Power amplifier question

[Silken Path]

Greetings. I'm trying to run a front and rear stereo configuration for Hauptwerk. On the front, I have two Behringer Truth 3031a monitors. At the rear, I have my -145 Conn pipes. These are the tall, mid-range model with four oval speakers in each. I'm using the variable bypass in my subwoofer and a small amp to provide the signal to drive the pipes.

Alas, I have killed a couple of inexpensive 100-watt-class compact Chinese amplifiers. The latest one doesn't have ANY return information in the manual, and it has expired on the 56th day. (The previous one worked for about a year and a day - just long enough to be OUT of warranty.)

So, enough is enough. I think I need to give it up with these Chinese cheapies. So... what would work better for me? It needs to have RCA inputs for this task, but I'd like to have XLR and balanced 1/4" as well, with a banana-plug/bare wire output. So far this one seems to be ringing the right bells.

https://www.sweetwater.com/store/detail/XLS1002

But is it overkill? Simply too powerful for the speakers in the Conns? (The previous amps were 60x2 and 80x2 @ 8 ohms, and the speakers were happy enough.)

Also, I saw where one representative for a Chinese amp in a comment thread on Amazon said not to run the speaker wires in parallel. Gee. Is that common advice? I certainly have the twin-lead for the Conns run side-by-side to the rear of the room.

[Tim_at_Jonas]

I expect that they meant not to connect the outputs together, though if the output stages are of questionable stability, I suppose it would be possible that there would be enough coupling between them via the cables touching to make them go nuts and blow.

I expect that these amps were not meant for a signal that is as dynamic as the organ, nor a signal with as much sustained signal. The XLS you liked to, or an equivalent Behringer 'Nuke' series, should do the job.

[John Kinkennon]

The Crown XLS1002 is a good solid amp that isn't going to break unless it is seriously abused. Don't be concerned about power ratings being too high. Speakers are more often destroyed by amps that are underpowered and driven so hard they go into clipping and release tons of high frequency energy into the speakers. I'd consider the XLS1002 a perfect match for your application. I've used both this small amp and the largest amp in this series, the XLS2500. I believe they change the model numbers (2500, 2501, 2502) and styling almost yearly.

[Silken Path]

Thank you, gentlemen. I'm going to order the Crown amp.

Tim, it was a real cheapie -- WAY too feature "rich" at the price -- so I suspect you're guessing correctly about coupling between the cables.

John, thanks, I was wondering if the 215 watts the amp makes at 8-ohms would blow the speakers sky high.

I like that the Crown has an adjustable bypass. I would like to keep the bass tones out of the Conn pipes (although somebody here has talked about putting modern automotive speakers in), and I've never been convinced the adjustable bypass on my (home theater) Sunfire DS subwoofer worked correctly. I'd think that I'd be able to hear movement from the sub to the pipes doing scales up from the bottom, but so far I haven't.

[jbird604]

For a less expensive option, here's a simple two-channel amp from Parts Express that is far better than the cheap Chinese amps. I have bought two or three of these and used them in organ installations and for organs at home at different times. A very basic home amp, no frills, but seems to put out a ton of power, and sound is pure and clean.

https://www.parts-express.com/dayton...to-on--300-591

[Silken Path]

Thanks, John - out of stock - guess a bunch of forum members read your post before I did. :)

Gee. I already ordered the Crown. (They hook you in with videos, downloadable manuals, and brochures... I'm ready for it!)

[Eric Mack]

I purchased the bare board 6x100 watt amplifier from PE and a Meanwell 40 volt power supply from Amazon. Both inexpensive. Works great so far. And, I eliminated a bunch of external amps

[jbird604]

I've often wondered if those barebones Class D amps from PE can really do the job. I have bought a few of the low-cost "Lepai" amps that are said to produce 10 to 40 watts or so, depending on the model and the power supply used. The seem to be ok, though I've not put one to the real test of using on a large organ installation. But the ones that claim to put out several 100 watt channels are certainly intriguing. How hard have you driven yours, Eric? Does the sound stay clean even at high levels?

