I am not sure I understand your question. I thought I answered that in this video. Or, maybe you are referring to overheating bias in a fixed bias amp? Let me know if you have a specific amp of interest.
Very cool thank you for taking the time to do this. It was interesting and informative to see your diagnostic process. It was cool seeing how you could guess what the component value and function was based on its configuration in the board layout. Hopefully if I watch more of your videos amps will make more sense!
Thanks Jethro. It's true that so many circuits use similar values, mainly lifted from the Fender Rule Book. Learn your AB763 circuit and you know >50% of all amps!
Nice one. Last year I bought a little vibro champ clone (ceriatone) without transformers and got those (Hammond 291AEX PT and ROLA OPT 10SE) as I could afford them. Just managed to successfully get the thing up and running a couple of weeks back and love it. Your shows have helped me to have just enough confidence to do that and this one relates quite well to my little beast. Thanks for that.
Nice video. Even a quite moderate temperature rise if it goes on hundreds of hours makes solder joints to deteriorate. For example if you open the socket of one of those energy saving lamps which contain a small PCB packed with several components, if it has a lot of working hours, usually all solder joints of it are very deteriorated (not nice and shiny at all) because of the heat treatment caused by the lamp itself.
Thank you, mark. Are you Australia’s greatest drummer, Mark Kennedy, that I had the great privilege of playing with once with Kevin Borich and Harry Brus?
Very Cool, Thankyou. Interesting, Informative and Entertaining Video as Always. Love my Artist Guitars Gear, and very interested in this Amp or your 12A. All The Best. Cheers
Thanks mate. Asa you have found out, its hard to beat Artist value or money. The TweedTone V is great for home use. The TweedTone 12A is good for home and rehearsals or small gigs. The 12" speaker gives it a huge sound. Because I designed it right the first time, it is going to operate in a much more comfortable zone. Both are great value for money.
That's very good feedback, Wayne. Thank you. Sadly, many budget amps are not economical to repair, but I will certainly do more of those which are viable.
Enjoying your channel very much. Why are you subtracting the screen current from the power calculation? If that current goes through the tube, shouldn't it be included in the overall power dissipation? Is it because tube power specs are given relative to the plate?
Tube max power dissipation specs are given to both plate and screen but usually bias is adjusted using only plate dissipation value as a measured object. If the circuit uses screen resistors, it is of course quite easy to measure voltage over screen resistor and calculate quite accurately real screen current as well, but screen current is usually so small compared to plate current that even if you consider screen current to be neglible, the plate dissipation calculation is not very far from thruth.
You are exactly correct. My standing 8% screen estimate is generally pretty close when I calculate screen current. Sometimes its a little higher, but I prefer to err on the side of a conservative dissipation. Thank you for that insightful response.
@@theguitaramptech I'm fine thanks..Selmer were popular with some people for a time in England in the 60s . Quite good amps. They were made in some place in London. In May or June Vox are bringing out another set of handwired amps-inc. an AC10 . You worked on the AC10 c1- the budget valve amp ..
@@vincentl.9469 a hand wired AC 10 would be a very nice amp. I really like my Chinese AC10 after some basic improvements. For me, it only has one shortcoming. The gain of the preamp stage is too hot for the integrated circuit, causing it to clip. There’s nothing that can be economically done to rectify this that I know of. It can be improved by replacing the preamp 12AX7 with a 12AY7 and keeping thepreamp knob Below noon.
@@theguitaramptech The chassis layout is not too clever either. I remember you pointed out they put a MOSFET in the first gain stage instead of a third 12AX7. False economy I think. .Problem I found if you put a low gain valve in the pre amp, the overdrive wont kick in so well and overdrive pedals, if you want that sound, wont work too well either. As long as the gain knob is lower than the master you should get good clean sounds. From the few pictures I've seen, this hand wired model has a taller square cab and effects loop at back. it will no doubt cost more ..at least double the Chinese C1 ..
@@theguitaramptech just thinking about this again;, I am right in saying a chip is put into the pre amp as cost saving? a cheaper way to produce distortion -or gain. cheaper than having an extra tube..
Thanks Chris. Another well-explained video. I appreciate the math. I vote for another video in this series.
Thanks mate. That's 1 vote for another in the Small Amp/No Schem series.
Would hope you would post the upgrades for retrofitting for those of us with the overheating/bias and other issues :)
I am not sure I understand your question. I thought I answered that in this video. Or, maybe you are referring to overheating bias in a fixed bias amp? Let me know if you have a specific amp of interest.
I WATCH ALOT OF AMP REPAIRS BUT ONLY REALLY LEARN FROM UNCLE DOUG/ D LABS AND YOU THX SO MUCH SOME DO WHILE OTHERS TEACH LOVE THE MESSY BUGGER JOKE
Thank you, Freddy. I appreciate you putting me in the same company as @uncledoug and @d-labelectronics
Very cool thank you for taking the time to do this. It was interesting and informative to see your diagnostic process. It was cool seeing how you could guess what the component value and function was based on its configuration in the board layout. Hopefully if I watch more of your videos amps will make more sense!
