Hello,
I'm trying to simulate a tube amp circuit in Microcap, but I'm gettin' the error "Matrix is singular".
Probably the error refers to the last part of the circuit, after the OD switch because if I delate it I don't get the error.
How can I resolve the problem (apart from delateing that part of the circuit...😛)
Thanks
I'm trying to simulate a tube amp circuit in Microcap, but I'm gettin' the error "Matrix is singular".
Probably the error refers to the last part of the circuit, after the OD switch because if I delate it I don't get the error.
How can I resolve the problem (apart from delateing that part of the circuit...😛)
Thanks
The attached file is the Microcap circuit file. As a practical matter, only somebody who has microcap can even see your circuit. Please post a *.pdf of the schematic.
(Yes, the Microcap circuit file is written in plain-text, so the circuit can probably be reverse engineered from the file, but I don't think many people are willing to put in a man-month worth of effort to do so.)
There are thousands, even millions, of specific reasons why a circuit becomes singular in a SPICE simulation. In LTSpice the error log file often gives clues to the problem.
In many cases it comes down to a circuit that is "too perfect". Adding some non-idealness - in the form of strategically placed 10 gigohm resistors, or 1 pF capacitors - allows the simulation to converge and run.
Dale
(Yes, the Microcap circuit file is written in plain-text, so the circuit can probably be reverse engineered from the file, but I don't think many people are willing to put in a man-month worth of effort to do so.)
There are thousands, even millions, of specific reasons why a circuit becomes singular in a SPICE simulation. In LTSpice the error log file often gives clues to the problem.
In many cases it comes down to a circuit that is "too perfect". Adding some non-idealness - in the form of strategically placed 10 gigohm resistors, or 1 pF capacitors - allows the simulation to converge and run.
Dale
Thanks for your help!
Here is and image of the schematic at present (it is not finshed yet).
I've also attached the pdf...
Here is and image of the schematic at present (it is not finshed yet).
I've also attached the pdf...
ahah... you got it!
I was using the 12AX7 model by Duncan Munro, now I've switched all tubes to 12AX7A by the same author and no errors comes up!
Thanks
I was using the 12AX7 model by Duncan Munro, now I've switched all tubes to 12AX7A by the same author and no errors comes up!
Thanks
Sorry if resume this old post, but I've expanded the schematic and now I get the error again.
In the attached zip there are the circuit, and 2 libs (one for the OT and one for the NMOSFET used in the power regulator)
The error I get is this
I guess the problem is feedback from RAW/B+1?
In the attached zip there are the circuit, and 2 libs (one for the OT and one for the NMOSFET used in the power regulator)
The error I get is this
Code:
The most common causes of singularities are structural and are caused by voltage loops and missing paths to ground.
These are checked for separately before the analysis is run, so if you get this message, the problem lies in the nature of the circuit.
Singularities can occur because of extreme nonlinearities and strong negative feedback in the circuit.I guess the problem is feedback from RAW/B+1?
Last edited: