Probably somewhere between ten to twenty feet of cable at 31 pF per foot.
Isn't the formula something like F = 10 / (2 * pi * Rg * C)? That would put 31 pF at 100 KHz, and 310 pF at 10 KHz. I'm assuming there is a 500K ohm grid resistor at the first input tube. Changing that will affect the results.
Isn't the formula something like F = 10 / (2 * pi * Rg * C)? That would put 31 pF at 100 KHz, and 310 pF at 10 KHz. I'm assuming there is a 500K ohm grid resistor at the first input tube. Changing that will affect the results.
Not much progess has been made since the board arrived on Monday. I think USPS was teasing me by getting the board to me so fast as the rest of the parts are now running late. 
Majority of the board components were shipped from Mouser on Monday via Priority Mail and they still aren't here yet.
So far, I've only received the FREDS and a couple caps from DigiKey and my ASC cap from Allied. Everything else is "on the way".
I do have one pic I can share though:
Majority of the board components were shipped from Mouser on Monday via Priority Mail and they still aren't here yet.So far, I've only received the FREDS and a couple caps from DigiKey and my ASC cap from Allied. Everything else is "on the way".
I do have one pic I can share though:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Thanks Ty, Nate, et al. Good to know I'm not dead in the water without them. I just wanted to confirm that I could run the amp without them installed. I will likely add them later just because but I'm not about to make a special order just for two diodes. I'll wait til I need some more stuff from DigiKey or Mouser to justify the shipping expense.
Meanwhile, USPS just delivered my KT88's and some used EL34's (for testing) along with all the board components from Mouser.
Meanwhile, USPS just delivered my KT88's and some used EL34's (for testing) along with all the board components from Mouser.
N1ESE said:
I got a box of tubes today as well, EL34s and 6L6GCs reporting for testing duty. I also made a discovery last weekend that I didn't have a DMM that could handle the B+ of the Simple so I remedied that with the purchase of a Fluke 179 this morning. 1000V will hopefully give me enough headroom to test this beast.
n_maher said:Simple so I remedied that with the purchase of a Fluke 179 this morning. 1000V will hopefully give me enough headroom to test this beast.
Nice, I need to get one that can handle 1000V myself. My current unit only handles 600V I think.
Just flicked the switch on the soldering station, time to install the resistors. I can't do too much else though as the tube sockets have not arrived yet. UPS has my AES order with the sockets and Hammonds arriving on Monday.
All resistors except for the missing ones for R17 and R27 have been installed. R1 will not be used. Missing resistors and FREDs have been reordered.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I have fried two sets of solid state diodes in my Simple SE. This was due to the implementation of the standby switch. Just in case you have not seen it on the web site, do NOT install the standby switch. With some transformers (I have Hammond 374BX) there can be a large voltage spike when the standby switch is turned on. Now, if you don't have a standby switch, you will want the B+ to come up slowly. This means using a valve rectifier rather than solid state.
Leave the solid state out and simply buy a spare GZ34/5AR4. Use the time/effort that you were going to use putting in the switch for SS/valve rectification to have selectable cathode bias for different valve types. See http://www.diyaudio.com/forums/showthread.php?postid=1526165#post1526165
No need for anything fancy to do this. I just used some cable ties to tie three resistors together. Closest to the board was an 820R resistor. This always stays in the cct and there will be a switch to place in parallel with it either a 1.0K (for 597R total) or 2.2K (for 450R total) resistor. before soldering the three resistor package to the board, solder all three legs at one end of the three resistors together. This then gets inserted and soldered to the PCB. At the other end, just solder the 820R resistor in to the board. The loose ends of the 1.0K and 2.2K get soldered to wires that run to a 3 position 2 pole switch (1 pole per channel). The return wire of the switch goes back to the 820R resistor. Now you will have the 820R in the cct at all times. Switch open curcuit gives 820R. This is good for 6L6. Switch paralleled with 2.2K gives 597R, this is good for EL34. Switch paralleling 1.0K gives 450R, this is good for KT88.
Cheers,
Chris
Leave the solid state out and simply buy a spare GZ34/5AR4. Use the time/effort that you were going to use putting in the switch for SS/valve rectification to have selectable cathode bias for different valve types. See http://www.diyaudio.com/forums/showthread.php?postid=1526165#post1526165
No need for anything fancy to do this. I just used some cable ties to tie three resistors together. Closest to the board was an 820R resistor. This always stays in the cct and there will be a switch to place in parallel with it either a 1.0K (for 597R total) or 2.2K (for 450R total) resistor. before soldering the three resistor package to the board, solder all three legs at one end of the three resistors together. This then gets inserted and soldered to the PCB. At the other end, just solder the 820R resistor in to the board. The loose ends of the 1.0K and 2.2K get soldered to wires that run to a 3 position 2 pole switch (1 pole per channel). The return wire of the switch goes back to the 820R resistor. Now you will have the 820R in the cct at all times. Switch open curcuit gives 820R. This is good for 6L6. Switch paralleled with 2.2K gives 597R, this is good for EL34. Switch paralleling 1.0K gives 450R, this is good for KT88.
Cheers,
Chris
Thanks Chris, I knew about the standby problem and thanks for the heads up on the cathode bias.
One more pic for the night. I just mounted a scrap piece of carbon fiber sheet to act as the front panel. Installed so far is a power switch and stereo jack for my iPod. Still have to mount the volume pot but it has not arrived from Japan yet. The flash glare from the camera is a bit intense.
One more pic for the night. I just mounted a scrap piece of carbon fiber sheet to act as the front panel. Installed so far is a power switch and stereo jack for my iPod. Still have to mount the volume pot but it has not arrived from Japan yet. The flash glare from the camera is a bit intense.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Power iron (374BX) and choke (193H) along with the tube sockets arrived today. I wasted no time mounting everything. Still waiting for the missing bias resistors to arrive so I can finish the board and no ETA from Edcor yet on the CXSE's ordered a week ago.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I was able to find some resistors locally so I was able to complete the board assembly. Only thing I'm waiting for now are the OPTs.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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