I'd be happy to build you the B1 boards if you want to then DIY build them into your own project.
I'm not trying to make money - I only charge £10GBP above what it costs me.
I'm not trying to make money - I only charge £10GBP above what it costs me.
I'm still waiting to see if anyone has any comments regarding a comparison between ZenMods Pumpkins (which I am still having problems with), Pass B1 and Pass P1.7.
Alexander (ZenMod), I haven't given up on the Pumpkins yet but they are still "whooshing" quite happily on power ON.
Alexander (ZenMod), I haven't given up on the Pumpkins yet but they are still "whooshing" quite happily on power ON.
for B1 with an 18VDC AC Adaptor. I measure about 23.5V without load.
The B1 load is quite small, so the output of the adaptor should remain around 23V?
I was thinking of adding some series diodes to drop the voltage down to 18V,
is it better this way or just leave as is?
The B1 load is quite small, so the output of the adaptor should remain around 23V?
I was thinking of adding some series diodes to drop the voltage down to 18V,
is it better this way or just leave as is?
The B1 load is also quite constant. Just use an RC filter to drop the voltage down to 18V (you could one filter for each channel if you want)...
Roscoe
Roscoe
I'm starting with a Capactive Multiplier that outputs about 26V DC. I'll probably got for two separate RCRC filters for the two channels to drop each to about 20V. Am I right in assuming that each B1 channel consumes about 50mA.
No it's not.
It's just like almost all other ClassA stages.
The output load current appears as a current modulation of the supply rail.
In an instantaneous sense, yes. But, over time, it's quite constant, which makes the use if an RC (or RCRC) filter quite appropriate....
This is also the case with class AB and class B if I am not mistaking !?! Or am I misreading what you mean ?
My DCB1 or Mesmerize is a quite constant load with or without signal at the input.
Yes, that comparison also applies to ClassAB and ClassB.
The slight (or maybe more than slight) improvement that the ClassA current modulation offers is that the current variation in one or both supply rails is directly equivalent to the audio signal passing through to the output.
In ClassAB and ClassB these modulating currents start from zero or a low constant current and follow a half wave rectified version of the Audio signal and then return to an abrupt stop at either zero current or that very low constant current.
That abrupt start and stop have a similar effect to the start and stop of a test square wave signal that has a defined rise time.
The current modulations of the ClassAB & ClassB have frequencies that are not audio.
The slight (or maybe more than slight) improvement that the ClassA current modulation offers is that the current variation in one or both supply rails is directly equivalent to the audio signal passing through to the output.
In ClassAB and ClassB these modulating currents start from zero or a low constant current and follow a half wave rectified version of the Audio signal and then return to an abrupt stop at either zero current or that very low constant current.
That abrupt start and stop have a similar effect to the start and stop of a test square wave signal that has a defined rise time.
The current modulations of the ClassAB & ClassB have frequencies that are not audio.
I would have thought there is no comparison given their different purposes.
Hi KatieandDad,
It's the type of capacitor that makes the difference, not if one 10uF or 2 x 4u7 in // - happily, they all have there own tonal characteristics.(ie Mundorf - Sonicap - SolenFC -etc, up and down the price ranges, too)
Single 4u7 should be more than enough unless your load impedance is unusually low and that could produce an alteration to the sound in itself, despite the buffer.
In your post 3225, I assume that you are placing the R-C-R-C filters before the Cmultipliers and just want to increase the Rs to reduce the rail voltage - sorry, but this simple solution changes the sound of the power supply quite dramatically and you might not like the result - a better option would be to use a fet as your active device in the Cmx to absorb a few volts, or add a zener (or led string) to convert it to a single pole regulator - another way that will give better results is to add another Cmx to the 0volt supply line as per the "Ultimte 1541A ..." thread, and others.
Simple device the B1, but so much hidden things!
Like the BOZ, you learn a lot by 'hands on' - it really get interesting when you add a Lightspeed Vol Control (another simple cct) and the extra clarity allows easier optomisation.
It's the type of capacitor that makes the difference, not if one 10uF or 2 x 4u7 in // - happily, they all have there own tonal characteristics.(ie Mundorf - Sonicap - SolenFC -etc, up and down the price ranges, too)
Single 4u7 should be more than enough unless your load impedance is unusually low and that could produce an alteration to the sound in itself, despite the buffer.
In your post 3225, I assume that you are placing the R-C-R-C filters before the Cmultipliers and just want to increase the Rs to reduce the rail voltage - sorry, but this simple solution changes the sound of the power supply quite dramatically and you might not like the result - a better option would be to use a fet as your active device in the Cmx to absorb a few volts, or add a zener (or led string) to convert it to a single pole regulator - another way that will give better results is to add another Cmx to the 0volt supply line as per the "Ultimte 1541A ..." thread, and others.
Simple device the B1, but so much hidden things!
Like the BOZ, you learn a lot by 'hands on' - it really get interesting when you add a Lightspeed Vol Control (another simple cct) and the extra clarity allows easier optomisation.
Well the B1 is built and under test.
First impressions are that it's not as bright as the Pumpkin.
It is ever so easy to DIY and is absolutely silent in operation, something that I cannot say about my Pumpkins.
I eventually used a single Capacitor Muliplier PSU to supply the B1 with just under 28V of clean DC.
I bought 4 x 2SK170 off E-Bay that were "supposedly" matched - they might well be. However, it's just "out-of-the-box" and it works splendidly.
All I need is a little bit of gain between my Arcam CD36 and the Aleph 4, and obviously a bit of volume control as well.
I haven't given up on the Pumpkins yet but they are proving to be disappointing.
The black wires that you can see in the foreground are to the toggle switch and the volume control. I dont want to spoil the case until I have made my final decision on the design.
First impressions are that it's not as bright as the Pumpkin.
It is ever so easy to DIY and is absolutely silent in operation, something that I cannot say about my Pumpkins.
I eventually used a single Capacitor Muliplier PSU to supply the B1 with just under 28V of clean DC.
I bought 4 x 2SK170 off E-Bay that were "supposedly" matched - they might well be. However, it's just "out-of-the-box" and it works splendidly.
All I need is a little bit of gain between my Arcam CD36 and the Aleph 4, and obviously a bit of volume control as well.
I haven't given up on the Pumpkins yet but they are proving to be disappointing.
The black wires that you can see in the foreground are to the toggle switch and the volume control. I dont want to spoil the case until I have made my final decision on the design.
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