I was mostly curious about the current...
It was my experience that it sounded (much) better at 18v than at 9v, 12V, or 15v. Though there is something REALLY special going on in the mids and soundstage at 9v, but the bass sucks.
Chris
p.s. I'm using a 2w PEC stereo pot in mine though. I am curious to try the Lightspeed one of these days though.
It was my experience that it sounded (much) better at 18v than at 9v, 12V, or 15v. Though there is something REALLY special going on in the mids and soundstage at 9v, but the bass sucks.
Chris
p.s. I'm using a 2w PEC stereo pot in mine though. I am curious to try the Lightspeed one of these days though.
Remove the LED's current limiting resistor from the B1 if you tap off of this.
You would put a jumper inplace of the resistor.
You would put a jumper inplace of the resistor.
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Joined 2002
Ive opted out for the lightspeed, instead a nice BRAND NEW 25k Noble pot. Just like Nelson say's, KISS method 🙂
Since my post was missed the first time I asked these questions, I'll try again...
I have the chassis in hand and I have checked the voltages of both of the output devices 17.8v / 4.8v. The numbers on the 18 volt device say 342 SFC with 2818RC below the 342 number. I haven't been able to find anything on that device. The 5 volt device says L7805SCT. I found that at Digi-key and it says it's output is 5 volts... http://www.datasheetcatalog.org/datasheet/stmicroelectronics/2143.pdf
The power supply has 2 caps and what look like 4 diodes.
The chassis is very nice and will make a great place for my B1.
Can or should I use this PS???
Thanks in advance for any help!
eddie
I have the chassis in hand and I have checked the voltages of both of the output devices 17.8v / 4.8v. The numbers on the 18 volt device say 342 SFC with 2818RC below the 342 number. I haven't been able to find anything on that device. The 5 volt device says L7805SCT. I found that at Digi-key and it says it's output is 5 volts... http://www.datasheetcatalog.org/datasheet/stmicroelectronics/2143.pdf
The power supply has 2 caps and what look like 4 diodes.
The chassis is very nice and will make a great place for my B1.
Can or should I use this PS???
Thanks in advance for any help!
eddie
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I pulled all the power supply past the transformer and used a 18v regulator board from Welborne. Be careful about which leads you use if doing similiar. I ended up using the leads that went to the +5v circuit. The +18 v leads were too high for the filter caps (35v) on the board. The orange wire needs to be insulated and tucked aside with the other unused secondaries. Also added IEC connector/line filter and line fuse holder on back panel.
Combine the voltages?
So, can I combine the voltages from both outputs to give me ~23 volts? Do I need any other caps with this arrangement?
eddie
So, can I combine the voltages from both outputs to give me ~23 volts? Do I need any other caps with this arrangement?
eddie
So you didn't use the output from the board in the chassis... but you did use the transformer. What was the reason you didn't use PS as it was?
eddie
I din't use original PS board because was concerned about 30yr old caps,etc plus better parts on Reg board did use
I have been trying to figure out a basis for tweaking the VCC. The input of my as yet unplugged B-1 will see a max of 2 VRMS. This suggests that as much as 6 V peak-to-peak can be expected. A quiescent Source voltage of 1/2 VCC with a 9V supply suggests that the follower has to swing from 1.5 to 7.5 volts. That may be tight. If I understand correctly (an unlikely possibility) the pinch off voltage has to be subtracted from the VCC and still leave headroom. At 9 Volts it seems to me that the circuit has to be dead nuts tweaked.
I rapidly become lost when it comes to calculating a supply voltage that minimizes noise, maximizes linearity, and accommodates the peak-to-peak voltage applied to the gate.
Shorting unused input on the B1
Since I only plan to use one of the inputs on the Pass B1 circuit board, should I, or do I need to, short the unused input to ground?
Thanks for any help.
Since I only plan to use one of the inputs on the Pass B1 circuit board, should I, or do I need to, short the unused input to ground?
Thanks for any help.
Hi,
you could leave out the switch and take the input straight to the switch output pad.
Or, just leave the switch in the always 1 position and then anything on the 2 position never affects the B1.
you could leave out the switch and take the input straight to the switch output pad.
Or, just leave the switch in the always 1 position and then anything on the 2 position never affects the B1.
I think if you take your inputs straight to the switch output pads, you bypass a resistor.
Perhaps best is hardwiring the switch pad with a tiny length of solid core wire, to make a permanent link to input A's "on" position, and ignoring input B, which will then be isolated.
Perhaps best is hardwiring the switch pad with a tiny length of solid core wire, to make a permanent link to input A's "on" position, and ignoring input B, which will then be isolated.