Anybody have an 8000 that they would be interested in selling?  The guy selling the Rotel is asking $150 which is about the most I can do right now.  I tried searching for Beomaster 8000's and only found 1 that was listed for sale (sold though) for $199.  If I don't really get anywhere finding an 8000 then I am going to go check out that Rotel on Saturday.

A fully-working Beomaster 8000 in good condition would set you back between £250-300 (or approx $500ish). Beware though, as older ones on eBay will probably need some repairs now as they are complex machines. They also weigh a ton, so shipping from outside of the US would probably be prohibitive given your budget.

They really are wonderful amps though :)

Wow, that being said I think I'll go look at that Rotel.  It has a high damping factor of 150 and I'm sure it produces really clean, high current capable sound.  There is a TNT Audio review of the Rotel from 2000 so I assume the model is not that old.  Is also cost near $700 in the US when released so $150 is not bad IMO.  I'll keep everyone updated, thanks.

Hey Daniel, a couple of things here.

To me, 60wpc won't be enough.

Audio manufacturers like to be sneaky and say "high-current design" making people think that it's better than a "regular" (???) amplifier design or something.

However, the Beovox MS150's are an 8 ohm nominal speaker. So, you can have a super special "high-current" design all you want, but the amp in question is only going to be able to deliver so much current into the speaker for it's given impedance.

Say you've got two amps, one a quality "regular" amp, and another, "high-current" design, both similar enough in design and layout to be fairly comparable, and both rated to deliver 40 V at the power supply rails. With the MS150's being "8 ohms" (which is a bit of a misnomer, and relates to the whole damping factor thing, which I'll get into in a minute), you're only going to be able to deliver 5 amps max into them (mathematically anyway, not counting losses and inefficiencies, and impedance irregularites), regardless of whether it's a "high-current" design or not. So all that "extra current" goes to waste!

No, but, do you see what I mean? Power is voltage times current, and current is voltage divided by resistance. Unless you're looking at wiring up three or four sets of MS150's in parallel, a "high-current" design (one that actually delivers on it's promises, at that) pretty much means nothing.

About the impedance and damping factor thing... Damping factor is simply a numerical value describing the load impedance divided by the amp's output impedance.

An "8 ohm" speaker like the MS150 or almost any speaker on the the planet isn't really a linear 8 ohm impedance. If it were, it would be a resistor. That's why speaker loads are described by impedance, which is basically a reactive resistive load. A speaker's impedance varies with things like frequency, enclosure tuning, voice coil heating, and non-linearities in the motor. It fluctuates just with the movement of the coil in and out of the magnetic gap. It presents the amplifier with a load possessing inductive and capacitive properties.

Even with a decently linear speaker like the MS150, which has impedance compensation networks in it's crossover, it will have a relatively large "double camel hump" in it's impedance graph around it's enclosure tuning frequency. Look at this chart I pulled off the Stereophile's website of a JBL speaker (first one that came up in a Google search):

See how the dark solid line varies between about 3.75 ohms and over 20 above and below the port tuning frequency?

Given Ohm's law, you'd think the amplifier's frequency response would mirror that of the speaker's impedance, and in crappy amplifier designs, it does! But a low output impedance (i.e. high damping factor) means that the amplifier is more of a constant voltage source, not letting the speaker's impedance affect it's frequency response.

And of course, the speaker itself will have a voltage sensitivity that looks a bit like it's impedance plot. This is why you can have a very irregular impedance, and still have a flat response (I don't know if this JBL has a flat response, I'm just saying it's possible in a design). Basically, there's less current delivered to it at certain frequencies, but the frequency response of the speaker doesn't dip because of the higher voltage sensitivity at that frequency.

Combined with an amp having a high damping factor, the final result can be very flat response, despite the impedance being all over the place!

By the way, I'm working on packing your 8" drivers. Hope you find it satisfactory.

Regards!

Jon

Hey Jon, thanks for the reply.  I am aware of everything you said, I have my associates in electronics and was a bench tech for a lighting control company for years (now manage the quotes team).  The only thing I meant by high current torroidal XFMR is that the 60 watts it is producing is probably constant RMS value (at louder volumes) and not a peak figure so many manufacturers use.

Damping factor as I have always known it basically means better cone control throughout the available frequency range but even more so at lower frequencies where cone movement is much greater.

I wish I would have one of these speakers complete to bring with and hook up to the amp.  The owner did say he has some larger speakers we could hook up but I know efficiency plays a huge role.