[Silken Path]

"Lepai" amps are in the same class I keep blowing up just running my ancient Conn pipes. Somebody told me that almost all the brands of these amps sold at Amazon and discount outlets are assembled in one huge city in China and workers and engineers flow from factory to factory continuously. This was also the home of hover boards, he claimed, a couple of years ago.

When I was young, I never imagined hover boards would have wheels. :)

[Eric Mack]

Hi John, as you know, I am very much a beginner. But, so far everything with this 6x100 amp appears to work. Here's a link to my recent voicing tests. The first video as a quick tour that shows the amp installed, too. The only modifications I made were 1) I replaced the power supply fan with a larger silent model (which explains the blue led) and I added a patch panel so that I can experiment with different speakers on different channels. http://www.thisold340.com/

[John Kinkennon]

I like that the Crown has an adjustable bypass. I would like to keep the bass tones out of the Conn pipes .

That is a great feature. I've used this amp to power a big Tuba HT subwoofer with one channel and used the other channel to feed higher frequency pedal tones to a second speaker. On the second channel I used the high pass filter to remove everything below 80Hz. With the ultra efficient folded horn sub the Crown XLS1002 has enough power to drive it to insane levels.

[Silken Path]

That's interesting, John.

I love my Conn pipes. I know that they're considered "low fi," but I like the kind of metallic, "blotty" sound they make. The fellow that I bought them from, a young, pretty terrific organist at a Lutheran church in Tampa, was using them "off the back" of an immense old Peavy or similar amp at his house. He estimated that that circuit was providing up to 100w total to the pipes.

The pipes, with this FX-Audio amp that has died, actually provide more mechanical noise from some organs (notably the Melcer Chamber Music Hall) than my much better front speakers. Hearing the pedals clunk and the stops bang in the back is sort of opposite what the person at the organ would expect. Thus I'm thinking of rearranging things to get the pipes much closer to me and then get something like two of the 20-series Truths to provide the back. This would then become surround sound after I get a better USB sound card.

Right now I'm using an inexpensive USB sound adapter that I got to prevent the wear and tear of plugging into the headphone/mic jack on my ThinkPad. It leaves a little to be desired. I have another one that I got for the same reason on my smaller ThinkPad Yoga -- it's one of the educational models you can run over with a car - and I'm wondering if I can get ASIO4All to recognize them both at the same time.

[kennyrayandersen]

Anyone had any luck with either a 2-channel amp with an electronic xover and a preamp out for the bass, or a 4-channel amp with a built-in cover? I'd like to bi-amp my stereo organ out to run the SATs and subs and it would be nice to do it with one box.

[John Kinkennon]

Anyone had any luck with either a 2-channel amp with an electronic xover and a preamp out for the bass, or a 4-channel amp with a built-in cover? I'd like to bi-amp my stereo organ out to run the SATs and subs and it would be nice to do it with one box.

Two of the Crown XLS series of 2-channel amps would be easy to use, similar to what I described earlier with matching high pass and low pass filters for the two channels. Use one amp for each speaker/sub pair. There aren't a lot of affordable 4-channel amps, but the Behringer unit is one obvious exception. It has a selectable crossover function which is fixed at 100hz which is about right for smaller speakers used in conjunction with subs. It should work well. I have no experience with discreet crossover units though there's no problem using them in theory.

[kennyrayandersen]

Appreciate the input John. It looks like one could bi-amp with the Behringer 6000 dsp as well without an electronic x over and though not crazy expensive at $350, is not insignificant. I already have a 200W/channel amp sitting there all lonely and all... I guess I could also look into a budget electronic x over and a less expensive amp for the satellites as another option... Lots of ways of skinning that car I suppose. If I didn't have that amp sitting there I wouldn't even hesitate on that NU4-6000!