Bauhausler
Rational Subjectivist
All;
I just stumbled on a spreadsheet I worked up a few years ago that I can share if anyone wants it. It computes gain and frequency response for 2-stage SE tube amps at 1/3 octave frequencies. Basically, you put in as variables the tube characteristics and values of the passive compnents and some info on the OPT and it calculates and plots the gain and frequency response at various parts of the circuit. I ginned this up because I was working on a design for a 2-stage SE that would have 12 db/oct hi-pass without extra filter networks. I found that by fiddling the coupling cap and cathode bypass caps I could get exactly the response that I wanted.
The spreadsheet does not have instructions, so right now it's probably suited to experienced excel users. I'll 'donate' this to AK and maybe somebody will want to write up some instructions. It's pretty complex and will take a long time to type up. I'd get to it eventually, but not right away.
In this example, the line 'spkr' represents the response of a passive speaker hi-pass crossover. 'tot db down' represents the response of the tube amp with the component values selected to mimic the speaker crossover responce. 'error' is the difference between them. You can get more accurate responses than this, this was just a handy example.
Here's a pic of what one of the charts looks like:
I just stumbled on a spreadsheet I worked up a few years ago that I can share if anyone wants it. It computes gain and frequency response for 2-stage SE tube amps at 1/3 octave frequencies. Basically, you put in as variables the tube characteristics and values of the passive compnents and some info on the OPT and it calculates and plots the gain and frequency response at various parts of the circuit. I ginned this up because I was working on a design for a 2-stage SE that would have 12 db/oct hi-pass without extra filter networks. I found that by fiddling the coupling cap and cathode bypass caps I could get exactly the response that I wanted.
The spreadsheet does not have instructions, so right now it's probably suited to experienced excel users. I'll 'donate' this to AK and maybe somebody will want to write up some instructions. It's pretty complex and will take a long time to type up. I'd get to it eventually, but not right away.
In this example, the line 'spkr' represents the response of a passive speaker hi-pass crossover. 'tot db down' represents the response of the tube amp with the component values selected to mimic the speaker crossover responce. 'error' is the difference between them. You can get more accurate responses than this, this was just a handy example.
Here's a pic of what one of the charts looks like:
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