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eXStatA Build Thread II - Page 6

post #76 of 567

Ok, sending 15 Stax connectors to Oz, with 4 passing through (2 to Bangkok for Chinsettawong, and 2 to Indonesia for noeb). Hope that will be enough, but...

 

.. there __may__ be more free connectors available, so there should be plenty for everyone.

 

I'll follow up on this tonight (can't get email during the day).

post #77 of 567
Thread Starter 
Quote:
Originally Posted by rbarth View Post

I used the one specified on the BOM   It has three pins in a triangular shape numbered 1, 2 and 3 and one smaller, unnumbered tab on top of them that has a small hole in it.  I have checked the wiring diagram and regret to say that I am not experienced enough to determine whether the answer to my question is there.  I have never wired a balanced connection before.  In the past, I have wired the ground from the inputs to the the pot I was using and then ran it from there to the amp board.  Is this the same case with balanced inputs?  If yes, I have two ground wires and four common tabs on my pot.  How do I connect this?  

 


OK. I can help, but it might have to bit later. Hang on.
 

Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #78 of 567

I really appreciate that and would be happy to hang on as long as necessary.  BUT:  I've decided at this 11th hour to add the 4PDT switch and RCA connectors.  So, if that changes things (I assume it will), I can get back to you when I have these added parts installed on my case -- probably in a few days in light of my current schedule.

post #79 of 567

Go to cavalliaudio.com > wiring > input wiring

 

There is a image there showing how to wire up the switch with an SE and a balanced input for a single channel

 

I agree the unnumbered tab on your XLR jack is a grounding tab for the connector/shield of the XLR plug. You do not need to do anything with that for now, or you can ground it to the star ground. Check to see if your source has a grounded plug, or you may generate a ground loop.


Edited by studeb - 7/27/10 at 1:29pm
post #80 of 567

Thanks Alex for the Hybrid boards. I'm actually on holiday so won't start building till the end of August, but I have a question regarding use of a stepped Attenuator.

 

I have two 4 deck 24 step "make before break" rotary switches similar to the ones that you see when googling "vishy Dale Stepped attenuator"  I Could use a ladder design, but I am considering building it as a balanced stereo attenuator and would then need an 8 deck switch if I wanted to go down that route. SO... I am wondering if I could build it as a shunt Attenuator.

 

Any thoughts on the pros and cons between Balanced/single-ended Ladder/shunt ?

 

Which of the two routes is likely to give the best result. I do intend to use good quality resistors and am ignoring the price difference and work involved with double the number of resistors to stuff onto the ladder version.

 

Or should I talk to Beefy about his solution!

 

 

Francis

 

[edit: with two 4 deck switches I suppose I could build both versions, but that would be a lot of soldering!]


Edited by paxeaxe23 - 7/28/10 at 9:11am
post #81 of 567
Quote:
Originally Posted by paxeaxe23 View Post
Or should I talk to Beefy about his solution!

 

That sounds like a really bad idea.

 

*

 

If you have a 4-deck attenuator, just build it series and use one of them. IMHO, the drawback to steppers is the granularity between steps, while series vs ladder/shunt is just e-peen.

post #82 of 567

Thats interesting. I'll try one in series and mount it into my SS amp when I get home and see if its any better than my ALPS Blue (which is only SE of course.) Not really had a lot of experience with the different options for stepped Attenuators, so thanks for the input!. I have been getting a lot of "stick" from my audiophile buddys about steppers and they all say under 48 steps is no use, but I have noticed that I only use a very small range on my SS amp and reckon if I calculate the steps right I can give myself a fairly good set of steps to listen with comfortably and safely!  I still have a spare ALPS if it all goes pear shaped. My main aim is to build the Hybrid Balanced all the way! Then I'll have to build a Balanced DAC.

 

 

post #83 of 567
Quote:
Originally Posted by paxeaxe23 View Post

Thats interesting. I'll try one in series and mount it into my SS amp when I get home and see if its any better than my ALPS Blue (which is only SE of course.) Not really had a lot of experience with the different options for stepped Attenuators, so thanks for the input!. I have been getting a lot of "stick" from my audiophile buddys about steppers and they all say under 48 steps is no use, but I have noticed that I only use a very small range on my SS amp and reckon if I calculate the steps right I can give myself a fairly good set of steps to listen with comfortably and safely!  I still have a spare ALPS if it all goes pear shaped. My main aim is to build the Hybrid Balanced all the way! Then I'll have to build a Balanced DAC.

 

 



I probably agree with your buddies, because I can't imagine myself ever using a default DACT, for example. Consider my M3, which is set at a gain of 2 (the lowest it can feasibly go) and I never go higher than 1/6 of a pot rotation. That would be just 4 steps for the whole range of what I listen to, and I would be literally stuck between steps 3 and 4.

 

But a custom jobbie could be very useful.

post #84 of 567

Ya mean, like one of these (yes, two different units):

 

attenuator.jpg

 

 

acc_dim.jpg

 

http://home.swbell.net/pabbi/Atten_chart.jpg

 

Only 42 steps, but, whatever.

 

Ok, Oz and Far East (Thailand, Indonesia, etc) ping me and let me know who needs Stax jacks - I have 15, with more incoming (graciously being provided by a fellow builder), so if 15 are enough, I'll send them now... if not, it will be a week or so. I'd like to send one package with customs forms.

 

Canada guys, I'd like to send one package there as well, if need be.

 

The tubes FS are all enroute - let me know of success (or failure - occasionally a tube doesn't quite make it intact).

 

Finally, where the heck are the builds - needs to be some fire in the hole!

 

post #85 of 567

are the parts list in Cavalli audio updated or does anybody have a newer SS parts list?

Better yet, does anybody have a parts list with the mouser or digikeys numbers?


Edited by gilency - 7/28/10 at 9:14pm
post #86 of 567
Quote:
Originally Posted by gilency View Post

are the parts list in Cavalli audio updated or does anybody have a newer SS parts list?

Better yet, does anybody have a parts list with the mouser or digikeys numbers?


The parts lists are outdated? But I built a BOM already! :(

post #87 of 567

sorry. Did not imply they are. I am merely asking if they are the ones to use or whether somebody has one with the Mouser or Digikeys list.

post #88 of 567
Thread Starter 

The excel BoMs on the website have part numbers, mostly from Mouser. They should be fairly current. Is this what you were asking?

Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #89 of 567

yes. thanks.

post #90 of 567

I got ahead of myself when I raised the subject of input wiring last time and need to put that on hold as I am having a problem bringing up my amp.  There is no smoke when I turn on the PS but the tubes don’t go on.  I left the power on for about five minutes and there was no glow at all. The amp is getting power, however:  -300 rail is measuring -170VDC; +300 is+ 420VDC.  All eight heater terminals are measuring between 168 to 170VDC.  P1 and P2 are not adjusting the offsets because the tubes are not working.  The tubes were advertised on eBay as a matched quad set of GE 6S4As.  Could they all be bad?  Any ideas?  If pictures would help I can post them early tomorrow.   

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