Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dragonbat13 on August 28, 2021, 06:35:26 am
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I want to "engineer/design" for the first time. I use those terms loosely.
A complete scratch build rolling my own chassis and selecting my own parts.
I'm leaning towards a rather simple Single end design using a kinkless tetrode. Most likely a Kt66
Haven't decided on much with the preamp except for a volume/treble/bass stack and perhaps a cathode follower. Leaning towards marshall circuits.
One goal is to mix a Plexi and higher power champ into one.
A little bit of channel switching may come into play along with a tube effects loop.
But right now I'm mostly interested in what others have built and played.
What output tubes did you use? What about speakers? I'm leaning on a 4x10 combo or a 2x10 with an extension 2x10.
Let's hear the experience!
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paper n pencil are still reasonably priced, burn through a few sheets. study every schematic for all the cool amps you've ever played through.
read all the threads from those that went before you. This site has some of the most accomplished builders you'll find.
keep refining with more paper, use a calculator when you get close to finalized design.
here's just one, of my last design/build processes. there are tons of others to choose from. don't try and invent the wheel, it's good, just adapt for your wheel barrel
SilverTone 1482_esq (el34world.com) (https://el34world.com/Forum/index.php?topic=25772.0)
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paper n pencil are still reasonably priced, burn through a few sheets. study every schematic for all the cool amps you've ever played through.
read all the threads from those that went before you. This site has some of the most accomplished builders you'll find.
keep refining with more paper, use a calculator when you get close to finalized design.
here's just one, of my last design/build processes. there are tons of others to choose from. don't try and invent the wheel, it's good, just adapt for your wheel barrel
SilverTone 1482_esq (el34world.com) (https://el34world.com/Forum/index.php?topic=25772.0)
For sure gonna do the paperwork before I buy anything.
And alot of searching for threads.
I have been a lurker on the amp garage and had not visited this site in a few years. I didn't know how much it has grown.
Thanks
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Take a look at "classic projects and building blocks" on the old AX84 site. https://ax84.com/archive/ax84.com/index.html
You might find something you are interested in.
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There is one project in particular on AX84 that I would put eyes on for ideas: https://ax84.com/archive/ax84.com/october.html
There's also "The Beast" Champ design as well, which has simplicity at its core and is in the Marshall vein.
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I may have that amp you are wanting to make. I had a buddy build me an AX84 SEL years ago. Was sorta JCM800 ish with a KT88. I’ve tweaked it into a Marshally super champ running a KT66 and I like it much more. I also paralleled the first two stages instead of cascading them, to make it like a JTM45/plexi lead pre. Normal and bright channels into a second stage and then CF tonestack. I also like the KT66 so much more. Takes some of the edge off the ratty tones that a SE amp tends to produce.
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I may have that amp you are wanting to make. I had a buddy build me an AX84 SEL years ago. Was sorta JCM800 ish with a KT88. I’ve tweaked it into a Marshally super champ running a KT66 and I like it much more. I also paralleled the first two stages instead of cascading them, to make it like a JTM45/plexi lead pre. Normal and bright channels into a second stage and then CF tonestack. I also like the KT66 so much more. Takes some of the edge off the ratty tones that a SE amp tends to produce.
This was my original thinking. The KT66 would take some of the edge off the top end. What output transformer are you using? I was thinking of using some hammond iron. I had read somewhere that Hammond output transformers were underrated output power wise so I was going to bring that right to the edge if I used one from them.
But like noted above, I gotta do alot more research before I come to that conslusion.
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Our friend Silvergun built a SE amp he loves and is playing gigs with, hope he chimes in on this. :icon_biggrin:
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My buddy used one of these when he built it. Chris used to run AX84 and has these custom wound. It’s well over spec’d for a single KT66. If you set on a 66, I think 15 watts would be sufficient though, and Hammond has a couple options.
https://reverb.com/item/42514200-ax84-heyboer-20w-semi-universal-single-ended-tube-output-transformer-el84-el34-6l6-6v6-kt88-etc
Any of the Hammond single ended ones below could likely work depending on how big you want to go.
125DSE
125ESE
125FSE
125GSE
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Our friend Silvergun built a SE amp he loves and is playing gigs with, hope he chimes in on this. :icon_biggrin:
Wellll...by popular demand. Here's the amp thread that Mr. Willabe is referring to.
But it's just 2 power amps that I run my Mesa Triaxis preamp through.
This is still my live rig.
Stereo SE KT88 power amps for live rig (el34world.com) (https://el34world.com/Forum/index.php?topic=19777.0)
I'll start a thread with the SE design that taught me how NOT to design an amp. HERE (https://el34world.com/Forum/index.php?topic=27908.new#new)
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I've built 2 different single ended amps using a 6L6 power tube. I used the preamp circuitry of the Fender type, similar to the Vibro-Champ AA-764 but no vibrato. One of the amps has volume, bass, treble, master vol, the other has vol, bass, mid, treb, master. I used transformers from vintage single ended PA amps that used a single 6L6, one was a Stromberg-Carlson, I don't remember what the other one was. They put out about 10 watts. I like the sound of the one without the mid control a bit better, but that might be due to the iron as much as the circuitry.
I put in a master volume so that I could push the preamp into distortion without blasting the volume. I find it easier to adjust the sound I want that way.
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Take a look at "classic projects and building blocks" on the old AX84 site. https://ax84.com/archive/ax84.com/index.html
You might find something you are interested in.
Those AX84 “building blocks” are known-good circuits and layouts. So many great ideas…
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My buddy used one of these when he built it. Chris used to run AX84 and has these custom wound. It’s well over spec’d for a single KT66. If you set on a 66, I think 15 watts would be sufficient though, and Hammond has a couple options.
https://reverb.com/item/42514200-ax84-heyboer-20w-semi-universal-single-ended-tube-output-transformer-el84-el34-6l6-6v6-kt88-etc (https://reverb.com/item/42514200-ax84-heyboer-20w-semi-universal-single-ended-tube-output-transformer-el84-el34-6l6-6v6-kt88-etc)
I've got one of these output transformers in my ever-evolving SE amp. 6V6 gives all the volume I can use, but nice to know I can use something bigger if I ever decide to. Highly recommended.