Hello once again, From the realm of ebay comes these pcb tube amp kits, I say kit, but really it's bare boards, and up to you for parts population.
Here is the schem, and pcb's I'm referring to, seeing as how they have a few of them.
Here is the schem, and pcb's I'm referring to, seeing as how they have a few of them.
An externally hosted image should be here but it was not working when we last tested it.
Can't see anything from your link.. Wish people would not post links to things that require login credentials to view them...
I uploaded them from my blackberry, to my linux server, forgot to change folder permissions, At least I know what I'm doing.
An externally hosted image should be here but it was not working when we last tested it.
That's good! (The linux part in particular..) 😀
Despite the mention of the Marantz 7 this phono stage appears to be quite different using passive EQ, the placement of the passive EQ is interesting in that it is between the second gain stage and the cathode follower, this might provide some SNR advantage particularly with low output MM and the high output end of LOMC, but might in some cases with very high output MM cartridges might also make it prone to HF overload.. (I place my passive EQ between the first and second stage for this reason.)
The high voltage PSU is an odd design, the tube rectifier provides some delay but might otherwise be little more than a fashion statement. The regulator is odd, the transistor in the gate circuit is strange. Unfortunately I am using Google Chrome here at work and it mis-handles the images minimizing them when I click on them so I can't weigh in on what's actually going on as I can't see it clearly enough... 😕
IMHO Actual verbatim clones of the Marantz line and phono stages sound pretty mediocre at best. I'm not a fan of the original either.. So with some care and a willingness to hack the board a bit you might actually end up with something decent.
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For those interested, BG1 in the power supply, is shown as a K310 (full name 2SK310), the NTE cross for it is a NTE67.
Having never used a 6X4, I hope it likes my single 310-0 tranny.
Having never used a 6X4, I hope it likes my single 310-0 tranny.
"Actual verbatim clones of the Marantz line and phono stages sound pretty mediocre at best"
Correct. An early project of mine was a lousy Liteaudio ls7b Marantz 7 clone. Junk.
Correct. An early project of mine was a lousy Liteaudio ls7b Marantz 7 clone. Junk.
Right click the images, and open them in a new window/tab for full rez pics.
I'm down with hacking this board up!
I'm down with hacking this board up!
Check out the store at tubecad.com. I finished both the aikido preamp and phono preamp. Very happy with the results.
807tubenut
I made the mistake of purchasing this board a few years back and made the bigger mistake of populating it with parts. Cut your losses now and don't go any further with the junk board.
I suggest that you purchase the Aikido board or put one together point to point.
I made the mistake of purchasing this board a few years back and made the bigger mistake of populating it with parts. Cut your losses now and don't go any further with the junk board.
I suggest that you purchase the Aikido board or put one together point to point.
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