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Re: Help with my JTM100 1203-80 layout
Posted: Thu Jul 18, 2013 11:46 pm
by axeman
Awesome thread, I want to build one of these too.
Re: Help with my JTM100 1203-80 layout
Posted: Sat Dec 28, 2013 3:28 am
by Homebelly
Just had some time to sit down and re-think the grounding.
Can some one confirm that this is all good?
I am especially interested in weather or not i need to ground the rectifier at location 5 if i have grounded the whole mains board at location 3..?
Grounding fixed by
Homebelly, on Flickr
Re: Help with my JTM100 1203-80 layout
Posted: Sat Dec 28, 2013 5:00 am
by neikeel
If you are doing Larry grounding then you split the bus on the cap board to ground the rectifier and mains to point 5 and take the screens back to 4 with your bias circuit ground and the PI to 3.
Re: Help with my JTM100 1203-80 layout
Posted: Sat Dec 28, 2013 2:50 pm
by Homebelly
neikeel wrote:If you are doing Larry grounding then you split the bus on the cap board to ground the rectifier and mains to point 5 and take the screens back to 4 with your bias circuit ground and the PI to 3.
Like this....?
Grounding fixed II by
Homebelly, on Flickr
Re: Help with my JTM100 1203-80 layout
Posted: Sat Dec 28, 2013 2:55 pm
by neikeel
Yes, pretty much
Looking forward to this project pics
Re: Help with my JTM100 1203-80 layout
Posted: Sat Dec 28, 2013 3:18 pm
by Homebelly
Cheers Bro'.. you have been a huge help.
Next up will be sorting out a picture of how to form the caps.
I have a kinda sorta idea, but the double rectifier is confusing me a little..
Re: Help with my JTM100 1203-80 layout
Posted: Sat Jan 04, 2014 5:06 pm
by Homebelly
Well, after moving house and city twice, seeing in the birth of my son, two redundancies and a a new job. Buying a house, moving in, cleaning it up, including tidying the garden, and getting ready for my second kid, I have finally finished building this project.
Still haven't fired it up as i need to form the capacitors in it.
But here are some pictures of the final amp.
Picture quality is a bit dark as its a wet and windy day here and the light in the kitchen was a little dark.
But any ways.. good enough for now.
DSC06198 by
Homebelly, on Flickr
DSC06197 by
Homebelly, on Flickr
DSC06195 by
Homebelly, on Flickr
Re: Help with my JTM100 1203-80 layout
Posted: Sat Jan 04, 2014 5:09 pm
by Homebelly
Re: Help with my JTM100 1203-80 layout
Posted: Sat Jan 04, 2014 5:10 pm
by Homebelly
Re: JTM 45/100 67 EL34
Posted: Sun Jan 05, 2014 6:22 am
by ol foot
Nicely done! Where did those caps come from on the power board?
Re: JTM 45/100 67 EL34
Posted: Sun Jan 05, 2014 11:52 am
by Roe
looks very nice! I'm very happy with my aluminium chassis dual rectifier amp. the ghosting is not too bad, and the response is very dynamic. Its a great amp for hendrix, kossoff, clapton and EJ
Re: JTM 45/100 67 EL34
Posted: Sun Jan 05, 2014 12:45 pm
by Homebelly
Hi Roe... I am getting ready to post a couple of questions about forming the caps.
I am wondering if i will need two 100K resistors, one for each rectifier, or just one across the first rectifier and cap?
I'm also not sure if the 1203-80 has a dedicated CT?
Re: JTM 45/100 67 EL34
Posted: Mon Jan 06, 2014 11:20 am
by Xplorer
Very cool ! Beautiful build !! Congrats on managing to build this one while you had so much to do in your life.
Looking forward to hear some clips now !
What power transformer are these ? i Wonder if i could use a 45/100 1204-43 power transformer, and i guess ... a black flag output transformer...
if a 45/100 OT can't work there.
What choke is it ?
Re: JTM 45/100 67 EL34
Posted: Tue Jan 07, 2014 1:20 pm
by Roe
Homebelly wrote:Hi Roe... I am getting ready to post a couple of questions about forming the caps.
I am wondering if i will need two 100K resistors, one for each rectifier, or just one across the first rectifier and cap?
I'm also not sure if the 1203-80 has a dedicated CT?
it's easier to form the caps before they are installed
Re: JTM 45/100 67 EL34
Posted: Tue Jan 07, 2014 2:28 pm
by Strat78
Roe wrote:Homebelly wrote:Hi Roe... I am getting ready to post a couple of questions about forming the caps.
I am wondering if i will need two 100K resistors, one for each rectifier, or just one across the first rectifier and cap?
I'm also not sure if the 1203-80 has a dedicated CT?
it's easier to form the caps before they are installed
I'm thinking along these lines too these days. With the tubes pulled you are exposing allot of the little pre-amp caps to voltages above their ratings if you do not use a variac when forming. Still it would be cool to know just how you would go about this with the dual rectifier.
