6L6 and I have had a few emails about this off-line. I don't want to (mis)speak for him, but he had a few points for me that reframed my thoughts on the matter. First, he pointed out that since the B1 is passive the source is driving the amps directly though the pre. If I understand correctly the point of the buffer is to have interconnects of relative length connect the source to the amp(s) without loosing bandwidth. I had noted that I really need to turn up the attenuator to get good volume (not liveliness). He replied that with a 1 volt output (i.e. cd player) and 11 db of gain into the ACAs that I built with the B1 I'd need to turn the nob up quite a, even with sensitive speakers (97db, 12 ohm), because the overall system gain is too low. I believe NPs notes on the B1 say that it was designed to take about a volt into an amp approximately twice that amount (~20 db). I believe that this lack of overall system gain is what causes the lack of liveliness; what you called being related to all the ancillaries. The original F5 has 15 db of gain. Depending on how much gain you put in your F5 and Pearl 2 builds the overall system gain may or may not be enough to sound right in the setup you're using. Swapping out for an Aleph J at 20 db gain might sound "more lively."
Of course I could be very wrong about all of this: I have a PhD in engineering, but don't know a damn thing about electronics...
Well done! Looks great. Which size Galaxy case did you use for your build?
I also have the Aleph J. I think I am one of those people that just prefers gain, to no gain. As you can see from my signature, I have many of the First Watt amps, and almost as many partially finished from this gorum. Also sets of speakers with various efficiencies.
Some combinations work fairly well with B1, where I have no complaint...that said, I always prefer one with gain when substituted in.
Yes, 6l6 is quite the source of help, he did so for me concerning my power supply for B1.
Mr Pass explained it like a car that must be floored to reach 55 mph, equating 55 mph as plenty fast, so why worry if it's full throttle. For many it is. For me in certain combinations. I always seem to prefer gain.
Right now, my B1 is doing duty as "home theatre" control amp, and often runs wide open.
Russellc
Some combinations work fairly well with B1, where I have no complaint...that said, I always prefer one with gain when substituted in.
Yes, 6l6 is quite the source of help, he did so for me concerning my power supply for B1.
Mr Pass explained it like a car that must be floored to reach 55 mph, equating 55 mph as plenty fast, so why worry if it's full throttle. For many it is. For me in certain combinations. I always seem to prefer gain.
Right now, my B1 is doing duty as "home theatre" control amp, and often runs wide open.
Russellc
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2U w/ Al. covers. I struggled a little bit with height (to fit NPs preferred caps plus stand-offs) vs. depth (length of hookup wire) for a width that would fit the board. In the end it was the correct height and width, but a little too deep (which means longer hookup wire that was preferred).
In any case, I'm happy with it, and it was my gateway drug to other builds.
/d
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Thanks for the case recommendation. I have all parts for the B1, except for the case, so I will likely go with your recommendation. I'm impressed with the HiFi2000 offerings through the diyAudio store, having used their chassis for three amp builds.
I hear you regarding amp building as a gateway drug!
Best of luck with your next build.2nd set of questions.
I have the board wired and out of the chassis.
I was trying to figure out the switch connections by using a multi meter.
And this is how I tried it.
With all the source connections not wired, I expected to read no connectivity between Left in and left out.
Would that be correct ?
Then what would be the L1 or L2 source jumpering that would connect left in to left out ?
Thanks
I have the board wired and out of the chassis.
I was trying to figure out the switch connections by using a multi meter.
And this is how I tried it.
With all the source connections not wired, I expected to read no connectivity between Left in and left out.
Would that be correct ?
Then what would be the L1 or L2 source jumpering that would connect left in to left out ?
Thanks
Take a look at the pictures in post #560. Wire your switch that way and you will be good to go.
I built the Mezmerize and it couldn't get a classical recording on a CD player up to normal listening level with an F5. So I replaced it with an O2 headphone amp which really woke up the F5, then through zone 2 pre-out of a Marantz AVR which was even more of an improvement.
Better Late Than Never!
Well, I only bought my B1 Rev0 board from Pass DIY around 2 years ago. It has sat populated on my desk for a year and a half waiting for a case, DPDT switch and PEC linear pots. Finally it is playing music!!!!
And what music it is playing. It replaces a Parasound P/HP 850 that I bought new about 15 or 16 years ago. I was hoping for improvement but am surprised at just how much better everything sounds! Highs are crystal clear, stringed instruments are more detailed, and bass is tighter. It's really cool to be able to hear the subtle differences of different kinds of cymbals and stringed instruments.
WOW!!!!!
Nelson, I can't thank you enough for sharing this great design with the diy world.
Well, I only bought my B1 Rev0 board from Pass DIY around 2 years ago. It has sat populated on my desk for a year and a half waiting for a case, DPDT switch and PEC linear pots. Finally it is playing music!!!!
And what music it is playing. It replaces a Parasound P/HP 850 that I bought new about 15 or 16 years ago. I was hoping for improvement but am surprised at just how much better everything sounds! Highs are crystal clear, stringed instruments are more detailed, and bass is tighter. It's really cool to be able to hear the subtle differences of different kinds of cymbals and stringed instruments.
WOW!!!!!
Nelson, I can't thank you enough for sharing this great design with the diy world.
Voltage and grounding questions
I'm powering my B1 with a Meanwell 24VDC wall wart. What's weird is that by itself it measures 24VDC at the plug, but when I attach it to the B1 the power only reads 9VDC at the input pads!
Also, this morning when I turned it on, and before playing music, I could hear a faint 60 Hz hum on both channels. The pcb is isolated from the chassis by nylon stand offs. So I'm wondering what/where I should ground the pcb in order to deal with the ground loop.
I'm powering my B1 with a Meanwell 24VDC wall wart. What's weird is that by itself it measures 24VDC at the plug, but when I attach it to the B1 the power only reads 9VDC at the input pads!
Also, this morning when I turned it on, and before playing music, I could hear a faint 60 Hz hum on both channels. The pcb is isolated from the chassis by nylon stand offs. So I'm wondering what/where I should ground the pcb in order to deal with the ground loop.
Hi everyone,
I'm thinking on going for LEDs to show the selected input channel, 3 inputs, 3 LEDs. I want to switch on the LED along with the signal by sharing 1 of the poles in the rotary switch. That means a 3 pole triple throw. I will be switching the cathodes to ground as shown on the schematic (excuse my shaky hand).
My question is, am I safe switching power with signal even if it's just 1 mA at ground level or is this a no-no? thanks guys.
I'm thinking on going for LEDs to show the selected input channel, 3 inputs, 3 LEDs. I want to switch on the LED along with the signal by sharing 1 of the poles in the rotary switch. That means a 3 pole triple throw. I will be switching the cathodes to ground as shown on the schematic (excuse my shaky hand
).My question is, am I safe switching power with signal even if it's just 1 mA at ground level or is this a no-no? thanks guys.
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