Some of those white ones are plenty secure. I have some that are rated at 30 amps and the screw clamp is very secure and very solid. They either came from Mouser or Digikey. Not all of them are that heavy duty. The smaller black ones I also used were not rated as high amp wise, and with ring ends may be more "secure", but nothing is inside my amps tugging on them!😀
I didnt use them like you did between boards and power supply, I used them for the slow start assembly with the CL-60 devices.
Russellc
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Nelson mentions you can skip the buffer if you have a low impedance source.In a later post he mentions <100 ohms.I am going to build this amp and have a Schiit Magni 2 headphone amp that has pre outputs (75 ohm) and enough drive to do this.My question is will I lose the "magic" of this amp by doing so? I know it will save me a few bucks but that doesn't matter.I just want to get it right.
The Jfets are very neutral. Any magic in that case comes from the transformer
being well driven. If the Schiit sound good into that load, then you are in
good shape.
😎
I have one last question. What would be the load impedance looking into the input of the Edcor (without the buffer),using a 6 ohm load(speaker).The Schiit can drive 600 ohms at 160 mW rms/ch, 2.1 W/ch into 16 ohms.
dunno , didn't measured and didn't simulate that
however , speaker impedance isn't having anything with input impedance at xformer input ..... simply because output mosfets are nothing else than another buffer
if you have two pairs of Toshiba JFets - try with them , and try without them
if not - either go for Shiit's cojones .... or make another sort of buffer
I believe one Greedy Boy already made diamond buffer iteration , as far I remember - for F6 , which is similar - having iron in input
however , speaker impedance isn't having anything with input impedance at xformer input ..... simply because output mosfets are nothing else than another buffer
if you have two pairs of Toshiba JFets - try with them , and try without them
if not - either go for Shiit's cojones .... or make another sort of buffer
I believe one Greedy Boy already made diamond buffer iteration , as far I remember - for F6 , which is similar - having iron in input
I finally mounted my Teabag boards to there heatsinks last night. It's taken awhile. The left channel powered up ok with the voltage across the source resistor R13 reaching 597mv after a few of mins and the offset was settable to a few mv's. Unfortunately the right channel took close to an hour to reach 455mv across R13 but the offset was adjustable to near zero.
Elfishi has recommended to check the voltage rise over C3 which I will do later as it means removing the board from it's standoffs and bending the mosfet pins.
Any other guidance will be much appreciated.TIA
Elfishi has recommended to check the voltage rise over C3 which I will do later as it means removing the board from it's standoffs and bending the mosfet pins.
Any other guidance will be much appreciated.TIA
cap is connected to two pins on optocoupler , so measure on optocoupler , no need to reach cap pins
if thermal connection of mosfets to heatsinks is stable , if all solder points are OK , if all resistor values are OK , then change optocoupler
if thermal connection of mosfets to heatsinks is stable , if all solder points are OK , if all resistor values are OK , then change optocoupler
I have little hook shaped test clips that I attach to cathode and anode of D1 and D3, respectively. Ne need to pull anything apart.
Edit: R8 and R9 may be better to reach on Tea-Bag's boards.
Edit: R8 and R9 may be better to reach on Tea-Bag's boards.
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all you need to measure is across source resistors , between the gates (both in front and after gate resistors, to confirm no gate leakage there , in case something is fishy)
Taken from Tea-Bag's blog---"Here I make special note of my mistake in construction. Somewhere between looking at the datasheet, remembering the symbology as presented for DIP-6 devices and soldering it in, I put mine in backwards. The amp mostly worked, but it did not settle down it's bias to the .650v that is expected once it gets going. So, since the 4N35 was square and the dot on one side, the dot goes towards the curved back end of the optocoupler. "
Maybe your's is in backwards.
Maybe your's is in backwards.
Thanks for the reminder but I remembered Teabags blog and it was the first thing that I checked. It was in the right way round.
Hopefully I will get chance to do some checks tomorrow
I've just done a quick check and all resistors are correctly placed. Across C3 I have 10.21v on the left channel with 8.76v on the right.The voltage across R13 is 598mv left but only 245mv right.
As suggested by Zen Mod I swapped out the 4N35 but unfortunately this has not made any difference.
The voltage across the right R13 continues to rise very slowly but maxs out at 450mv after approx 45 minutes.
As suggested by Zen Mod I swapped out the 4N35 but unfortunately this has not made any difference.
The voltage across the right R13 continues to rise very slowly but maxs out at 450mv after approx 45 minutes.