[GermanGuy]

Will try my best to support you!

 

[ianmedium]

Well done German Guy, what a really generous thing to do!
Bmichels, any help you need with tubes just ask and I too will do all I can to help.

Just to start though I will re-post the exact details of the tubes we need for this amp as the last time I did was a while ago and it is hard to have to go through all the posts.

So, for the Voltage Gain stage we need either 1U4 or 1T4 tubes. The 1U4 are predominantly US made tubes, I have not seen any European tubes with that designation. The only difference between 1U4 and 1T4 is that the 1T4's use a little bit more power. I have found the difference to be 2 notches on the potentiometer difference.

Now, the 1T4's have several designations depending on where in the world they were made. Generally 1T4 is a US designation though it is seen on European made tubes that were exported to the US.

The various designations for the 1T4 are: DF91/CV1971 and less common.. W17/1K2

For the power stage there is only one choice.. 3S4 which is also known as: DL92/CV820 and less common.. VT-174/N17/2P2/CV484

Hope that helps!

Now for something rather special!

Over the past few months I have been having PM conversations with a lovely chap who's forum name is Ericed8. He got his modified TU-05 this month. His has the different input and out puts and is in black but he has taken this a stage further. His English (he says) is not so good so he asked me to post the details and pictures, personally I think it great and I really hope that you join in the fun mate as you are the first official modder of the TU-05!!

See, Ericed8 has done some rather special upgrades himself to his unit, Siltech cables, an even better quality stepped potentiometer that fits due to his case being longer than the normal ones.

I will share the pictures here (with his blessing). Just feast your eyes on his superb work and check out that amazing looking pot and the wonderful Carbon Fibre wrap job he has done on the case!

Here are the details of his modifications..


"I got my tu-05 from this month and I really love this amp.
Also I try to mod this amp and improve its sound quality and case.
I change the VR to dact ct2 and changed the inside cable to "siltech".
Also I cancel the led light's function that improve playing time and sound quality.
The last mod I use carbon to paste my case.
In conclusion, my amp can playing more 10 hours, and more better sound performance."


And the pictures of this rather special 05'!



How about that! Fantastic work mate, truly wonderful job. I really hope your pictures posted on the thread inspire you to post on here, don't worry about your English, it is great but your experiences in doing this modification and thoughts would be wonderful.

Thank you for sharing this with us, its Official Ericed8 has now been bestowed with the title...

Modderus, supremous amplifious TU-05!

 

[AJHeadfi]

Nice, looks like much effort put in there.

 

[bmichels]

GREAAT Job indeed.  And the Carbon finish add some sophisticated aspect...
 
Could you explain what you mean by "I change the VR to dact ct2" ?   
 
Also, how can the battery duration be extended to 10 hours ?  Just by canceling the LED's light function ?? I don't think that Leads have a significant power drain !  Is there something else in the Mod that could improve battery life ?

 

[AJHeadfi]

Quote:

GREAAT Job indeed.  And the Carbon finish add some sophisticated aspect...
 
Could you explain what you mean by "I change the VR to dact ct2" ?   
 
Also, how can the battery duration be extended to 10 hours ?  Just by canceling the LED's light function ?? I don't think that Leads have a significant power drain !  Is there something else in the Mod that could improve battery life ?

 
A VR is a variable resistor or potentiometer, the dact ct2 is a stepped attenuator, both are devices to control gain with each with different qualities.
 
Certainly an amazing battery life for a class A valve amplifier, which are usually very inefficient but impart a musical quality.
 
Also the absence of noise in the output with it all cramped in there is admirable.

 

[bmichels]

A VR is a variable resistor or potentiometer, the dact ct2 is a stepped attenuator, both are devices to control gain with each with different qualities.

Certainly an amazing battery life for a class A valve amplifier, which are usually very inefficient but impart a musical quality.

Also the absence of noise in the output with it all cramped in there is admirable.

Thank you for clarifying what is à dac ct2. But does this mean that now he has à Step by Step volume increase instead of an infinite number of positions ?

Also, i still wonder How to explain the 10 hours bettery VS the 7 hours stock ? It can't be only the LED off ! ! Any idea ?

 

[Ericed8]

My English isn't good, cannot express very well.
Mr. Shikada put too much led's light inside which are "8" pieces.
I will test the real playing time on next Tuesday.
DACT very well VR's brand and ct2 is stepped attenuator.
Ct2 is real good VR which is balance even the sound real low also high quality VR will let sound have more better performance.
Sorry about my English, if you guys have any modified question, you guys can PM me.

