Recently I was lucky enough to get the PCB and Korg Nutube 6P1 from one of our forum members. Thx Wolla.
Below is a link to this design and build from Pete Millet.
http://www.pmillett.com/nuhybrid.html
He sells the PCB and nutube and provides a bill of material, or BOM for short, that can be sourced from Mouser. After a day or two trying to find the required parts and alternatives to the ones not available from RS I decided, after reading on AVForums, to contact TRX Electronics. I sent them the BOM and an hour later received a proforma invoice. The order was placed and I received the parts the next week. Kudos to TRX.
I studied the build and placements and decided to tackle it this past weekend.
Apart from the occasional banana plug termination and re-solder here and there this is my second real build with the CMOY being my first.
Two boxes waiting to be assembled, hmm build
The PCB and Nutube
Parts from Mouser still in the bags.
I installed the resistors, diodes and 8pin sockets. This isn't to bad...
... but then things started going south a bit from here.
First I installed half the small electrolytic caps incorrectly :facepalm:. After removing them and installing them the correct way I think I messed up the track on one of the connections. Ok let's hope for the best.
Secondly the relay sent by TRX was not the right replacement being to big. Ok not their fault I should have double checked the order. Urg do I go to Communica now or wait a few days for an order from RS? I decided to go to Communica and fortunately they had one for me :Whoohoo:.
Caps, bias adjust pots , transistors, voltage regulator, relay and inductor or choke.
Finishing the install by adding the RCAs, volume pot, headphone out, power switch, power LED, op amps and of course the nutube.
After inspecting everything I did the first power on test. No smoke and a nice bluish-white glow from the nutube. I adjusted the bias output accordingly and it was time the first sound test...
I'm only getting sound on the right channel? WTF. After disconnecting everything I re-checked again. Is it maybe the one track I messed up. Perhaps the volume pot. After looking at the schematic I realized that I stupidly assumed provision was made for a volume pot with a on-off switch witch was not the case. With a lot of hassle I removed the volume pot, removed the two back legs, insulated them and re-installed the volume pot. During this "struggle" I definitely messed up more tracks and connections. :Ooooooh:. I tried again and now its worse. The sound is very soft. Touching the volume makes a buzzing noise and will bring back sound but again only on the right channel.
At this point I felt very disappointing and despondent. After disconnecting everything I came close to giving up and throw this project in the dustbin :vsad:. Instead I just left it for a while.
Ok what do I do now. There is no way to fix the tracks. Do I buy a new PCB. Do I recover what I can and try point-to-point?
Point-to-point!!! (This was also suggested by Chris and Wola, thx)
I grabbed the schematic again and started testing all the connections. Everything looks fine except for the connections from the input to the volume pot. One channel's ground is fine but not the other. Lets bridge between the two. I also connected the two input using some wire straight from the inputs.
Ok let's try again.
It's working yeah :Whoohoo:
Below is a link to this design and build from Pete Millet.
http://www.pmillett.com/nuhybrid.html
He sells the PCB and nutube and provides a bill of material, or BOM for short, that can be sourced from Mouser. After a day or two trying to find the required parts and alternatives to the ones not available from RS I decided, after reading on AVForums, to contact TRX Electronics. I sent them the BOM and an hour later received a proforma invoice. The order was placed and I received the parts the next week. Kudos to TRX.
I studied the build and placements and decided to tackle it this past weekend.
Apart from the occasional banana plug termination and re-solder here and there this is my second real build with the CMOY being my first.
Two boxes waiting to be assembled, hmm build
The PCB and Nutube
Parts from Mouser still in the bags.
I installed the resistors, diodes and 8pin sockets. This isn't to bad...
... but then things started going south a bit from here.
First I installed half the small electrolytic caps incorrectly :facepalm:. After removing them and installing them the correct way I think I messed up the track on one of the connections. Ok let's hope for the best.
Secondly the relay sent by TRX was not the right replacement being to big. Ok not their fault I should have double checked the order. Urg do I go to Communica now or wait a few days for an order from RS? I decided to go to Communica and fortunately they had one for me :Whoohoo:.
Caps, bias adjust pots , transistors, voltage regulator, relay and inductor or choke.
Finishing the install by adding the RCAs, volume pot, headphone out, power switch, power LED, op amps and of course the nutube.
After inspecting everything I did the first power on test. No smoke and a nice bluish-white glow from the nutube. I adjusted the bias output accordingly and it was time the first sound test...
I'm only getting sound on the right channel? WTF. After disconnecting everything I re-checked again. Is it maybe the one track I messed up. Perhaps the volume pot. After looking at the schematic I realized that I stupidly assumed provision was made for a volume pot with a on-off switch witch was not the case. With a lot of hassle I removed the volume pot, removed the two back legs, insulated them and re-installed the volume pot. During this "struggle" I definitely messed up more tracks and connections. :Ooooooh:. I tried again and now its worse. The sound is very soft. Touching the volume makes a buzzing noise and will bring back sound but again only on the right channel.
At this point I felt very disappointing and despondent. After disconnecting everything I came close to giving up and throw this project in the dustbin :vsad:. Instead I just left it for a while.
Ok what do I do now. There is no way to fix the tracks. Do I buy a new PCB. Do I recover what I can and try point-to-point?
Point-to-point!!! (This was also suggested by Chris and Wola, thx)
I grabbed the schematic again and started testing all the connections. Everything looks fine except for the connections from the input to the volume pot. One channel's ground is fine but not the other. Lets bridge between the two. I also connected the two input using some wire straight from the inputs.
Ok let's try again.
It's working yeah :Whoohoo:
