Convert Or Add XLR Inputs To Power Amp?

[DaveThreshold]

This is almost embarrassing to ask on THIS forum. LOL But here goes..... How can I add XLR inputs to a given amplifier, which only has the usual RCA inputs? Would it be different with different amplifiers? On one of my two Threshold S-300's it has the "E" mod, which includes XLR's, and RCA's, and a switch to choose between them. That's what I would like to do to other amps.

I'm shopping for a third amp, so that I can tri-amp with me DQX-2496 xover. This would broaden the field a lot, because I would like the third amp to be balanced also.

Many thanks!

[OMNIFEX]

Why not just buy an XLR-RCA adaptor? There is no benefit adding XLR connections to a device that already has RCA other than cosmetic reasons.

[Wavebourn]

Jensen Transformers offer good transformers for such a purpose.

[lgreen]

For a solid state solution, you could use an INA134. This will take the balanced XLR signal and convert it to single ended which then goes right into your amp to use normally. It should help with long cable runs. I put XLR inputs on my Gainclone using this technique.

Here is a schematic of what i did.

[h_a]

If I understand you correctly you just want a way to hook up XLR lines to your RCA-only amp, that is just adding the connectors without additional electronics.

That means your amp has no means for a balanced signal and therefore it also has no real advantages (except if you are living in extremely noisy area so that improved interference rejection on the balanced 1m interconnect helps you a bit).

Have fun, Hannes

[DaveThreshold]

Thanks for your input everyone! (I couldn't resist.) Seriously though, I've been using adapters similar to this:

http://www.avcable.com/Merchant2/mer...R-ADAPTER-MALE

My idea of adding balanced inputs was to do away with the extra connection between the balance out, and the adapter. I'm thinking I should just do what I've been doing with the adapters. Here is another question: Does anybody know of GOLD PLATED adapters like the one in the pic, only gold? I mean gold on the rca part, and on the XLR pins. Cardas makes some, but they're $80 each. The cable I'm using is Mogami OFC, and I hate to dumb it down to the cadmium, or what ever metal that is on the connectors that I'm using now.

[carlmart]

I still don't get what you want to do, after seeing that adapter you showed.

You have a source and several power amps that you want to connect in parallel, right?

Some of those amps have balanced inputs (with XLR) and others with unbalanced inputs (RCA).

1) So you want to add balanced inputs (active) to the unbalanced inputs?

2) Or you want just to add XLR connectors to the unbalanced inputs, not adding a balanced interface?

[jackinnj]

Originally posted by DaveThreshold
This is almost embarrassing to ask on THIS forum. LOL But here goes..... How can I add XLR inputs to a given amplifier, which only has the usual RCA inputs? Would it be different with different amplifiers? On one of my two Threshold S-300's it has the "E" mod, which includes XLR's, and RCA's, and a switch to choose between them. That's what I would like to do to other amps.

All you need is a Greenlee socket cutter, a little round file and an electric drill:

[bear]

A real answer:

Please post the specific amps that you have. Are they all Threshold?

Some amps can be electronically converted to balanced input without much difficulty. Others are not so simple.

To drive most amps that can be converted requires changing the feedback configuration and then the input drops significantly in impedance. Sometimes the performance or stability of the amp can be affected negatively.

The solution using a balanced to SE opamp has some merit, but a whole lot depends on the rest of your system and what it can reallyresolve or not. For most folks the IC that does the trick is sufficiently good. (especially if you are driving things with any Behringer gear).

You can also build a sophisticated circuit using opamps to do the same thing as the single opamp converter chip.

Then too, you could go whole hog and build it up out of discretes... but we can ignore that for now.

The Jensen transformer is a good way to go. I think it "mellows" the sound a bit, but that is not bad for most people's systems anyhow. Go to the Jensen site and see what they offer - they have schematics too...

_-_-bear

[carlmart]

Originally posted by bear
The Jensen transformer is a good way to go. I think it "mellows" the sound a bit, but that is not bad for most people's systems anyhow. Go to the Jensen site and see what they offer - they have schematics too...[/B]

Lundahl is also worth investigating.

But using a transformer is not that simple either. Other mods might have to be implemented on the source.