Recent content by atmasphere

I am of the opinion that the last thing most manufacturers would want is the ability to know how the equipment sounds just from examining the measurements! that of course is a slightly different topic! ;)

I think its close. The thing that relates to distortion is that the ear uses harmonics to tell the difference between sounds. IOW all harmonics are assigned a tonality which is why we can tell the difference between a trumpet and a clarinet. When you add harmonics you alter the tonality. That...

The first thing to understand is moving to a different system in a different room introduces a lot of variables. The playback apparatus can be different which is an enormous variable all by itself. I know exactly what you're talking about as I've heard the exact some thing. Now if two amps are...

Even with fairly simple measurement equipment (an oscilloscope, a dummy load, Voltmeter and signal generator) I've been able to make measurements and hear their implications in a very direct way. However, if you've read thru this thread, I recently explained exactly what measurements are...

The problem is you've not seen all the measurements that can be made. You've only seen the ones that were published. So you are drawing a conclusion based on a very limited sample size, not only with the equipment, but with the measurements too. I can see how you might have come to your...

Yes, the important measurements are usually not published and worse, most people don't understand their significance anyway. To illustrate the issue there is a famous quotation of Daniel VonRecklinghousen (head of HH Scott engineering during the 1960s): If you understand what this says, then...

This statement is false. What usually happens is the important measurements are not published. Many people think this though, as if measurement technology was somehow frozen in the early 1980s. Its been advancing quite nicely since that time! What is important is the distortion spectrum. It...

Finding those cases these days is pretty hard...

Good job on the front panel of that National!

Replace every capacitor feeding the B+ to the radio section (RF front end and IF amplifiers). They might only be 0.01uf but I've found that this is always worth doing, in addition to the usual electrolytics in the main supply.

The first statement is false: all that is needed is a differential input. That way you can receive a balanced input and use either output of the differential amplifier to drive the rest of the circuit; no 'conversion' needed. Regarding the output transformer, when you have multiple taps there...

Or you might be able to rewind the coils. After all, they are only a certain amount of turns on their forms. If you can find a schematic it would tell you what the values are (and might even specify the number of turns required).

My solution for that is to make my own recordings and commit them to LP or Cd or whatever. It really helps if you have the master tapes or master files and were there when the recording was made. These days excellent recording equipment is available for quite a bit less than a lot of people...

Those look like coils to me! I don't think I see even a single capacitor in this shot. They will be a bit of a trick to source if you damage one- be careful!

The meter should be pretty accurate. It will be more accurate mid scale.