DIY Stax SRM-T2 Chassis Group Buy

[GeorgeP]

Thought it might make sense to make a new thread on this so as not to pollute the T2 thread. So this would be limited to the chassis, any potential board run, and any other potential group buys for traffos or transistors (if numbers warrant).  I am hoping to move forward by the end of the week. Please keep in mind, if you are in and make your deposit, you are committed and will not back out unless you find someone to take your spot (so if you are not well established, then paypal gift only). Please express interest here or by PM.

 

 

I have also included a link to the results of the first group buy:

 

 

 

[Whitigir]

Excellent opportunity George ! Thanks for making it possible

[samsie]

I am interested in the chassis set.  I would like to have an estimation before I commit.  

Edited May 1, 2017 by samsie

[GeorgeP]

Probably a bit confusing, but the cost is set out in the April 23rd post quoted above. Total cost for the chassis with brackets is $1550 USD, plus shipping. The chassis set weighs about 30lbs. I was waiting for one other downpayment before confirming the order with the shop, so let me know in the next day or so.

[samsie]

sorry, a bit too much for me.  Maybe I would join in when there is a group buy for a set of transformers

 

sam

[GeorgeP]

Yes, not for the faint of heart as these are north American prices with everything made to order locally. And at nearly the same cost as Kevin's chassis run from 2010 I think we are doing pretty good price wise.

Will probably post something at some point later on regarding transformers.

[gwrskien]

Has drawings for the chassis been posted somewere? I don`t have a T2 pcb, or any plans to trye and get one, but i am a machinist, and are just curious about the machining part of it..

[GeorgeP]

No, there are no posted drawings. Also the heatsinks are made from a custom die and are extruded in 12ft lengths with a minimum order of 4 lengths.

If you want to build your own, get four heatsinks at just over 16" in length (3u) and then cut and machine to rest to line up. Shouldn't be difficult if you have the equipment and know-how.

So it starts like this (but the front and back plates have a lip built in that lines up with the heatsinks):

 

 

[Earspeakers]

I can vouch for these chassis, I've got two and am finishing the first built. Well worth every penny, would cost many times this in a finished product. 

[Whitigir]

I am looking forward to these to be produced so I can get on building my T2

[gwrskien]

I think i have seen one of those finished, probably in here it think... I thought it was a Blue Hawaii inside.. Custom work and custom parts adds up quickly..  but man they look good.

[GeorgeP]

I will be closing the group buy this weekend and firming everything up with the shop on Monday. Thereafter communication regarding the chassis buy will be via pm/email given the small numbers.

If anyone else not involved in the group buy is interested in boards or traffos (I know Marc has already voiced some interest), let me know.

[Kerry]

I might be interested in transformers.

[luvdunhill]

Still interested in transformers.

[GeorgeP]

1 hour ago, Kerry said:

I might be interested in transformers.

Were you using Paul's transformers? And does your chassis have the same space allowance as Kevin 's?

[Kerry]

I'm using SumR now.  Yes, I have pretty much the same space allowance as Kevin's.  I did tweak some of the voltages so it dissipates a little less heat.

[justin]

whats the transformer specs? i havent ever looked at that for the t2. looks like all 3 transformers are different?

[GeorgeP]

Looks like your LV has an extra winding(8VAC) and one of your HV traffos is missing the 75VAC? Would the standard windings also work for you or do you need these modifications?

[Whitigir]

I am in for transformers as well  count me in! From where and what pricing though ?

[GeorgeP]

2 minutes ago, Whitigir said:

I am in for transformers as well  count me in! From where and what pricing though ?

Nothing for sure yet. Will start making inquiries in a week or two.

[Kerry]

I used 425VAC, 270VAC & 70VAC for the negative rails, and yes I dropped the 75VAC (not used anyway) on the second transformer, which is 425VAC and 235VAC.  I'm using the doubler for the bias so I could get away with lower HV on the positive rail.

On the LV I added the 8VAC so I could power the digital attenuator which needs 5VDC.

I'll probably need different from most, but thought I'd enquire anyway.

[GeorgeP]

From what I recall from Paul (TEC), the savings lies in using the same core (assuming the volume is sufficient). PM me your specs. For reference, SumR on the left and TEC on the right (had this swapped - too sleepy with all the rain we've been getting):

Edited May 5, 2017 by GeorgeP

[Kerry]

PM Sent

[Skooby]

It would be nice to also have 5.0VAC tap-offs from the 6.3VAC filaments on LV trafo for future 20B usage...