The Beomaster 8000 only did 150W at 4 ohms and only 100W at 8 ohms.  Compared to the Rotel, that is far less than 3dbW.

Thanks again for the 8's, really looking forward to receiving them.  Yesterday I re-soldered a few joints on the crossovers (cold or broken traces/pads) and glued down some of the inductors that became loose.

Well, I'll just say that the BM8000 should be rated as "at least 100 watts continuous into 8 ohms". It's very stout power supply can deliver 55 V max to a speaker load. It does suck up to 700 watts from your power outlet. At stupid volumes, my lights dim with the beat of the music. Of course, whoever wired my house was an idiot, but that's another matter I'm working on...

I'd venture to say it'd eat that Rotel for lunch.

And it looks so purdy!

Of course, the downside is that they're old now, and most will need servicing. I have 2 actually, but one is a bit beat, and I'm keeping it for parts should my nicer one ever need something hard to find!

Somewhere on here, quite awhile ago, I remember reading that the BM8000 output 192 watts of power per channel, but I don't know into what kind of load it was.

Anyway, there's many amps that would make the BM look wimpy too. Hope you can find something you like that isn't ridiculously priced.

Jon

Jon:

arned:

Beovox MS150 has - like the other speakers in this serie - an effective overload protection if they get "to much", - so dont worry.

With these loudspeakers I would go for the Beomaster 6000 with 2 x 75 W (IHF). In different test at the time in 1981/82 it was in many ways better than Beomaster 8000.

I disagree. I've had both (still do, but my 6000 is non-operational for the time being...), and the 8000 is the far superior product. Much more dynamic and powerful.

Jon

I've never had the chance to compare them, but as Arned wrote: Different tests at the time did say that the BM6000 was better than the 8000. But, then again -it is the owner's taste that counts...

Well, I'll just say that the BM8000 should be rated as "at least 100 watts continuous into 8 ohms". It's very stout power supply can deliver 55 V max to a speaker load. It does suck up to 700 watts from your power outlet. At stupid volumes, my lights dim with the beat of the music. Of course, whoever wired my house was an idiot, but that's another matter I'm working on...

All I can say is wow, 700 watts!?  That is almost 6 amps, that does pull same major current. 

I hear you on the house, I spent a whole winter re-wiring my entire house.  I added outlets everywhere and have 20 amp branches pulled for my small shop, bathrooms and kitchen.  The rest of the house has a max of 8 outlets per 15 amp circuit...no more issues.

DKAudio:

Well, I'll just say that the BM8000 should be rated as "at least 100 watts continuous into 8 ohms". It's very stout power supply can deliver 55 V max to a speaker load. It does suck up to 700 watts from your power outlet. At stupid volumes, my lights dim with the beat of the music. Of course, whoever wired my house was an idiot, but that's another matter I'm working on...

All I can say is wow, 700 watts!?  That is almost 6 amps, that does pull same major current. 

I hear you on the house, I spent a whole winter re-wiring my entire house.  I added outlets everywhere and have 20 amp branches pulled for my small shop, bathrooms and kitchen.  The rest of the house has a max of 8 outlets per 15 amp circuit...no more issues.

This is what I need to do. I've already re-wired part of my upstairs. I'd like to eventually add a dedicated circuit for the main B&O system.

Jon

I received the parts from Jon yesterday and just dropped the speakers off durring my lunch break.  It sounds like they should be able to use the parts to make another good driver.  Unfortunately, he said both spiders need to be replaced on my 10's, they are sagging a lot.  I was quoted a little over $200 for everything. 

I didn't get the Rotel (scheduling issues with the seller) I'm now looking at getting an Onkyo M-5140 amp and Onkyo P-3200 preamp.  Any opinions on those?  They were made from 89-91 and I cannot find much info on them.  The amp does 110RMS into 8ohms, the guy is asking $200 (came down from $250).  Let me know your thoughts.

Thanks

DKAudio:

Unfortunately, he said both spiders need to be replaced on my 10's, they are sagging a lot.  I was quoted a little over $200 for everything.

The cost won't be an issue when you hear these speakers - they are truly awesome. Are you planning on replacing the capacitors in the crossovers? This will improve them even more. I know Martin (member Dillen) does a complete kit for this.

Chris.

Have you considered this?

I have one that's the heart of my desk top system.  Sources are my custom built PC (ripped CDs and DVDs) and B&O RX2 turntable; speakers are B&O S45-2s.

