Ebay "clones" PCB

807tubenut · 30th July 2010, 02:42 PM

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.

kevinkr · 30th July 2010, 03:40 PM

Can't see anything from your link.. Wish people would not post links to things that require login credentials to view them...

807tubenut · 30th July 2010, 03:55 PM

I uploaded them from my blackberry, to my linux server, forgot to change folder permissions, At least I know what I'm doing.

kevinkr · 04:22 PM

Quote:

Originally Posted by 807tubenut

I uploaded them from my blackberry, to my linux server, forgot to change folder permissions, At least I know what I'm doing.

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.

807tubenut · 30th July 2010, 04:15 PM

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.

whitelabrat · 30th July 2010, 07:25 PM

"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.

807tubenut · 30th July 2010, 07:35 PM

Right click the images, and open them in a new window/tab for full rez pics.

I'm down with hacking this board up!

807tubenut · 3rd August 2010, 01:57 AM

Did anyone have recommended modifications to this design?

toufu · 3rd August 2010, 01:58 AM

Why not just get an Aikido phono preamp and be done with it?

807tubenut · 3rd August 2010, 01:59 AM

Iv got the board?

30th July 2010, 02:42 PM	#1
807tubenut diyAudio Member Join Date: Jun 2010 Location: SinCity	Ebay "clones" PCB 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.

30th July 2010, 03:40 PM	#2
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	Can't see anything from your link.. Wish people would not post links to things that require login credentials to view them... __________________ www.kta-hifi.net

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30th July 2010, 03:55 PM	#3
807tubenut diyAudio Member Join Date: Jun 2010 Location: SinCity	I uploaded them from my blackberry, to my linux server, forgot to change folder permissions, At least I know what I'm doing.

30th July 2010, 04:15 PM	#5
807tubenut diyAudio Member Join Date: Jun 2010 Location: SinCity	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.

30th July 2010, 07:25 PM	#6
whitelabrat diyAudio Member Join Date: Dec 2006 Location: Maryland	"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.

30th July 2010, 07:35 PM	#7
807tubenut diyAudio Member Join Date: Jun 2010 Location: SinCity	Right click the images, and open them in a new window/tab for full rez pics. I'm down with hacking this board up!

3rd August 2010, 01:57 AM	#8
807tubenut diyAudio Member Join Date: Jun 2010 Location: SinCity	Did anyone have recommended modifications to this design?

3rd August 2010, 01:58 AM	#9
toufu diyAudio Member Join Date: Jun 2008 Location: San Francisco	Why not just get an Aikido phono preamp and be done with it?

3rd August 2010, 01:59 AM	#10
807tubenut diyAudio Member Join Date: Jun 2010 Location: SinCity	Iv got the board?

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