hey! can i make a castoum wolverine board, which has just 2 transistors instead of 3 or 4? i dont need that much power, and ya know, to make stuff cheaper. i assume i will have to rework the output stage board, but the ips? what about it?
Post #4201 answers your question. Moving away from the build guide and your on your own.
Regards
Regards
yeah got it, all am asking is if its possible, also no. i am not ignoring the effort. this thing is awesome!
Just use a EF3-3 board and install 2 output pairs. It will work just fine at low output levels but I question the practicality of it as each output transistors is about $3 USD
Fired up the second channel today to dial in bias and offset.
With my scope i saw the following output. The frequency seems to be just about 50kHz which means it must be the Cobra S2. I am however a bit surprised that the noise exhibits an amplitude of nearly 300mV. Is this normal with a SMPS? The input is shorted at the terminal, and my scope is connected directly to the board, so i don't think it should be due to bad wiring. 🤔
With my scope i saw the following output. The frequency seems to be just about 50kHz which means it must be the Cobra S2. I am however a bit surprised that the noise exhibits an amplitude of nearly 300mV. Is this normal with a SMPS? The input is shorted at the terminal, and my scope is connected directly to the board, so i don't think it should be due to bad wiring. 🤔
Hi Ponti17,
This Kindle of signaler is just usual when measuring at the output of an smps or on a circuit fédéral from it: if as I understand this is with the probe tip shorted, this is then pure common mode noise current -which the score translate into diff mode- that you are seing.
Also: measurements should be made over 50 ohms impédance and the ground wire of the probe removed and replaced by a wire as short as possible directly attached to the probe groupe ring. Otherwise, what the score displays is Just crap....
Hope this helps.
Kal
This Kindle of signaler is just usual when measuring at the output of an smps or on a circuit fédéral from it: if as I understand this is with the probe tip shorted, this is then pure common mode noise current -which the score translate into diff mode- that you are seing.
Also: measurements should be made over 50 ohms impédance and the ground wire of the probe removed and replaced by a wire as short as possible directly attached to the probe groupe ring. Otherwise, what the score displays is Just crap....
Hope this helps.
Kal
Sorry for that.
Now a quizz: guess where in the text thèse genuine words should appear:
Kind, fed, scope, ground...🙄
Now a quizz: guess where in the text thèse genuine words should appear:
Kind, fed, scope, ground...🙄
Thanks a lot! I still find instrumentation quite difficult sometimes, and your response is a big help 🙂
I'm looking for a grey ribbon cable to use to connect Q103 to the EF3-3 board. I'd appreciate a recommendation.
Thanks
Thanks
Hi Chiptech,
Have you got the latest build guide?
There is an update to the Vbe multiplier section which is worth having a look at.
- Dan
Have you got the latest build guide?
There is an update to the Vbe multiplier section which is worth having a look at.
- Dan
This may be of interest to builders and designers - Digikey now has a listing for 2SC4793 and 2SA1837 's by EVVOSEMI
Might be worth one of the well-equipped team members to grab and test a couple compared with the Toshibas?
The spec sheet doesnt mention a Cob and the speed looks low.
Might be worth one of the well-equipped team members to grab and test a couple compared with the Toshibas?
The spec sheet doesnt mention a Cob and the speed looks low.
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Can I ask which Micro Audio Cobra smps you are using. I can really benefit from your wiring schema as I have a modded S1. Good luck with the noise.
Up to you but perhaps try the new thermal arrangement with Q103 on the main heatsink between the driver transistors and Q104 in free air on the board.
Do you want to send me a couple to measure ?
Right. But that would require drilling a new hole. That skill is above my pay grade.