merlin 410 paging with home amplifier

[drunkphoneman]

I have a Merlin 410 with a recently installed, (Refurb) paging card. I have the system connected thus:

XM radio connected to the M1 M2 ports, (100 ft. run from source on doubled 24 AWG.)

T and R connected to the AUX in port via RCA cable to a 100 watt amp, (Again 100 ft. on doubled 24 AWG.)

I get music on hold, overhed music and paging, but I have to crank the amp to nearly 100 % to hear it clearly.

Of course, this is going to burn-out my amp, but I'm not sure where the signal is failing.

A few other notes:

With XM connected directly to the amp I can run at 40 % and have good sound quality

I have an 8 pair speaker selector connected to the amp via spk 1 and spk 2 connectors running to 16 8 ohm speakers.

all speakers are 8 ohm house speakers, (No volume control, though ceiling mounted.)

The speaker selector gets -extremely- hot running at 90+ %.

My butt set picks up the feed from the system, (While standing at the amp) though 2/3 regular volume versus off of the XM directly.

I have heard rumors of a resistor or transistor that can cure this, but nobody is sure of the size.

Any help is greatly appreciated!

 

[dagwoodsystems]

The volume problem is due to an impedance mismatch between your Type II cartridge and your amplifier.

The “T” and “R” terminals on the Merlin 410 cartridge provide a 600 ohm, dry balanced output. However, the AUX port on your amplifier is expecting an 8 ohm unbalanced signal.

The mismatch is cured by something called a matching transformer. A very popular one that's designed to solve this very problem is the Bogen WMT1A (see

http://www.bogen.com/products/pdfs/specialelectronicspdfs/WMT1As.pdf).

But before you go buy anything, check to see if your amplifier has a "telephone" input. If so, then simply connect the T&R from the cartridge to that input instead.

Tim Alberstein

http://www.dagwoodsystems.com

 

[drunkphoneman]

Thanks, Tim,

I'm new to the group and hadn't noticed your reply until this evening.
I have heard the 600 ohm term from several folks, (Even one guy that said "It's a balanced unbalanced thing, but I can't remember what you do.") so I am glad to see you have it nailed down.

The amp I am using doesn't have a telephone input so I will check with my local suppliers tomorrow and see what I can dig-up.

I'll post the results by Friday.

 

[Dexman]

Bogen makes some nice paging amplifiers.

http://www.bogen.com/products/telephonepaging/

My church uses a TPU100B in conjunction with a Merlin Magix telephone system and the results are quite good.

If it ain't broke, I haven't fixed it yet.

 

[drunkphoneman]

A follow-up to Mike's suggestion on the Bogen transformer.

I purchased the transformer for $30 from my supplier and installed it, the volume returned and sounds clean throughout the facility. All speakers are at 100% for music and paging.

Thank-you thank-you thank-you

I contacted my client the night I noticed the reply to discuss the option of the transformer. He said he was currently online and about to purchase a $400 amp.

Man,timing can make or break a relationship!

Many thanks to Mike at dagwoodsystems.com, if somebody in CA needs a good Tech, check him out.

 

[dagwoodsystems]

Thank you!

And the name would be Tim...there's no Mike here, but I'm glad to be of help nonetheless (perhaps the handle "drunkphoneman" played a part in the name mix-up? Happy Friday, my friend!)

The other fellow who assisted with good advice is Paul, aka Dexman. I've spoken to Paul many times.; he is a real gentleman who is always willing to help.

Tim Alberstein

http://www.dagwoodsystems.com

 

[Dexman]

I think I'm getting a swollen head.

If it ain't broke, I haven't fixed it yet.