Soundcraftsmen purchase help

I see, points all taken. Guess then I'd need to simply ask others what amps they've found effective in controlling boxes with substantial bass output

....back to the Soundcraftsmen topic, I still can't believe how good a sound I'm able to get from an $80+shipping investment in my shoebox S800 coupled with the L7....

OT...I know few here are big on MCH music but I've gone a bit wild this past week on ebay with Chicago 2, Diana Krall, Beatles Love, Michael Brecker Pilgrimage, Natalie Merchant Tigerlily, with my L1, L5, L7 HT setup been having a really good time.....if I was to pick one disc as a recommendation it would be Beatles Love, what the George/Giles Martin did with original recordings into surround for the Circ de Soleil show is beyond stunning, and has a non-Beatles fan like myself spending lots of time with that disc...if you are a Beatles fan and have MCH this is an absolute must have....

Output impedance could be .05 Ohms in some cases, this would give high damping factor.

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Originally Posted by james zep

Hello everyone, I'm new too.

This topic interest me, especially since I bought this afternoon an MTX Soundcraftsmen A400 Pro.
I tried it with a par of Kappa 8. I know these speakers are hard to drive, but not as the Kappa 9. Anyway I tried really slowly with the A400 Pro and it shut down… or at least it seems to want to. I was waiting for any signal of that kind to immediately turn the volume and the amplifier down. So nothing was damage, then I used the Kappa with my Grand Integra M508 and they worked perfectly.
But could you tell if my A400 Pro, might have a problem or this is due to the Kappa impedance dipping below 4 ohm. Another strange thing, I couldn’t see the clipping LED flashed or turn on. Did the Kappa didn’t let them time enough to do so?
Could an A400 pro drive those Kappa 8. Now my plan is actually to use it with a par of AR 303a, will it be ok? (They have an average impedance of 4 Ohm and supposedly they doesn’t dip down more than 3.6 Ohm at a certain frequency).


Thanks.

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Hello,

Like JBLAddict said the SC should not have an issue moving those speakers. My previous experience with one of my A400PROs was similar and I traced the problem to the input board. There was an update done to these boards which shows on the schematic. Make sure you check your wires and speaker crossovers to make sure no short is present. Also try the amp with different speakers to see if it still tries to shut off. The symptoms your amp is experiencing don't sound like blown outputs.These models with the PCR supply turn the fan on at high speed when the output mosfets or the power supply thyristors are shorted. make sure the two 11,000 mfd capacitors under the board are not loose. Look for cold solder joints or loose connectors/wires throughout. PM me if you need help or a schematic for that baby.

I have 2 Soundcraftsmen PM860s that I've had for over 20 years, and it looks like 1 of them may have died. I'm hoping it can be repaired! A few months ago the Truclip A red light came on, and while the amp still works I am getting sporadic static on the left channel now, (somewhat similar to when you turn them off while still playing music). I was hoping it might just need a new capacitor, but what do I know!

I've taken it in to an electronics repair shop near my house and they seem to think it is something more serious, but need some schematics to be sure.

IF ANYONE HAS SCHEMATICS FOR THE PM860, or knows where I can find them, I would be very grateful! I love these amps and would love to keep them as a pair. Any advice on what to check that I can pass on to the electronics repair shop would be a great second option.

*fingers crossed*

PM me with your email address, I'll shoot ya a copy. rickedd46 - I PM'd you about schematics you may have for the newer mtx Soundcraftsmen stuff as I don't have any of those.

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Originally Posted by bmackin

I have 2 Soundcraftsmen PM860s that I've had for over 20 years, and it looks like 1 of them may have died. I'm hoping it can be repaired! A few months ago the Truclip A red light came on, and while the amp still works I am getting sporadic static on the left channel now, (somewhat similar to when you turn them off while still playing music). I was hoping it might just need a new capacitor, but what do I know!

I've taken it in to an electronics repair shop near my house and they seem to think it is something more serious, but need some schematics to be sure.

IF ANYONE HAS SCHEMATICS FOR THE PM860, or knows where I can find them, I would be very grateful! I love these amps and would love to keep them as a pair. Any advice on what to check that I can pass on to the electronics repair shop would be a great second option.

*fingers crossed*

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I guess I should introduce myself! I'm a Soundcraftsmen nut just as much as a bunch of you are! I have 3 900x2's, a Pro-Power 10, Pro-Power 4, PM860, PM840, PCR800 amps as well as a Pro-Control 4 preamp and the one equalizer with the analyzer in the middle (can't remember the model). I just got done fixing my latest 900x2 purchase, needed caps all over the place. It lived life in a church until one of the main filter caps shorted which blew two scr's and burned a trace on the power supply board. After previously paying through the nose for capacitors on another 900x2 of mine, I narrowed down these part numbers from digikey that work fine and have minimal cost:

900x2 PR1800 PM1600 Pro-Power 8 should all take these:

Digikey 565-3299-ND - 100V 10,000uf correct diameter, but a tad short on height (4 of these are needed), about $12 a piece (cheap compared to paying $50 a piece!)

Digikey 495-4227-ND - 100V 10,000uf two of these are needed, a tad higher but the scr heatsink does clear the chassis cover when installed, I just used these on the repair i finished last night.

75 volt caps - should fit the bulk of the soundcraftsmen amps, they are a tad shorted than stock so you will have to shim them on the bottom on some models so the power supply board doesn't hit the transformer. Digikey 565-3331-ND They are 75V 18,000uf. Since they are bigger than the stock 11,000 uf they should give a little extra reserve on the power supply. I have 4 of these on backorder from digikey, $13 a piece, to try them on my Pro-Power 10. I bought this amp new and haven't ever changed any caps so it's probably way past due.

Again, just an intro of myself and a few tidbits of knowledge I have about these amps.

-Matt

Soundcraftsmen schematics: I have schematics for a bunch of Soundcraftsmen schematics (not the mtx soundcraftsmen stuff though, but I doubt things are much different). so if anyone needs something, pm me with your email addy.

-Matt

Hey Matt, welcome to the forum, and thanks for your offer.

A lot of my Soundcraftsmen gear could use a "tune up" by now. I just need to build up the momentum to "git 'er done!"

I still have A100s, A200s, and A400s in use every day. They're all from the MTX era.

Holy cow! How many do you have? I rarely see any of the Axxx series on ebay nor craigslist, where do you find them hiding?

-Matt

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Originally Posted by Titanium Dome

Hey Matt, welcome to the forum, and thanks for your offer.

A lot of my Soundcraftsmen gear could use a "tune up" by now. I just need to build up the momentum to "git 'er done!"

I still have A100s, A200s, and A400s in use every day. They're all from the MTX era.

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Originally Posted by blazer40

Holy cow! How many do you have? I rarely see any of the Axxx series on ebay nor craigslist, where do you find them hiding?

-Matt

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Of the A Series amps I have 2 A100s, 2 A200s and 3 A400s.

I've also got 5 PCR800s, 1 S800, 1 S860, 1 Pro-Control Three, and 1 A2502.

Don't even ask about the the pres, EQs, and analyzers.

Hey Matt,

Thanks for the schematics! You're a legend! I've sent them off to the repair shop. Hopefully I'll be listening to my PM860 again in no time.

Thanks again!

- Bill

Bill,


Here's a power supply schematic that will most likely match your amp. The one I sent before was for a PP10 which has some extra stuff. Disregard the writing on it as I don't know who did that, I got this version with an amp I got off ebay.

-Matt

Matt -

Thanks again! I'll pass this on to the repair shop. I'm hoping to hear from them in a few days. I'll let you know how things turn out.

Cheers,
Bill

rickedd46
blazer40
Titanium Dome

So great to meet all of you!
blazer40, you have 3 900X2 amps?

I have 4 of the same PR1800 and 1 900X2.
2 I bought new in the late '70's
2 I got used on eBay. They were on the other coast...
the 900X2 I just bought on craigslist and I'm awaiting delivery.

I love these things. My only complaint is I wish they had a bit more capacitance in those big caps after the power supply, so they had more headroom to at least attempt to reproduce short transient bursts beyond their continuous rating. But there's enough power to go around despite that limitation. I used to have 2 Crown CE4000 switching amps and they also had a lot of power (considerably more than a 900X2)...and also had no dynamic headroom for even attempting to handle short transient bursts beyond their continuous rating.

Think I could fit more modern caps with higher capacitance in the same place as the original stock caps, for an upgrade? Or would I have to add an additional cabinet to each amp, to hold a bank of caps?

Or am I just freakin' nuts for wanting to?

Yes you can upgrade the caps, but some of the high capacitance versions are pricey. I re-capped all of my 900x2 amps over winter and ended up with 10,000's on the big 4 (same as originals) and 10,000's on the two smaller ones (in place of 6800's i think) under the power supply boards.

I ended up at about $12 per cap for the bigger ones, so about $150 total on those. (that was the killer for me, having to get 12 of them for 3 amps!) This is why I stayed away from upgrades. which would have just run the price thru the roof.

I did manage to get some caps rated at 18,000 for my Pro-Power 10s, nice upgrade from the stock 10,000 size.. (would also fit a bunch of the other Soundcraftsmen amps too).

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Originally Posted by cyclecamper

rickedd46
blazer40
Titanium Dome

So great to meet all of you!
blazer40, you have 3 900X2 amps?

I have 4 of the same PR1800 and 1 900X2.
2 I bought new in the late '70's
2 I got used on eBay. They were on the other coast...
the 900X2 I just bought on craigslist and I'm awaiting delivery.

I love these things. My only complaint is I wish they had a bit more capacitance in those big caps after the power supply, so they had more headroom to at least attempt to reproduce short transient bursts beyond their continuous rating. But there's enough power to go around despite that limitation. I used to have 2 Crown CE4000 switching amps and they also had a lot of power (considerably more than a 900X2)...and also had no dynamic headroom for even attempting to handle short transient bursts beyond their continuous rating.

Think I could fit more modern caps with higher capacitance in the same place as the original stock caps, for an upgrade? Or would I have to add an additional cabinet to each amp, to hold a bank of caps?

Or am I just freakin' nuts for wanting to?

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