If anyone is like me and wonders what happens when only the left or right channel has the bias meters on. Or if the back tube and front tube are the ones on. Yes, yes it does change things.

Brad,

From a practical, measurable perspective. I rebuilt the crossovers for my speakers. I wanted to try a speakerformer in place of the resistors to attenuate the Voxativ. The MKIV interacts with the load in a way the MKV doesn't. On the sales page or somewhere else Steve talked about how he designed the MKIV to intentionally do that. While it does have its benefits it also has its down sides. One of the downsides is that the speakerformer didn't play well with it.

The speakerformer plays very well with the MKV.

Oh man! The speakerformer is amazing! Resistors turn excess voltage into heat. The speakerformer (autoformer) turns excess voltage into current preserving the energy. Sounds more Zen to me than a resistor.

I did wait a week before adding the speakerformer to get a sense of how the amps differed.

The Torii MKV has a lot of the same characteristics of the Torii MKIV. The MKV takes on a bit of the UFO SET characteristics. It's not a straight line difference. Almost a right angle triangle that scoots towards the UFO SET sound.

This means the MKV still has the control, power, shimmering highs, expansiveness and X factor that the MKIV has. It adds in the togetherness that I really love about the UFO SET.

I did wonder if I would get the MKV roll a bunch of tubes and then go back to the MKIV. I listed the MKIV for sale yesterday.

I'm at a place with my system that I don't want to be analytical with it. I just sit back and am mesmerized and in awe. Why would I want to get all analytical when I have that going on?

I do have 4 QDA-13 diffusers coming and 4 ACDA-12M modules coming. I then hang my ceiling treatment. It's already so good... what will that bring?

I ran the stock tubes for a few days. Really enjoyable.

Currently running

EML 5u4g
Westinghouse 0A3
GL KT77 (My favorite tube in the MKIV and I tried a lot!)
EH Gold pin 6922 (input)
Cryotone ECC88 (inverter)

Minus the Cryotone ECC88 and add a RCA 0C2 and that is the same tube compliment I was running in the MKIV.

Having dialed in the tubes I like with the MKIV they translate to the MKV in a very similar way. I have no desire to try different tubes.

Once my brother gets his new speakers I'm going to let him try some of my power tubes in his ZMA to see if he wants any. Then I'll be thinning out my tube collection. I've a bunch of quads with 100 or less hours on them.

This is starting to get really off topic... I have a feeling that the larger fuses 6.3 x 32mm vs. 5 x 20mm sound better. With my MKIV I could easily pick out some of the stock fuse characteristics. After 20ish hours with the MKV I was blown away with how it sounded like it had a specialty fuse.

I ordered a pair of Audio Magic M-1's before I received the amp. I didn't realize it was the larger fuse so I needed to exchange them. I put the M-1's in a day ago. The MKIV with the 5 x 20mm was a dramatic difference with an aftermarket fuse. MKV not so much. Thing is, the MKV is still changing its sonic character so I'll revisit fuse difference later. I am curious about changing the rectifier fuse to see what kind of difference that makes. That's a pricy experiment though.

Thanks for the insight. I'm still curious. I have 3 units that use the larger fuses. Problem is 500mV would only have a use for the rectifier. It won't be any time soon if I do try other fuses.

Any observations on the bias switch positions?

The pop through the speakers when flipping the switches happens on mine too, I'm guessing it's normal. The UFO25TH makes a really aggressive pop when switching between hi/lo bias.

Are the meters dancing? If not the tubes are not being played too loud.

What noise are you hearing with the KT77s?

I give the tubes 5ish minutes before I play any music through them. After that I'll let it rip. I rarely play loud though.

In two or more weeks I'll try swapping back to the stock fuses. The packaging says 125 hours burn in needed.

I should have named this thread Torii MKV general discussion.  

gotcha!

There is a natural ebb and flow to conversations leading to changing topics. It's all good in my book.

I'm preferring all 4 switches off vs. on. Over the next few days I'm going to see if I prefer the inner or outer switches on leaving the others off.

Nigel, it changes with rectifiers. The Mullard GZ34 same as your pic. The type 80 I just put in drops the needle two units. If I was using the 5AR4-WC my guess it would move up two units from your pic.

I figured it would change with rectifiers.

It's wild isn't it? Need to try 2 on 2 off now.  

Quote:


“There is no left and right. There is only up and down” - Ronald Reagan 👍

With the EML 5u4g, 2 on 2 off are doing all the right things.