Switching box to do blind test for amps (Vic)

[Guest Runaway]

Following the tubes vs SS amp thread with interest.  Thinking of doing a blind test between 2 or 3 amps - Devialet 120/200 (Class A/D SS), Jadis DA50S (KT88s) and Pass Labs Aleph 3/ Cary SLP05 (Class A SS/ tube pre combo).  

 

Looking for a device which can switch between the 2 or 3 amps to the same set of speakers and one that can switch between the same source and the 2/3 amps - otherwise it would take too long.  

 

Already have some guinea pigs bred for this purpose ( @bebop  @evil c @holliswhy @WhoRu?

Edited April 26, 2018 by Runaway

[evil c]

47 minutes ago, Runaway said:

Following the tubes vs SS amp thread with interest.  Thinking of doing a blind test between 2 or 3 amps - Devialet 120/200 (Class A/D SS), Jadis DA50S (KT88s) and Pass Labs Aleph 3/ Cary SLP05 (Class A SS/ tube pre combo).  

 

Looking for a device which can switch between the 2 or 3 amps to the same set of speakers and one that can switch between the same source and the 2/3 amps - otherwise it would take too long.  

 

Already have some guinea pigs bred for this purpose ( @bebop  @evil c @holliswhy @WhoRu?

Any half decent bottle of red and I'll get subjected to anything! 

Could have probably done with one of these myself - although have heard rumors of degradation to the sound so have never bothered.

I have just run identical runs of the same speaker wire with banana plugs and swapped over between my SS & Tube amps so would be quick enough to remember sound before, although sonic memory probably only extends about 20 seconds! 

[sir sanders zingmore]

I'm interested in this !

 

Might be a bit tricky with the toob amp though - don't they need to have a load on them when they're on? 

Not sure how to get round this?

[Zaphod Beeblebrox]

30 minutes ago, Sir Sanders Zingmore said:

I'm interested in this !

 

Might be a bit tricky with the toob amp though - don't they need to have a load on them when they're on? 

Not sure how to get round this?

Excellent point. A couple of 8R2 (8.2 Ohms) 10 Watt resistors should do the trick. Most comparator boxes will allow the connection of a dummy load. If one cannot be found, then it can be fabricated without too much difficulty. 

Edited April 26, 2018 by Zaphod Beeblebrox

[Sam Z]

I have a switch box I can lend, they do degrade the sound a little but at least they do it equally between the different inputs/outputs.

[Full Range]

WARNING  

 

A switching box is OK for SS V SS 

But not SS V Tube 

 

A tube amp requires it to connected to speakers at all times or you will smoke it 

By cutting the circuit you risk damage 

 

Happy to be corrected as protection measures may have been installed in new tube amp designs 

 

 

[Guest Runaway]

43 minutes ago, Sam Z said:

I have a switch box I can lend, they do degrade the sound a little but at least they do it equally between the different inputs/outputs.

Thanks. Will PM you for details.

[WhoRu?]

1 hour ago, evil c said:

Any half decent bottle of red and I'll get subjected to anything! 

Could have probably done with one of these myself - although have heard rumors of degradation to the sound so have never bothered.

I have just run identical runs of the same speaker wire with banana plugs and swapped over between my SS & Tube amps so would be quick enough to remember sound before, although sonic memory probably only extends about 20 seconds! 

Did someone say red wine?

[sir sanders zingmore]

17 minutes ago, Full Range said:

WARNING  

 

A switching box is OK for SS V SS 

But not SS V Tube 

 

A tube amp requires it to connected to speakers at all times or you will smoke it 

By cutting the circuit you risk damage 

 

Happy to be corrected as protection measures may have been installed in new tube amp designs 

 

 

 

1 hour ago, Zaphod Beeblebrox said:

Excellent point. A couple of 8R2 (8.2 Ohms) 10 Watt resistors should do the trick. Most comparator boxes will allow the connection of a dummy load. If one cannot be found, then it can be fabricated without too much difficulty. 

 

[frednork]

Have a Beresford 2 amp and 2 speaker switcher if of use

[Guest Runaway]

59 minutes ago, frednork said:

Have a Beresford 2 amp and 2 speaker switcher if of use

Thanks.  Will PM you shortly.

[flanders]

With the Beresford switcher suggested above, how do you run the one source to both amps? Y splitters?

Edited June 19, 2018 by flanders

[eltech]

Any 4 in 1 out source selector can be used in reverse to have one input switch to 4 outputs.

 

https://m.ebay.com/itm/4-Port-4-Input-1-Output-AV-Audio-Video-RCA-Switch-Selector-Adapter-Splitter-Box-/332689731661

 

[davewantsmoore]

On 26/04/2018 at 4:36 PM, Full Range said:

A tube amp requires it to connected to speakers at all times or you will smoke it 

Happy to be corrected as protection measures may have been installed in new tube amp designs 

Depends on the amp as to whether no load will cause a problem.  Consult the manual.

[flanders]

58 minutes ago, eltech said:

Any 4 in 1 out source selector can be used in reverse to have one input switch to 4 outputs.

 

https://m.ebay.com/itm/4-Port-4-Input-1-Output-AV-Audio-Video-RCA-Switch-Selector-Adapter-Splitter-Box-/332689731661

 

Thanks. Just remembered my passive pre has 2 variable outputs:

http://www.tisburyaudio.co.uk/mini-passive-preamplifier

This should mean no switching from source to amps is required.

 

@Runaway, Beresford also does a  2 amps / 1 speakers version:

http://www.homehifi.co.uk/S/tc-7210.htm

 

[davewantsmoore]

You will need to make sure each amplifier is producing the same SPL.    Amplifiers often have different gains.  A small difference in volume won't sound like a difference in volume, it will make the louder amp sound 'better'.