Miller & Kreisel S-1B satellite crossover update

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I have a mint pair of MK S-1B's that sound great. But I wonder if updating the caps will offer any improvement and figured I would see if anyone here has experience. Mine have the Peerless dome tweeters. I did find another thread on AK where the owner pulled the crossovers. The caps are small and easy to get to, but there were comments about the position of the inductors (there are 4).

What I'm hoping to get is some experienced advice on how to chose caps that will be an improvement. I've seen so many opinions on types of caps that I want to avoid getting into a roller coaster of "rolling" caps until I find the right ones, which would take awhile, but also open up the possibility of reaming the threads on the panel fasteners by repeatedly opening up the speakers.

I'm not looking for esoteric options, but something that is a known quantity.
 

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I had the version of the S-1B after this, with the rounder faceplates.

Mine had adjustments allowing you to tailor the sound somewhat. As I further recall, after opening one up, there were a lot of caps.

I suggest you put together a schematic with XSim crossover simulator before doing any alterations. It could very well be that a lot of the caps are not going to be used for your particular settings, so altering may be useless.

You also don't have a lot of room to work in there. This is really going to size limit you. You certainly won't have space to replace every cap with a Mundorf Supreme.

Take it apart, put together a schematic, and post pics.

Best,

E
 
Found a pic:

P1020848.jpg


Those coils are very poorly placed, and the caps are physically tiny. Perhaps you should consider a completely external crossover instead? I would only keep the coils in the original.

Here's a thought, how about replacing the whole thing with a two-channel plate amplifier instead?

Best,

E
 
I'll do that, thanks for the suggestion!

Now that you mention the character contours, I have found the setting that works best, as they sound now. I think that IF I make a change it is in consideration of possible future owners and making changes that keep that adjustment.
 
What I meant to say, is those electrolytic caps are going to be a lot smaller than any nice film caps, so replacing them in place will be a challenge.

Among the physically smallest caps I recommend are the Mundorf MKP range. I avoid Solens except in low pass filters where price is a major issue.

An alternative may be to replace the electrolytics with modern versions, and use small value film caps to bypass them.
 
Found a pic:

Those coils are very poorly placed, and the caps are physically tiny. Perhaps you should consider a completely external crossover instead? I would only keep the coils in the original.

Here's a thought, how about replacing the whole thing with a two-channel plate amplifier instead?

Best,

E

You hit on the placement issue I read somewhere else, and that two of the coils should be turned 90 degrees. The caps are small and at that size, I can't imagine having to spend much for good replacements.

As for the two-channel plate amp, the reason I bought these was as a second setup in my main room to use my restored Sansui BA-3000 amp. Right now, I'm going from the amp to a MK V-125 powered sub, then out to the sats. If there is a better way to utilize that amp with both channels, I'll do that.

So here's my dumb question. Aside from cost, which right now, I can't afford to replace with a plate amp ... wouldn't that mean that the BA-3000 is not going to have any sonic effect through the sats?
 
What I meant to say, is those electrolytic caps are going to be a lot smaller than any nice film caps, so replacing them in place will be a challenge.

Among the physically smallest caps I recommend are the Mundorf MKP range. I avoid Solens except in low pass filters where price is a major issue.

An alternative may be to replace the electrolytics with modern versions, and use small value film caps to bypass them.

My source amp (BA-3000) has Mundorf power supply caps (x2) and mostly Nichicon/Elna on all the boards. Not that it matters to use Mundorf caps in the speakers, but it's a brand that I am comfortable with their quality.

Modern versions will be smaller at the same values, but I don't understand speaker design to know if increasing certain values will be advisable.
 
I appreciate thinking out side the box ... or cabinet ;)

I'll replace the caps for sure, but I'm guessing I may need to consider repositioning coils? What about internal wiring? I was looking at Madisound, who sells the Supra speaker wire I like, and they mention using the same wire for crossovers. I don't need to go overboard, but just asking.

During my lunch hour, I'll pull a panel and post pics to see if mine is the same as the pic you shared. I assume it is, but I know some companies made subtle changes to product without telling anyone.

My serial numbers are: 114883 / 114884
 
Well, this all depends how far you want to go.

