I want ot A/B pre-amps- how?

[drummergrl]

What kind of switch can be used to set up 2 preamps into one amp to compare back and forth?

 

[Northwinds]

Maybe a source selector with both preamps plugged into it? The below one is like $150 and made in the USA (no affiliation)

http://www.bhphotovideo.com/c/product/637949-REG/RDL_EZ_HSX4_EZ_HSX4_4_Channel_Audio_Switcher.html

 

[prighello]

Wont the gains be different thou?

 

[Northwinds]

I would imagine she would have to preset the gains on both preamps first to as close as possible. She would need 2 CD players also, one for each preamp, best scenario both same models

 

[Duane]

I have one of these, a JVC JX-S300. They can be found on Ebay. Comes with a remote. Switching between inputs is silent. Very good option for A/B testing.

http://support.jvc.com/consumer/product.jsp?modelId=MODL003015

 

[sqlsavior]

You'll need to switch both inputs and outputs. This does it:

http://www.avahifi.com/index.php?option=com_content&view=article&id=271&Itemid=259

IMO, rapid A/B switching is of limited value. As you approach the high-end, the switch itself becomes a question mark, even at the Comparator price-level. Rapid A/B switching is nice for comparing overall tonal balance, but for comparing between better units, there's nothing like getting really used to one (like for a couple of months) and then switching. Improvements are easier to recognize than downgrades, or sideways moves, in that scenario, in my experience. If you're not very pleased with a new piece, and hearing new things on old recordings, it's not an upgrade.

If your sources are robust, here's the budget "preamp" to beat:

http://www.promitheusaudio.com/tvc.htm

 

[Rob41]

You'll need to switch both inputs and outputs. This does it:

http://www.avahifi.com/index.php?option=com_content&view=article&id=271&Itemid=259

IMO, rapid A/B switching is of limited value. As you approach the high-end, the switch itself becomes a question mark, even at the Comparator price-level. Rapid A/B switching is nice for comparing overall tonal balance, but for comparing between better units, there's nothing like getting really used to one (like for a couple of months) and then switching. Improvements are easier to recognize than downgrades, or sideways moves, in that scenario, in my experience. If you're not very pleased with a new piece, and hearing new things on old recordings, it's not an upgrade.

If your sources are robust, here's the budget "preamp" to beat:

http://www.promitheusaudio.com/tvc.htm

Aside from the recommendation of a preamp for a very specific listener/system, this advice is spot on. While preamps lower in the food chain will often be clearly differentiated during an A/B test, the higher in the food chain you go the less discernible the differences become.

The OP may desire a vintage preamp, a preamp with a sub output, tubes, discreet, etc.

 

[drummergrl]

If your sources are robust, here's the budget "preamp" to beat:

http://www.promitheusaudio.com/tvc.htm

strangely cool looking, would love to try one out some day

 

[E-Stat]

You'll need to switch both inputs and outputs. This does it:

And for a much more important reason: 99% of switch boxes use common grounds. So what? You end up comparing A+B to A+B rather than A to B!

It is for that reason the vast majority of DBTs are bogus. You get equally mixed results when you attempt to compare cables using a Y adapter. In that case, I've measured the results - you end up combining the metrics of both cables at both ends.

The best way is to compare them separately, but minding the gain so that you have a valid comparison. Also, I find that rapid Audio Cowboy switching provides no value. Listen to each for extended periods of time with content you know very well.

 

[jheu02]

If you have help to do it, you can have someone physically change cables. Audio memory should be good enough to tell a difference if there is one. You just want to make sure YOU don't know which is which and then listen for differences.

 

[62vauxhall]

I see you popped up here and still dancing with preamps. This will probably be frowned on, but I used a cheap $15 Made In China phono/turntable switch. It is intended to connect two turntables to one amp but I used it to connect two preamps to one power amp.

With two RCA "Y" connectors, I split the output from one signal source (turntable in my case) and plugged each into both preamps. The preamp outputs went into the phono switchers turntable inputs and it's "To Amplifier" outputs went into the power amp.

I needed rapid switching in order to tell a difference because my acoustic memory is short. I'm sure that my method will get shot down, but it worked for me. One thing to be cautious of is to operate the switch gently. It is after all pretty much a piece of junk and I found that "hard switching" made a disturbingly loud "CRACK".

 

[E-Stat]

I found that "hard switching" made a disturbingly loud "CRACK".

What that tells you is that you are listening to characteristics of both preamps al the time.

 

[BigElCat]

I have one of these, a JVC JX-S300. They can be found on Ebay. Comes with a remote. Switching between inputs is silent. Very good option for A/B testing.

http://support.jvc.com/consumer/product.jsp?modelId=MODL003015

I saw these at close-out prices on Ebay. They make one with a volume knob, too, a passive pre. Very interesting. I wish there was one with digital inputs. I'd buy it ASAP.

 

[BigElCat]

I would imagine she would have to preset the gains on both preamps first to as close as possible. She would need 2 CD players also, one for each preamp, best scenario both same models

Find a source selector with dual outputs, I have a Radio Shack one that does. You would need two of them, one for the sources, and one for the Pre-Amps.