[nwboater]

I'd be interested in hearing more about your adventures along these lines. Looked up the EMU DAC and yes it does look interesting, certainly cheap and cheerful! Amazing really if the mic and line level pre's are as good as the general comment out there. Might be a good way to rip vinyl!
Dave

Hi Dave,

I started a new thread in the Cheap & Cheerful' forum on the 0404USB DAC.

Rod

[usp1]

Not quite sure what you're suggesting, but if soldering is a put off you're probably better off going w/ the stock PS and maybe tinker down the road. The stock kit sounds terrific as it is, and I'm sure you want everything to go right the first time...

I am not explaining myself well. What I was thinking of was starting with the stock kit and adding an outboard bank of capacitors (the aforementioned Panasonic tsha) in addition to the on-board stock caps. My thought was that one could solder on leads from the outboard bank to (perhaps) the underside of the pcb.

I have not entirely given up on the idea of soldering an unpopulated board with panasonic caps. I could always buy an extra unpopulated PS board from Tom to see if I can do the soldering.

[jtwrace]

I am not explaining myself well. What I was thinking of was starting with the stock kit and adding an outboard bank of capacitors (the aforementioned Panasonic tsha) in addition to the on-board stock caps. My thought was that one could solder on leads from the outboard bank to (perhaps) the underside of the pcb.

Why?  Do you really think this amp requires it?  Personally, If you feel the need to upgrade the caps then do that but adding more isn't necessarily going to give you more sonic performance.

I think it would be wise to put the kit together and listen to the unit first then if you still have the burning desire to DIY crazy, then have at it. 

[usp1]

OK...I will start with a basic kit and then move up from there. I was simply brainstorming.

[jtwrace]

I was simply brainstorming.

Nothing wrong with that at all.  I built an amp then before I knew it I had a bunch of cases.   

[poseidonsvoice]

Why?  Do you really think this amp requires it?  Personally, If you feel the need to upgrade the caps then do that but adding more isn't necessarily going to give you more sonic performance.

I think it would be wise to put the kit together and listen to the unit first then if you still have the burning desire to DIY crazy, then have at it.

+100

I'm with jtwrace on this one. The version I auditioned was bone stock and sounded fantastic. The only reason I am building mine with 40,000 uf Mundorf E-lytics is because I have them on hand, not because I special ordered them for this project.

Anand.

[jtwrace]

The version I auditioned was bone stock and sounded fantastic.
Anand.

That's because it was assembled by ME.   

[kingnubian]

Ok this is my first post here on Audio Circle. Seems like a very informative & friendly place, specially for diy kit newbies like myself.

Pleasantries aside, I wish to purchase the SDS-254 kit but would really rather use it as an Integrated amp. How would I go about adding a volume pot (50k, 10k, Alps Blue???) to the mix & what additional components would I need and what are the pitfalls.

Couldn't I just wire the input directly to the volume pot & then on to the amp's input (Diagrams appreciated.)? Seems to easy to be correct...lol.....

[steve k]

That kit already contains gain pots for both channels so you'll already have built in volume control.
steve

[srb]

That kit already contains gain pots for both channels so you'll already have built in volume control.
steve

My understanding was that the gain controls attenuate the gain within a limited range, i.e. not down to "0" volume.  And if I am mistaken and they do, you would probably want to replace them with a ganged stereo pot so you wouldn't have to adjust two pots to change volume as well as fiddle to get equal balance.
 
Steve

[steve k]

They do go down to zero but as you say, replacing them with a stereo pot would be more convenient.
steve

[kingnubian]

They do go down to zero but as you say, replacing them with a stereo pot would be more convenient.
steve

Exactly!

[roymail]

They do go down to zero but as you say, replacing them with a stereo pot would be more convenient.
steve

I had thought about that option, but you might want to check with Tom first.  As I understand it, the purpose of those gain pots is to adjust the amp's gain to match your preamp, and not as a dedicated volume control.  But what do I know? 

[kingnubian]

I had thought about that option, but you might want to check with Tom first.  As I understand it, the purpose of those gain pots is to adjust the amp's gain to match your preamp, and not as a dedicated volume control.  But what do I know? 

Well the included gain pots can stay, but what I'm after is a volume pot.

[Barry_NJ]

what's the difference between atenuating gain and volume of an amplifier?

[srb]

I would think reducing the gain of the amplifier would have an effect of limiting dynamic range as opposed to a volume attenuator on the input.
 
Steve

[kingnubian]

Here is an email answer I got today from ClassDAudio regarding my request for info about adding a volume control. It seems that adding a volume control is very possible.

Question: Do the included gain controls manage each channel individually or does one affect balance only?
-------------------------------------------------------------------------------------
"Hi XXXXXXX,

Yes, it's possible to use a ganged volume pot on the amp. The SDS comes with 2 high quality gain controls you can use as volume control, so all you have to do is get a dual ganged pot... very easy.

I don't have time to draw up a diagram right now, but I can when I have more time.

Please let me know if I can be more help.

Thanks,
Tom"
---------------------------------------------------------------------------------------

Another question. Will the kit fit into this case? I love the case's dimensions and it is predrilled perfectly for my use.

http://cgi.ebay.com/DIY-Audio-Aluminium-Chassis-Power-AMP-Metal-case-03-/160469515048?pt=LH_DefaultDomain_0

[Barry_NJ]

Another question. Will the kit fit into this case? I love the case's dimensions and it is predrilled perfectly for my use.

http://cgi.ebay.com/DIY-Audio-Aluminium-Chassis-Power-AMP-Metal-case-03-/160469515048?pt=LH_DefaultDomain_0

The amp module would fit, but I sincerely doubt it would hold the power supply.

[Barry_NJ]

I would think reducing the gain of the amplifier would have an effect of limiting dynamic range as opposed to a volume attenuator on the input.
 
Steve

Interesting, I'd asked a similar question in the lab...

http://www.audiocircle.com/index.php?topic=83491.0

it was also addressed here earlier regarding the attenuator pots with the SDS kits. I figured I'd rather run without them, and use my pre-amp to control volume, but the general consensus was that they were needed to shelve down the amp. I figured more gain would give the impression of greater dynamics. I'm finding it somewhat confusing.

[srb]

That was the intended use for the gain controls, to be able to adjust the gain of the amp relative to the gain of the preamp.  This was easier than having to modify the board with fixed resistors for 26dB gain or 32dB gain or whatever, particularly if it needed to be changed again for use with a different active preamp, passive preamp or buffer.
 
If the gain is turned down for low volume listening, say to 10dB gain, and a large dynamic peak of 10dB or 20dB comes along, it seems to me that the amplifier would not have the sufficient gain multiplier to be able to reproduce it.
 
At higher listening volumes, this is probably a moot point.
 
Steve