Ithink i have found it. Pin 5 is getting the signal,but thats the last of it. I think it is solder connection between pin 3 and output cap. Ill post pics soon.
Salas,
What's the purpose of that 120 Ohm resistor in your schematic that is connected between G2 and plate?
What's the purpose of that 120 Ohm resistor in your schematic that is connected between G2 and plate?
It makes it a triode without a resistor as well (direct connection).
My question was - what's that resistor's purpose there? Any particular reason other than "everyone else put some resistor there"?
My question was - what's that resistor's purpose there? Any particular reason other than "everyone else put some resistor there"?
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Try a simple one like this first. Connect signal grounds also to the shown pre-amp star.
*Do I see the plate load resistor directly on +force and then the +sense wire going elsewhere in your pic? It will not do. 2 wire pairs go to 2 defined B+ and GND points. No more on the regulator outputs is allowed.
Attachments
Mine is connected this way with the exceptionthat filament ground is attached to sense. I will route it to psu grounds like your pic. Sense wires are both connected to same place as force. Signal grounds are connected as you have them drawn. I will rework signal wiring before work.
Thats where one screw up is. I have B+ connected above Rl and S+ connected below Rl. Found it while rerouting grounds. Unfortunnately i zapped a filament this morning, so i will have to get some more tubes. Lets hope the one channel works. I am changing my avatar to Muddy Waters.... because thats what i do to a thread.
Bingo! Sense transistor was stealing my signal. I have to readjust B+ and install new tubes and we should be ready to go.Thank you for entertaining a fool for so long. Ight as well get a tube rectifier while i am at it. Can i put all the pre filter with seperate psu enclosure. I noticed Gregpry did this. Got shielded AC cable bringimg in both rails currently. Could put small decoupling cap in main box.
I suggest you bring it to ''full play'' status as it is first, 100% nice with no ground loops etc. Evaluate for a while, then you take next steps. Of course you can change arrangement or substitute rectifier, but evolve a good grasp of its practical routing and sound signature first.
Excellent advice. Just excited to get it running. I like things to be tidy, so i immediately started thinking about ways to "clean it up". PRefilter outside of the box would help a lot. Oh well. In time. Thanks Salas.
I understand you want to finish it optimally all in one go but a P2P tube preamplifier with specialized regulators and CCS for heaters, two channels in a box and all that routing, can bring too much new data in one go for a first attempt by a class A Mosfet background guy. So far much is done in not too much magic smoke. Take a breath.
Made music at lunch. Problem was cut gate resistor on bottom BJT that came from changing it out. Making music, but distorted and definetly not amplified any. Will check input resistors as well as other connections. Acting almost like a buffer.
Salas,
I will build the preamp with the 7C5 tubes and the SSHV1 regulator , is it useful to use a regulator for each tube 🙄 ?
I will build the preamp with the 7C5 tubes and the SSHV1 regulator , is it useful to use a regulator for each tube 🙄 ?