Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Tube and solid state power amp software

Not open for further replies.


Junior Member level 1
May 27, 2001
Reaction score
Trophy points
Activity points
proteus tube triode

Dear friends
I would like to inform you that you can find small but very useful program for calculating tube and solid state power amps. Program name is MatchNet 2.1 and you can find it at:

BTW Elektroda is very nice forum!I like it very much!

this topic is of interest to me

most of the bigger cad packages support valves

non better than proteus

so even the lits version is very very good with valves

Well i thought very interesting this software 'case it uses the transcondutance, Cgp capacitance. I think the only problem is it doesn't use Cin and Cout to do the match impedance.
But i liked it so much 'cause it uses also a grid current to calculate the vacuum tube plate impedance.
Everybody knows that if we are using a B class polarization bias ( grounded grid ) amplifier, the plate impedance is different to an other that uses a control grid voltage.


Yes, it uses Cg1k and Cg1g2 or Cg1a to calculate input impedance.
For plate tank circuit calculation it is normaly to calculated output resistance add paralel output capacitance of tube (mainly Cg1a for triode and Cg2a for tetrode)

If you are regarding grounded grid tube amplifiers:
Input Section: Consist of a RC parallel where
1- The capacitance is normally specified in the tube data sheet (Cgk).
2- The catode's resistence is about 20 Ohms for RF triodes.
Use the impedance data above to calculate the matching network. As the Q of the catode impedance is relatively low, it is easy to get a broad impedance matching.
3- Now you mount the matching network in the physical socket of the tube.

For tuning the input matching proceed as foolows:
1- Place the tube in the socket
2- Connect a 20ohms resistor between catode and ground, with a very small leads (or use a short and wide cooper foil).
3- Apply filament to the tube (only filamente te plate voltage should be off).
4- Connect a swepper generator to the input of the matching circuit so that the return loss curve can be measured.
5- Tune the matching circuit, tweking the components to get a return loss between 18 e 20dB across the band of interest.
6- When done take the 20 ohms resistor out. You are ready to begin working in the output stage. What is subject for the next chapter.

I hope this can help somebody!!


Re: Tube power amp software

I think you can find good models of common vaccum tubes for Pspice.
In this case the demo version should be enought for a power amplifier design...

Not open for further replies.

Part and Inventory Search

Welcome to