Tundra Mono 2

valentine · Post by **valentine** » 2014-11-20 09:56

From when are the current Mono's upgradable to the Mono 2 specification?

Post by **lejonklou** » 2014-11-20 14:14

valentine wrote:From when are the current Mono's upgradable to the Mono 2 specification?

Hi Valentine!

From as soon as the Tundra Mono 2 is launched. January 2015 is planned.

Inside Europe, the amps will need to return to me (handled by your retailer). In other parts of the world, we are working on the distributors performing the upgrade (to keep the price as low as possible, the performance will be exactly the same).

Right now all the required metal parts are being machined, hope to get them for inspection next week. I'm excited!

Ozzzy189 · Post by **Ozzzy189** » 2014-11-20 14:56

valentine wrote:From when are the current Mono's upgradable to the Mono 2 specification?

I hope you decide to keep the monos and get them upgraded Daniel. Then try sagatun monos before looking into exakt. I think you'll be blown away.

pleddyboy · Post by **pleddyboy** » 2014-11-20 16:40

Will there be an upgrade available for the Tundra Stereo version ?

macrotech2 · Post by **macrotech2** » 2014-11-20 16:49

This is exciting - any idea of price yet?

Post by **lejonklou** » 2014-11-20 21:58

pleddyboy wrote:Will there be an upgrade available for the Tundra Stereo version ?

No, Tundra stereo will remain as it is.

macrotech2 wrote:This is exciting - any idea of price yet?

Thanks! For me too. No, not yet.

valentine · Post by **valentine** » 2014-11-22 18:36

Ozzzy189 wrote: I hope you decide to keep the monos and get them upgraded Daniel. Then try sagatun monos before looking into exakt. I think you'll be blown away.

That option is still open. I still love the mono's very much and they are also a very good fit with my MDSM and M109's. I will continue the discussion on the Tundra Mono thread....

Post by **lejonklou** » 2014-12-01 23:12

As I shared a picture on Facebook of a piece of copper with seven holes in it, I should also mention it here:

The main improvement of Tundra Mono 2 is the addition of 1.2 kg of copper in each unit. The copper comes in two pieces that clamp the output transistors and cools them twice as fast as before. The faster cooling makes the transistors vary less in temperature - it's mainly the bass beat/notes that heats them up and between each note they cool down again. With less such variation in temperature, there is less variation of other parameters in the transistors.

What does this sound like? You might be surprised. The day after tomorrow you can listen to the almost-ready prototypes at Ljudkompaniet in Uppsala (where my professional career in HiFi started in 1991 - I'm coming back home!)

I will soon start a separate thread about Tundra Mono 2 and the improvements that have been done. I just have two more tests left; one possible component change and one last thermal interface material that will hopefully arrive from Japan by the end of this week.

moog_man · Post by **moog_man** » 2014-12-02 00:09

So interesting, Fredrik

1.2kg sounds like a lot of copper..... is it?
And are the unit box sizes the same?

Best wishes for the upcoming audition sessions.

kr,

Post by **lejonklou** » 2014-12-02 07:32

moog_man wrote:So interesting, Fredrik

1.2kg sounds like a lot of copper..... is it?
And are the unit box sizes the same?

Best wishes for the upcoming audition sessions.

Thanks!

Yes, the unit is the same size as before. As copper is heavy, it's not difficult to fit several kg inside. I tried less at first, but to smoothen temperature variations as effectively as possible, more than 1 kg was best. Adding several kg was unnecessary, and in addition made the warm up time exceedingly long.

I forgot to mention that the demo at Ljudkompaniet is Wednesday the 3rd of December and we start at 18.00.

rowlandhills · Post by **rowlandhills** » 2014-12-02 11:25

Two questions.

You mention warmup time. How long do you feel the Monos now take to be fully warmed up?

Secondly, is there any reason why a heat sink like this wouldn't improve performance on the Tundra stereo too?

HIDDENSYSTEMS · Post by **HIDDENSYSTEMS** » 2014-12-02 12:17

I'd say minimum 30 mins, 60 better, 120 minutes ideal

Ozzzy189 · Post by **Ozzzy189** » 2014-12-02 14:08

How much is the upgrade going to cost Fredrik? I am pretty sure no one is expecting a massive lump of copper fitted into an amp for nothing!

Post by **lejonklou** » 2014-12-02 16:33

rowlandhills wrote:You mention warmup time. How long do you feel the Monos now take to be fully warmed up?

I will measure, listen and report my findings as soon as the last thermal interface material has been evaluated. I have high hopes for the stuff arriving from Japan - and if it works it will likely change things (torques, idling currents and warm up time).

rowlandhills wrote:Secondly, is there any reason why a heat sink like this wouldn't improve performance on the Tundra stereo too?

No.

Ozzzy189 wrote:How much is the upgrade going to cost Fredrik? I am pretty sure no one is expecting a massive lump of copper fitted into an amp for nothing!

Yet to be confirmed. The specification Is not yet final. The upgrade procedure will also be quite time consuming, but the goal is to set the upgrade price as low as possible.

ThomasOK · Post by **ThomasOK** » 2014-12-02 20:21

Hmmm! You put the copper on the outside, polish it all up, add a big meter and you can charge five times as much for it!

Tony Tune-age · Post by **Tony Tune-age** » 2014-12-02 20:43

Are there any pictures of the newer mono power amplifiers?

