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Amplifier suggestions?

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jwb

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Amplifier suggestions?

PostSun Apr 11, 2021 8:19 am

I need to get an amplifier to drive my 3 Johannus speakers and subwoofer. The amplifier needs to meet a few requirements:
- I need at least 4 channels. If the only viable option is 2 units x 2 channels, then that is ok, as long as the price is within budget and the noise generated by the 2 units combined is not too much.
- The 3 speakers are rated at 100W (4 ohms) each and the subwoofer is rated at 150W (8 ohms). What watts per channel should I look for?
- The amp needs to be quiet. That means either convection cooled or having a silent fan.
- The mains input voltage should be able to accept up to 240V (so no American 120V only products!)
- Total cost should be not more than $2000 approximately. I am situated in South Africa, so most likely would have to source it internationally on Amazon (or a reliable online store that ships to South Africa) if I can't source it locally. This adds a lot to cost, therefore I am looking for as cheap as possible.

For anyone using amplifier and passive speakers, what do you use? Anything that can be recommended that is quiet (and decent) and would not break the bank? My technical knowledge around amplification and speakers is quite limited and the info on the internet is also quite confusing!

Thanks
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josq

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Re: Amplifier suggestions?

PostMon Apr 12, 2021 1:57 am

Hi Jwb
Considering that...
* speaker specs are way more important than amplifier specs
* active speakers (with build-in amplifier) nowadays typically have better specs than passive ones
* $2000 is quite a budget
...I would recommend to sell the Johannus speakers, and get one or two pairs of active speakers from trusted brands like Genelec, Adam, JBL.

For subwoofers, REL and SVS are among trusted brands, but if the speakers go low enough (<50Hz) a subwoofer is not strictly needed.
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jwb

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Re: Amplifier suggestions?

PostMon Apr 12, 2021 1:34 pm

Thanks for the suggestion, josq.

I am also using a Johannus console and these speakers (although external) are part of the console. At this stage I can't replace both console and speakers and I would not like to sell the speakers separately from the console (there is no real market for that here).

The reason why the speakers can't work utilising the external audio in on the console is that it only uses 2 channels (being channels 2 and 3) and completely ignores the sub and 3rd speaker (which are channels 1 and 4). This is hard wired and can't be changed.

In my case active speakers are also not that practical since the speakers are intended to be mounted quite high up on the wall (it is in a double volume space). This makes getting electrical cables to them a bit of a problem. I guess this problem is not totally insurmountable but it will be easier if I only have to lay speaker wires and don't have to worry about any further adjustments on the speakers themselves (they will be difficult to get to after installation).

From anyone using external amplifier(s), I am still interested to know what is being used (and how happy people are with their amplifiers).
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engrssc

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Re: Amplifier suggestions?

PostMon Apr 12, 2021 1:40 pm

Overkill for you probably, I use Crown CT8150's with very good results. Likewise I have used smaller Crown amps on occasion with good results.

Rgds,
Ed
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jkinkennon

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Re: Amplifier suggestions?

PostMon Apr 12, 2021 6:42 pm

From what I've seen 4 channel amps are overpriced presumably because they are a bit of a novelty. I'd look at the two channel Crown amps in the XLS series or similar. I run the Crown XLS 2500 which is certainly larger than any of us need but going too small is the danger due to distortion artifacts burning out drivers. Better to be a bit too large. These amps are affordable and well made. Another advantage of an amp like the XLS 2500 is that the fan will likely never turn on. I've never heard mine. As likely the most popular range of amps in existence they are surely available locally.
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dw154515

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Re: Amplifier suggestions?

PostMon Apr 12, 2021 8:54 pm

Drew A. Worthen
Master of Music in Composition - Butler University
http://www.drewworthen.com
Director of Music & Website Admin - Greenwood UMC
http://www.greenwoodumc.org
Design Engineer - American Sound and Electronics - Indy
https://americansound.cc/
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larason2

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Re: Amplifier suggestions?

PostMon Apr 12, 2021 9:41 pm

If all your speakers work with the Johannus, then your johannus has the appropriate amplifiers built into the console. It therefore makes more sense to get a small mixer like the Behringer Xenyx 1002FX or the Yamaha MG06x and mix the Johannus built in input and the external input you wish to go through the speakers into the existing amplifiers. You’ll have to fiddle around more inside the organ, but you’ll save a lot of money, and you won’t have to take down the speakers.
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engrssc

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Re: Amplifier suggestions?

