martin manning wrote: ↑Wed Jul 12, 2017 10:31 pm
1. Yes, that will prevent a shock when inserting a fuse, in this case the amp would have to be plugged in with the mains switch turned on for that to occur. Fusing the center tap is a questionable practice since there will still be high voltage present if it opens (you should really fuse both red leads), and when the bias supply comes from a tap on the HV secondary as it does in your case, the bias supply caps will likely be destroyed when the fuse opens.
2. No problem. Run the standby switch wires down on the chassis, parallel to each other or twist them together, and arrange other wires to cross them at a right angle.
When you say (you should really fuse both red leads) do you mean Red / Blue and Red / Yellow for the Bias tap?
Thanks,
Both reds to the rectifier I presume. I only read your question not all the posts. Dont fuse the bias if you lose your negative voltage you will fry your tubes
Like this, but be aware of the the issues with using only one fuse on the CT ground (red/yel) lead I mentioned above. The better (two fuses) system would require that you add another fuse holder.
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martin manning wrote: ↑Thu Jul 13, 2017 2:08 am
Like this, but be aware of the the issues with using only one fuse on the CT ground (red/yel) lead I mentioned above. The better (two fuses) system would require that you add another fuse holder.
martin manning wrote: ↑Thu Jun 01, 2017 12:39 am
Parallel the primaries for 120V operation (connect 1 and 3, and 2 and 4). For the secondary you can use 5 and 7 or 8 and 7.
Martin you seem to know the most about the The Hammond 186B12 that I am using for the relays. For the 120 Volt should I just connect 1 and 2 at the same points as the White and Black wires from the PT?
Thanks,
Dave
norburybrook wrote: ↑Sun Jun 04, 2017 5:23 pm
I use a Hammond black coated FX pedal box and drill it out for the two switches, two LED's and a midi 5 pin din socket.
use another midi 5 pin din socket on the back of the amp, star quad cable and some 5 pin connectors and you're good to go.
footswitch.JPG
Marcus
I am thinking of doing something very similar. Would a standard MIDI cable work?
Actually on the combo I just built I didn't bother putting a connector on the footswitch and just wired 5 meters of star quad cable to a 5 pin din plug at the amp end and had it hard wired at the footswitch end.
As Martin said, as long as the plugs and sockets are compatible it doesn't matter what they are. If you can build an amp you can certainly solder a 5 pin DIn cable/socket, fiddly as they are
norburybrook wrote: ↑Sun Jul 16, 2017 1:49 pm
Actually on the combo I just built I didn't bother putting a connector on the footswitch and just wired 5 meters of star quad cable to a 5 pin din plug at the amp end and had it hard wired at the footswitch end.
As Martin said, as long as the plugs and sockets are compatible it doesn't matter what they are. If you can build an amp you can certainly solder a 5 pin DIn cable/socket, fiddly as they are
M
So I am doing a combination of ideas. I got the 3 button Marshall generic switch from amplifiedparts.com, gutted it and will drill out the wire hole to fit the 5 PIN DIN. For $25 it is a nice case with rubber pad on bottom. Then I will either build a cable like a MIDI cable with all 5 wires but first see if a standard MIDI will work. If you are wondering why it's not complete is that I needed to order another 5 PIN DIN female socket. So amp and footswitch should all be completed this week.
Doing some research on another forum also said this:
>> The mono price midi cables have all 5 pins connected through! so you can use them for both DIN Sync and MIDI!
If that is true a 15 FT cable is $4 plus shipping. That would be awesome.
Dave
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Well I will be working with a professional amp builder when we fire this up for the first time. I pulled this from the OTS 100 tab from the Voltage spreadsheet from Ceriatone. Can someone confirm these are the correct voltages I should be working with?
Thanks,
Dave
Voltages For Checkout.png
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Certainly good for ballpark values. Your PT may not have the same spec, you may have different plate resistor values in your amp, and the variation among tubes alone could cause differences of 5 or 10V. The power tube voltages will be set when you bias them, so those values will fall out for your plate voltage, and they won't be identical. In short there is no exact target for the voltages and you may be tweaking things to your taste anyway.
martin manning wrote: ↑Sun Jul 16, 2017 10:01 pm
Certainly good for ballpark values. Your PT may not have the same spec, you may have different plate resistor values in your amp, and the variation among tubes alone could cause differences of 5 or 10V. The power tube voltages will be set when you bias them, so those values will fall out for your plate voltage, and they won't be identical. In short there is no exact target for the voltages and you may be tweaking things to your taste anyway.
