Hi guys,
I want a amp to experiment with. A basic design that I can change out tone stacks and use different tubes, and make other experimental modifications to.
I have a chassis built that is 8" X 21" that fits a Cabinet that I have. That gives me a lot of room to make changes.
I have most of the parts on hand to build most any design.
I have been considering both a JTM45 or a Fender AB763. Both would have a master volume or power scaling added to the design.
Any recommendations of which would be best for experimenting with.
Thanks,
Billy
I want a amp to experiment with. A basic design that I can change out tone stacks and use different tubes, and make other experimental modifications to.
I have a chassis built that is 8" X 21" that fits a Cabinet that I have. That gives me a lot of room to make changes.
I have most of the parts on hand to build most any design.
I have been considering both a JTM45 or a Fender AB763. Both would have a master volume or power scaling added to the design.
Any recommendations of which would be best for experimenting with.
Thanks,
Billy
Hi JonSnell,
I decided to build the JTM45 circuit first. Well...I had in mind to use a Mesa style twin rectifier and a switchable solid state diode power supply. I will most likely build a Fender style circuit next.
I think I have enough room to cut holes for 6 pre amp tube sockets and cap three of them in the chassis I just finished for future changes.
I don't have in mind to use KT66 output tubes so it will not sound just like a Marshall to begin with.
This amp will be something to experiment with. The idea is to build a sort of universal chassis with as much room and ease of change as makes sense. The chassis is made from 1/8 aluminum and screwed together with angle aluminum so any part of the chassis can easy to replace. This amp will not get moved around much so "road worthy" is not a big consideration.
Thanks,
Billy
I decided to build the JTM45 circuit first. Well...I had in mind to use a Mesa style twin rectifier and a switchable solid state diode power supply. I will most likely build a Fender style circuit next.
I think I have enough room to cut holes for 6 pre amp tube sockets and cap three of them in the chassis I just finished for future changes.
I don't have in mind to use KT66 output tubes so it will not sound just like a Marshall to begin with.
This amp will be something to experiment with. The idea is to build a sort of universal chassis with as much room and ease of change as makes sense. The chassis is made from 1/8 aluminum and screwed together with angle aluminum so any part of the chassis can easy to replace. This amp will not get moved around much so "road worthy" is not a big consideration.
Thanks,
Billy
I hands down love the AB763 much more than any Marshall circuit I have tried.
BUT, as Jon pointed out you only know what amp you should build. I always bring my own amp places because it's part of my sound.
BUT, as Jon pointed out you only know what amp you should build. I always bring my own amp places because it's part of my sound.
JTM45 is pretty much the same circuit as a '59 Bassman. Only the parts make the difference, mainly xfmrs and output tubes.
Craig
Craig
Hi guys,
I like the AB763 also. I have one of the originals. Amps are like blues songs, everyone copies everyone...lol I don't need another amp to play..lol I got more than my share of amps. I can only get by with this by telling my wife it is a "research tool"...lol
I have got way to old to wag a heavy amp around to the occasional nights I play out. I have a Zinky Blue Velvet I really like. Small amp with a big sound. It does well for the blues/rock/country stuff I play. It is a little less than 30 watts and if that is not enough then mike the damn thing. I have a late 1970's Roland JC 120 if I get crazy and feel like playing jazz. It is the only transistor amp I ever really liked.
Well..on to laying out turret boards.
Thanks,
Billy
I like the AB763 also. I have one of the originals. Amps are like blues songs, everyone copies everyone...lol I don't need another amp to play..lol I got more than my share of amps. I can only get by with this by telling my wife it is a "research tool"...lol
I have got way to old to wag a heavy amp around to the occasional nights I play out. I have a Zinky Blue Velvet I really like. Small amp with a big sound. It does well for the blues/rock/country stuff I play. It is a little less than 30 watts and if that is not enough then mike the damn thing. I have a late 1970's Roland JC 120 if I get crazy and feel like playing jazz. It is the only transistor amp I ever really liked.
Well..on to laying out turret boards.
Thanks,
Billy
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Yes there are exceptions, and that is one.
Speakers and enclosures play a big role and maybe that's the biggest influence. Start plugging an AB763 into some Celestion's in a sealed enclosure and I will complain. Putting most Marshall amps through different speakers can warm things up but I usually have to compensate with the tone controls to get the sound decent.
