Attached is my attempt at updating my Harmon Kardon Citation II amplifier to a PCB version.
It took me 7 versions,and a learning curve to understand the schematic & pcb software.
A friend of mine said that I should sell it as a kit, but I'm too old, 71 and I don't have all of the knowledge required to do so.
I do have a BOM built, and have determined that the cost to do this amp is about $650 for parts , minus tubes. KT88 cost about $400 for 4. The 12BY7A tubes price varies depending on where you buy them.
I'm curious if you or anybody else might be interested in my project.
If you are interested, please feel free to contact me.
Thank you for looking at my project.
It took me 7 versions,and a learning curve to understand the schematic & pcb software.
A friend of mine said that I should sell it as a kit, but I'm too old, 71 and I don't have all of the knowledge required to do so.
I do have a BOM built, and have determined that the cost to do this amp is about $650 for parts , minus tubes. KT88 cost about $400 for 4. The 12BY7A tubes price varies depending on where you buy them.
I'm curious if you or anybody else might be interested in my project.
If you are interested, please feel free to contact me.
Thank you for looking at my project.
Nice looking project. The schematic appears to duplicate the original, including the compensation networks, but the output transformer is completely different, so I'm curious about the amp's stability. Do you have any test data to share, like square-wave response, frequency response, etc? Also, I see you are using a 6.6K Antek with 40% screen taps, but the original transformer had a 3.3K primary and lower screen taps. What kind of power output are you getting?
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To answer your questions.
1. I did this project to eliminate wiring and to see if I could. Do it.
2. Am a 71 old retired technician , a manual writer, and did it for fun.
3. For testing all I have is a oscope, signal generator and fluke 8060a meter.
4. will try to do some testing after the Holidays.
5. don’t knowif 5 k pot is wire wound. It is adjusted for mid range.
6. nice catch on transformers, also didn’t do choke. Transformers were purchased for cost. I’m a retired guy trying to keep expenses down , and get the wife too upset with my hobby.
1. I did this project to eliminate wiring and to see if I could. Do it.
2. Am a 71 old retired technician , a manual writer, and did it for fun.
3. For testing all I have is a oscope, signal generator and fluke 8060a meter.
4. will try to do some testing after the Holidays.
5. don’t knowif 5 k pot is wire wound. It is adjusted for mid range.
6. nice catch on transformers, also didn’t do choke. Transformers were purchased for cost. I’m a retired guy trying to keep expenses down , and get the wife too upset with my hobby.
The PCBs look great! I would put it on a scope and check
1) How much feedback you're getting
2) Inject a 10kHz square wave at about 1 watt to see what the high-frequency response and stability look like.
1) How much feedback you're getting
2) Inject a 10kHz square wave at about 1 watt to see what the high-frequency response and stability look like.
Thanks for the compliments.
Here are some more pictures. Don’t have a good top view of the main pcb,sorry.
I’m thinking of selling two sets of the main pcb & power supply, a complete BOM, schematics and my build information and test setup, plus a silkscreen of the main pcb. A silkscreens of the power supply are not needed because if it’s simplicity.
I’m asking for $50 for everything including shipping.
I have a PayPal account but I would have to see how to set it up to receive payments.
Here are some more pictures. Don’t have a good top view of the main pcb,sorry.
I’m thinking of selling two sets of the main pcb & power supply, a complete BOM, schematics and my build information and test setup, plus a silkscreen of the main pcb. A silkscreens of the power supply are not needed because if it’s simplicity.
I’m asking for $50 for everything including shipping.
I have a PayPal account but I would have to see how to set it up to receive payments.
Attachments
Addition note , I won’t be able to do anything with the response till after the holidays.
i’’m also looking into adding two VU meters to the front and possibly changing the analog meter to a digital one. Still working on this , waiting for parts. Next years project.
i’’m also looking into adding two VU meters to the front and possibly changing the analog meter to a digital one. Still working on this , waiting for parts. Next years project.
Are you sure you won't lose money at $50 including shipping? Those are large boards.
