atmasphere
Responses from atmasphere
| Break in period After reading this thread I am surprised that there are still those out there that adhere to the idea that break-in does not exist. Some years back we looked into the phenomena to try to figure out what was going on. As a manufacturer I can tell y... | |
| Balanced in phono stages preamp? Hi Herman, the input of the preamp is differential so the cathodes are tied together. The cathodes are also tied to a 2 stage vacuum tube constant current source whose cathode is tied to a resistor that is tied to B- (-250V).So my bias references ... | |
| Balanced in phono stages preamp? Hi Herman, the point is that to operate balanced differential you *don't* need a common reference point. I don't know how that idea got started but it is mythological insofar as differential amplifiers are concerned.As I have mentioned before, to ... | |
| Balanced in phono stages preamp? Hi jh, if I provide two independent floating bias supplies for the input of the preamp, I don't have to have the grid resistors go to a common point. This way the cartridge does not have a 'center tap'. Yet it still works exactly the same way- no ... | |
| Can tube amps give true high end bass? There are several problems that most transistor designs face in order to play bass.The first is, perhaps a bit counter-intuitively, that they are direct-coupled. Direct coupled amplifiers have response to DC, but when you think about it, the power... | |
| Balanced in phono stages preamp? Hi jh, It sounds like we're not talking about the thing. How about if I create a bias voltage for the input section that is set at something other than ground? I could set it a -1 volt for example. You really want to eat those resistors?? | |
| Best amps for rock and heavy metal I play a fair amount of metal and have a lot of friends who play in metal bands too. But my system is all tube. My speakers are fairly efficient (97 db) and they go to 20 Hz, so with 60 watts I can play any volume I want and shake the house at the... | |
| Balanced in phono stages preamp? So in this particular case, the differential circuit *does* care about ground.Well, no it doesn't. In our preamp we have two resistors because we have to have a 47K input impedance and because the tubes require a grid leak resistance- for biasing.... | |
| What Makes a Good RIAA or Line Stage? Dr. Stanley Lipshitz also published a set of simple formulas for exacting RIAA reproduction. His articles on the RIAA curve can be regarded as reference material. | |
| Balanced in phono stages preamp? Hi Hagtech, when you get a chance, take a look at the schematics for the Ampex recording equipment- something tube like the 351 electronics. What you will see is that the output has an *optional* switched center tap on the output matching transfor... | |
| Balanced in phono stages preamp? Hi Jeff_jones, we wondered the same thing so we put the same circuit into a more budget priced preamp to see how it works. The same advantages appeared and the phono section of our MP-3 is quiet with cartridges of 0.2mV, while at the same time hav... | |
| What Makes a Good RIAA or Line Stage? Hi Thom, I thought I ought to point somethings out. A phono section needs to be really accurate. Many seem that way, but are not as they add something in trying to be 'detailed'.I have found that high overload is a good thing. So our MC section ov... | |
| Balanced in phono stages preamp? Hi jh, the way differential amplifiers work is that ground is ignored. Our preamps are fully differential from input to output and so the ground is merely a shield- no currents are passed through it. This helps prevent ground loops.As I mentioned,... | |
| What Makes a Good RIAA or Line Stage? Hi Thom, having been in the business of balanced phono production longer than anyone else (since 1989- all the prior balanced phono circuit art were not *production* circuits) I can safely tell you that there is a lot of misconception brought out ... | |
| Balanced in phono stages preamp? That is simply not true. It is not required. A cartridge connected to a single ended input sometimes will hum with the ground connected and sometimes without. Sometimes the ground connection makes no difference.This is consistent with balanced ope... |