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jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
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by jam-mill » Tue Feb 02, 2016 4:35 am
Finally able to spend some time building.
Bought a couple of blank chassis from rjguitars and am now starting to build.
Start of chassis fabrication process and layouts of preamp and power supply boards.
Unfortunately, I buggered up drilling one of the screw holes when the drill 'walked'
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John 15:12-13
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
1 others liked this
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by jam-mill » Tue Feb 02, 2016 4:39 am
Another pic and the layouts
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John 15:12-13
10thTx
Posts: 1864 Joined: Sat Dec 30, 2006 1:13 am
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by 10thTx » Tue Feb 02, 2016 11:51 am
How close is this schematic to the amp you are doing?
I attached a SCH version if you'd be willing to edit it to reflect what you are doing?
With respect, 10thtx
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jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
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by jam-mill » Tue Feb 02, 2016 12:44 pm
10thTx wrote: How close is this schematic to the amp you are doing?
I attached a SCH version if you'd be willing to edit it to reflect what you are doing?
With respect, 10thtx
Pretty darn close.
Yes, I will update the schematic. The only thing that looks questionable to me, at this point, is the bias pot wiring.
Regards,
-jack
John 15:12-13
10thTx
Posts: 1864 Joined: Sat Dec 30, 2006 1:13 am
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by 10thTx » Tue Feb 02, 2016 1:12 pm
OK, thanks! Please check over all of it carefully especially the B+ rail because I am not sure what you are doing with that?
Once you repost a schematic, I will delete mine from the previous post to avoid confusion.
IF you don't have ExpressSCH, then maybe you can use another program to edit the GIF file.
THANKS for sharing your work! I will be very interested in hearing how this amp turns out for you.
With respect, 10thtx
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
1 others liked this
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by jam-mill » Sat Mar 04, 2017 4:46 am
It has been a year, but starting to make more progress on this amp.
Ready to drill front faceplate and chassis.
IMG_0922.jpg
Job complete.
IMG_0923.jpg
Rear faceplate and chassis drilled.
IMG_0926.jpg
Faceplates after some clean-up.
IMG_0927.jpg
Decals applied.
IMG_0928.jpg
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John 15:12-13
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
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by jam-mill » Sat Mar 04, 2017 4:51 am
Front view - some hardware installed.
IMG_0957.JPG
Rear view - some hardware installed.
IMG_0958.JPG
Top view - relay p/s, main p/s, pre-amp board (in-progress)
IMG_0971.jpg
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John 15:12-13
Bombacaototal
Posts: 1675 Joined: Thu Oct 06, 2016 5:53 am
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by Bombacaototal » Sat Mar 04, 2017 7:19 am
Looking really good. Thanks for posting
I am curious if you are going to change the GNFB because of the scaling factor given difference in total output (25w vs 100w) which I ask about here
http://ampgarage.com/forum/viewtopic.ph ... 4&start=75
Unfortunately here hasn't been much response and I am still a bit in doubt on the best way to go about it
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
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by jam-mill » Sat Mar 04, 2017 4:04 pm
Here is the FET board.
IMG_0975.jpg
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John 15:12-13
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
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by jam-mill » Sat Apr 22, 2017 2:41 am
The amp is finished; power-up day is tomorrow.
IMG_1013.JPG
IMG_1014.JPG
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John 15:12-13
M Fowler
Posts: 14019 Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND
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by M Fowler » Sat Apr 22, 2017 12:48 pm
Your build looks very good and I want to build a ODS Reverb one of these days.
Mark
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
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by jam-mill » Sun Apr 23, 2017 3:22 am
Mark,
Thank-You for acknowledging the effort; you comments are appreciated.
Power-up went smoothly. Had to change a resistor in the bias circuit to get the range
needed. Also, I seemed to have swapped the cathode connections on the reverb tube.
Will continue the bring-up process tomorrow.
Regards,
-jack
John 15:12-13
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
Post
by jam-mill » Sun Apr 23, 2017 6:53 am
Couldn't wait until tomorrow to finish the bring-up process and
glad that I didn't - this circuit sounds great with a strat!
No snubbers on V2 and it does not sound harsh; plain-ole JJ's
sound just fine.
John 15:12-13
jam-mill
Posts: 222 Joined: Sun Nov 17, 2013 8:37 pm
Location: San Diego, CA
Post
by jam-mill » Sun Apr 23, 2017 7:02 am
Bombacaototal wrote: ↑ Sat Mar 04, 2017 7:19 am
Looking really good. Thanks for posting
I am curious if you are going to change the GNFB because of the scaling factor given difference in total output (25w vs 100w) which I ask about here
http://ampgarage.com/forum/viewtopic.ph ... 4&start=75
Unfortunately here hasn't been much response and I am still a bit in doubt on the best way to go about it
Have pondered the same thing and investigation into some other 6V6 circuits was not terribly revealing.
Although, the old Brown Note ODS used a 6K2 feedback resistor (in a least one layout I've seen). That
particular amp was designed to be able to use either 6V6 or 6L6 output tubes though. Will have to look
at some old Fender circuits to see what was employed there...
I think the Aiken amp pages give some good info on computing feedback voltage.
John 15:12-13
Bombacaototal
Posts: 1675 Joined: Thu Oct 06, 2016 5:53 am
Post
by Bombacaototal » Sun Apr 23, 2017 8:17 am
jam-mill wrote: ↑ Sun Apr 23, 2017 7:02 am
Bombacaototal wrote: ↑ Sat Mar 04, 2017 7:19 am
Looking really good. Thanks for posting
I am curious if you are going to change the GNFB because of the scaling factor given difference in total output (25w vs 100w) which I ask about here
http://ampgarage.com/forum/viewtopic.ph ... 4&start=75
Unfortunately here hasn't been much response and I am still a bit in doubt on the best way to go about it
Have pondered the same thing and investigation into some other 6V6 circuits was not terribly revealing.
Although, the old Brown Note ODS used a 6K2 feedback resistor (in a least one layout I've seen). That
particular amp was designed to be able to use either 6V6 or 6L6 output tubes though. Will have to look
at some old Fender circuits to see what was employed there...
I think the Aiken amp pages give some good info on computing feedback voltage.
Thanks. Mine I am plugging the GNFB to the 16ohm tap and using the same values as the 100w (4 ohm)
Let me know what you go for at the end