You might consider adding a classic power up reset circuit to your board, so the ring counter and other elements remain in a reset state until the power rails come up to valid levels. During the time the power rails are slewing, it's hard to predict the exact behavior of the circuit, so it's...

Hi All First, I think the SoundMax is "ok", the Crystal setup I had in my old Dell Laptop was "pretty good" and the 710 is "good to very good". I bought the Intel motherboard hoping that it would sound as good or better than the Crystal setup and it did not. Disappointed, I sought out a...

Nothing special about the mod - I used non-polarized blackgates for the two caps used to couple the wolfson DAC to the black 1/8" jack. There is really nothing to see in a photo, as these caps are the same size and installed in the same place as the stock units. The board at $25 plus a...

I have an Intel 865PERL mobo and an IBM T42, both with SoundMAX. In the laptop, the sound is downright flat compared to the Crystal setup I had in my old dell, although an amp improves it a bit it is still shrill on the top end and kind of dies during complex passages. The bass is a bit thin...

2 please, PM sent Thanks

It really depends on what regulators you use -- the LM338 and LM317 have different equations for adjusting their outputs. I followed the datasheet for the LM317 and set both of them so their output would be 21V. Look at the data sheet for the device you use to get the correct values of...

I found that the heatsinks ran at about 45C in this application -- screwed through the holes in the PCB, with simple radio shack goop as a thermal grease. As I indicated before, just set the output at 16, then adjust the regulator outputs so roughly half the voltage drop happens at the...

Depending on the transformer you choose, simple TO-220 style heatsinks work just fine (you need wider ones for the opamps), and are surprisingly cheap. If you use separate heatsinks for each device, and keep them from touching, you don't need any sort of pad either, just a dab of heatsink goop...

Amazing... I guess that's why we all wear glasses when we work, right? Glad no one got hurt!

I hate to ask this, but what on earth were you doing when this happened? These beauties, like most diagonal cutters, are rated only for non-ferrous (read Cu and Al) wire of a fairly small guage (according to the Xcelite site, these are rated up to 20ga. soft wire) wire. Anything larger or...

Sorry I took so long to acknowledge arrival -- been very busy! Mine arrived and look great!

FYI, My extra "group buy" transformer has been sold.

I'm thinking of selling off my dynahi parts, as I'm taking a different path. YGPM

I have to admit that I'd rather have a modern dso -- Tangent is right, nothing compares to capturing something that happens infrequently and being able to study it! In an ideal world, I'd have a modern DSO -- no question -- it's simply too hard to justify given my relatively infrequent use...

My 2 cents... I have a nice 4 channel Tek 2246 that I got from eBay and had recal'd for personal use -- total cost with a cart was $450. It has nice clean, small traces and all the triggering modes I could want for "weekend warrior" use. 100MHz bandwidth, and on-screen cursors for voltage and...

Quote: I can't imagine what the Kester smells like as I thought the Cardas smelled terrible It is pretty noxious... I would not use it in a closed space...

FWIW, I've tried several types of solder recently. I was running out myself and grabbed a few feet of various types from friends and gave them a go. IF YOU ARE LOOKING FOR SONIC IMPACT OF THESE, DO NOT READ ON... Kester Sn96.5/Ag3/Cu.5 #58 flux -- Stinky and the final joint are not shiny...

Here is a picture that might help -- I think we're getting mixed up between overshoot (at the end of the rising/falling edge) and this little glitch I see at the *start* of the edge. All photos are same voltage/time scale. This is the thing I cleaned up by adding the small cap across R17...

AMB -- Thank you. I have not been active on the design side for almost 20 years and I'm admittedly rusty. I appreciate your feedback (no pun...). I confirmed that the caps are on R17 and R47, only one per channel. Bottom line is that the amp puts out very nice square waves and sounds...

R17 or R21 and it's mate on the other channel (I can't remember which and I'm about 1000 miles from the board as I write this...) I *think* it was R17, but I'll have to check. This was on the DGARDNER DYNALO board as described on his resource page...

THIS IS IN RESPONSE TO PPL's earlier email... It ended up in the wrong place... r.e. Dynalo -- it's REALLY well matched transistor and resistor wise, and still needed 10pf across the feedback resistor in the gain loop, and 5pf in the second to last stage, across a resistor -- there is a...

Quote: Originally Posted by mono So is it presumably a bad thing to just foregoe the output filter completely? That is, anyone predict the noise will be excessive or have this experience from moddin' something similar? I've an AV710 lying in front of me and I was toying with the idea...

I agree completely -- these are both very nice opamp choices for the PIMETA. We also did a less-rigorous test in the one PPA I own. I hid what was installed from my son and just asked him if he liked what he heard. He always gravitated toward the AD86xx's. I still prefer the OPA627's in...

I want to hear about your findings! I found a couple of square wave test files on the web by searching google for "wav audio test signals". I don't remember the link, or I'd put it here. If you wish, send me PM with your personal email and I'll send you a zip with the whole bunch of test...

Last month, my son and I did a blind "bake off" of op amps with my 650's using a pair of PIMETA's I put together for a couple of his friends. Single 634, cascode class A bias in place. We tried: AD8610/20 soic brown dog (also tried 3x 8610) OPA627 soic all three OPA637/627 soic brown...