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How to connect turntable to two phono preamps?

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Posted on November 26, 2020 at 13:10:03
clarets2
Audiophile

Posts: 79
Location: CA
Joined: March 31, 2006
 I would like to connect my VPI Scout TT to two different phono preamps without denigrating sound quality and also without a switch if possible.
This will allow on the fly a/b comparisons through my main preamp.
Ideas as to how to achieve this please.

 

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RE: How to connect turntable to two phono preamps?, posted on November 26, 2020 at 14:49:05
immatthewj
 Could you use an RCA 'Y' jack out of the turntable?
I'm not sure if that is allowable or not. & then you still need to get both preamps into your amp. I'm not sure if you could put 'Y' jacks on back of your amp or not.

 

RE: How to connect turntable to two phono preamps?, posted on November 26, 2020 at 15:41:58
Tre'
Industry Professional

Posts: 17305
Location: So. Cal.
Joined: February 9, 2002
 Assuming that each phono preamp has the usual 47k ohm input impedance, the cartridge will see them both at the same time in parallel. The cartridge will see 23.5k ohms instead of 47k ohms and that will change the performance of the cartridge.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: How to connect turntable to two phono preamps?, posted on November 26, 2020 at 15:43:31
PAR
Audiophile

Posts: 1732
Location: South London, UK
Joined: June 4, 2019
 You do say " without denigrating sound quality". You will find this very difficult to do and to maintain the correct electrical matching of the cartridge's output to the two phonostages' inputs. Just simply try your pickup arm's cable with connection via a "Y" connector compared with directly into a phonoamp. You may be astonished how much the extra connectors and wire screw up the sound.

Further I really don't think that rapid a/b switching will tell you much about how good a preamp is going to be as a long term partner for your turntable anyway. It will reveal differences but that is not the same as revealing which is best. So many people have made what they later find out are bad choices by using such a method of comparison. It is also why the "comparator" (a switching system to immediately compare different equipment combinations used in virtually all audio stores - at least here in the UK - during the late 1960s and early 1970s) is no longer to be found.




"We need less, but better" - Dieter Rams

 

RE: How to connect turntable to two phono preamps?, posted on November 26, 2020 at 18:06:42
clarets2
Audiophile

Posts: 79
Location: CA
Joined: March 31, 2006
 I was just hoping to have a choice between preamps as they sound very different to me and are material dependent i.e. jazz vs classical or tight vs ambient recording
What about this as an option?
https://soundapproach.com/rek-o-kut-low-noise-stereo-phono-aux-switch.html

 

RE: How to connect turntable to two phono preamps?, posted on November 26, 2020 at 22:50:23
PAR
Audiophile

Posts: 1732
Location: South London, UK
Joined: June 4, 2019
 The switch makes no difference to the technical point that both I and Tre' make about maintaining the correct electrical matching between the cartridge and the phono input. It offers no solution. On the other hand I suppose one could say that it may be equally bad for connecting either phonostage.

The way I would look at your problem is simple: If one phonostage is only good for one type of music and the other only good for another type of music then neither are any good. A phonostage, or any piece of audio equipment, should be capable of satisfactorily rendering any kind of music (or speech for that matter).


"We need less, but better" - Dieter Rams

 

How deep are your pockets?, posted on November 27, 2020 at 06:06:23
Phil_S
Audiophile

Posts: 1145
Location: Washington DC
Joined: July 17, 2003
 This will do the trick for you.

 

RE: How to connect turntable to two phono preamps?, posted on November 27, 2020 at 09:30:14
mlsstl
Audiophile

Posts: 1079
Location: Midwest
Joined: September 1, 2015
 Basically, if you want to quickly A/B two different phono preamps using the same turntable without plugging in/unplugging cables, your only options are to either connect the turntable with a Y cable or use a switch.

As other have already noted, either way has its problems since phono cartridges are sensitive to both the impedance and capacitance loads. Most moving magnet cartridges need a 47Kohm load. Using a Y cable into two preamps will cut that load in half and change the sound of the cartridge.

OTOH, using a switch leaves the load at 47Kohms but puts the switch in the signal path and also adds an extra length of cable from the switch to the preamps, which will increase capacitance. This will also affect the sound.

Of the two, I think the switch option is the lesser evil. After you do your back-to-back comparison, I'd then recommend you give an extended listen to each setup without the switch and see if your initial conclusions hold up. It is possible that the increased capacitance would adversely affect one preamp more than the other.

 

RE: How to connect turntable to two phono preamps?, posted on November 27, 2020 at 09:56:15
fstein
Audiophile

Posts: 2996
Location: fstein
Joined: May 18, 2006
 Schitt Sys
$49

 

RE: How deep are your pockets?, posted on November 27, 2020 at 15:53:58
clarets2
Audiophile

Posts: 79
Location: CA
Joined: March 31, 2006
 Ouch! Not that deep!
I was thinking of this
https://soundapproach.com/rek-o-kut-low-noise-stereo-phono-aux-switch.html?gclid=Cj0KCQiAwf39BRCCARIsALXWETxjlH2XY1O7poYENWleoj3O8GRhA4OZO4ipW0Hgffj-K89Pta7_UIMaAocFEALw_wcB

 

RE: How to connect turntable to two phono preamps?, posted on November 27, 2020 at 16:01:06
clarets2
Audiophile

Posts: 79
Location: CA
Joined: March 31, 2006
 And yet many of us have different cartridges and choose to load them differently in different situations with different pressings or music.
You live in a very narrow or massively expensive audio world if you can live with single choices at every level for all your audio sources.
I'm just trying to fins a way to simply live with 2 excellent phono stages for a while. One may win me over or I may move on.
I may end up manually switching the RCA connections or may experiment with this
https://soundapproach.com/rek-o-kut-low-noise-stereo-phono-aux-switch.html?gclid=Cj0KCQiAwf39BRCCARIsALXWETxjlH2XY1O7poYENWleoj3O8GRhA4OZO4ipW0Hgffj-K89Pta7_UIMaAocFEALw_wcB

 

Long shot: Manley Skipjack, posted on November 28, 2020 at 08:41:25
Bill Way
Audiophile

Posts: 1884
Location: Toms River NJ
Joined: May 28, 2012
Contributor
  Since: December 14, 2012



This could be an excellent, if pricey solution. It's 4-into-1 or 3-into-2 switch box. It also does the inverse, and multiple boxes can be daisy-chained. It supports signal levels from LOMC to line level, and any combination of balanced and single-ended gear. Despite its small size, it weighs 6 pounds, so your hefty cables won't pull it off the shelf. The factory is doing a direct-sale special for a few units they have on hand. The user manual is on their web site. Email EveAnna for details.





WW
"Put on your high heeled sneakers. Baby, we''re goin'' out tonight.

 

RE: How to connect turntable to two phono preamps?, posted on November 28, 2020 at 10:14:18
Jonesy
Audiophile

Posts: 3157
Location: Winnipeg, Manitoba
Joined: September 1, 2005
Contributor
  Since: March 1, 2018
 Didn't realize a product like this (your link) existed. Worth a try at this price point. Keeping in mind what inmates warn to watch for.

If you try it, let us know how it goes?

Cheers!

Jonesy


"I know just enough to get into trouble. But not enough to get out of it."




 

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