[iFi audio]

Two years after purchasing, initially not all that impressed with the performance of the iTube2 from memory now a distinct increase in distortion. Maybe it wasn't burned in properly, every now and again, the iTube2 was resurrected but it didn't work out. Never mind, last night I watched the TechMoan video on the Chifi buffer tube amp. The presenter was gushing over the sound of the warmth of tubes, so why not give the iTube2 another shot.

The iTube2 was wired in the unbalanced tape loop, and couldn't program it for 0db buffering, had to switch to 9db pre-amp mode to match levels correctly. Rest of the settings were 'flat'. The iPower 15V supply was used. Once the levels were the same (by ear) on HD800S, there was a shift in the sound stage when listening to the digital chain. After a few attempts on different material, conformed the difference in the sound stage, but at 2230 it was not practical to launch the speakers to find out how the sound stage changed. Tonality was not much in it, but was obscured by that image problem.

Playing Michael Jackson's Thriller (EPIC - ES 38112 from 1999) which has great sound stage depth and height on speakers, the differences were readily apparent. The height of vocals dropped some 150mm, and the depth affected, but couldn't judge that accurately, but very noticeable in a direct A/B. I'm not sure if different cables will help, there's timing problems here that some cables could fix, but hazard a guess, they would be more than the iTube2 costs. With the iTube2 surface temperature around 30C , currently is placed on a coffee coaster from ceramics. In the winter it's not so bad, but summer would be a different situation.

Not a fan of the iPower supply, having replaced it with a linear supply for the micro3 USB with great results, thinking is the timing between channels could improve and therefore the image could be closer to the 'original'. Will dig out an alternative supply and give it a shot.

Later report:

OK, changed the iPower to a variable DC bench (SMPS) supply, some 5A, 1mV ripple set for 15V. Well the height was returned, but the image, very strange now. Vocals in the middle, and everything else left or right, so where's the music from centre to left, and centre to right...? Just gone. So with a 'real' linear supply, it's possible to return the missing information, but to be confirmed. for those wish to know in pre-amp mode, current draw is 400 mA at 15 V. ifi advise that the itube2 can run from a 12V supply probably 500 mA.

I feel there's already too much effort to discover how to wring out the best out of the iTube2. If anyone wishes to take this further, a linear supply like a Keces, Teddy Pardo, Acopian would be one way forward. Icing on the cake would be 'classier' interconnects from the Nordost Blue Heaven family, or the red Wireworld types would bring some extra results to discover that extra piece of info. The PSU and the cables are a significant cost, but if these are already about, then have a shot.

Gear:
Supermicro Win2016, Roon, JCAT Net Femto Ethernet card
Lumin U1
Accuphase DC-950 DAC
Accuphase C-2420 Pre-amp
Accuphase AL-10 interconnects
Accuphase P-4200 Power amp
KEF 205/2 speakers
Sennheiser HD800S

Thanks for your feedback!

 

[One and a half]

Had some thoughts and ideas as to why the sound stage behaved the way it did. In checking the specs on the GE GL-5670 tube, the plate current depends on the plate voltage which for given parameters can be 150V or maximum of 300V. Now, the input supply to the itube2 is 15V, so there needs to be an SMPS to boost it to the 150V/300V necessary for the tube.
If the same technology is used in the iPower as for the DC/DC converter internally, the the SMPS noise will remain and affect what comes out of the analog outputs.

Hmm. So no matter what can be achieved externally, internal designs remain.

OTOH, the Yaqin SD-CD3 is mains powered and requires simple transformers and rectifiers to deliver 300V or more to tubes, maybe have a look at this design a little closer. Two tubes

 

[Vitaly2017]

Hi
Would need some help please I would like to add the itube2 into my home av receiver but I am not sure if it will work... i see it has rca audio out and some sort of audio pono in via rca.

Here a link of my unit.


http://www.ca.marantz.com/ca/Produc...CatId=AVReceivers&SubCatId=0&ProductId=NR1509

 

[Bansaku]

Hi
Would need some help please I would like to add the itube2 into my home av receiver but I am not sure if it will work... i see it has rca audio out and some sort of audio pono in via rca.

Here a link of my unit.


http://www.ca.marantz.com/ca/Produc...CatId=AVReceivers&SubCatId=0&ProductId=NR1509

I don't see any issues at all. The micro iTube2 has RCA out and your receiver has 3 sets of RCA in.

 

[TheoS53]

Hi
Would need some help please I would like to add the itube2 into my home av receiver but I am not sure if it will work... i see it has rca audio out and some sort of audio pono in via rca.

Here a link of my unit.


http://www.ca.marantz.com/ca/Produc...CatId=AVReceivers&SubCatId=0&ProductId=NR1509

Nope, iT2 has no Phono stage, both the input and outputs are regular RCA analogues. If you're using a turntable, then you'd need to take the Phono out of the turntable to the input of the iT2, and then the output of the iT2 would go to the Phono input on your Marantz.

 

[TheoS53]

However, you cannot use the iT2 if the Marantz is your only device (i.e you have no turntable, or other amplifier or receiver, etc etc)....the whole point of the iT2 is to sit between 2 devices

 

[Vitaly2017]

Aaa that sucks.

I whanted to use the receiver and thought it could output to it2 and then back to the receiver....

 

[Vitaly2017]

K new idea!

Can I use wm1z 4.4 to rca to it2 then out to tca to 4.4 to ba300s oriolus?

I know its gona be maybe silly that will be 2 amps and tubes over each.

Does that work and make sense?

 

[Bansaku]

K new idea!

Can I use wm1z 4.4 to rca to it2 then out to tca to 4.4 to ba300s oriolus?

I know its gona be maybe silly that will be 2 amps and tubes over each.

Does that work and make sense?

Absolutely! just set the gain to 0 on the iTube2 and you're golden.

 

[Vitaly2017]

Absolutely! just set the gain to 0 on the iTube2 and you're golden.

Even if there 2 tube amp in the chain?
And I can use itubes2 as pure tube buffer to?


Haha golden is well said lol.

Golden as my wm1z ;p

 

[Bansaku]

Even if there 2 tube amp in the chain?
And I can use itubes2 as pure tube buffer to?

Like I said setting the gain to 0 will do the trick (turns it from a pre-amp to buffer). While you may have 2 tube devices in the chain, the micro iTube2 is a pre-amp with a plethora of features; 3D settings, bass boost, and 3 filter modes.

 

[Vitaly2017]

Like I said setting the gain to 0 will do the trick (turns it from a pre-amp to buffer). While you may have 2 tube devices in the chain, the micro iTube2 is a pre-amp with a plethora of features; 3D settings, bass boost, and 3 filter modes.

Thanks that sounds fantastic I hppe it end in a nice synergy with my ier-z1r.

I got another interesting question.
Is there a way how to power the it2 via a powerbank for example?

Of course I am trying to bypass the wall charging method.

I am in a semi truck and wall charger i have are bad. Too much noise and no ground here. Noise engine and the alternator and the agm battery isnt clean thing....

 

[Bansaku]

Thanks that sounds fantastic I hppe it end in a nice synergy with my ier-z1r.

I got another interesting question.
Is there a way how to power the it2 via a powerbank for example?

Of course I am trying to bypass the wall charging method.

I am in a semi truck and wall charger i have are bad. Too much noise and no ground here. Noise engine and the alternator and the agm battery isnt clean thing....

Yes, you "can" power the iTube2 with a power bank, but it's something you'd have to make yourself. I made myself one with 4x Li-On batteries (3.7V 9800mAh) in a holder with the correct plug fitting the iT2, all from eBay for like, $10 IIRC.

If your Semi has a standard 2 prong power outlet do not worry about noise. The iT2 comes with the iPower which does a great job eliminating noise.

 

[iFi audio]

Like I said setting the gain to 0 will do the trick (turns it from a pre-amp to buffer). While you may have 2 tube devices in the chain, the micro iTube2 is a pre-amp with a plethora of features; 3D settings, bass boost, and 3 filter modes.

This =

 

[Vitaly2017]

This =

Is that good or bad lol ?

Do you know if its okey to take 4.4 balanced to RCA into it2? Does it matter what type of signal goes in, like balanced or unbalanced ?
Or it simply becomes analog once passed threw rca...