Ozzzy189 · Post by **Ozzzy189** » 2014-12-02 22:03

I'd imagine they'll look the same unless the added bulk requires a new case. In that case, lol, I'd imagine the old one would be re usable for sagatun or tundra stereos. Just a thought.
I do hope the new amps get upgraded feet though, that's a fairly high priority imo.

Post by **lejonklou** » 2014-12-02 22:08

Thanks, Thomas. That's a great tip. ;o)

Tony: On the outside, it will look very much like the original Tundra Mono.
But it will say Tundra Mono 2 on the back.

Ozzy: I have made at least 25 other feet constructions, but fact is that the original feet still sound best. Performance-wise they are also insensitive to the weight of the unit, which has not been the case with many other designs. So adding a kg or two is no problem.

I have one final test to make and that is an almost identical rubber foot, but in a different material, that does not leave marks on the case if you stack the units.

Ozzzy189 · Post by **Ozzzy189** » 2014-12-03 00:36

Excellent news Fredrik , I do have marks on my maple rack from your feet! Lol
Can't wait to hear it!

Post by **lejonklou** » 2014-12-19 16:45

Progress!

Almost ready, but one detail remaining.

Will share more details tonight or tomorrow.

tokenbrit · Post by **tokenbrit** » 2014-12-19 20:03

Tease!

Looking forward to details in time for Xmas even if the actual 'gift' of the upgrade to Mono 2 will be a just little belated - hopefully in time for the Chinese New Year 2015, Feb.19 ;)

Happy holidays :)

Post by **lejonklou** » 2014-12-20 22:45

Alright, here it is.

The upgrade of Tundra Mono to Tundra Mono 2 consists of the following changes:

1. The aluminium cooling block is replaced with two pieces of copper, with a total weight of 1.2 kg. This is the most important part of the upgrade, as it cuts the variations in temperature (caused by the music you are playing) in half in all critical areas. Less temperature variation means a more stable foundation for the music.

2. A new Thermal Interface Material (TIM) between electronic components and cooling block is used. The old material was Swedish and it was really good. The new one is just released, undoubtedly the best in the world and made in Japan. Thermal resistance through these interfaces is now one fourth of what it used to be. When heat moves fast, the music (in particular the bass) sounds Rock Solid.

3. The above two improvements cause a change in optimal torques (higher than before) and idling currents (lower than before). To facilitate the adjustment of idling currents, a new "status port" connector will be added to the rear panel.

4. One component on the circuit board is changed to a better sounding type.

5. A cable that connects mains ground to chassis is changed to a new type, with optimal direction and length (+/- 1 mm).

6. Here comes the last detail - a problem that I might have solved yesterday. As transistors are now clamped with high pressure in between pieces of solid copper, thermal expansion of the materials becomes an important factor. When things heat up, they expand and pressure increases dramatically. Therefore the package needs to have a controlled flex - one that keeps the pressure constant, regardless of temperature.

I started by choosing materials in the package that would cancel eachother out in terms of thermal expansion, but when testing it quickly turned out that parts are not heated equally. The heat has an origin and the air around the package cools some parts more than others. This I should have realized from the start, but I had chosen to ignore it and see how it would work out in practice. Well, it was not optimal, as the pressure did increase as the amplifier heated up.

To achieve a constant pressure inside the package, I have now ordered a leaf spring with the size and stiffness that should be required. I am right now listening to the prototype Tundra Mono 2's, which were fitted yesterday with my own "lab made" version of this spring. And it works! The benefit is that the amplifier sounds at its best both when I play really loud (and the parts heat up) and when I use a low midnight volume. After Christmas I will get the factory made spring and test that it does the same job.

If all goes according to plan, the Tundra Mono 2 upgrade will be released in late January 2015. I think you'll be impressed by what it does to your music.

Inside Europe, upgrades will be handled by your retailer, which will ship the units to my lab in Uppsala, Sweden. In the United States, your retailer will ship the units to Nokturne Audio, where Thomas OK will perform the upgrades. Outside Europe and the USA, we have still to decide who will perform the upgrade. Our aim is to make it as easy and practical as possible for the customer, while always making sure each Tundra Mono 2 performs perfectly.

And yes, I will soon get back to you with a price!

tokenbrit · Post by **tokenbrit** » 2014-12-21 00:18

Does that mean the copper blocks are retained or clamped, but with a leaf spring underneath the retainer clamp to allow for thermal expansion? Any long term concerns or special transportatiom or handling issues foreseen due to the spring?

All sounds like good news in terms of musical improvements and consistency. Congratulations on the progress with the update to Mono 2, and the advancement of your design. Can't wait to hear for myself. Tom is already knows he will have my two Monos to upgrade.

mrco99 · Post by **mrco99** » 2014-12-21 01:23

Hi Fredrik,

I have bought a pair of Monos privately from the UK and there is no retailer in my residing country.
Should the Monos be sent back to the UK first or straight to your laboraty for the upgrade?

Cheers,

Marco

Ozzzy189 · Post by **Ozzzy189** » 2014-12-21 02:10

Sounds like a complete overhaul and a large amount of extra work and testing, hopefully it's a pretty substantial improvement and I can't wait to get down to Chris' at HiddenSystems and have a good listen.

Tundra Mono 2

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