Preamp with multiple outputs

[Ramarge3653]

Hello,

I have a question regarding my current preamp with only one output. I'm using the Dynavector P75 as my preamp and it only has 1 output. I recently added a Woo Audio 6 SE as my dedicated headphone amplifier, however anytime I want to use the headphone amp I have to disconnect the RCA cables from the output of my P75 which is connected to my Outlaw RR 2150 for my 2 channel speaker setup, and plug a new set which are running directly into my Woo Audio Amp. I really wish this preamp had at least 2 outputs and then a toggle switch to select which out I want to use, but unfortunately it doesn't. I honestly don't mind physically disconnecting the cables whenever I want to listen to my headphone amp, but I'm sure after time either the connection on the preamp or the cables will physically become worn. Honestly, on average I probably switch the connection 2 times per week. I'm hoping someone will reply with, "Disconnect all you want it won't hurt a thing" because I honestly love the P75 preamp and don't want to upgrade to a new preamp with multiple outputs.

Any thoughts on the wear and tear of disconnecting the RCA cables?

[josephazannieri]

Yo Ramarge3653:

If you are willing to build it, you can make the switching by putting a DPDT switch in a small metal box and running the wire right to the different places it needs to go. I will be happy to give you the design. It is the same one that I use to choose between the two arms and cartridges on my Garrard 301, just turned around backwards. Give me a PM with your Email address, and I will send you the design.

In this application, you can also use one of those cheap input-selector AV switches and turn it around backwards. Me, I just build 'em.

And good luck from that backwards old guy,

Joe Z.

[analogaudio]

Have you considered another possibility, using a splitter cable plugged into the preamp output, presuming regular RCA type cables you need a pair with one plug that ends in two sockets, Radio Shack should be your first stop. With this in place you can listen to either amp, both are driven by the preamp at the same time, quite OK.

Ted

[Ramarge3653]

Thanks for the reply. I prefer the idea to having a toggle switch vs. the splitter option. I really don't want to have a rigged up solution, I really would prefer a professional installation of an additional set of RCA connections, and a toggle switch to switch between the 2. I honestly don't feel comfortable performing this upgrade myself and would really like to send it to a custom audio shop that handles this type of customization. Can anybody reply with a known shop that is willing to handle this type of project?

Thanks in advance and thanks a lot for the info so far.

-Matt

[Ramarge3653]

Have you considered another possibility, using a splitter cable plugged into the preamp output, presuming regular RCA type cables you need a pair with one plug that ends in two sockets, Radio Shack should be your first stop. With this in place you can listen to either amp, both are driven by the preamp at the same time, quite OK.

Ted

Does this reduce the signal quality? I honestly don't know and just assumed that using a Y splitter would degrade the sound. Any thoughts or inputs on this? If it is proven that the Y splitter doesn't affect sound then this is by far the easiest solution ever.

Thanks,
Matt

[duficity]

very few preamps with dual outputs have a switch to toggle between them. However, you could just turn off the amp you werent using and listen to the one you want. I have a couple of Nikko Beta preamps that have dual outputs, Beta 1 and III. Let me know if you are interested.

[analogaudio]

The answer to the question about quality can be approached two ways, theory and practice. The theory is that it depends on the output impedance of the preamp in question, this is not always stated in the manual, but it will probably be somewhere in the range 100 Ohms to 1000 Ohms, lower (100) is better. This specification has been around for decades and is easliy achieved by active preamps using both IC, discrete transistor active stages, tube equipment is likely to be on the high side of the range.

The input impedance of the amplifiers being driven are most likely in the range 10000 to 100000 Ohms and the combination of two in parallel being driven at the same time is therefore between 5000 and 50000 Ohms. These impedances are easily driven by the preamp spec above, the difference between loading with one amp or two is very likely below the threshold of measurement and audibility. If the preamp does not have output impedance in the 100 to 1000 Ohms range, such as passive devices, the above does not apply.

In practice in the very unlikely event that some mismatch occurs you will hear the consequences in the form of reduced headroom (premature overload distortion).

People may be nervous about splitters because of the risk of connecting two outputs to each other accidentally. No damage occurs but the distortion can be pretty severe, of course it disappears as soon as the mistake is undone.

Ted

[LPspinner]

Have you tried feeding the input of the Woo Audio 6 SE headphone amplifier from the tape outputs from the Outlaw RR 2150 Receiver and leave the rest of the system configured as it would be for normal loud speaker listening ? This will allow you to use the Woo Audio 6 SE headphone amplifier with all sources and the inconvenience of swapping plugs should be eliminated.

Hope this helps.
LPSpinner