PCB Can Be Done Right!
- Thread starter Fresh_Start
- Start date
Bludave
New member
Re: PCB Can Be Done Right!
Its probably hiding something he didn't want in the picture
Its probably hiding something he didn't want in the picture
Fresh_Start
New member
Re: PCB Can Be Done Right!
I'll bet you a pitcher of beer that's the answer :friday:
Chip
I'll bet you a pitcher of beer that's the answer :friday:
Chip
joelap
Red&Goldologist
Re: PCB Can Be Done Right!
From Merlin Blencowe's website www.valvewizard.co.uk (I highly recommend purchasing his book on preamps, its the best I've read on the subject of tube preamp design)
"The common pre-amp valves (ECC83 / 12AX7 etc.) when run from a 6.3V supply, should be wired from one side only [see right], not by looping one heater wire all round the valve socket, which would create a hum loop and cause excessive interference noise (though many amp makers DO make this mistake and get away with it). The wire twisting must be kept very tight right up to the socket, where it matters most. Their pin arrangement is also deliberate, so that the main heater pins (4 and 5) can be orientated towards the chassis wall, allowing heater wires to be run along the wall away from any other sensitive signal wiring."
Like this:
And not like this:
Aside from the fact that the twisting is not tight enough/uniform enough, see how the black wire to pin 9 loops all the way around the tube? Defeats the purpose of twisting the wires, and you end up with 300mA of AC current per tube crossing the high impedance wire which connects to the grid of the tube. Can induce hum and noise and what have you.
From Merlin Blencowe's website www.valvewizard.co.uk (I highly recommend purchasing his book on preamps, its the best I've read on the subject of tube preamp design)
"The common pre-amp valves (ECC83 / 12AX7 etc.) when run from a 6.3V supply, should be wired from one side only [see right], not by looping one heater wire all round the valve socket, which would create a hum loop and cause excessive interference noise (though many amp makers DO make this mistake and get away with it). The wire twisting must be kept very tight right up to the socket, where it matters most. Their pin arrangement is also deliberate, so that the main heater pins (4 and 5) can be orientated towards the chassis wall, allowing heater wires to be run along the wall away from any other sensitive signal wiring."
Like this:
And not like this:
Aside from the fact that the twisting is not tight enough/uniform enough, see how the black wire to pin 9 loops all the way around the tube? Defeats the purpose of twisting the wires, and you end up with 300mA of AC current per tube crossing the high impedance wire which connects to the grid of the tube. Can induce hum and noise and what have you.
Wattage
High Voltologist
Re: PCB Can Be Done Right!
Nah the meth head would have disaasembled it that neatly
Nah the meth head would have disaasembled it that neatly
Jolly_Rancher
New member
Re: PCB Can Be Done Right!
Mesa boogie has been known to cut corners and have bad layouts because of their cost-cutting measures. They are a mass-produced high-end amp company. Nothing like THD or 65 Amps, or the other "garage-based" builders. Andy Marshall's THD amps have been said to have the best PCB designs on the planet. I know they sound untouchable!
Yes, looks are sometimes deceiving. I think it's safe to say that if it look too clean, it's probably no functioning as well as it could be if function was #1 in the mind of the builder. boogie asserts things in their marketing about how they believe in all of the mojo affecting religious ideals such as electromagnetic radiation, capacitance, and such of wires touching other wires, as well as high-frequencies traveling on the outside of the metal, but they don't act on those words.
Mesa boogie has been known to cut corners and have bad layouts because of their cost-cutting measures. They are a mass-produced high-end amp company. Nothing like THD or 65 Amps, or the other "garage-based" builders. Andy Marshall's THD amps have been said to have the best PCB designs on the planet. I know they sound untouchable!
Yes, looks are sometimes deceiving. I think it's safe to say that if it look too clean, it's probably no functioning as well as it could be if function was #1 in the mind of the builder. boogie asserts things in their marketing about how they believe in all of the mojo affecting religious ideals such as electromagnetic radiation, capacitance, and such of wires touching other wires, as well as high-frequencies traveling on the outside of the metal, but they don't act on those words.
eschoendorff
New member
Brown Note
New member
Re: PCB Can Be Done Right!
I'd rather put bad layouts into the category of pure incompetence and hasty design than cost cutting and mass production. There's actually nothing wrong with surface mount devices and ribbon cables, though an experienced designer is needed to design the pcbs. PCB layouts are actually *very* hard to lay out properly and even the best need to make a few duds before the product is finished. Marshall has used the same PCB layout since the early 80's in their 800 series and they work well enough and sound awesome.
I'd rather put bad layouts into the category of pure incompetence and hasty design than cost cutting and mass production. There's actually nothing wrong with surface mount devices and ribbon cables, though an experienced designer is needed to design the pcbs. PCB layouts are actually *very* hard to lay out properly and even the best need to make a few duds before the product is finished. Marshall has used the same PCB layout since the early 80's in their 800 series and they work well enough and sound awesome.
joelap
Red&Goldologist
PCB Can Be Done Right!
PCB layout is an art backed up by science. There's a reason it's referred to as artwork. It's also one of the few things you can copyright (or one of those protection things). For instance I can build a 2550 clone using the same exact parts and be fine legally. But if I use the same layout, I'm in legal trouble.
PCB layout is an art backed up by science. There's a reason it's referred to as artwork. It's also one of the few things you can copyright (or one of those protection things). For instance I can build a 2550 clone using the same exact parts and be fine legally. But if I use the same layout, I'm in legal trouble.