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Author Topic: Restoring old peecker sound PA equipment. Need help.  (Read 7732 times)

Eugen Jeličić

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Restoring old peecker sound PA equipment. Need help.
« on: August 12, 2014, 01:47:23 pm »

Hello there.
Long story short. My father used to have a disco club (1997 - 2001.) we recently got all the equipment from the club back after it's been stored for over 10 years and not used.
Now all the equipment was produced by the italian company "peecker sound" 4x 900w (4ohm) amps. 4x500w (4ohm) amps. Running 4 18 inch peecker sound woofers and 4 mid-hii 12+horn peecker sound speakers. Recently i started restoring the equipment so i can start renting it. It's all working very well. I spent about 30 hours cleaning the amps and we tested it all outside with a DJ:

https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/t31.0-8/10498590_10202625694784276_4804679082402610285_o.jpg

Now finally here is my question. The drivers in these speakers seem to be in perfect condition. And damn they sound good! But i just can't find any specifications (except the 8ohm impedance rating). And i'd really like the datasheet for these drivers. Now when i took them out i soon realised they look exactly the same like some RCF drivers.

There is a good chance that these are RCF drivers. On the back there is a "acoustic research labs" sticker. But that is just a section of peecker sound company so it doesn't tell me much. They however look exactly the same like some RCF speakers. On the 18 woofer there is an engraving:

L121000

i know some RCF speakers are marked with L12 right?
I wanted to send you some pictures of these drivers to ask you if you could please help ne indentify them. Guys from peecker sound don't reply the emails. If you recognise these 18 an 12 drivers please give me the models thank you very very much.

Here are the pics

http://s30.photobucket.com/user/athlon-64/library/peecker%20sound%20oprema

So i seem to have found one of the drivers. The 12" inch in the mid-hii speaker seems to be an
RCF L12-544k

on the back of each one of my speakers there is a number engraved. On the 12' speaker it was L121001. When i first saw the L12-544k online i realised it looks the same. Then i saw the number and finally... that is the speaker.

Now i still haven found my 18's and i have another question. Are these genuine RCF drivers or are these copies from peecker sound? Either way they sound damn fantastic but considering the engraved number. The fact that drivers are absolutley identical and both produced in Italy. I think this is and RCF with a different sticker right ??

So here is my 12 driver:

http://i30.photobucket.com/albums/c316/athlon-64/peecker%20sound%20oprema/IMG_2458_zps390461a0.jpg

and here is a L12-544k that i found online:

http://mla-s2-p.mlstatic.com/9134-MLA20013034555_112013-O.jpg

http://www.preciolandia.com/ar/parla...-81gozc-a.html

Take a good look at the engraved number on this RCF that i linked and my driver and you'll see it's the same number. So is this a genuine RCF driver from 1997 ?

Also can you help me find these 18's i have :/
« Last Edit: August 12, 2014, 01:57:09 pm by Eugen Jeličić »
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #1 on: August 13, 2014, 08:37:26 pm »

Are these genuine RCF drivers or are these copies from peecker sound? Either way they sound damn fantastic but considering the engraved number. The fact that drivers are absolutley identical and both produced in Italy. I think this is and RCF with a different sticker right ??
Eugen,

Look like genuine RCF drivers, whether they are simply re-badged standard models, or variants made specifically for Peecker might be something RCF could help you with.

Nice clean up job, the stuff looks near new!

Art
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #2 on: August 14, 2014, 01:41:25 pm »

Eugen,

Look like genuine RCF drivers, whether they are simply re-badged standard models, or variants made specifically for Peecker might be something RCF could help you with.

Nice clean up job, the stuff looks near new!

Art

Well i know but i have sent them an email and a facebook message. Got no replies :(
Do you know how to contact them and get some info back ?

Than you. I'd really love to find the missing channel for my TVA1800 amp but i doubt i will have any luck. The amps are from 1997 but still working fantastic. They are very very heavey but honestly that's the only thing i don't like about them.

And one more question. Do you think the best option is to run 3 woofers from 900w amps (they get about 550 at 8 ohms) and then run the 4th woofer from the 2x500 amp in bridge mode and make it give the forth base 550w so all 4 of them run equally. Or i should just use the system even better and hook up 2 woofers at 2 bigger amps and then the other two at 2x500 amps in bridge mode. That way i would be running my woofers 2x550w + 2x ~800w.

So in short terms. Is it a problem if 4 woofers are not getting equal amount of power?   
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Richard Turner

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #3 on: August 14, 2014, 09:07:33 pm »

I would have the amplifiers properly bench tested General consensus is 10 years without charge recharge cycle on large capacitors before failure is extremely likely
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Looking at retiring. Local PA market has shrank to 2 guys with guitars and bose l1 compacts or expecting full line array and 16 movers on stage for $300... no middle left going back to event DJ stuff, half the work for twice the pay.

Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #4 on: August 15, 2014, 05:58:05 am »

I would have the amplifiers properly bench tested General consensus is 10 years without charge recharge cycle on large capacitors before failure is extremely likely

Well the fact that they have not been used in 10 years has concirned me but i have been using them for the past 3 weeks a lot and 2-3 times ran them at almost maximum load for about 4 hours. Had absolutley no problems at all :/

I also checked out all the capacitors in the amps. None of them is bloated or leaky.
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #5 on: August 15, 2014, 03:33:27 pm »

Well i know but i have sent them an email and a facebook message. Got no replies :(
Do you know how to contact them and get some info back ?

So in short terms. Is it a problem if 4 woofers are not getting equal amount of power?
I have no personal contacts at RCF.

If the four woofers get a reasonably similar amount of power, no problem, but if one is getting more power than the other three, it will burn first.
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #6 on: August 15, 2014, 04:04:53 pm »

I have no personal contacts at RCF.

If the four woofers get a reasonably similar amount of power, no problem, but if one is getting more power than the other three, it will burn first.

Well that is very logical but let's say my woofers can take a 1000W RMS. 3 of them are getting 600w and one of them is getting 800w. I never clip the amps and watch out the power. So i don't burn any of the woofers. Is it a problem then for one of the woofers to run under a higher load then the others? I want to know will it affect sound quallity.
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #7 on: August 15, 2014, 06:51:08 pm »

Well that is very logical but let's say my woofers can take a 1000W RMS. 3 of them are getting 600w and one of them is getting 800w. I never clip the amps and watch out the power. So i don't burn any of the woofers. Is it a problem then for one of the woofers to run under a higher load then the others? I want to know will it affect sound quallity.
The driver getting 800 watts compared to 600 watts will be about a half dB louder and slightly more distorted than the others.

Saying your woofers can take 1000W RMS does not make it so, however- doubtful that a 1997 woofer would be rated more than around 500 watts RMS.
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #8 on: August 15, 2014, 07:39:11 pm »

The driver getting 800 watts compared to 600 watts will be about a half dB louder and slightly more distorted than the others.

Saying your woofers can take 1000W RMS does not make it so, however- doubtful that a 1997 woofer would be rated more than around 500 watts RMS.

I understand. So there is not much point forcing it. Right now they get about a maximum of 550w from my amps and when you hear them that really seems to be perfect. If i want my system to be louder i need more speakers. Not amps right now.
The driver is most probably an RCF L18P540. It's the only driver that looks exactly the same. If that's true we are talking about a 99.5dB - 350w RMS/700w program/1500w peak driver.

So in case you were buying an amp for a speaker with those specifications what kind of power do you think would be good? My peecker gives it about 550w (it's a 900w @4ohm amp, i don't know about 8 ohms but i think it's around 550) Do you think that's well balanced?

The only reason i have been asking all of this is because there are multiple ways to connect my system with the amps. One of them is using two 2x500w @4ohm amp in bridge mode to run 2 woofers. In bridge mode they are 8 ohm amps so each woofer would be able to get 1000w.
In case i ever do that i just want to know how far can i feel safe to push it.
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #9 on: August 16, 2014, 01:13:38 pm »

The driver is most probably an RCF L18P540. It's the only driver that looks exactly the same. If that's true we are talking about a 99.5dB - 350w RMS/700w program/1500w peak driver.

So in case you were buying an amp for a speaker with those specifications what kind of power do you think would be good? My peecker gives it about 550w (it's a 900w @4ohm amp, i don't know about 8 ohms but i think it's around 550) Do you think that's well balanced?
550 real watts is probably plenty for that type of speaker. Xmax is only 4.5mm, so if you see the cone move more than 9mm peak to peak (only 3/8 inch), it is exceeding it's linear range, more power would just increase distortion.

Doubling Xmax allows 6 dB more output (but also requires at least 6 dB more power), the better Italian PA woofers are now in the 15mm Xmax range, and there are some woofers with even double that Xmax now!
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #10 on: August 16, 2014, 02:17:26 pm »

550 real watts is probably plenty for that type of speaker. Xmax is only 4.5mm, so if you see the cone move more than 9mm peak to peak (only 3/8 inch), it is exceeding it's linear range, more power would just increase distortion.

Doubling Xmax allows 6 dB more output (but also requires at least 6 dB more power), the better Italian PA woofers are now in the 15mm Xmax range, and there are some woofers with even double that Xmax now!

