mudkicker78
Member
It was right there touching but not attached.
Nobsound 6p1 Amp flaws/mods
- Thread starter StepheK
- Start date
Glad it was something simple. If you notice AC hum, try going with a 22uf first cap, but if it sounds OK, just leave the 4.7uf in there.
mudkicker78
Member
mudkicker78
Member
Thanks for quick replying. I thought the ground was the red wire at the T. I'm glad out of all the new digital tech out there that these are simple to work on.
First off, I would like to thank you for the series of videos on the Nobsound 6p1. After watching your videos, I was curious and bought the same amp with the added headphone output.
Would I be able to do the mode using the same part list?
I was able to acquire the schematic here:
This is the photo of the amp:
Thank you very much!
Would I be able to do the mode using the same part list?
I was able to acquire the schematic here:
This is the photo of the amp:
Thank you very much!
Attachments
That looks like the same schematic, I'm curious how they implement the headphone jack.
mudkicker78
Member
Now I have a question about the resister mod you did. The resister you moved crosses through the output tube from left to right 2 spaces away from the coupling cap on either side. Please forgive me as I am not looking at a schematic. I don't know the pin out. Should that wire remain after moving the resister or remove it?
Attachments
So powered on with all tubes, no smoke
Voltages seem to be ok, I matched both left and right. One thing doesn't seem right is the heater voltage, it's reading 3.4v not 6.3v.
I did proceeded to hook up to my daughter's system and a very slight thump when turned on. No output to speakers.
The meters on the front, How do they work? Do they measure the input signal?
Voltages seem to be ok, I matched both left and right. One thing doesn't seem right is the heater voltage, it's reading 3.4v not 6.3v.I did proceeded to hook up to my daughter's system and a very slight thump when turned on. No output to speakers.
The meters on the front, How do they work? Do they measure the input signal?
So powered on with all tubes, no smoke
I did proceeded to hook up to my daughter's system and a very slight thump when turned on. No output to speakers.
The meters on the front, How do they work? Do they measure the input signal?
Hello @wendell . Can you confirm what are the other voltages you are getting from the transformer.
It is weird. It looks like you might have a 220v transformer. Assuming you are using a voltage regulator to step down 126v to 116v. Then 116v/220v*6.3v=3.32v on the heaters.
Hello @wendell . Can you confirm what are the other voltages you are getting from the transformer.
I hooked it up straight to my kitchen wall. In my daughters bedroom it will be hooked up to an APC Line 1200. Here some voltages
Ok. Did you measure directly on the 2 tube heater pins? Or between transformer tap and ground? Or between both transformer taps? Because I believe the transformer produces -3.3v and 3.3v which is seen as 6.6v on the heaters.
I measured on the tube socket pins where all the wires are soldered. So the heater voltages should be good on the 6SN7 and 6p1p.
What's going on with the recitifier heater voltages? Are they suppose to be that high?
Any ideas why I'm not getting any output to speakers? I'm gonna try another source.
The rectifier heater voltage should be 5v at the pins.
@StepheK do you any idea of what could be happening?