I strongly suggest you map out the schematic first. It is _possible_ that only 2 of those coils are used at a time, so interference may be less severe than we think.

Also, instead of wires, I'd replace those resistors. Mills are smaller, affordable and best sounding.

Best,


E
 
That's an interesting speaker, my friend. Sort of PA-type thing I like:

Tweeters: Two 1" soft-dome
Mid-woofers: Two 5" polyproylene cones
Power: 7 1/2 watts min., 400 watts max.
Frequency Response: 75 - 22 KHz +/- 3db
Impedance: 4 ohms

Two SEAS 5" polycones, two Vifa tweeters. Maybe soft dome, maybe mylar/plastic. :cool:

Wired in parallel, you'd guess from the 4 ohm impedance.

You don't usually have to work too hard to get 5" polycone plus tweeter working well. Second order LR2 or even third order BW3 3.5kHz filters usually do it, especially since time-aligned. Doubling drivers usually gets people moaning about combing effects, but I don't mind that.

Doubling drivers TTMM is an interesting piece of physics. You get the same sound level for half the room power on axis. Thing is they radiate less above and below axis, so sound quieter, especially to the neighbours. It's the projecting PA sound. Loudness falls off less with distance. MTTM is another valid layout.
 

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Thanks Steve. I do like them, and they give me an option in my living space that I like. I'm dealing with acoustics in a new house, and my room has a vaulted 11' ceiling, so the big speakers are tricky. These sound good just about anywhere I put them ... so worth doing the crossovers to make sure I'm getting the most out of the original design.
 
Pulled crossovers and found that one cap is a different brand on one, same value, but probably ran out of the KSC used on all other NP caps. I'll post pics today. Camera battery is charging .... a few notes.

Cement resistors on the character adjust circuits are stacked and each side is glued. Not sure if that is necessary, but the values are:

10W on the midrange side
2/3/6/15 ohm

5w on the treble side:
2/4/7.5/15 ohm

The remaining cement resistors are:
6 ohm, 5W
7.5 ohm, 5W
2.5 ohm, 10W

The rest of the (radial) electrolytic caps are all 50 VDC:

4 uF (axial)
8 MFD
16 MFD
18 MFD
32 MFD

Have to get back to work. I'll pull PCB later to map circuit, unless Ken has a copy he'll share. :)
 
Well, I can't figure out how to pull the pcb off down by the speaker terminals. They appear to snap in place, but I have now broken a small piece of one, and see that the same place on the other crossover has the same broken piece. I may want to source someone's clean terminals since I'm guessing there is not room to put modern posts. I have a set, but they are too big.

Here's three pics. The third shows solder points that I am guessing need to be desoldered to pull apart?
 

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Photos

Here are photos of the crossover.
 

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An honest person, confronted by one of the many interpretations of a goodish loudspeaker might concede that some ideas are better than others. :cool:

IMO, every loudspeaker makes some concessions to the room. Your Room is the Monster... It's easy enough to design a great loudspeaker. But put it in a small room, and it all goes wrong...

Here's Troels Gravesen's small MT speaker: Peerless HDS PPB 830860

I really don't find anything Mathematically difficult about converting that to an MTTM or TTMM design.
 

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An honest person, confronted by one of the many interpretations of a goodish loudspeaker might concede that some ideas are better than others. :cool:

IMO, every loudspeaker makes some concessions to the room. Your Room is the Monster... It's easy enough to design a great loudspeaker. But put it in a small room, and it all goes wrong...

Here's Troels Gravesen's small MT speaker: Peerless HDS PPB 830860

I really don't find anything Mathematically difficult about converting that to an MTTM or TTMM design.

The room IS the monster ... but I like having a little more space than the last place.

It is possible that a DIY monitor project would be in my future, but probably not for another year. I have too many projects to catch up on.
 
There are various approaches to a nebulous concept known as "Bafflestep". This is something about bass reproduction.

IMO, you just concentrate on voices and midrange.

635372d1505410707-classic-monitor-designs-mtm-scanspeak-raal-ribbon-selah-audio-jpg


IMO, you are ahead of the field in concentrating on voices. I could quote various areas of Quantum Theory about this. But, for sure, it's all about information. And the PA theory is right.
 
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