battradio
Electron trainer
Yes
Magnavox 142 - rebuild/modification thread
- Thread starter Jcricket
- Start date
Yes
Here is the layout. THey are currently painted a black wrinkle paint. I really don't like it. I am going to repaint them.
Any ideas on colors?? Help please. I will paint the tranny cores, the end bells and the chassis. So up to three colors are possible.
The amp will be wraped in a wooden base - probably walnut or birds eye maple, depending on the color scheme.
Mark
Any ideas on colors?? Help please. I will paint the tranny cores, the end bells and the chassis. So up to three colors are possible.
The amp will be wraped in a wooden base - probably walnut or birds eye maple, depending on the color scheme.
Mark
Attachments
ferninando
Lunatic Member
black and red looks good. blu and yelo, red and yelo.
sparksaflyin
Active Member
That's looking great!!!
I am wiring it up and realized I ordered the wrong caps. According to the schematic, I need .22 coupling caps. I have .47. Will those work? I can order the others and will if there are any issues at all with me using the .47. Just thought I would ask before I put them in.
Mark
Mark
Scuzzer
Fixed Bias
Battradio had an interesting point about the phase shifts in the splitter in this post: http://www.audiokarma.org/forums/showpost.php?p=4186690&postcount=342. Perhaps even 0.22 caps are too high.
I made a note to check this out the next time I mess with mine but I haven't had a chance to play with it lately.
I made a note to check this out the next time I mess with mine but I haven't had a chance to play with it lately.
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If the original phase splitter is still in place (simple paraphase type) then Bat's warning is well founded. While increasing the value of the coupling caps actually reduces phase shift for any given frequency, it also extends the response down so low that the inverter circuit can start to oscillate in a manner commonly called "motor boating". If (or when) the inverter is converted over to a floating paraphase type discussed earlier, this becomes much less of a concern (yet another advantage of the floating type), as the feedback connection for the inverter section in that format reduces its gain to the point that motor boating is far less likely to occur.
Dave
Dave
Floating Paraphase splitter with the 12at7's is what the circuit will be. I still need to wire up the PS and the feedback circuit.
Then I should be ready to bring it up on a varaic and see what happens. Maybe I will be lucky enough to get that done today.
So, I will try .22(I can rob them out of another project that is half done).
What differenc will I see or hear by changing the coupling caps?
Mark
Then I should be ready to bring it up on a varaic and see what happens. Maybe I will be lucky enough to get that done today.
So, I will try .22(I can rob them out of another project that is half done).
What differenc will I see or hear by changing the coupling caps?
Mark
Question folks. What do you use for a shielded input cable. The one that goes from the rca input to pin 2 on the 12at7?
I was thinking about taking on of my old rca intereconnects and cutting it up.
I also have soem RG6 but that is like stuffing an elephant in a shoe box - ugly to say the least.
THoughts?
I was thinking about taking on of my old rca intereconnects and cutting it up.
I also have soem RG6 but that is like stuffing an elephant in a shoe box - ugly to say the least.
THoughts?
What is on the amp now are the end bells painted black. I didn't have the scres I needed to put it togetehr right. I am using he edcors as shown, but they are black now.
I hear black absorbs more sonic vibrations, reduces overall distortions and dampens the sonic artifiacts caused by the copper impurities in the amp. :yes:
I actually just painted the iron and it is drying now.
BTW- the amp is much more burgandy and maroon than the pinkish/purple it shows. I didn't think about the high contrast when i took the picture on hte pool table ot the reflections fom the glass. It looks much better in person.
I hear black absorbs more sonic vibrations, reduces overall distortions and dampens the sonic artifiacts caused by the copper impurities in the amp. :yes:
I actually just painted the iron and it is drying now.
BTW- the amp is much more burgandy and maroon than the pinkish/purple it shows. I didn't think about the high contrast when i took the picture on hte pool table ot the reflections fom the glass. It looks much better in person.
Actually, I have been on a hunt for several weeks now for the elusive 6v6g, rarely seen in these parts.
After much diligence I have finally obtained about 40 of them. I can get at least physical matches out of them. Maybe even some electrical matches if I am lucky.
After much diligence I have finally obtained about 40 of them. I can get at least physical matches out of them. Maybe even some electrical matches if I am lucky.