With that said I use my own circuit that I like, I may have posted it on here I am not sure. If I can dig up the schematic I will post it.
The circuit you are building is a good one, as pointed out Jim Marshall stole it from Leo Fender. It's just not my cup of tea. Sound will largely be impacted by what you plug it into.
It's funny the only solid state amp in our practice space is a Roland Jazz Chorus 120, it's just a great sounding amplifier.
If you are using this as a learning tool maybe try and design your own circuit. Plenty of folks including myself on here that can help. Just pick what sort of sound you are after and what effects and controls you would like. Personally I feel like having two channels is a waste so I never build amps like that, most clones of classic circuits have two channels.
Hi Famousmockingbird,
Wow!! I think I will call you "bird" from now on!!..lol Long name. Thanks for the offer to help, I may need some!!
I am finishing up the chassis now. It is made from 1/8 inch aluminum,perhaps a bit thick but it is what I had on hand. I still need to put it in the milling machine and cut the holes. All the panels are removable so it is easy to change things. It was a good bit of work to make it like this. I also have a TIG welder so I can spot weld it at any time.
I also had this Marshall head cabinet someone gave me,so I made the chassis to fit it. I am not in love with the red tolex but, oh well!! It is in nice condition.The Marshall logo is easy to remove.
I just built a JTM45 Metro Amp for someone else, more or less stock with a master I put in it for him. The owner liked it but I did not like the sound too much...what's the word...harsh...
Well it sounded better with my Marshall stack than with the 2 12" Eminence speakers in the combo cab from Weber he got. I sort of wanted to see what the same basic circuit would sound like with 6V6's or 5881 and perhaps a different tone stack. Still thinking actually. I am not in any big hurry.
I also have a Mesa Boogie Nomad 45 project I am fiddling with trying to make it into a good sounding amp, without much success I might add...lol Mesa amps are a PITB to work on. Too much stuff jammed into too little space plus the seven zillion relays and JFETs for the three channel switching...jeezs!! Actually I have never played a Nomad so I don't know what one working correctly would sound like. The clean channel is not bad but channel 2 and 3 sound like crap.
I would like to see the schematic you mentioned.
Cheers,
Billy
Wow!! I think I will call you "bird" from now on!!..lol Long name. Thanks for the offer to help, I may need some!!
I am finishing up the chassis now. It is made from 1/8 inch aluminum,perhaps a bit thick but it is what I had on hand. I still need to put it in the milling machine and cut the holes. All the panels are removable so it is easy to change things. It was a good bit of work to make it like this. I also have a TIG welder so I can spot weld it at any time.
I also had this Marshall head cabinet someone gave me,so I made the chassis to fit it. I am not in love with the red tolex but, oh well!! It is in nice condition.The Marshall logo is easy to remove.
I just built a JTM45 Metro Amp for someone else, more or less stock with a master I put in it for him. The owner liked it but I did not like the sound too much...what's the word...harsh...
Well it sounded better with my Marshall stack than with the 2 12" Eminence speakers in the combo cab from Weber he got. I sort of wanted to see what the same basic circuit would sound like with 6V6's or 5881 and perhaps a different tone stack. Still thinking actually. I am not in any big hurry.
I also have a Mesa Boogie Nomad 45 project I am fiddling with trying to make it into a good sounding amp, without much success I might add...lol Mesa amps are a PITB to work on. Too much stuff jammed into too little space plus the seven zillion relays and JFETs for the three channel switching...jeezs!! Actually I have never played a Nomad so I don't know what one working correctly would sound like. The clean channel is not bad but channel 2 and 3 sound like crap.
I would like to see the schematic you mentioned.
Cheers,
Billy
Attachments
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Cutting holes in the chassis for the tube sockets.
https://youtu.be/4ticSbbsiLw
Perhaps I will start another tread for the build.
Cheers,
Billy
https://youtu.be/4ticSbbsiLw
Perhaps I will start another tread for the build.
Cheers,
Billy
from "Solid-State Guitar Amplifiers" by Teemu Kyttälä
http://www.thatraymond.com/downloads/solidstate_guitar_amplifiers_teemu_kyttala_v1.0.pdf
“…… what is less well known is that behind the cosmetic exterior of the supposedly classic amplifier might lie something completely different. Take for example the Roland Jazz Chorus JC-120: There are at least eight or nine different versions of this respected amplifier – most of them quite different from another."
Which one is yours?
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