Transformer Model
Thanks! I will definitely add it to my library. I since gave up on simulation, the values I got were close, but as far as detailed analysis I did not want to spend much more time on. Also, I ditched Edcor for Hammond. I did not want to wait for their 6-9 week lead time, and their SE transformer are very limited. Hammond had exactly what I needed (gse125) for about 10 bucks more, and Newark had a discount so I pulled the trigger. Maybe I will test this amp and go back and compare it to simulation amd see how close they are.
Thanks! I will definitely add it to my library. I since gave up on simulation, the values I got were close, but as far as detailed analysis I did not want to spend much more time on. Also, I ditched Edcor for Hammond. I did not want to wait for their 6-9 week lead time, and their SE transformer are very limited. Hammond had exactly what I needed (gse125) for about 10 bucks more, and Newark had a discount so I pulled the trigger. Maybe I will test this amp and go back and compare it to simulation amd see how close they are.
I have added a few things since the last post, presence/feedback that ridded of squeeling due to high gain preamps. I cannot seem to get rid the 60Hz Hum. Looking at my power supply, I don't have a choke. Would this be the issue? If I did not want to add one, do I need a resevoir cap and series resistance to the supply circuit I have attached?
Attachments
The capacitance in the last stages of your power supply are only 1uF. Usually these are more in line with the earlier values.
For hum there is a troubleshooting method.
1. Frequency? 60 hz or 120 hz?
2. Does it increase with increasing the volume, or just there constantly.
3. If you remove the preamp tube does it go away?
For hum there is a troubleshooting method.
1. Frequency? 60 hz or 120 hz?
2. Does it increase with increasing the volume, or just there constantly.
3. If you remove the preamp tube does it go away?
A single ended amp has more hum than a dual tube push-pull type.
For 60 Hz it is either the heater circuit, or the transformer itself radiating the 60Hz.
You can eliminated the heater as the cause by temporarily substituting a DC supple for the heater. A 6V toy car battery, like a Power Wheels, but it has to be 6V.
You can test the transformer by extending the wires that connect it and just moving it away from the rest of the circuit.
Can you take a picture of the wiring? Sometimes teh routing of the heater wires can cause hum.
For 60 Hz it is either the heater circuit, or the transformer itself radiating the 60Hz.
You can eliminated the heater as the cause by temporarily substituting a DC supple for the heater. A 6V toy car battery, like a Power Wheels, but it has to be 6V.
You can test the transformer by extending the wires that connect it and just moving it away from the rest of the circuit.
Can you take a picture of the wiring? Sometimes teh routing of the heater wires can cause hum.
Ive got some reallllllly ugly wiring, which is part of the problem. I had a really small chassis that I bought from a surplus store, that was way too small. If I put a a dc bias or supply on the heaters, right now I have a small 5 and 15v, 1 amp voltage regulators or a 50vac tap spare that that I can make DC. How do I wire it to the heater terminals?
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