Well to be honest when i ran them at the amps maximum of 550w they worked very well. Sounded fantastic. Nice, warm, powerfull but still precise and punchy. So the reality is it's probably not worth forcing them more then that. If the drivers we are talking about are L18 P540's. And that's the only part i'm still not sure about. Because if they are not there are a few RCF drivers that look the same like mine but have 700w RMS handling capacity and 1400 program. And if i have one of those drivers then it's worth getting a more powerfull amp. But i can't believe it's so hard to indentify a driver :/

One more question. I'm a 100% sure that 12's in my mid-hi speakers are RCF L12-544K. They have a RMS handling capacity of 300w and AES handling capacity of 400w. That means i can feel safe running them under a 450w load? Because in the case of connecting 2 of those in parralel on one of my big amps each one would be able to get 450w if i push the amp to it's max. Those drivers should be able to take that power right?
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #11 on: August 16, 2014, 03:50:39 pm »

I'm a 100% sure that 12's in my mid-hi speakers are RCF L12-544K. They have a RMS handling capacity of 300w and AES handling capacity of 400w. That means i can feel safe running them under a 450w load?
Eugen,

The speaker presents a "load" to the amp. The amp can deliver more power than it's rating if clipped in to that load, as much as double if hard clipped.
The older AES signal used in the RCF rating has a 6 dB crest factor, which is less than most music, which generally has more like 12 dB crest factor (which is the crest factor in the new AES signal  :'().  Assuming you are not clipping the amp, and not running unusually compressed music, 450 watt peaks will not be a problem at all, as the average power the load must dissipate is probably only 1/10th that around 45 watts.

That said, with some electronic dance music, the crest factor below 100 Hz may be as little as 3 dB, same as a sine wave- with that type of signal the AES rating could be more than the woofer may handle.

Art
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #12 on: August 16, 2014, 04:11:51 pm »

Eugen,

The speaker presents a "load" to the amp. The amp can deliver more power than it's rating if clipped in to that load, as much as double if hard clipped.
The older AES signal used in the RCF rating has a 6 dB crest factor, which is less than most music, which generally has more like 12 dB crest factor (which is the crest factor in the new AES signal  :'().  Assuming you are not clipping the amp, and not running unusually compressed music, 450 watt peaks will not be a problem at all, as the average power the load must dissipate is probably only 1/10th that around 45 watts.

That said, with some electronic dance music, the crest factor below 100 Hz may be as little as 3 dB, same as a sine wave- with that type of signal the AES rating could be more than the woofer may handle.

Art

So crest factor is basically saying how much louder are the peaks in comparison with the song's average right? So by the new AES rating the 544K would be rated as an even more powerfull speaker?

So i'm going to rent my system in in about 14 days. I allready made a deal. I found a missing module for my amp so the system i'm going to be bringing is:

4x900w @4ohm (about 550 @ 8ohm) + 4x500 @4 ohm (about 300 @ 8 ohm) 

Those amps are going to be running my 4 woofers and 2 (12 + horn) RCF speakers.
I was thinking about the best way to hook it all up and i'm really not sure. I might connect my 4 woofers directly to big amps so they can get up to 550w (they are 8 ohm speakers) because i know they work fantastic with that power. Since i don't know witch exact RCF drivers they are i don't want to take any risks.
And then connect each 12+horn speaker to my 2x500 amp in bridge mode. So in birdge it's a 1000w @ 8ohm amp. Witch means it can give my 12+horn speakers up to a 1000w. I would then put those amps at 45% power and leave it like that. Do you think that is the best solution?
« Last Edit: August 16, 2014, 04:14:17 pm by Eugen Jeličić »
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #13 on: August 16, 2014, 04:59:42 pm »

1)So crest factor is basically saying how much louder are the peaks in comparison with the song's average right?
2) So by the new AES rating the 544K would be rated as an even more powerfull speaker?
3) I would then put those amps at 45% power and leave it like that. Do you think that is the best solution?
1) Yes.
2) Yes.
3) A 50% reduction is -3dB. Reducing the amp input does nothing to protect speakers, one simply can turn up the source by +3dB (note how little a change that is on a fader) and the amp puts out the same power. Turning down the amps also makes it easier to clip the system upstream, which can tend to roast HF drivers, as clipping increases upper harmonics.

Short of having limiters that have separate peak and RMS settings set specifically for the driver's capabilities, the only safe solution is turning down the source material if you see any clipping. And as mentioned before, with the right (or wrong) type of music, even without clipping, your amps potentially have enough power to fry the sub's voice coils.

Dance music has changed since 1997...
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #14 on: August 16, 2014, 09:09:35 pm »

1) Yes.
2) Yes.
3) A 50% reduction is -3dB. Reducing the amp input does nothing to protect speakers, one simply can turn up the source by +3dB (note how little a change that is on a fader) and the amp puts out the same power. Turning down the amps also makes it easier to clip the system upstream, which can tend to roast HF drivers, as clipping increases upper harmonics.