Thanks Jethro. It's true that so many circuits use similar values, mainly lifted from the Fender Rule Book. Learn your AB763 circuit and you know >50% of all amps!
Nice one. Last year I bought a little vibro champ clone (ceriatone) without transformers and got those (Hammond 291AEX PT and ROLA OPT 10SE) as I could afford them. Just managed to successfully get the thing up and running a couple of weeks back and love it. Your shows have helped me to have just enough confidence to do that and this one relates quite well to my little beast. Thanks for that.
What a great compliment. Thank you.
Excellent - although way beyond my level of knowledge of course. Amazing how much you know and how well you present it.
What can I say? You are a fine judge! 😂
❤ I love the work. Thank you for sharing.👍
Thank you for your kind words.
Nice video. Even a quite moderate temperature rise if it goes on hundreds of hours makes solder joints to deteriorate. For example if you open the socket of one of those energy saving lamps which contain a small PCB packed with several components, if it has a lot of working hours, usually all solder joints of it are very deteriorated (not nice and shiny at all) because of the heat treatment caused by the lamp itself.
Yes, as you say, and continual temperature changes.
Hi Chris. Thank you again for another great video. Greetings from Germany - cheers
In that case, I'd probably suggest 220R to 470R.
@@theguitaramptech Hi Chris,
I will meet Ian on wednesday. Cheers
Thanks Markus. And that you for the photos.
Great video again, Chris!🔥🔥
Thank you Phillip!
Thank you, informative. I have one of these amps.
Thank you, mark. Are you Australia’s greatest drummer, Mark Kennedy, that I had the great privilege of playing with once with Kevin Borich and Harry Brus?
Very Cool, Thankyou. Interesting, Informative and Entertaining Video as Always. Love my Artist Guitars Gear, and very interested in this Amp or your 12A. All The Best. Cheers
Thanks mate. Asa you have found out, its hard to beat Artist value or money. The TweedTone V is great for home use. The TweedTone 12A is good for home and rehearsals or small gigs. The 12" speaker gives it a huge sound. Because I designed it right the first time, it is going to operate in a much more comfortable zone. Both are great value for money.
I actually prefer the videos about budget amps.
That's very good feedback, Wayne. Thank you. Sadly, many budget amps are not economical to repair, but I will certainly do more of those which are viable.
Thanks😊
Thanks Peter
Enjoying your channel very much. Why are you subtracting the screen current from the power calculation? If that current goes through the tube, shouldn't it be included in the overall power dissipation? Is it because tube power specs are given relative to the plate?
Tube max power dissipation specs are given to both plate and screen but usually bias is adjusted using only plate dissipation value as a measured object. If the circuit uses screen resistors, it is of course quite easy to measure voltage over screen resistor and calculate quite accurately real screen current as well, but screen current is usually so small compared to plate current that even if you consider screen current to be neglible, the plate dissipation calculation is not very far from thruth.
You are exactly correct. My standing 8% screen estimate is generally pretty close when I calculate screen current. Sometimes its a little higher, but I prefer to err on the side of a conservative dissipation. Thank you for that insightful response.
Hi Chris. how are things? Have ever repaired or come across Selmer Amps ? what were your thoughts on those ?
I'm going great, thanks. You? I haven't worked on a Selmer. They're not common in Australia.
@@theguitaramptech I'm fine thanks..Selmer were popular with some people for a time in England in the 60s . Quite good amps. They were made in some place in London. In May or June Vox are bringing out another set of handwired amps-inc. an AC10 . You worked on the AC10 c1- the budget valve amp ..
@@vincentl.9469 a hand wired AC 10 would be a very nice amp. I really like my Chinese AC10 after some basic improvements. For me, it only has one shortcoming. The gain of the preamp stage is too hot for the integrated circuit, causing it to clip. There’s nothing that can be economically done to rectify this that I know of. It can be improved by replacing the preamp 12AX7 with a 12AY7 and keeping thepreamp knob Below noon.
@@theguitaramptech The chassis layout is not too clever either. I remember you pointed out they put a MOSFET in the first gain stage instead of a third 12AX7. False economy I think. .Problem I found if you put a low gain valve in the pre amp, the overdrive wont kick in so well and overdrive pedals, if you want that sound, wont work too well either. As long as the gain knob is lower than the master you should get good clean sounds. From the few pictures I've seen, this hand wired model has a taller square cab and effects loop at back. it will no doubt cost more ..at least double the Chinese C1 ..
@@theguitaramptech just thinking about this again;, I am right in saying a chip is put into the pre amp as cost saving? a cheaper way to produce distortion -or gain. cheaper than having an extra tube..
✌️ Promo_SM
Hi Edgar. I don’t know what your message means.