PostTue Apr 13, 2021 9:11 am

My experience is that Johannus amps in their lower and mid class organs leave much to be desired. For example the frequency response is not linear but more or less skewed to the Johannus system of tone generation. There is a marked difference when playing HW thru a Johannus amp even with relatively good to excellent quality passive speakers as opposed to the same HW setup using Crown amps. It's all in the ear(s) of the beholder. :roll: I can't speak to the high end Johannus sound systems. :|

In an installation some time ago, due to budgetary issues, the client initially used the built in Johannus amps and were disappointed in the results of (in their words) - The highly acclaimed Hauptwerk software.. My comment - Don't blame Hauptwerk.. Later after just "upgrading" to a Crown CT4150, they (all) were amazed at the difference. For one thing in clarity of the speech and in the very natural, detailed sound.

There are no built in cooling fans., not needed., amp runs exceptionally cool even at full rated power - 125 watts.

These amps have a built in feature of being able to (remote control) mute and unmute the speaker outputs allowing for being able to silence the speakers while listening via a headset.

A review of the 8 channel version CT8150

https://www.youtube.com/watch?v=yzK_p70BC8w

Rgds,
Ed
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magnaton

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Re: Amplifier suggestions?

PostTue Apr 13, 2021 2:40 pm

I agree with Ed, and have mentioned this before: digital organs (mainly Johannus, Rodgers, and Allen) have their amps, sound source, and speakers all deigned to work as an integral system. You can get unsatisfactory results when trying to swap in a something different into this set chain. I heard an Allen home installation where all the speakers were Bose (no Allen speakers) because the owner was retired from the company and had access to any speakers he wanted. As you can imagine, it sounded different, more colored, and lacked a lot of the mid range you'd expected to hear.

I've only heard Johannus speakers when attached to their organs, so you'd have to report back to us how they work with HW. Here is another option for a 4 channel amp. This is a quiet unit and I think read somewhere that the fan only comes on when needed.
https://www.parts-express.com/ART-SLA4-Power-Amplifier-245-8628?gclid=Cj0KCQjwgtWDBhDZARIsADEKwgNFV61UdBA6Wk4-puAFw90dxaKGJ_0PHHiYg9H2d0JQb4lPR4lyVwQaAh21EALw_wcB

Danny B.
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engrssc

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Re: Amplifier suggestions?

PostTue Apr 13, 2021 4:04 pm

engrssc wrote:There are no built in cooling fans., not needed., amp runs exceptionally cool even at full rated power - 125 watts.


To clarify that statement, I was referring to the Crown DriveCore™ series of professional amplifiers. None of them have or need to have cooling fans and thus are completely silent (and run very cool relying on convection as the form of cooling). 8)

BTW, Rodgers used these Crown amps in their high end organ installations. That is before Rodgers was bought by the parent company of Johannus.

Rgds,
Ed
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jwb

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Re: Amplifier suggestions?

PostWed Apr 14, 2021 11:53 am

Thanks for all the feedback. I have been looking at the Crown CT8150, but it is just too expensive. It is not available here in South Africa, and I would need to import it. With shipping, taxes and import duties, it comes to more than $3300. Also, it is rated with max power of 125W which is less than the subwoofer's 150W (RMS). I read somewhere (I think on Sweetwater) that the amp should be more powerful than the speakers to allow for some headroom (they recommend double). Having said that, I highly doubt that I will ever play with the speakers at max volume (with the Johannus digital organ, around 2/3rds of the max volume it gets too loud for me).

So far the best option seems to be the 2 x Crown XLS 1002 (which is smaller than XLS 2502, but would still have ample headroom at 350W per channel). The alternative would be Crown CT 4150, but it has the same power rating (125W per channel) as the CT8150.

The Behringer NX4-6000 looks also good. It would be the most cost effective solution. I am just concerned it may be too powerful (about 8 times the speakers rating - not sure how much that can be an issue) and how noisy it is.

Jaco
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engrssc

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Re: Amplifier suggestions?

PostWed Apr 14, 2021 10:21 pm

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jkinkennon

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Re: Amplifier suggestions?

PostThu Apr 15, 2021 9:58 am

jwb wrote:So far the best option seems to be the 2 x Crown XLS 1002
...
The Behringer NX4-6000 looks also good.


I've used the Crown XLS 1002 to drive an efficient HT Tuba sub with one channel powering the sub and the other feeding a wide range PA speaker to produce the high pedal tones. It's a great amp.

The Behringer looks good and their amps seem to be reliable -- well, based on one job where we use five of them. Certainly the price is right.

I've used Dayton plate amps and they have been reliable for me. They won't go down to 16 hertz due to internal filtering but that is probably not an issue with a Johannus sub.
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Romanos

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Re: Amplifier suggestions?

PostThu Apr 15, 2021 10:50 am

You could get a separate dedicated subwoofer amplifier from somewhere like Dayton audio... that might behave better for that particular speaker.

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