If not looking to make a profit, you could just post the Gerber files instead.
It's kind of a big headache to mail out a bunch of stuff at irregular intervals.
I gave away a large number of parts, and it was a lot of work to package and mail them out.
If not looking to make a profit, you could just post the Gerber files instead.
It's kind of a big headache to mail out a bunch of stuff at irregular intervals.
I gave away a large number of parts, and it was a lot of work to package and mail them out.
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Good idea, I didn’t think of that. Thanks, the gerber files are already zipped.
That means everything could be emailed. As several zipped files.
Thanks,
That means everything could be emailed. As several zipped files.
Thanks,
It's perfectly ok if you want to make some profit from your design time and IP,
but if that's not your intention, it's so much easier to email, or even post here, the zipped Gerber files.
You can post them here by clicking on the "attach files" button when composing your post.
A BOM and schematic included would be really helpful as well.
but if that's not your intention, it's so much easier to email, or even post here, the zipped Gerber files.
You can post them here by clicking on the "attach files" button when composing your post.
A BOM and schematic included would be really helpful as well.
How about some photos with 100Hz, 1kHz, and 10kHz square wave input, at 1W output into 8 ohms?
I'll do some testing when I get my amp back from a friend. after the holidays. Wil post results then.
Happy Holidays, I have provided all of my files for you to build this unit , if you choose too.
Some suggestions from after build.
1. Make sure you have a SHORTING STICK to discharge the caps on the power supply.
2. Disconnect main power and short out main caps on pcb ,before doing any troubleshooting.
3. There is 460 VDC present through out the main pcb . Pease take Caution.
4. The steel chassis is hard to work with.
5. As provided in the BOM , I got my printed circuit boards from JLCPCB from China for their cost. Quality was OK for me.
6. Remember this build and bias adjustments worked for me, ANY changes made by you, I'm not responsible for the results.
7 I wanted to see if I could eliminate some point to point wiring and replace the wiring with a pcb. A good friend who help me think on this project, said it doesn't matter what others think what other people think about it, You got it to work and that is all that matters.
8. Finally, I'm just an 71 old hobbyist have fun. I'm NOT and engineer, so what you see is what I got.
9. If someone does tackle this project, I would like to see your results.
10. I'm working on adding VU meters to the front of the unit, because I like them . And Tw, o I'm testing a LED digital displays to replace the bias analog meter.
11. As stated above, I'll post my testing results when done.
Happy Holidays, I have provided all of my files for you to build this unit , if you choose too.
Some suggestions from after build.
1. Make sure you have a SHORTING STICK to discharge the caps on the power supply.
2. Disconnect main power and short out main caps on pcb ,before doing any troubleshooting.
3. There is 460 VDC present through out the main pcb . Pease take Caution.
4. The steel chassis is hard to work with.
5. As provided in the BOM , I got my printed circuit boards from JLCPCB from China for their cost. Quality was OK for me.
6. Remember this build and bias adjustments worked for me, ANY changes made by you, I'm not responsible for the results.
7 I wanted to see if I could eliminate some point to point wiring and replace the wiring with a pcb. A good friend who help me think on this project, said it doesn't matter what others think what other people think about it, You got it to work and that is all that matters.
8. Finally, I'm just an 71 old hobbyist have fun. I'm NOT and engineer, so what you see is what I got.
9. If someone does tackle this project, I would like to see your results.
10. I'm working on adding VU meters to the front of the unit, because I like them . And Tw, o I'm testing a LED digital displays to replace the bias analog meter.
11. As stated above, I'll post my testing results when done.
Like I said earlier, this is an enormous amount of work. Thanks so much for posting it.
I'd emphasize #6--"I'm not responsible for the results". Period. This is a difficult build not to be attempted by novices. Experienced only.
I know a guy who has a pair of original Cit II OPTs...and too many projects already...
I'd emphasize #6--"I'm not responsible for the results". Period. This is a difficult build not to be attempted by novices. Experienced only.
I know a guy who has a pair of original Cit II OPTs...and too many projects already...