ps.ps I built a SPICE model for the 227 and it shines in simulation too.

Quote: Originally Posted by rickcr42 When considering a "slew rate" you must also consider "at what fequency ? At what voltage ? Does this vary with load ? Vary with voltage ? stable into a reactive or capacitive load ? " when everything is said and done anything over 25V/uS is...

Xytronic 988. You get to desolder too. Great machine. Higher cost then the rest I suspect though.

My OPA2227 amp (10x) driving HA3-5003 buffers is dead quiet at any volume. I built a PCB board. Check grounding and circuit layout. Rob

If it's a commercial board then it is most likely FR4 with one ounce copper. Small traces and pads are very prone to lifting, when I think I'm going to do a lot of removal work I put a pin in and use it as a jack. Also even though you're only using a 25 watt iron doesn't mean it won't 'cook'...

Just another reason I don't like 9 volt batteries. You really can't recharge them well, here's why. They are constructed of to many smaller cells and it is easy for one cell to be charged more then another which leads to early battery failure. The replacement cost it high and the current...

Copper is a 'gummy' metal and tougher to machine then aluminum. It has the tendency to cause drills to jam. I would use carbides to machine it (C7) and one of the waxed tube lubricants. Higher speeds but slower feeds. I would drill it with the same bits I use for brass. That is I would stone...

Just finished my first amp. (I'm an EE and have been building circuits and kits for 40 years. I also do my own boards) Because this is my first headphone amp. I used jumpers for the input caps and crossfeed circuits. I also used two 47 ohm resistors in the HA3 for current limiting (200 ma). I...

AKG340