My father asked me to help him with fixing his citation 12 and he asked me if I could convert it to MOSFET using Nelson’s design. I said sure. I cleared the board and this is how far I have gotten on the main board.
Both channels have been done this far. I’ve then realized that the bottom of Nelson’s page had an option for a complementary output, which he said is the better design. So from what you see above, I have to remove the diodes as Nelson removed them. The schematics between the two pretty close, but there were a few changes. After investigating, I found that there was a board that was put out by member TAZZZ. This member made more changes to the schematic, but it is very close. I’m wondering if these changes were due to using different outputs and transistors since the originals are no longer available. Regardless, if I use TAZZZ’s design or use Nelson’s from his DIY page I do intend on using IRFP240 and IRFP9240. For the transistors, I am still trying to figure that out. Either MPSA42/92, 2N5551/2N5401, or since TAZZZ’s boards used 2SA970 and 2SC2240 I may go a different direction. Possibly KSA992/KSC1845 for their low noise if the current is low enough, or possibly BC550c/BC560c is voltage is low enough, or maybe ZTX694b/ZTX795a if people consider these low noise. I know Echowars is a fan of them.
Anyways, my question is, is there a design that is preferred? If I go with Nelson‘s original plans, it would be less expensive as I can use the original board. His board layout on the page is very hard to read, does anyone happen to have a cleaner image of it? There is a member here who has TAZZZ’s boards available, his second version of the design, but with the cost of the boards and shipping from Germany, it could add up. I do understand that if I go with Nelson’s design, and I make the changes to the outputs and to the transistors that I may need to make changes to the schematic, so that might be inevitable.
Just curious if there was a preferred design between the two. If shipping from Germany and cost of boards ends up being too much were there any Gerber files made available to have your own printed? I really want to get this amp going for my father. I just really don’t know what is the right way to go.
Thank you,
Dan
Both channels have been done this far. I’ve then realized that the bottom of Nelson’s page had an option for a complementary output, which he said is the better design. So from what you see above, I have to remove the diodes as Nelson removed them. The schematics between the two pretty close, but there were a few changes. After investigating, I found that there was a board that was put out by member TAZZZ. This member made more changes to the schematic, but it is very close. I’m wondering if these changes were due to using different outputs and transistors since the originals are no longer available. Regardless, if I use TAZZZ’s design or use Nelson’s from his DIY page I do intend on using IRFP240 and IRFP9240. For the transistors, I am still trying to figure that out. Either MPSA42/92, 2N5551/2N5401, or since TAZZZ’s boards used 2SA970 and 2SC2240 I may go a different direction. Possibly KSA992/KSC1845 for their low noise if the current is low enough, or possibly BC550c/BC560c is voltage is low enough, or maybe ZTX694b/ZTX795a if people consider these low noise. I know Echowars is a fan of them.
Anyways, my question is, is there a design that is preferred? If I go with Nelson‘s original plans, it would be less expensive as I can use the original board. His board layout on the page is very hard to read, does anyone happen to have a cleaner image of it? There is a member here who has TAZZZ’s boards available, his second version of the design, but with the cost of the boards and shipping from Germany, it could add up. I do understand that if I go with Nelson’s design, and I make the changes to the outputs and to the transistors that I may need to make changes to the schematic, so that might be inevitable.
Just curious if there was a preferred design between the two. If shipping from Germany and cost of boards ends up being too much were there any Gerber files made available to have your own printed? I really want to get this amp going for my father. I just really don’t know what is the right way to go.
Thank you,
Dan
Does anyone know if the MF-12c board by Tazzz has a gerber file available to order my own? I see others here have had them made and I was hoping to get four or five pair made up.
Thank you,
Dan
Thank you,
Dan
In essence, since I am a sissy, I would follow Papas design in this particular case. If the schematic is hard to read, I would be so rude as to drop Pa an email and circle the things that are unreadable and ask him for clarification. Or post here for help, there are masters here too and perhaps Pa too will see the post.
If you choose Tazz’s approach, I would reach out to him and ask for Gerbers, via e-mail or PM if he is here on the forum.
If you choose MOSFETs, try to get hold of Harris devices for lower distortion.
As for your other questions others should answer.
If you choose Tazz’s approach, I would reach out to him and ask for Gerbers, via e-mail or PM if he is here on the forum.
If you choose MOSFETs, try to get hold of Harris devices for lower distortion.
As for your other questions others should answer.
This would only apply to IRFP9240 P channel parts. Classic HK12 design is NPN or N channel parts.
If you want complementary parts use IRFP9140 types from anyone.
If you want complementary parts use IRFP9140 types from anyone.
