Hi,
I've been an LS3/5a user since my first job, which was at BBC Research Dept in Kingswood Warren, although I was in the service planning dept. But I was able to use my staff discount to be buy my first pair.
Used them ever since, although I added the AB-1 when it came out, then later the AB-2 from Stirling, along with upgrading to Stirling thin-wall cabinets and Cicable external crossovers and then Stirling V2s with Xtracable external crossovers. Always with Quad power amps (306->707->909 monos->QMPs), and lately Music First Audio pre-amps.
So earlier in the year I visited Stirling Broadcast to get some help replacing a blown T27, but saw that Doug was suffering health issues and also saw that he had accumulated a lot of stock that he had built up in the covid era. His friend and neighbour, who was helping look after him, pointed this out and also questioned what could be done with it. As I like a challenge I said I would help and try to get it all sold. That was back in May 2024 and I am still working on it!
So the reason for joining was that I have always wanted a better quality crossover in the AB-2s, feeling uneasy that the crossover in the V3 LS3/5as is of a very hgh quallity (nearly as good as my external crossovers) but when using the AB-2 as it was designed, this crossover is being fed a band-passed signal from the mediocre crossover in the AB-2. When using my external crossovers the situation isn't quite as bad as the HF of the LS3/5a comes straight from the external crossover and doesn't touch the AB-2.
Now I am a software engineer that is trying to retire early so loudspeaker design is not my forte. When I worked at the BBC I did start to get into it and built a box to test the resonant frequency of a Nakamichi speaker I was putting in my car so I could build an enclosure for it, but never got around to completing that project.
Although I have tried to persuade Derek Hughes to design me a better AB-2 crossover (and AB-1 before that) he doesn't seem very enthusiastic (perhaps unsurprisingly), but he has pointed me to a suitable air-cored inductor to use, and also made some comments about replacing the two capacitors (one elctrolytic and a smaller PP which must be a bypass -according to what I read only a few days ago!).
I've been reading a bit online and also just bought some courses on udemy (!) but one of his specifications, that the replacement PP capacitor (the electrolytic is going) has to have a voltage rating of between 50V and 150V is causing me problems. So my first technical question after this introduction is probably going to be about that !!
Andrew
I've been an LS3/5a user since my first job, which was at BBC Research Dept in Kingswood Warren, although I was in the service planning dept. But I was able to use my staff discount to be buy my first pair.
Used them ever since, although I added the AB-1 when it came out, then later the AB-2 from Stirling, along with upgrading to Stirling thin-wall cabinets and Cicable external crossovers and then Stirling V2s with Xtracable external crossovers. Always with Quad power amps (306->707->909 monos->QMPs), and lately Music First Audio pre-amps.
So earlier in the year I visited Stirling Broadcast to get some help replacing a blown T27, but saw that Doug was suffering health issues and also saw that he had accumulated a lot of stock that he had built up in the covid era. His friend and neighbour, who was helping look after him, pointed this out and also questioned what could be done with it. As I like a challenge I said I would help and try to get it all sold. That was back in May 2024 and I am still working on it!
So the reason for joining was that I have always wanted a better quality crossover in the AB-2s, feeling uneasy that the crossover in the V3 LS3/5as is of a very hgh quallity (nearly as good as my external crossovers) but when using the AB-2 as it was designed, this crossover is being fed a band-passed signal from the mediocre crossover in the AB-2. When using my external crossovers the situation isn't quite as bad as the HF of the LS3/5a comes straight from the external crossover and doesn't touch the AB-2.
Now I am a software engineer that is trying to retire early so loudspeaker design is not my forte. When I worked at the BBC I did start to get into it and built a box to test the resonant frequency of a Nakamichi speaker I was putting in my car so I could build an enclosure for it, but never got around to completing that project.
Although I have tried to persuade Derek Hughes to design me a better AB-2 crossover (and AB-1 before that) he doesn't seem very enthusiastic (perhaps unsurprisingly), but he has pointed me to a suitable air-cored inductor to use, and also made some comments about replacing the two capacitors (one elctrolytic and a smaller PP which must be a bypass -according to what I read only a few days ago!).
I've been reading a bit online and also just bought some courses on udemy (!) but one of his specifications, that the replacement PP capacitor (the electrolytic is going) has to have a voltage rating of between 50V and 150V is causing me problems. So my first technical question after this introduction is probably going to be about that !!
Andrew
You shouldn't have any problem with the capacitor replacement, since many are available these days.
Even higher voltage rating is fine and causes no problems, other than a larger physical size.
Even higher voltage rating is fine and causes no problems, other than a larger physical size.
Hello Andrew and welcome!
Nice to have someone with such personal reference to a legendary speaker!
Nice to have someone with such personal reference to a legendary speaker!
Derek specified that range though, and said that meant that none of the Jantzen ones available were usable, and they are 400V rated.
