Hi All,
My son wants to build a B1 & will be ordering the board + JFETS from PassDIY. Regarding the power supply, how sophisticated does it have to be? In the B1 article NP suggests that regulation is not necessary, but what is needed in the PS? Based on what we have on hand, I'm thinking a rectifier (monolithic), a couple of 3300uF capacitors, and a bleeder resistor. Will this work? If so, what am I sacrificing by taking this minimalistic approach? The transformer is a 15V toroid I got at the electronic surplus store for $3 (I picked up a few).
Thanks...
My son wants to build a B1 & will be ordering the board + JFETS from PassDIY. Regarding the power supply, how sophisticated does it have to be? In the B1 article NP suggests that regulation is not necessary, but what is needed in the PS? Based on what we have on hand, I'm thinking a rectifier (monolithic), a couple of 3300uF capacitors, and a bleeder resistor. Will this work? If so, what am I sacrificing by taking this minimalistic approach? The transformer is a 15V toroid I got at the electronic surplus store for $3 (I picked up a few).
Thanks...
Chuck - good plan, it will be completely fine -- probably better than you will expect. It doesn't even need to be that complicated, as it was made to run off a cheap linear DC wall-wart, which is what you describe minus the caps.
Thanks 6L6, again. Soldered it up, getting a little over 20V out. Will need to redo some of it to add shrink tubing and make it zap-proof.
Found this leftover filter in my junk box.
Is there any benefit to use this in front of B1 psu?
An externally hosted image should be here but it was not working when we last tested it.
Is there any benefit to use this in front of B1 psu?
I have a strange behaviour here: just assembled a B1 with old JimsAudio boards I had available. These boards have a layout problem with the connection s but I fixed it.
The buffer works correctly but... led does not light.
I thought it was simply blown but it is not.
Checking voltage on the led I have only 0.4V there and it seems not enough to power the led.
Is it correct..?
The buffer works correctly but... led does not light.
I thought it was simply blown but it is not.
Checking voltage on the led I have only 0.4V there and it seems not enough to power the led.
Is it correct..?
LEDs need to have Vf across them to pass sufficient current to light them up.
Vf varies from ~1.4Vf for an IR type to ~3.3Vf for a white or blue type.
None will pass enough current at a voltage of ~0.4Vdc
Vf varies from ~1.4Vf for an IR type to ~3.3Vf for a white or blue type.
None will pass enough current at a voltage of ~0.4Vdc
Thanks.
I do not worry too much about the led not working there since it's only a status led without any other purpose. But I would like to have a signal of the buffer with current on: where could I drain those few volts in order to make it work with no damage for the buffer functionality?
Ask Jim's for a build guide?
Ask Jim's for customer support.
Ask Jim's in case there is a PCB routing error.
Ask Jim's for customer support.
Ask Jim's in case there is a PCB routing error.
You've probably already checked this, but it could be something simple like wrong value of the LED resistor (R4 in NP's original schematic).
Right now I'm using B1 with old carbon type 50k alps pot. Schematic suggests 25k. Should I change anything on B1? Is ladder type stepped attenuator better than carbon pot?
Sure, it's the regular 15k as per schematics...
What I found today is even more strange: feeding the B1 with a 12v battery I find in that led crazy values, going from 0,2v to 8v, absolutely instabile and crazy.
Wtf.. 😕
Here is my B1. Rather compact! Less noise I hope, because it was a b**** to fit everything. Will change the wall wort for a battery soon.
The sound is much better than with just a pot. It took me two days to build it. First days of Easter vacation and I am already done. Now what to do?
The sound is much better than with just a pot. It took me two days to build it. First days of Easter vacation and I am already done. Now what to do?
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6L6, finally implemented your version of the power supply last night. I find it made a considerable improvement over the lap top style power supply I bought off of Ebay. It also was considerably better than the Duracell battery setup I cobbled together. Didnt help with gain of course, was listening full throttle with the 86 db speakers that were at hand in that room. Sound was way better than before...I still prefer a little gain with the F-5, which I was using. But sound was much more full than before.
For those of you using similar supplies, try the little regulated version 6L6 uses in this build!
Russellc
For those of you using similar supplies, try the little regulated version 6L6 uses in this build!
Russellc
I wonder why the battery version was not as good. This was my next plan, but I could try the power supply version. Where did you find the power supply board and transformer?
Scroll back to the beginning, 6L6 provided a list of parts (not very many at all) and gives the source for the board (Peter Daniels) although it would be simple to point to point. With my Lap top supply, it was transparent, but no body at all. With the little regulated supply, it is full with a richer sound. Better to me in every regard. I had relegated it to disuse until this.
Russellc
Russellc
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