Peavey phantom power: +15V?

[Rhodesplyr]

The owner of a small performance space nearby has kept asking me if I would take a look at his Peavey XR-680C mixer amp because the phantom power wasn't working. I checked it one day and found +15V at the XLRs rather than +48V. A group with a condenser mic had tried to use their mic with this mixer and found that their mic wouldn't work.

I figured something was wrong with the supply, so I looked up the schematic and found that the phantom power supply comes from the +15V regulated rail, so it's apparently working like it was meant to.

I'm guessing that this was only designed to operate something like an active direct box. Would there be any other explanation?

The guy actually has a nice Alesis mixing board, but he's thus far stonewalled my recommendation (and the recommendations of about three other people) to use it instead of the Peavey, saying, "It's too complicated." Maybe this will break down his resistance.

[km6xz]

Electret elements will work on 15volts so for most bands and solos with condenser mics are probably using that style mic instead of true condenser mics. Mics that need 48 volts are usually not used in such venues where they are subjected to smoke and breath blast. Did he say the model of mic that did not work with 15v?
A couple nights in a smoke filled club would deposit enough smoke born ash and tar to require expensive cleaning of the capsule
The owner might have a point, less to break and a lot more reliable of a unit that is almost musician proof compared to the fragile Alesis mixers. Most of the Alesis mixers sounded pretty good however but were not road worthy, or live venue sturdy.

[Rhodesplyr]

What happened in this case was that an acoustic group came in to perform and wanted to use their own condenser mic, which they brought with them, and they gave the owner a lot of grief about why, when they turned the phantom power on, it wouldn't make their mic work properly.

This is a small performance space, more like a large living room than a venue--and smoking is not allowed. (In fact, smoking isn't allowed in restaurants or bars at all around here anymore--much to my relief since I'm allergic.)

As for reliability, the XLR connectors on this particular Peavey have a tendency to come apart. The owner's main argument for using it is that he paid someone a lot of money to refurbish it, which wasn't done very well, in my opinion, since some parts of it still don't work right.

One group of friends of mine did a show there, and I brought in my old Mackie VLZ-1202 (old enough to be US made, I think) and a Crown power amp. The difference was not subtle.

[Mark Black]

I would think that if aforementioned acoustic group was serious about using their pet condenser microphone anywhere & everywhere they would own an inline phantom-power module, but maybe that's just me being a grumpy old sound guy...

I periodically see mixers that have something less than 48V available for phantom. Definitely a cheap-out on the part of the manufacturer, but as km6xz mentions will work for a lot of the cheaper mics.

[Rhodesplyr]

I would think that if aforementioned acoustic group was serious about using their pet condenser microphone anywhere & everywhere they would own an inline phantom-power module, but maybe that's just me being a grumpy old sound guy...

No, I agree with you completely. And, from what everyone said, they used the house's Sennheiser dynamic mics and sounded great...

[km6xz]

The Alesis will not be very rugged but will sound better than the Peavey, and your Mackie is built better than either. You Crown obviously was a better choice for power also, apples and oranges sort of comparison. The Peavey has the advantage of being simple and hard to set up wrong by visiting musicians. After being a warranty station for all the brands mentioned, I would rate the Peavey has being more reliable and tolerant of abuse of what he has now. The EQ of the Peavey is a bit murky sounding however. The current problems with the repair should be addressed with the shop that fixed it. If the sections not working never worked, the shop, if they had any integrity would take care of it even if out of shop warranty. But as we all see, a lot of people will accept work but not know anything about the application or the specifics of the device. There really are not very many competent techs or shops in the country. By the way, the modular Peavey XLR jacks are easy and very cheap to replace. Of all the companies Peavey is the best for getting parts and for having reasonable prices. Order a couple jacks and keep them on hand.
If they do not have the visiting musicians fiddle with it, the Alesis will sound pretty good and be usable. If be wants a reliable but disposable mixer, a Behringer cheapie is hard to beat for cost/performance ratio. One could be had for less than a repair charge on a mixer. But the decision is the owner's and he might have other criteria that is unknown by any of us.
If one really wanted musician proof mixers they would look for a very old Tapco no frills mixer with rotary faders...most built several decades ago are still running in bars and theaters now, covered in dust, kitchen grease, and dried beer. The rotary faders are 400% more resistant to dirt, abuse and physical damage than a linear fader. Next to in in such hostile venues was a CS800 Peavey amp most often. The Tapco's were not versatile or fancy but they were as bullet proof as they came.

As a bit of trivia: For live mixing, rotaries are faster than linear faders so old radio and sound men still prefer them. Linear faders are much more prone to breakage and accumulating. The rotaries also had the advantage of smoother fades and cross fades than anyone can fade a linear because those require whole arm movement. The human arm is a great tool but when used to apply only a slight pressure or tension, smoothly, due to the large muscles involved and the resolution of the feedback system, there is constant jitter. Fingers and hands match to light force needs with much greater precision. Digital mixers, in mastering, often resort to auto fade functions for song fading between cuts because you can hear manual 100mm fader lack of smoothness when done manually. That was never a problem for rotary faders.