I was asked to share this schematic that I drew up to help me when I build an Express clone. I have added component numbers and a few notes. Certainly, there is NOTHING ORIGINAL about it. It comes from the A1b schematic (Kelly '90) with corrections by UR12 based on the Francesca pics.I suppose the voltage measurements came from Kelly '90. I certainly want to share it with those who might benefit from it, but would like it to be accurate and not CONFUSING. I am sure it will be of no benefit to you guys who can draw it (or build it) in your sleep, but it helps my organizationally challenged brain Any suggestions about making it better and correcting any mistakes will make it better for all of us. It strikes me that consistent component numbers may help discussion. I have numbered from input through preamp, then power amp, then power supply, as suggested by bnwitt. I have used Concept Draw Pro (Mac software similar to Visio) to make the drawing, and have attached a .cdd file for Mac users. I have also attached a .vdx file (XML for Visio) and the more universal .pdf file. The .pdf file seems to magnify nicely. The .cdd file works well, and I'm proud to say I can't open the .vdx file Just kidding PC users
I am working on a Liverpool schematic and will post it when finished.
Let's play
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Last edited by drhulsey on Sat Mar 29, 2008 2:32 am, edited 7 times in total.
Lookin good! I might be wrong but I believe our own ampdoc (Dave Hicks) was the person who originated the "Kelly" schematic. Even so, it is nice to get a really good and accurate schematic drawn up. Thanks for taking the time to do this.
Here's the Liverpool schematic redrawn from zompzwin (M. Krÿger). This is certainly not as beautiful as his, but I have added component numbers and a couple of notes. No bias caps on this one, Stephane Again, I have this in xml for Visio and cdd and can email to those interested. Please, look this thread for the Liverpool schem AND a layout: http://ampgarage.com/forum/viewtopic.php?t=3199
Last edited by drhulsey on Wed Aug 22, 2007 1:59 am, edited 2 times in total.
For the Express, believe you need to clearly mark the bias (similar to the B+ 1-5). It leaves the bias pot "area" at the junction of the 15k, 47k, and 10uf (R30, R31, and C22).
Runs to the junction of the two 220k resistors (R16, R17), which you do have marked.
Eyes We don't need no stinkin' eyes The hurrier I go the inaccurater I get
Thanks, Allyn. I know you get tired checking all this stuff! Revised version above. I hope it will be helpful.
Thanks for cleaning up the Kelly schematic. I know a few people have complained that it had a couple of errors, but I just never got around to it since there were so many discussions re the inaccuracies.
Ditto more "good" information.
gearhead wrote:For the Express, believe you need to clearly mark the bias (similar to the B+ 1-5). It leaves the bias pot "area" at the junction of the 15k, 47k, and 10uf (R30, R31, and C22).
Runs to the junction of the two 220k resistors (R16, R17), which you do have marked.
I see lines Millions of lines
Wow- how'd I miss that one Thanks
Revisions made above and thread cleaned up.
ampdoc1 wrote:Thanks for cleaning up the Kelly schematic. I know a few people have complained ...
Dave, how could anybody complain At least, you DID it with the best info you had at the time I really needed an excuse to use my new ConceptDraw program and thought adding some labels might be helpful to some- just a little sharing Thanks for all your sharing