Guys, to cut a long story short, one of the main advantages that an external regulated PSU offers is that there is no need to use exotic shielding or manufacturing techniques . Just let distance work its magic. No mu-metal, no annealing, no other geeky words whatsoever ...   Additional...

Quote: Agreed, but I still could add an electrostatic shield between primary and secondary since the transformer was made to order and even though stray magnetic field is low it could be even lower using a mu-metal gasket (annealed ). Any kind of transformer other than that of EI's and...

Quote: The supply is external so even if I had used a low radiation shielded transformer the cable that connects the external supply to the amp would remain.   The wires connecting the PSU and the amp are five (V+,GND+,V-,GND-, safety ground connected to the chassis). If they were three...

Quote: Yes I could do it. For the matter of fact usually the positive voltage regs perform better than their negative voltage equivalents.   But putting a positive voltage regulator for the negative power supply induces asymmetry. What I mean is that any common mode interference in...

Quote: The LT1083 is a 7.5A positive reg and it is in a TO3P package.   The LT1033 is supposed to be the negative regulator equivalent of the LT1085 3A reg and is obsolete.   These (1085, 1033) are pin compatible with the 317/337 regs but the LT1033 is hard to source, is not a...

Quote: The volume pot is between the two opamp stages. Each stage has a gain of +2. The second stage has the diamond buffer inside its feedback loop (see the LME49600 datasheet or anything like that to see what I mean).   Yes the amplifier is DC coupled. The maximum DC offset is below...

Thanks for the comments.   The new amplifier is going to look even better.   As far as noise concerned, unfortunately I have no decent ADC/DAC combination to measure it. An E-MU 0404 USB might do the job but for now the only thing I can do is just make an estimate. With SpectraLAB I...

I have the HD555s and have listened to them with LME49720HA . I 'd say that they match pretty good. The thinner-than-OPA2134 sounding LME's tend to balance and slightly liven up the smooth sound of the HD555's. I don't know however if they'll match the HD700's Normally no adapter is...

      I liked it so much that I got me some professionally made double sided through hole plated boards!   I heard the prototype in comparison to a respectable headphone amp with better headphones  than mine and really hi-end sources and I liked it a lot over the other amp. The...

All that prototyping frenzy took place about a year ago.   Now about the external PSU, the reasons that I made that choice were practical but also technical. First of all if I had to place the transformer inside the headphone amp box then I had to provide some serious real estate for a...

I needed a headphone amp to drive my pair of headphones, not like they needed amplification in terms of SPL but in terms of SQ (Sennheiser HD555 with foam pad removed and damping added on the surrounding walls around the drivers).    I wanted to design my own amp that would upgrade the sound...

How about these: http://www.ti.com/ww/en/embedded/c5000/index.shtml?DCMP=dsp-c5000-c553x-110830&HQS=cheapdsp

Choose straight or right angled according to what serves your purpose best and puts less stress on the jack. For what it's worth, the NYS* parts are actually REAN, which has been acquired by Neutrik, and are lower budget parts (have not used them, but I assume that any branded plug will be...

Here you are: http://www.amazon.co.uk/Neutrik-NPT3RC-Right-angled-Professional/dp/B000LB15XE/ref=sr_1_1?ie=UTF8&qid=1323028806&sr=8-1   That white thing (the whiskers) is just reinforcing the cable.

The problem probably is due to poor jack quality or added stress when the cable flexes. Low flexibility + added length -> stress on the connector when a bending force is applied. The heatshrink reduces flexibility so try to use the shortest length possible if any at all. If you replace the...