delivery services are just like amplifiers: some love how they sound and others hate how they sound. that itself says a lot about the wisdom of branding one carrier as good or bad.

Quote: Originally Posted by rembrant Most of us know and understand these limitations. The last thing we need is some one with a horrible attitude either restating or refuting our statements while insinuating that we are all undereducated and beneath them. what you know and what...

Quote: ideally, you don't want the amp's input impedance (=R2//opamp's input impedance =~R2 since opamp's input impedance is much larger than R2) to overwhelm the pot - but even if that happens it is not the end of the world. some people asked me why letting R2 overwhelming the pot is...

Quote: Originally Posted by Jules When someone ask you why you are suggesting a modification, responding by saying even a high school dropout would recognize why makes people think you are a smart ass, or an idiot. People are reading on here to learn, not to be insulted by you...

Quote: Originally Posted by Pars A large value (actually any value) inside the FB loop will effect the gain. I believe even a dropout from a half decent highschool would disagree with that statement. Quote: What I am interested in is your reasoning about why a large...

the postal employee is right about the priority mail not guarantying 2-3 day delivery. i think this was heavily discussed when it first came out a few years ago and usps's commercials then said something like "2-3 day delivery to most places". well, at least you learned a lesson and...

Quote: Originally Posted by Fred_fred2004 He can't he's what we used to call a Troll he spouts rubbish and pretends to know stuff in when reality he is just an attention seeking pratt. Trying to sound important fred, you did such a wonderful job describing yourself. a job well...

Quote: Originally Posted by Pars http://www.tangentsoft.net/audio/cmo...angent-sch.pdf R5 is inside the feedback loop, and most people do not use it, but short it. In my experience going above 100 ohms (by mistake; 470 ohms to be specific) caused massive distortion. I don't see how...

Cmoy got the overall gain right but it was done via a 50% attenuation, achieved through R1/R2. and R1 is indeed needed. you don't want the opamp's base / gate to see the signal directly. R1 is there to help with parasitics. but R1 = 100K is just too big. 1K is a typical number, sometimes...

Quote: Originally Posted by Fred_fred2004 Then why don't you explain it or is that beyond you why explain it to you when you obviously don't understand it?

Quote: Originally Posted by krisjan well i've been looking at Basic Troubleshooting for Headphone Amplifiers and i'm quite sure my problem is listed as Quiet hiss in the headphones...as i said the bsg cmoy also has it... and I am sure you are right about it, .

Quote: would higher impedance phones have less hiss at higher source volumes? hiss is almost a universal sign of opamp oscillating and you shouldn't have it at all if the amp is working properly. that aside, a higher impedance phone means less attenuation by R5, everything else...

Quote: Don't know about bias cancellation circuitry on these opamps. in principle, you should always pay attention to offset cancellation. as anything in life, there are exceptions. the need for offset cancellation depends on the magnitude of the bias current. in your case, the...

Quote: Originally Posted by n_maher Maybe it's just me it is you. we even tip our newpaper delivery guy. I have yet to have a major problem with usps and fedex. ups did recently deliver our package to a neighboring town (which has the same street address as ours) but...

Quote: Having read a couple of articles about the de-coupling, I was curious how much difference it would make if they were not placed right beside the DAC. I used to have tremendous amount of trouble to power on a 8dip PIC device: one out of 10 times it would power on but others it...

Quote: Originally Posted by Fred_fred2004 higher R5 actually improves sound quality (lower distortion, better able to drive long cables, prevent accidental shorts, etc.). but it does lower the loudness, which is another way to cure the high gain in cmoy. This isn't fair to new people...

well, having a schematic helps a lot. it does seem that the output stage is properly biased: the to92 transistors form a constant current sink to drive the diodes. the design is a single rail type and you have to have the input / output caps. a few things to do: 1) you can bypass...

it looks like a fairly good amp. the use of a discrete buffer (to225 transistors) is a good sign - many of the amps built here don't even have that. I would try to figure out how the output buffer is configured and if it is underbiased - it looks like a class AB buffer biased with 3 diodes...

Quote: Originally Posted by Fred_fred2004 Unplug the headphones can you still hear a faint hiss if so its the same hiss you hear when you hold a seashell to your ear. that could also be the sound of some ceramic decoupling caps.

Quote: Originally Posted by dgbiker1 1. Use as little resistance as you can stand for R5, the higher R5, the lower the SQ. higher R5 actually improves sound quality (lower distortion, better able to drive long cables, prevent accidental shorts, etc.). but it does lower the...

Quote: 1.The amp produces a very light hiss. the amp is oscillating. you can build a simple RF probe to confirm it if you want. the stock design does not have power supply decoupling - which is a must for an opamp amp. Put a 0.01u or higher cap, preferrably tantalum, or...

Quote: Originally Posted by cobaltmute It is a fairly simple concept to understand and figure out. tough questions are easy to understand, that's why so many people have understood them so many times. Quote: What I want to know is, should I put resistors there with the...

Quote: Originally Posted by Ron.id What should I do when I want to remove those input caps (C2)? Should I put resistors there with a same value as R3? Actually I run my cmoy without C2, it sounds ok to me. I use AD8397 or AD8066 for the op-amps. if you are reasonably sure that...

Quote: Originally Posted by rds he (professor millwood) is also the same guy who called dcp02 (a bicmos product) the same as dcp01 (a bipolar product). to just name a few of his entertaining bits. I'm not going to bother refuting you point by point anymore. You've done a great...

a 50w NON-ADJUSTABLE iron is too much. the Vellman sounds l ike a great iron.