Mikante wrote: ↑Tue Dec 12, 2023 6:59 pm
Thank you i understand now.
I have added a 220k before pin 7 and replaced the bypass cap switch and feedback resistor.
ok it is working like it should i see you want more gain but this is limited topology.. need more tubes for more gain.
here you can increase 220k to 470k grid stopper to V1b pin 7, and shield only one side of the shielded wire ..
you can also increase grid stoper to output tube to 47k and more..
Is my first champ build, take it easy on him
As i said, it is not coming out from the video, but it is definitely better. I will be playing it loud to see if it doesn t get worse after some playing as it did before. Trust me if you were here you d notice. I d like not to add other components. I understand what the "grid resistor" does now much better and can say, it helps a lot but you lose some dynamic response and feel from the amp. I will not go back that is for sure.
Some nice tones are coming out of it. Congratulations on your first build.
If it helps to know, it sounds similar to how I remember my champ sounding from years back.
I recall I used to play it with the volume almost wide open, and then I rolled back the volume on the guitar for the best sound - I had a small speaker (8 or 10" - I can't remember).
Some nice tones are coming out of it. Congratulations on your first build.
If it helps to know, it sounds similar to how I remember my champ sounding from years back.
I recall I used to play it with the volume almost wide open, and then I rolled back the volume on the guitar for the best sound - I had a small speaker (8 or 10" - I can't remember).
Thank you, i am satisfied, mostly because i have learned a lot. My plan is to build a 12 inch speaker cabinet that i can use for the champ and my next build. The sound is good as it was from the begining but now i can push it a little bit past half volume and the overdrive is much better. Also it seems that the problem i had with this amp is now ok. I will be playing it and do some record.
I really appreciate all the help i got here from you people
no problem, just go forward nothing will explode (i hope)
you can tweak as much as you want to the max, after you can reduce and find optimum from this topoogy.
lead dress is very important in building amps, where to put coax where not, which wire can be placed to which wire and where not.. etc..so yoy can check on this subject all the articles..
enjoy!
That is something i need to address, soldering, wires and technics. Playing with pedals and basic effects building is all I had before this, obviously, a tube amp needs extra care and experience.
Here the new board. New parts are coming i will be cleaning all the soldering.
838D8CBC-56C2-4049-B7B2-740965907F81.jpeg
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A few more things to think about when you are rebuilding or building in general:
Here's an article on grounding that is relatively easy to understand. https://www.valvewizard.co.uk/Grounding.html
Where you locate grounds tends to matter a lot less in pedals. The higher gain and more complicated tube amps get the more important the ground scheme becomes.
Heat and vibration are very important. The larger resistors get hot, so do tubes. Keep electrolytic caps away from hot stuff when possible and leave room for air circulation. Hanging large filter caps in the air without support is a bad idea. They weigh too much. It's best to have the cap's body supported by something or the leads might snap. A dab of silicone helps.
Building on terminal strips is way harder than using a board if you're not use to it, so good on you for making it work.
maxkracht wrote: ↑Wed Dec 13, 2023 4:20 pm
A few more things to think about when you are rebuilding or building in general:
Here's an article on grounding that is relatively easy to understand. https://www.valvewizard.co.uk/Grounding.html
Where you locate grounds tends to matter a lot less in pedals. The higher gain and more complicated tube amps get the more important the ground scheme becomes.
Heat and vibration are very important. The larger resistors get hot, so do tubes. Keep electrolytic caps away from hot stuff when possible and leave room for air circulation. Hanging large filter caps in the air without support is a bad idea. They weigh too much. It's best to have the cap's body supported by something or the leads might snap. A dab of silicone helps.
Building on terminal strips is way harder than using a board if you're not use to it, so good on you for making it work.
Thank you very much for pointing that out, with the new parts on the way i can plan a better layout, especially for those large filter caps which i didn t like hanging there in the first place, this was purely aesthetic. now reading your post, i see bigger and more important problems in my design.
I have moved the 6v6 cathode caps further away from the resistor, i say caps because i din t have 20uf so i placed two 10uf there instead, not for long. For the rest, i will finf a way to support bigger components and leave enough room for those in the critical spots.
Mikante wrote: ↑Tue Dec 12, 2023 6:59 pm
Thank you i understand now.
I have added a 220k before pin 7 and replaced the bypass cap switch and feedback resistor.
ok it is working like it should i see you want more gain but this is limited topology.. need more tubes for more gain.
You can actually get quite a bit of gain/distortion from the 2 triodes and single pentode and still sound good. It'll require different biasing of the preamp stages, and careful tuning of the low frequencies, and of course grid stoppers, which you've mentioned. I've also found a trick of using a low pass filter at the output transformer to smooth out clipping produced by the output tube (and anything in front of it)
The VHT Special 6 'Ultra' has a good schematic with this filter on a switch. They call it a "Texture" switch. I think something like this is vital on a SE amp if you want good output distortion.
It's true i've lost my marbles and i cant remember where i put them
Great i ll check the vht then.
Rignt now the amp sound is good, both clean and crunch, i rarely push it even more so i don t think i am going to change anything, maybe the grid stopper on the power tube and the v1b bypass cap value with this one being the hardest choice, since i dont like having a switch there, i will have to choose. Probably 0.68uf which is giving the perfect gain and low cut setting the amp needs. Not the best choice for the clean though, 10uf i think is perfect for that.