 

 

 

 

[bmichels]

Thanks Ericed8.
Also, did you changed the 4 tubes or do you still use the stock tubes that come with the amp ?

 

[Ericed8]

You are welcome

I am using mullard to be my whole tubes that have real warm sound performance and still have details.

 

[seeteeyou]

.

 

[AJHeadfi]

To me it looks like the TU-05 is using a transformer coupled output. Obviously the quality of these transformers is very important, TU-05 may have one up competitors here. WooAudio WA7 Fireflies also uses the output transformer coupled approach. TU-05 has a battery for power, the WA7 has a transformer from mains power.
 
There have been gain controls created using transformers, with different windings used for each level, an expensive approach but one pursued strictly for sound quality. 
 
Maybe somebody that has heard both WA7 and TU-05 could comment on sound between these two somewhat similar amplifiers?

 

[ianmedium]

Well, I have slept on these modifications and some thoughts come to mind.
I can see where the wire will make a difference in SQ as, to a lesser extent taking the LED's out of curcuit but the volume pot has me scratching my head as if one goes for the upgraded components then there is already a really high quality stepped attenuator and even with my most sensitive IEM's I have had zero issue with channel imbalance and the pot is one of the best I have ever used, it seems to neither add or detract to the sonic picture.

It is not an infinite pot either ( the stock upgrade).

I have personally found an all Mullard set up a little thick sounding for my tastes and wonder if the upgrade in cable and it's sonic benefits could not be achieved by balancing the tube compliment as I have done.

I think it marvelous though that ere are folks out there willing to experiment though I think for me I will stop at tube modification!

I can certainly see how the wrap would damp case vibrations. I have come to another solution for that though and practical on two levels!

The wooden cradle I made is lined with cork and the fit of the amp is snug so that helps damp the case, though the case is pretty thick, thicker than some home amps I have seen!
The other thing I have done and has proved to provide worthwhile sonic benefits is to adopt the still points principal of mechanical decoupling.
Basically the school of thought is that instead of damping one uses direct metal supports which then drain away vibration from the case into the support base.
This works especially well under drives and transformers
Now these things are hideously expensive and far too big for this amp so I experimented with the brass "olives" or rings one uses to join two copper pipes together with in plumbing.

For a couple of bucks I got three, two are at the back where the circuit boards are and the other is directly below the bottom transformer.

The amp rests on those and they in turn rests directly on my wooden cradle.

What this has done is firm up and deepen the bass a little and added a little more sparkle to the top up.
Also it firmed up the soundstage insofar as better imaging.

In all, cradle, cork and rings I spent less than $15 and it works wonderfully!

Oh, by the way, it is so lovely to have people to converse with at last here

 

[GermanGuy]

So here is THE source:

Name : Carsten Künzig
Street : Am Roten Kreuz 17
City : 74722 Buchen
Country : you may think in the right direction: germany

Fax. 06281/563351
E-Mail : GermanTubes@aol.com

Just had a nice conversation with Mr. Künzig (yes he answers phone calls on sunday):

- he speaks english
- he ships worldwide
- has nearly a million! Nos and other Tubes on stock (no joke)
- accepts requests and orders via email
- accepts paypal for payment

- the ebay shop is just for recognition of his business
- philips dl92 should be more on stock than we need
- he will visit his warehouse today to check stock for lorentz and other df91 tubes as well as for the philips dl92
- i will get a feedback within the next days

- he mentioned that he is not that specialized in this rather rare dl type tubes, but i think that can be seen in relation to his overall stock
- he also mentioned that he sends out between 100 and 200 orders a day

Okay, let's begin the race and let's hope we get all we wish, need or want

P.S. race has started already - just ordered one set of philips dl92

 

[GermanGuy]

A question to all
- anyone here who got his tu-05 amp shipped to europe and getting problems with customs due to missing CE sign or CE conformity declaration?
- is there a CE sign on the tu-05?

 

[smial1966]

GermanGuy,
 
Thank you very much for posting the details of Mr. Kunzig and his vast collection of valves, as it appears that he may be able to supply the rare Lorenz tubes. Keeping my fingers crossed!
 
There was no issue with customs clearance and my TU-05. Though it was labelled as `audio parts' and assigned a low value to avoid paying punitive import taxes. 
 
Cheers,
Andy.
 
Quote:

A question to all
- anyone here who got his tu-05 amp shipped to europe and getting problems with customs due to missing CE sign or CE conformity declaration?
- is there a CE sign on the tu-05?