JDS Labs C5 portable amplifier appreciation + discussion thread (check 1st post for review) - Page 29

Originally Posted by Gradyoactive 

Has anybody tried the C5 with 250 ohm headphones?  I plan on buying Beyer DT250's and I need an amp that can power their 250 ohm impedance.  

Originally Posted by miceblue 

...you can use the C5 while charging it via mini-USB.

Originally Posted by IanM 

 

useful to know thanks!

 

one more question, are any other colours planned for the C5?

Originally Posted by HybridCore 

I'm hoping for something to match the ODAC case. 

Originally Posted by audionewbi 

they sell silver case with C5, unless your ODAC is black that will be a nice match, dont you think?

Originally Posted by HybridCore 

Doesn't silver or black on the ODAC only indicate faceplate colors? I just assumed since I didn't see photos of a silver case for the ODAC.

 

Unless you're referring to just the faceplates matching.

Originally Posted by audionewbi 

you are 100% correct, ODAC has a slate colour with silver face plate, my apologies. C5 also offer the same configuration. So if you you like silver face plate with slate body on your C5 it will match the ODAC.

Originally Posted by HybridCore 

Doesn't silver or black on the ODAC only indicate faceplate colors? I just assumed since I didn't see photos of a silver case for the ODAC.

 

Unless you're referring to just the faceplates matching.

Originally Posted by miceblue 

John allowed special requests, but that offer is no longer available. What's wrong with the OPA2227?

Originally Posted by adamlr 

not to pick a fight, but the opamp isnt the only component in the design. shouldnt the overall sound be considered, rather than just the opamp? granted, i dont really know, but im pretty sure you can have two different amps, using the same opamp, but still sounding different. is fussing over one single component advisable? john said the c5 was designed around the 2227. and from what i can tell, the c5 measures pretty well with it. so why not?

Originally Posted by burrrcub 

 

 

It's prone to static interference and it ruins my experience.

Originally Posted by miceblue 

Static interference? Wouldn't that be an issue with the enclosure rather than the op-amp? I don't think switching the op-amp would fix that issue.

Speaking of which, I did hear the cell phone interference sound through my headphones when passing through a certain area near where I live (the "boo boop, boo boop, boo boop, boo boop, boo boop" sound such as when you get a text or something).

Originally Posted by burrrcub 

 

My c421 with 8620 never had that problem and it's known to not get any interference.  My source is my cell phone and the static goes away when I'm on airplane mode.

Originally Posted by miceblue 

Hm that's interesting. Perhaps it's not the enclosure then since I think the C5 and the C421's enclosures are identical, except the front plate of course. Still, the circuit is different from the C421, so you can't completely blame the op-amp.

Originally Posted by burrrcub 

 

I'm sure it's the opamp.  My UHA-6S MKII had similar static problem with the OPA209.  Switching to the 8610, it went away.  Even Nick at Leckerton confirmed certain opamps are more likely to have interference than others. 

Originally Posted by Uncle Erik 

Your cell phone is actually a radio transceiver more than a phone. Cells put out up to 0.25W of power and they check in periodically with the nearest cell tower, whether or not you're using the phone.

What you're hearing is RFI interference from the phone. It broadcasts and your amp picks up the signal. RFI can be a tricky beast to tame. It's sorb of like waterproofing something where you can't see the water, it reflects off some materials and comes in through small cracks.

The most obvious way to solve it is to keep your amp away from the phone. Shielded cables, ferrite beads and other methods can work, but RFI can still get in. If you're building an amp, be sure to use an aluminum case - it's great shielding. I think Nevada Surplus has some cases that are RFI tight at a good price. Still, try to move your rig away from the phone. Radio signal strength drops off exponentially with distance.

Originally Posted by miceblue 

It is a very attractive colour in my opinion. Not very many companies offer portable amplifiers with different colour options, so having something other than the regular 'ol black or silver is a neat offer.

 

I tried the K 701's with "Crysis Warhead" and boy does that bass boost switch do wonders for explosions! I'm loving it so far; the K 701's detail retrieval + imaging + C5's bass boost "theater-effect" explosions.