[scottiebabie]

no worries dough'man(LOL). according to wiki a transducer is a device that converts one type of energy to another. in this context, it stands for any type of audio drivers. u are absolutely correct in that a scratchy pot usually denotes dirt, dust &or oxidation. sometimes DC current also causes static noise (ie scratchiness) followed by significant distortion as the vol is increased. best way to tell is to try the amp with another unmod'd source to see if the noise is still present. if not then u know its the unblocked DC offset.
 
most amps have a cap somewhere along the signal path before the drivers so if it were me, i'd short out the DC coupling caps. best way is to just solder a wire to both ends of the caps on the underside of the board. since the caps arent removed, just a quick snip is all thats needed to reverse the mod.
 
if it were me, i'd do it. wait.....i did do it! LOL! if it becomes an issue, its a cakewalk to rectify it. remember - the best cap is no cap! heh

 

[dough head]

Thanks for the info, Scottie!
 
Must look into the amp next

 

[]eep]

I have a question about an external PSU. The TeraDak you use, is that the 'Upgraded Power Supply for Teralink X1 or X2'? It is only 8V, is that right? Can I turn it up to 12V?

 

[ardilla]

 

Quote:

I have a question about an external PSU. The TeraDak you use, is that the 'Upgraded Power Supply for Teralink X1 or X2'? It is only 8V, is that right? Can I turn it up to 12V?

 
 
Jep, that's the one. Using a voltmeter to measure the output and a tiny screwdriver to trim the "Trimming Potentiometer" (see picture) you can adjust between 8 and 13 V appr. But 9V is best (Muse doesn't get so hot). Inside the MuseDac on the board it is printed 9-12V, so it is very much ok. 
 
See the tiny copper-ish screw inside the green circle:

 

 

 

[dough head]

Got a new Muse and did the cap shorting out using Walkers SST, easy to remove and did not involve any heat at all, therefore no dangers of cooking anything in the process.
 
Outstanding wee dac, especially in this setup!

 

[]eep]

So the TeraDAk PSU is easy peasy. And not expensive too. (thanks to the 'strong' euro... before it goes down the drain too. Don't get me started be4 I start a whole lecture about world politics. :rolleyes

 

[scottiebabie]

Quote:

Got a new Muse and did the cap shorting out using Walkers SST, easy to remove and did not involve any heat at all, therefore no dangers of cooking anything in the process.
 
Outstanding wee dac, especially in this setup!

LOL! aint it the bomb for a cost nuffin mod??!!! its funny how we try to mod it with uber $$$$ mega huge caps when all it takes is something simple (&best of all...freee!) to release the magic. good for u doughboy!
 

 

[dough head]

I am always on the lookout for cheap, Scottie

 
 I made my own isolation stands, speakers(although a guy who knows his electronics did the wiring), earthing loom and so on. Yeh, cheap runs through me like writing in a stick of rock.

 

[]eep]

Sure it is best trick to avoid components altogether if you don't need them. Only in my case I have to keep them compliant to standard because I sell them again. Would save me a lot of work. I'm beginning to feel like I'm all thumbs while when I was young I had no problem with scale models 1:76.

I just ordered a new one, so maybe I'll keep that one for myself and try it on my tube amplifier (1 of them). I'm not really comfortable using it on my t-amp. I already blew one and that's more than enough for me.

 

[scottiebabie]

could be just my opinion but i do think its darn easy to solder a shorting wire btwn the cap leads at the bottom of pcb & even more easier to snip snip back to ori specs. the only thing that could damage the dac is a reverse current feed from amp back to dac for whatever the reason. if this does happen, i highly recco hoofing to the nearest lottery outlet asap to buy a ticket or 2 - who knows lightning mite strike the same place twice! heh!
 
otherwise its the best 'upgrade' i've ever gotton, free or otherwise 

 

[wasp131]

Hi scottiebabie,I think you misunderstand what that cap does in this circuit, Im no electrical engineer but from what i have read the cap is there to filter/block any dc voltage from reaching your amp,
The signal is ac voltage,but can have some dc voltage polluting the ac signal and the caps block this from leaving the dac and entering the amp, some amps have caps on the input to stop this, as its very bad news for your speakers/headphones if any dc gets through and is amplified by your amp,it will pop your drivers.
So the caps are protecting your gear from dc,You can get away with no caps on the output of your dac if your amp has input caps protecting it,most do,but not all. Can any more knowledgeable guys confirm this.

 

[wasp131]

I found the store on ebay i bought mine from, have versions using four different caps on the output.
Of course they are charging £5 extra for these tweaked versions.

ebay link

 

[scottiebabie]

Quote:

Hi scottiebabie,I think you misunderstand what that cap does in this circuit, Im no electrical engineer but from what i have read the cap is there to filter/block any dc voltage from reaching your amp,
The signal is ac voltage,but can have some dc voltage polluting the ac signal and the caps block this from leaving the dac and entering the amp, some amps have caps on the input to stop this, as its very bad news for your speakers/headphones if any dc gets through and is amplified by your amp,it will pop your drivers.
So the caps are protecting your gear from dc,You can get away with no caps on the output of your dac if your amp has input caps protecting it,most do,but not all. Can any more knowledgeable guys confirm this.

nope no misunderstanding on my part but u are absolutely correct in the function of those caps. i did mention in my prior posts that they are DC coupling caps or DC blocking caps. the DC offset (outputted by the DAC/s itself) can be an issue esp when amplified by the amp as driver coils may overheat & driver cones maybe over driven & be damaged.
 
as mention alot of amps have a cap somewhere along the signal path although they are some that are fully DC coupled (&these are the amps one must be very careful about). the best way to check is by hooking up a DMM to the speaker taps & measure the DC offset directly. conservative recco is anything up to 20mw although my research says its fine up to 50mw. anything past that is not healthy to say the least.
 
if u have an amp thats DC coupled then the ori DAC with DC coupling caps are a must. otherwise, its golden. btw its a wonderful audio experience anytime one can safely remove a cap in direct signal path. caps (no matter the quality & expense) introduce a multitude of sonic degradations of which bass rolloff (high pass RC filter), phase distortions & capacitor material distortions rank highest IMO.
 
so my bottomline is & always will be - take em off if its anyway possible. geee....sounds like a pickup line!!!

 
 

 

[wasp131]

That info ties in nicely with what ive read

 
I think i was thrown a little when you said "the only thing that could damage the dac is a reverse current feed from amp back to dac for whatever the reason"
ive not run across that problem in any of my reading.
I was going to do this mod myself but i don't think it would be wise on a stax amp.

 

[]eep]

Quite right. But like I said, I can't sell 'm that way. I can't risk damaging other ppls stuff.

I saw the modified versions on Ebay. Were they actually sent from within the UK? I can't see how they make money on that if that were so. Including VAT and all. Seeing as they are the same price in China (on Taobao they cost ¥300 which is about 30GBP).
Nice idea to sell modified ones, only what's the use swapping one electrolitic cap for another? Very minor.