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Done and some nostalgia as it's been a decade since this was going on... 

Just bought a japanese hifi magazine issued back in 1995. It has the great omega+T2 combo on its cover with four pages of technical info of the t2. A nice collector's item under $20. 

The whole capacitor thing is interesting. Back in the day I developed a supermarket security gate to detect product tags and hence shoplifting, which for a few years was in use globally. This used two

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Plus it will be very difficult to answer.  Not many of us here actually own the SRM-T2 and no direct listening comparison was compared between the original and DIY T2 version.  Maybe KG has done it but I did remember reading that Birgir prefer his BH over the SRM-T2 during the initial phase of the DIY T2 project.

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The one problem with the original T2 which both Birgir and Kevin addressed is the amp is no longer within spec by this stage due to the heat and unregulated power supply it is powered off. The biggest advantage the DIYT2 has over the original T2 is better, bigger and regulated power supply it runs off as well as a bigger footprint with the circuit board so everything isn`t sandwiched together so closely like the T2. This ensures no thermal limitation problems are met or exceeded.

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  • 2 weeks later...

That makes sense. Maybe Stax thought the market didn't have the stomach for a bigger 2 box chassis? Capacitors for example are spec'd typically at 105C and say 3000 hours. In reality a good designed amplifier should run at 50% or less of that temperature and thus the caps would last years as opposed to months. Not to mention the tolerance of all the parts affected by wild temperature swings....

 

I like the idea of a huge no holes barred Stax amplifier. It sounds nuts to do such a thing to power headphones. If it sounds better I don't worry, and am not bothered by chassis size either. Respect to those DIY'ers who take sit on.

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Maybe price and a market was something that held them back. I have no doubt that Stax was and is capable of designing a grand $50k amp if they wanted to. The problem is how many will sell on the market to make it a viable effort for them to do so. Not to mention all the old HV semi-conductors are mostly EOL but there are new stuff which some companies only sell or make at a minimum (10000+ for example) quantity order. It's all supply and demand.

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On 11/11/2018 at 3:53 PM, tumpux said:

Reviving an old thread, but I think for archiving purpose it would be great if the outdated pictures links on this thread are updated with the current ones.

True...... the amount of pics available on google is too little..... always wonder what is shown in the dead pics above......

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Beautiful..

What happen with this amp on a daily basis? Is it still work? Is it true that on the back of the amp unit, there is a plate with the owner's name? Any plan to stuff a Carbon into this shell for its 30th anniversary?

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I sold it back in 2010 as it makes no sense to keep it.  It doesn't sound as good as people think it does and the hum bothered me a lot.  Well that and it was doomed to fail so I just recapped it and moved it on. 

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It's a feature that it can cook eggs on the top panel...  ;)  Kinda funny when the only option in Iceland is to take off the top panel and have a fan close by to cool it. 

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17 hours ago, spritzer said:

I sold it back in 2010 as it makes no sense to keep it.

I see.

It's very interesting though, because among all people I think you will be the one who has a soft spot for a historical piece such this, keep one or two around and do something interesting with it.

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I put Pearl tube coolers on mine. The idea is that the glass envelope runs at a lower temperature, which is reckoned to be a good thing. The jury is out whether it does what it says on the tin, but none of my output tubes have failed. So far. That was a bit of a fatal statement thinking about it ? 

For clarity that is on my Gilmore T2, not the Stax hot plate.

Edited by Craig Sawyers
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I got those coolers after seeing yours actually, it was kind of like paying for peace of mind/sense of security when xf2s are a billion dollars a quad haha

Sent from my Pixel 2 XL using Tapatalk

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8 hours ago, tumpux said:

Some more questions, from the pictures look like there are sleeves on the input stage tubes. Are they for cooling purpose?

Is the original T2 use any exotic capacitors?

I don't have a soft spot for what was a compromise from the start.  The chassis they ended up with was not what they wanted to do as the tubes were supposed to be in chimneys to take away a lot of the heat but it was probably too expensive.  The stuff on the input tubes are shields to try and keep crap out of them. 

They used nice caps but no audiophile BS. 

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Wow...... The pics is back......true gem in head-fi history, thank you for uploading them again after years

btw the t2 is much smaller than I thought with a headphone stand at the side for comparison

and the way they put all the relay at the back as well as the way they put two sands in a single heatsink is funny

 

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The whole capacitor thing is interesting. Back in the day I developed a supermarket security gate to detect product tags and hence shoplifting, which for a few years was in use globally. This used two audio frequencies superimposed on a 20Hz triangle wave. The amp was class D (quite something for thirty-odd years ago) and hence needed an output filter. Designed one, and bought the bits - chunky inductor, and polypropylene capacitors. First thing was that the inductor melted, and that was when I found out about proximity effect. The second thing was that the capacitors howled like a banshee being tortured with a hot poker.

Anyway the capacitor thing was really interesting. I tried a variety of manufacturers, and found that acoustic output was determined by tight winding of the foils. Second that axial tubular ones were quieter than radials. That was down to the manufacturing process for the radials. First the foil is wound on a cylindrical former. The former is pulled out and what remains is squashed flat. The voids that are inevitably left cause the noise through electrostatic forces.

The quietest were cylindrical audio capacitors - a design now made by Kimber. Far too expensive for the product of course. But I found Roderstein axial ones that were also silent and cost much less. Roderstein is now owned by Vishay.

Anyway, it was an interesting exercise. As far as I know no-one tests audio grade caps by passing an audio band signal through them (of an amp or so) and listening to them. Any acoustic output is (a) frequency dependent and associated with mechanical resonance in the capacitor structure and (b) is clearly associated with a loss mechanism.

Aha - found a few left over - they were MKP1845, and Vishay still make them https://www.vishay.com/docs/26023/mkp1845.pdf . Just E6 values, which is a pain.

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