15335A or 15095A? Help me pick one

[CaribMissionMan]

I've loved the sound of old Altec gear for years, and I've just jumped into the deep end of the pool by purchasing some items off of eBay and attempting to put them together into a PA system for our churches here in Saint Lucia.

I have purchased
ONE - A7-500-8 VOT (w/ 511B horn, 808-8A HF driver, 416-8A LF speaker, N501-8A crossover in a 825B cabinet)
TWO - 1594B amps,
TWO - 511B horns with 904-8A drivers
TWO - 811B horms with 808-8A drivers

Right now, I trying to figure if I need a pair of 15095A or 15335A transformers to use in the pair of 1594B amplifiers I got. They sound great just wired for high impedience input, but I'm not likely to keep things that way.

My Mixer (a Mackie 1402 VLZ) has both Mic level (balanced) and line level (unbalanced) but which should I use with the 1594B and which transformer should I go with?

I would like to purchase some new 515's from Great Plains Audio and build some additional 825 cabinets to go with the 511's. But that is down the line yet.

Give me your advise guys.

[bfish]

Welcome, Reverend!

If your system gain and noise levels are satisfactory with it wired direct, you won't need to use transformer isolation, and you won't experience the accompanying -6dB insertion loss. The 1594 is a high impedance input amp, so it can be driven by most devices with equivalent or lower effective output impedance. If you needed isolation, you'd use the 15095A in the 1594 if the driving device was a low impedance (~600 ohms), or a 15335A if it's a high-impedance output.

[CaribMissionMan]

It DOES work very well wired directly, but you asked if I "needed isolation". To be honest, I don't know if I do or don't. I understand that by inserting a transformer, I isolate the signal from the amp, but I'm not sure why I would choose to do so or not. (differing ground potential?, hum elimination?) Can you explain the reasons for each option?

Thanks, from sunny Saint Lucia!