hi All, hoping someone can weigh in on a couple of questions:
I have a 5.1.2 full set of these speakers (recently ditched the sub for an SVS PB-12 NSD) and am using the BS22s as surrounds with a C22 up front and FS52s as my LR. I recently replaced the crossover components (same values) and added the Vifa tweeter to the C22 along with a 3.9uF and 2r before the positive terminal on the Vifa as suggested in other threads. After all that, I'm finding that the new tweeter is a bit muffled to my ears, which is obviously disappointing. Any tips would be greatly appreciated.

Additionally, I like tinkering and so decided that even though they're my surrounds I wanted to do the upgrade described in this thread to my BS22s. My question is this: Given the fact that I have a great sub, would I be better off using the upgraded BS22s as my LR and getting new surrounds (hopefully I could find another set of BS22s). Will the upgraded BS22s outperform the FS52s despite their size and extra woofers since I have a dedicated, powerful sub? It's hard to imagine that being the case, and I'm somewhat attached to the way the towers look, but of course I'd rather have the best sound possible.
 
I just picked up a pair of 22-lr speakers to play with. I happen to have a pair of vifa(peerless) DX25 tweeters on the shelf. Would they be a good substitute? A little more work to mount them,
 
Pjblakey - if you are still wondering, no, the DX25 is not a good sub for the BC25. Different Fs and sensitivity. The DX is a somewhat better tweeter on paper. That said, the most important element to any speaker system is the crossover and Dennis did a great job with these. He is one of the best designers out there. It's well worth the $45 to get the correct tweeters.
 
Thanks for the response. I went ahead with the DX25 since I already had most of the crossover components. Enough to build entirely new crossover boards that I secured to the bottom of the cabinet.
They compare very favorably with my other 2 way diy projects. I spent quite a bit of time comparing them to a friends Spendors and we were both impressed.
Room positioning is critical for bass performance. 12” from the front wall created a bass bloom. Stuffing the ports killed the bass.
I found that open ports and 3 feet from the wall was best. No measurements. Just music.
 
I notice the Parts Express part number 264-1040 for the tweeter comes up as a "Peerless by Tymphany". Did Vifa get taken over or bought out?
 
leesonic said:
I notice the Parts Express part number 264-1040 for the tweeter comes up as a "Peerless by Tymphany". Did Vifa get taken over or bought out?
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It looks that way. The model number and part number are the same on the Parts Express web site, and if you click on the Manual & Resources link on the current listing for 264-1040, it takes you to this PDF data sheet:

https://www.parts-express.com/pedocs/specs/264-1040--tymphany-bc25tg15-04-spec-sheet.pdf

Which still shows the Vifa labeled tweeter in the data sheet. It looks like the tweeter is made in Hong Kong by Tymphany, but now sold under the Peerless brand name.
 
The shocking news for us DIY speaker enthusiasts late last year - Tymphany has decided to exit the DIY market. But there are still some BC25TG15-04 tweeters at Parts Express, Madisound, & Meniscus. I don't know how many are left at these vendors, but Digikey also carries them. They show 785 in stock and they are $8-9 cheaper per tweeter than the others. It might be a crap shoot with their packaging though. I had a pair of small Vifa/Tymphany ring radiators arrive with some dents in them last Fall. They just threw them both in a plastic bag and stuffed it in the box with my other parts. Hopefully they pack better when it's a regular dome tweeter.
 
I'm just about to start this mod on my set. A few years back i used these stock on my first SE tube amp and I loved em. I can't wait till I'm done with the mod so I can test the new amp I'm building.
PXL_20221223_211129771.MP.jpg
I've made a few changes. The capacitors are film and the iron core inductors has been tossed in favor of a 1.5H air core inductors.
PXL_20230131_004912870.MP.jpg

It was a lot of trouble tracking down the rat shack circuit boards(God I miss that place) and I'm not even sure that everything will fit now...

Edit. 10uf electrolytic on the left film on the right.....
PXL_20230131_005654479.MP.jpg


Anyone have any advice on doing this point to point?
 

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I cut a generic perf board down close to the size of the stock PC board. I added the .5mH to the bottom side of the board and it all barely fit through the hole. It wasn't pretty, that's for sure.

That big air core and 10uF poly cap might make it really tough. It looks like the 1.5mH might fit underneath and not hang out too far on the sides if it's laying down on the board. If it works out, be sure to post some photos!
 
I think I should have thought out my purchase of that cap... capacitors are a black art and I picked the (midgrade ) parts without thinking it through..

I'm trying to find out if it's even beneficial to have a film cap in that part of the circuit.
 
Most people probably wouldn't notice the difference, especially in the woofer shunt position. But these speakers are very clear & open sounding, despite the ultra budget drivers. Dennis did such an amazing job and you may actually hear a change for the better with that poly cap. Plus there's the benefit of replacing a cheap E-cap with a film type. I have a stash of cheap NP 100v E-caps from Parts Express that are only 5 years old. I bought them for prototyping crossovers and now some measure North of 20% over their rated capacitance.
 
TomSc said:
Most people probably wouldn't notice the difference, especially in the woofer shunt position. But these speakers are very clear & open sounding, despite the ultra budget drivers. Dennis did such an amazing job and you may actually hear a change for the better with that poly cap. Plus there's the benefit of replacing a cheap E-cap with a film type. I have a stash of cheap NP 100v E-caps from Parts Express that are only 5 years old. I bought them for prototyping crossovers and now some measure North of 20% over their rated capacitance.
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I have a pretty cool LCR meter that can do ESR, capacitance,q at different frequency's and a bunch of stuff I don't understand yet lol. I'll have to check what the readings are on what I purchased.
 
I tested some film capacitors that can be used for this build. I purchased from parts from parts express a few months ago and they're not formed. ( I Don't have a HV supply) The meter is an LCR.
I measured ESR and dissipation at 120hz to 100khz
( I can also measure Q and a few other things. let me know if the other readings are needed)

(The site isn't letting me post pictures I'll upload later)
 
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The caps in question. Typical midgrade parts.PXL_20230131_135823612.MP.jpg
The results. Nothing surprising. The film caps are close to zero throughout the frequency range.
I included a brand new F and T electrolytic cap for comparison purposes. Unfortunately it's reading off the charts. PXL_20230131_135853103.MP.jpg
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For a quick test I checked an old rubycon psu cap. Its readings are closer to normal.
PXL_20230131_140400135.MP.jpg
 

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