guys this has been on my mind now for weeks. my only history with tube is a old st70 and 6 years ago a cary rocket 88.
has to be monobloc chassis and 40 50 or even 60 watts.
i want point to point wiring and no pc boards.
never built a tube amp from scratch so need something suitable form a first timer to jump into.
where do i start?
do i buy transformer first or tubes?
how do i pick the right output transformer?
i would like to get a start on purchasing related items
thanks
gordie
has to be monobloc chassis and 40 50 or even 60 watts.
i want point to point wiring and no pc boards.
never built a tube amp from scratch so need something suitable form a first timer to jump into.
where do i start?
do i buy transformer first or tubes?
how do i pick the right output transformer?
i would like to get a start on purchasing related items
thanks
gordie
You need a kit q/all parts incluse, this site are plenty of multi tubes OTL amps in kits form, prices are not cheap though:
Transcendent Sound DIY Specialist in Vacuum Tube OTL Amplifiers
Transcendent Sound DIY Specialist in Vacuum Tube OTL Amplifiers
thank you
i will go with anything that will fit this build need . that kt120 sounds interesting.
i would like to stay in the 40' 50 or even 60 watts.
see it's not that i use that much all the time no
maybe at the loudest 30 watts.with most times 6 to 10 watts .
so is it possible to build this with 2 kt120?
fullrangeman
that site has cool looking stuff but i don't understand why that stuff is all rated so low watts
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ok but the kt120 states 850v and that has me scared.
kt 90 will be good as well
after all i don't want to over load it.
i would love to have 2 manly big heavy monsters
so do you mean i should buy the tubes first and that will dictate the trans?
Yes, both go together. Here's another option:
A431S Triode USA Output Transformer for Dynaco 4300 Ohm 60W/120W for Dynaco MADE IN USA
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I say no to the KT120 tube. I've seen the plate curves and they are distressingly non-linear. 
A PP KT88 setup will easily yield 60+ WPC. Make the PSU substantial and approx. 3 dB. of dynamic headroom will be available.
Check the archives for Modern Mullard. Mullard style circuitry is reasonably "idiot resistant" and it is a solid performer.
A PP KT88 setup will easily yield 60+ WPC. Make the PSU substantial and approx. 3 dB. of dynamic headroom will be available.
Check the archives for Modern Mullard. Mullard style circuitry is reasonably "idiot resistant" and it is a solid performer.
> but the kt120 states 850v and that has me scared.
That is a MAXimum rating.
The wires in my house are rated 300V. All my stuff is 120V/240V. Am I scared?
My pickup truck is rated nominal 1,500 pounds. I don't like to lift over 50 pounds. Am I scared?
No, I know I want a wire or truck rated much higher than how I will use it.
The one app-point in the datasheet shows a 400V condition. Usually a push-pull pair of 6550/KT88 will run 450V-600V; for only 60W out, the lower numbers suffice. The KT120 "can" run higher voltages, even 850V if you dare. But why? Power output may increase, but general reliability may fall off. IMHO if you want More Power, buy More Tubes. That 3/4-ton truck didn't try to get its mighty 235HP from one cylinder, they used eight. Quad-bottle amps were my workhorses in the ~~100W class.
I don't like the KT120 because the 6550/KT88 has been around for over 50 years, usually with multiple sources, while the KT120 is new and single-source. If I had to make a mega-amp for my Summer 2017 Tour, no thought for the future, sure a -120 job might be a bit more compact. But something I plan to live with for years, I like parts that are sure to be easy to get down the road.
That is a MAXimum rating.
The wires in my house are rated 300V. All my stuff is 120V/240V. Am I scared?
My pickup truck is rated nominal 1,500 pounds. I don't like to lift over 50 pounds. Am I scared?
No, I know I want a wire or truck rated much higher than how I will use it.
The one app-point in the datasheet shows a 400V condition. Usually a push-pull pair of 6550/KT88 will run 450V-600V; for only 60W out, the lower numbers suffice. The KT120 "can" run higher voltages, even 850V if you dare. But why? Power output may increase, but general reliability may fall off. IMHO if you want More Power, buy More Tubes. That 3/4-ton truck didn't try to get its mighty 235HP from one cylinder, they used eight. Quad-bottle amps were my workhorses in the ~~100W class.
I don't like the KT120 because the 6550/KT88 has been around for over 50 years, usually with multiple sources, while the KT120 is new and single-source. If I had to make a mega-amp for my Summer 2017 Tour, no thought for the future, sure a -120 job might be a bit more compact. But something I plan to live with for years, I like parts that are sure to be easy to get down the road.
For first starter I will look here: http://triodedick.com Well documented, even not mantained from long time.
Specialy Mono Bill II project. Very well explained.
Or just read Baby Huey theme in this forum. You can't go wrong.
I will avoid a lot of capacitor coupling stages, both examples are plain 2 stage design.
Think about transformers, most important and expensive part (power, output, choke, even interstage, if you have a passion to old, good WE designs)
Some links for inspiration:
A Tiny History of High Fidelity, Part 1
The Amity, Raven, and Aurora
Reference to god design (by my view point): K&K Audio | Power Amplifier
Good luck with your project!
Kiril
Specialy Mono Bill II project. Very well explained.
Or just read Baby Huey theme in this forum. You can't go wrong.
I will avoid a lot of capacitor coupling stages, both examples are plain 2 stage design.
Think about transformers, most important and expensive part (power, output, choke, even interstage, if you have a passion to old, good WE designs)
Some links for inspiration:
A Tiny History of High Fidelity, Part 1
The Amity, Raven, and Aurora
Reference to god design (by my view point): K&K Audio | Power Amplifier
Good luck with your project!
Kiril
thank you
i had a look at a modern mullard as mentioned where i found the opus 5.0 ultra pp
downloaded the drawing but i see no value given for c1 and c5.
also this calls for a 4.2k 100w output and got me thinking
what makes the watt level in a tube amp ? the power rails voltage or ther output trans?
i had a look at a modern mullard as mentioned where i found the opus 5.0 ultra pp
downloaded the drawing but i see no value given for c1 and c5.
also this calls for a 4.2k 100w output and got me thinking
what makes the watt level in a tube amp ? the power rails voltage or ther output trans?
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