If not the NAD 7175PE:  I used to drive my desk top system with an NAD 7140 receiver that was bridged for 80 wpc, with an outboard bridged NAD 2140 power amp.  I was pleased with the results, but wanted the more inputs and listen/record feature of the 7175.  You should be able to get both of those pieces for less than $200 combined on a popular auction site.  The 7175 should sell for less than $200, probably closer to $150 than $200.

I think I am going to go with the Onkyo seperates, thanks though.

Hey,

So did you pick up the Onkyo components?

Jon

I did, they are in perfect condition, look like they were purchased last week, not 1989-1990.  I hooked them up yesterday (was out of town) and am using Bose 201's for speakers.  It is probably the cleanest stereo I have ever heard, and I've heard tons of them...for example...McIntosh amp/pre with Magnepan's and a Wilson Audio Watchdog.  I cannot wait until the B&O's are complete to see what those sound like!

I need help quick!  :) 

The drivers are finally home and repaired, they look great.  I know the 10's mount with those metal u-channels and rubber pieces.  I am missing the ones for the 8's so I made some that match the ones for the 10's.  However, once the sonatube is on the 8 there is not really any room for the metal clips and rubber pieces.  How are the 8's mounted?  Is the trim ring bolted down and the 8 is loose in the sonatube but held tightly once the baffle is screwed in?

I really want to finish and only have those to mount, I am very anxious, I've been waiting over 10 years to hear these things!

We need pictures!

No, the 8" drivers are held in by the screw-down clips.

Try putting the 8's with trim ring on first, screwing the clips down on them, and then putting the sonotube on. See if that works. Make sure the sonotube slides over the edge of the trim ring, but put four pieces of duct tape on the north, south, east, and west sides of the sonotube, where it connects to the plastic trim ring, as well.

Jon

Also, give the 10"'s plenty of time to break-in. With new spiders, the bass is going to sound stiff at first. For new drivers, I like to flex the spiders by hand for a little bit until I hear the adhesive on the flexy part of the spider start to crack. Seems like they loosen up faster when I do that.

Jon

I was hoping you were going to reply!

The diameter of the basket (where the metal clips would hold them down) is the same diameter as the sonatube.  If I put the tube on first there is no where to screw the clips down to the driver.  If I put the clips on first there is not nearly enough room to put the tube on.

Here are some pics...

The first one is the sonatube over the driver but no screw down clips on.  You can see the diameter of the tube is the same as the basket.

The second is showing how the clips can go on but the tube will not fit over the driver if they go on first.

Uploaded with ImageShack.us

Yeah, it looks like you might have to trim down the clips you made by a smidge. The rubber pieces just barely overlap the rim of the trim ring when they are affixed.

Either that, or re-drill the holes over a bit if there's more room to slide the clips back.

Only other thing I could suggest is to put the sonotube on, align the clips at an upward tilted angle, get the screw started, and then the clips might cut slightly into the tube as you tighten them down in equal increments (one side halfway, then opposite side halfway, etc. Kind of like tightening lug nuts on a wheel).

I want to say it was a small fight fitting even the B&O clips on when I put mine back together...

Jon

P.S. - By the way, don't be temped to leave the tubes off. I was, and wondered what the difference would be. The cabinet is too small for both of the driver's (8" and 10") VAS, even with the 8"'s high pass filter. There's more midbass (above 60Hz), but appreciably less low bass (30-50Hz) output than with the tube in place.

I got one cabinet done but am very leery.  I cut down my clips and they are tight against the plastic trim piece that goes around the woofer (hard to explain but it is the piece that has the white rubber gasket and what you see around the surround once complete.  It is not hitting the basket at all and I see no way how it ever could've.  I just hope the tube is pushing pretty hard against the back when you screw the baffle in, that should keep the 8's tight.

The rubber rectangles need to be clamped down on the lip of the midbass' frame.

There should be an 8" black trim ring as well that goes around the circumference of the 8"'s frame, on the back side. Not the decorative trim ring on the front. Did you remember to fit this trim ring over the midbass' frame before you installed the sonotube over the driver? I can't tell from the pictures. The sonotube fits onto this ring, and if it's missing, that would probably be why you're having problems installing everything.

Jon

Notice said trim ring between the midbass and sonotube...

Jon:

Yeah, it looks like you might have to trim down the clips you made by a smidge. The rubber pieces just barely overlap the rim of the trim ring when they are affixed.

When I said this earlier, I meant the trim ring on the back that attaches to the sonotube, not the decorative one you see from the front. Sorry if I misled you.

Jon