I’m sorry Nelson, what would only apply to the IRFP9240?
I do understand the citation is an all NPN design
The reason I mentioned using IRFP9240 and IRFP240 is because I have at least 60 of each. Are you saying that you recommend IRFP9140 and IRFP140 or are you saying go with IRFP9140 and IRFP240?
Sorry, a little confused here.
Are the 9140/140 better for your schematic? If so I’ll order them.
Dan
I do understand the citation is an all NPN design
The reason I mentioned using IRFP9240 and IRFP240 is because I have at least 60 of each. Are you saying that you recommend IRFP9140 and IRFP140 or are you saying go with IRFP9140 and IRFP240?
Sorry, a little confused here.
Are the 9140/140 better for your schematic? If so I’ll order them.
Dan
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I think that contacting Tazzz is out, he hasn’t been seen since March of 21. I’m not super familiar with how to get around, but with his email address be available here?
Dan
Dan - IR P channel devices exhibit a shelved frequency response deviation in their transconductance. It's not like it's the end of the world, but other manufacturer's don't have this "issue"..
I’m placing an order with digikey today, do you have a recommendation as to what device numbers I should grab? Harris?
I grabbed a bunch if the IRFP devices since Nelson seems to like them and they’re used quite frequently in the DIYaudio store projects. I have multiple boards for the diy PASS amps and preamps.
Dan
I grabbed a bunch if the IRFP devices since Nelson seems to like them and they’re used quite frequently in the DIYaudio store projects. I have multiple boards for the diy PASS amps and preamps.
Dan
The Vishay/IR version if the IRFP9240 is the only part involved as far as I know.
Like William said, it's not the end of the world...
Like William said, it's not the end of the world...
That’s the only part that has the shelved frequency? I was trying to understand what you said in your first post of this thread.
Are you telling me to go with IRFP9140 and IRFP140 over 9240/240 I am wanting to go with complementary outputs, and I saw in your design from long ago that at the end of the article you placed the schematic for the complementary output design. Is the IRFP9240 not a device you use?
Dan
Looks like the IRFP140 is on back order. At least the NPBF. I guess I will just place my order and then once I figure out what is being said exactly I can place another order.
Dan
Dan
Dan: To elaborate on what has previously been said, this ONLY applies to International Rectifier 9240’s. What is the consequence? As far as I remember, a little more midrange distortion, mostly 2nd order in an unbalanced design/unbalanced inputs. Which actually means a quite comfortable sound. So if you have the 9240 allready, USE IT! (Milk that cow, to quote a Pass Labs article about the issue). My two cents 
Edit: The 9140 and 140 have more complementary transconductance curves than a 240 with the 9140, as I understand it. But again, you can easily avoid this issue by using what you’ve allready got. Even Pa used to care about mileage costs, before defecting to Elon Musks spaceships. So use what you have I say. I use the combo myself.
Edit: The 9140 and 140 have more complementary transconductance curves than a 240 with the 9140, as I understand it. But again, you can easily avoid this issue by using what you’ve allready got. Even Pa used to care about mileage costs, before defecting to Elon Musks spaceships. So use what you have I say. I use the combo myself.
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Okay, thank you so much, I really appreciate the explanation. So you say it affects the IR 9240s, does it the same with the Vishay devices? That’s what I have. So you’re using the IRFP9240 and IRFP240? That’s what I have. So like you say use it. Oh I see Nelson mentions the Vishay has the issue as well.Dan: To elaborate on what has previously been said, this ONLY applies to International Rectifier 9240’s. What is the consequence? As far as I remember, a little more midrange distortion, mostly 2nd order in an unbalanced design/unbalanced inputs. Which actually means a quite comfortable sound. So if you have the 9240 allready, USE IT! (Milk that cow, to quote a Pass Labs article about the issue). My two cents
Edit: The 9140 and 140 have more complementary transconductance curves than a 240 with the 9140, as I understand it. But again, you can easily avoid this issue by using what you’ve allready got. Even Pa used to care about mileage costs, before defecting to Elon Musks spaceships. So use what you have I say. I use the combo myself.
So is Nelson telling me to use the 9140 and 140 to avoid this distortion? I did order some, but not sure when the 140s will be delivered. I’ll look through my stash and see what else I have.
Dan
I've used these outputs in my original F5. Without some measuring equipment, difference is likely undetectable, and if so, is likely pleasant.
To avoid all, use 140 outputs. You might like others better or just as good.
To avoid all, use 140 outputs. You might like others better or just as good.
Take note of what Papa said, he seldom spells it out straight; it is not the end of the world. Just chill