From my short investigation I found this quote, which might be the reason:
"When the voltage rating of a capacitor is increased for a given value of capacitance one of two things or a combination of both has to happen. The dielectric material must be changed or the plate spacing must be increased or a combination of both. There is a school of thought that it is possible for that to have an effect on the signal especially if the plate spacing is increased then then plate area must be increased to maintain the same value of capacitance and spreading the charge over a greater plate area may change the signal. Voltage rating of 100V is more than adequate for most any consumer system. Higher voltage ratings will certainly result in slower transient response."
I think I need to do some more reading and go through my udemy course (!) before questioning him some more. Those low voltage ratings are common in electrolytics but the lowest PP I can find is 250V.
Depends on the uF value of course. As an example, here is a table of many DIGIKEY film capacitors
33uF and smaller in that voltage range or less, with metallized polypropylene dielectric.
Film types are common in as low as 50V ratings. Many feel that higher voltage rating capacitors
sound better in speakers due to less dielectric stress.
33uF and smaller in that voltage range or less, with metallized polypropylene dielectric.
Film types are common in as low as 50V ratings. Many feel that higher voltage rating capacitors
sound better in speakers due to less dielectric stress.
220uf 50V electrolytic with a 6.8uk 250V PP in parallel.
I think this is an area I need to investigate a lot more ! I was hoping it would be a simple case of finding a Mungdorf film cap of the right uF and just replacing the current two caps, so I could get on with the laborious task of building tygan grills for the LS3/5as I am trying to sell, but that was too much to hope for 🙂
I think this is an area I need to investigate a lot more ! I was hoping it would be a simple case of finding a Mungdorf film cap of the right uF and just replacing the current two caps, so I could get on with the laborious task of building tygan grills for the LS3/5as I am trying to sell, but that was too much to hope for 🙂
Just an example, there are many others. Vendors' search engines are your friend.
https://www.digikey.com/en/products/detail/wima/MKP4F046806G00JSSD/9370479
https://www.digikey.com/en/products/detail/wima/MKP4F046806G00JSSD/9370479
No, but they've got nothing film at 220uF within that voltage range so I need to get clarification on those requirements from Derek, but I need to also do some research and learning so I can be a bit more targetted with my questions, rather than ask for a short tutorial !
What a wonderful connection to the people and history of the LS3/5a. You are very fortunate.
This is total blasphemy, but I recommend bypassing the passive crossovers all together and using a digital crossover like the miniDSP 2x4HD or FLEX and four channels of amplification or a pair of Hypex Fusion two channel plate amps with built in DSP crossovers. Most people have several stereo amps just sitting in the wings. There's a very good reason KEF did it years ago. I have built several pairs of speakers using the LS3/5a cabinets and modern drivers in the past four years. I spent many hours designing and building passive crossovers that are really great. The first system I built used the miniDSP and I've never matched the performance of that build with the passive crossovers. In my opinion there are only tiny improvements to be had from changing coils and capacitors in the passive crossovers. Here's a picture of my last build.
This is total blasphemy, but I recommend bypassing the passive crossovers all together and using a digital crossover like the miniDSP 2x4HD or FLEX and four channels of amplification or a pair of Hypex Fusion two channel plate amps with built in DSP crossovers. Most people have several stereo amps just sitting in the wings. There's a very good reason KEF did it years ago. I have built several pairs of speakers using the LS3/5a cabinets and modern drivers in the past four years. I spent many hours designing and building passive crossovers that are really great. The first system I built used the miniDSP and I've never matched the performance of that build with the passive crossovers. In my opinion there are only tiny improvements to be had from changing coils and capacitors in the passive crossovers. Here's a picture of my last build.
I also own ls35a.com, although I point it to Paul Whattons site. And I did the LS3/5a room at the London HiFi News & RR hifi show in 2001 and 2002 🙂
I've just bought a miniDSP SHD, but as I quite like the band passed nature of the LS3/5a and AB-2 combination so I was treating that as one speaker unit for the minDSP and then adding some old M&K mx70b subwoofers on the other channel.
I've tried the mix in a simple way with my Oppo 205 restricting how low the AB-2 goes and then using the controls on the M&Ks to match under that, and it worked well, hence getting the miniDSP to make it work better.
I use Quad QMPs to drive my LS3/5as, getting another set for the AB-2s alone seems a bit OTT.
I've just bought a miniDSP SHD, but as I quite like the band passed nature of the LS3/5a and AB-2 combination so I was treating that as one speaker unit for the minDSP and then adding some old M&K mx70b subwoofers on the other channel.
I've tried the mix in a simple way with my Oppo 205 restricting how low the AB-2 goes and then using the controls on the M&Ks to match under that, and it worked well, hence getting the miniDSP to make it work better.
I use Quad QMPs to drive my LS3/5as, getting another set for the AB-2s alone seems a bit OTT.
This work for you? https://willys-hifi.com/collections...-220uf-63v-bipolar-electrolytic-capacitor-raw
jeff
Unfortunately, often all the parts one needs for a project cannot be obtained from just a single vendor.
Bipolar electrolytics may be somewhat more difficult to source as well.
Falcon would also be a source. https://www.falconacoustics.co.uk/l...or-q7-systems/replacement-capacitor-sets.html
jeff
jeff