[Big Red Machine]

IF we have time #1, Yooper and I are contemplating a shootout of several devices:

Dodd batt pre and MW 36.5 pre
Stock TP and modded SB3 with Cullen PSA DLIII DAC

All else would be constant - cables and amp and speakers.

Any procedural suggestions?  We won't be able to switch back and forth with 30 second sound bursts I believe unless we hook one through the other in bypass.

[darrenyeats]

Listen double blind, is my number one suggestion for a formal shootout. 
Darren

[saisunil]

I have upgraded (better switches, RCAs, Wire and mute between selections) Mapletree Line Router. I have used it once.

- If you have two line-outs from CD/Source - then both preamps can be directly connect to the CD/Source.
- The Line out from each preamp can then be connect to the two inputs on the Line Router.
- The Line out from the Line router can then be connected to the power amp.

- You'll have to use the SPL meter to get same output (using a white/pink noise track) from both pre-amps - by adjusting their volume control.

- When you Switch from one input to the other on the Line router - you will be hearing through one preamp or the other.

In addition to this you must have proper listening to each pre-amp without the line router in the signal.

The Line Router gives a quick A-B impression - it is useful but not conclusive.
Extended listening in a relaxed fashion give you a more dimensional picture.

Good Luck
Cheers
Sunil.

[Big Red Machine]

Listen double blind, is my number one suggestion for a formal shootout. 
Darren

Isn't double blind an oxymoron?

[BobM]

There's a few thing I like to do. If you can accomplish these then I think you stand a better chance of hearing differences.

- let everything warm up and burn in
- try to hook things up so the only difference is the component being tested
- if you can, hook it up so you just have to throw a switch to go back and forth
- if you have different volume levels, make your measurements beforehand and mark where the volume needs to be for each component
- switch back and forth as much as you need to to hear subtle differences, or better yet, have someone else do it while you listen
- play a wide variety of music. What sounds better on one piece may not be better on another.
- take some aspirin before you start

Enjoy,
Bob

[darrenyeats]

Yes part of any double blind test is removing all indications of which is which. This means level matching with an SPL meter is mandatory.

But even if you don't listen blind then do the level matching like saisunil wrote. Do so with noise or a multi-band signal and an SPL meter.

If you've never done a blind test then give it a try. It's very interesting, you might even say exciting, to sit there and not know what's playing! It's a challenge to your audiophile credentials and you just feel it in a more personal way than with an academic discussion of blind testing on an audio forum.

"Double" blind means that no-one in the room knows what's playing. In some situations you can do this simply by letting the listener set up the connections, and then the assistant flicks inputs not knowing what is what. So neither knows which is playing until the end.
Darren

PS: Plus I agree with everything Bob said!

[rydenfan]

The transporter vs SB3 with DAC will be an easier shootout to accomplish because you can run them both to the same gear and just use different inputs. All you will need to do is ensure everything is level matched.

The Dodd vs Modwright is tougher because with the manor in which the tubes and circuits heat up they take between 30-45 minutes to truly sound there best. So switching them on and off will not give you the most accurate results.

[Danny Richie]

The first thing I'd suggest is to just listen to them to see what the differences really are. If the differences are significant then you won't need to do a blind/double blind comparison to decide which sounds best.

It the differences are subtle then go to a blind A/B comparison to eliminate bias if there is any.

If it is close then you might also consider a method of playing a 20 to 30 second segment 3 or 4 times over to really learn the sound of each device then switch. I often focus less on the notes and more on the space between the notes. Listen for the attack and decay of an instrument like an acoustic guitar or piano. Also space between instruments and or vocals. Background level or noise floor is good to key on as well.

I don't know about the Mod Wright but the Dodd pre has a mute setting that will shut down the audio circuit but leave the tubes lit and ready for switching back again without having to wait for warm up.

Have fun with it.