Short of having limiters that have separate peak and RMS settings set specifically for the driver's capabilities, the only safe solution is turning down the source material if you see any clipping. And as mentioned before, with the right (or wrong) type of music, even without clipping, your amps potentially have enough power to fry the sub's voice coils.

Dance music has changed since 1997...

When i sayed 45% i meant. I put my woofer amps at the max output and the mid-hi amps at 45% and then WATCH the signal. Of course if the signal hits +3dB i might fry my 12's but that should not happen.
Basically i want to use the system as much as i can. It's going to be in a closed club full of people. And there is going to be a DJ playing comercial electronic music. I'm going to need as much power as i can get.

EDIT: I'm going to be there watching the system all the time and the DJ is going to be plugged into my mixer so i have tone control. In case i see clipping i can turn down fast. The problem is.If i conenct my 2x 12+horn speakers into my 2x500 amps (bridge) the amp is going to be capable of outputing 1000w into each speaker before it clips. So clipping is not the problem i might have. The danger i want to avoid is destroying my speakers by giving them too much healthy power. If they are 300w RMS rated by the old standard. Lets say that is 800w program power by todays standard. (And that's optimistic) they won't be able to handle that much or more.

Let me put it this way. Let's say i'm connecting those speakers to an amp that can putput 3000w into an 8ohm speaker. I want the amp to give them about 450w. Maybe a little more at the peaks but that's it. Amp clipping is not what i'm going to be afraid of in that case. But overpowering the speaker is going to be a fear. How do i solve this?
« Last Edit: August 16, 2014, 09:15:06 pm by Eugen Jeličić »
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #15 on: August 17, 2014, 05:05:28 pm »

But overpowering the speaker is going to be a fear. How do i solve this?
Alcohol can be used to overcome fears ;^).
Limiters that have separate peak and RMS settings set specifically for the driver's capabilities can eliminate their being overpowered.
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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #16 on: August 18, 2014, 10:39:41 am »

Alcohol can be used to overcome fears ;^).
Limiters that have separate peak and RMS settings set specifically for the driver's capabilities can eliminate their being overpowered.

So there is no way to know when i'm going to blow my speaker with too much power other then listening to it and praying for the voicecoil no to melt?
Considering i don't have those types of limiters.
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Art Welter

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #17 on: August 18, 2014, 01:33:04 pm »

So there is no way to know when i'm going to blow my speaker with too much power other then listening to it and praying for the voicecoil no to melt?
With experience, you can learn to recognize distortion, which generally precedes blown drivers by a good margin, though it may be hard to recognize when playing music which already has a lot of distortion in the recording. Comparing the output of good isolation headphones at a lower level to the speaker sound makes it easier to hear if the speakers are being overdriven.

Drivers also tend to suffer thermal compression, as the voice coils heat up, their impedance rises, and amps deliver less power in to a higher impedance.
If you notice increases in mixer level don't result in similar SPL increases, it means the voice coils are getting hot, and when too hot for too long, they burn.
An SPL meter is helpful, if you know the system can only do "X" clean  level when it's cool, don't expect it to do any more when it's hot. You can switch between "A" and "C" (or flat) scale to see whether the level above 1000 Hz is increasing more than below.

Unfortunately, DJs  often start out near "full tilt" and then try to increase the level from there, as their hearing threshold goes up, the speakers are capable of progressively less output, which is why re-cone companies stay in business  ;).


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Eugen Jeličić

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Re: Restoring old peecker sound PA equipment. Need help.
« Reply #18 on: August 18, 2014, 02:24:19 pm »

With experience, you can learn to recognize distortion, which generally precedes blown drivers by a good margin, though it may be hard to recognize when playing music which already has a lot of distortion in the recording. Comparing the output of good isolation headphones at a lower level to the speaker sound makes it easier to hear if the speakers are being overdriven.

Drivers also tend to suffer thermal compression, as the voice coils heat up, their impedance rises, and amps deliver less power in to a higher impedance.
If you notice increases in mixer level don't result in similar SPL increases, it means the voice coils are getting hot, and when too hot for too long, they burn.
An SPL meter is helpful, if you know the system can only do "X" clean  level when it's cool, don't expect it to do any more when it's hot. You can switch between "A" and "C" (or flat) scale to see whether the level above 1000 Hz is increasing more than below.

Unfortunately, DJs  often start out near "full tilt" and then try to increase the level from there, as their hearing threshold goes up, the speakers are capable of progressively less output, which is why re-cone companies stay in business  ;).

Well thet is some very usefull info there :) Thank you very much.
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