# 0124 Schematic

[ampdoc1]

I saw someone asked for a schematic on this. This may not be exactly perfect, but I looked up some old info, scoured the pics, and used the posted drawings on the layout to come up with this schematic.
I have not "done" the FET preamp/switching/or 1/2 power circuitry,...there is plently of info otherwise on this site.
Note, I don't believe either description of the loop network was correct. As I believe it is wired, the "network" is only in circuit if the send is used (therefore Ayan's observation that a cable in/out of the loop showed increased highs). Otherwise, the MV to PI connection is made through the tip and switch on the Return jack.
Please let me know if you find errors.

David

[Funkalicousgroove]

The network on the loop is bypassed when you plug into the power amp in. The preamp out jack is a standard #11 with no switch, the hot lead of that switch connects to one end of the 220K/250pf network, the other end of the network connects to the shorting aparatus on the power amp input jack- so the network is always "in" unless you use the power amp in jack. I put one in my amp and like it quite a bit.

[ampdoc1]

Funk,

You describe it exactly as I have pictured. The network is always connected to the return/in jack, but is not "active" except thru the send/out jack.

[ampdoc1]

Funk,

I didn't read you comments carefully,..you are exactly correct.

[jaysg]

re: 0124...I'm having trouble finding the pictures of this. Are they on another site or in the Dumble Files and I have to look harder. Also, any idea of the year for it?

[ampdoc1]

Go to page three of the Dumble discussion, and look toward the bottom for the thread "Everything you wanted to know.....". There is a link on that page for all the pics and some layout drawings

[jaysg]

Thanks. There aren't any pictures there anymore, but it's nice to see that it's an 84 with an 88 update to the Skyliner tone stack.

[Robert]

Very nice of you to take the time to work out the schematic. Thank you. I did notice the bypass caps on V2a & V2b (OD1, OD2) are noted as 4.7uF on Gil's written layout rather than 10 uF as indicated on your schematic. The spreadsheet in the other thread is very interesting as well!!

[HiGain]

Thanks for doing this!

The grid circuit to CL2 is different that I have seen. I think I need to go back and examine some more pictures....

Jake

[Pete]

Thanks for doing this!

The grid circuit to CL2 is different that I have seen. I think I need to go back and examine some more pictures....

Jake

yes, I think that CL2 grid should be 220k bypassed with 500pf
nice work, thanks ampdoc

other points I've noticed
both cathode bypass for V2 = 4.7 mf
I think most people agree with 100k L (B) drive & level controls
V1b coupling is .05mf

[skyboltone]

I can't get the scheme to load. Must be doing something wrong.

Dan

[Bob-I]

Thanks for doing this!

The grid circuit to CL2 is different that I have seen. I think I need to go back and examine some more pictures....

Jake

I think there's some mistakes there. I think the series resistor should be 220k, not 22k and the bypass cap should be 470pF not .047uF.

[ampdoc1]

Thanks guys! Most of these mistakes I had caught when prepping the exel file. But keep them coming. I'm going to go through the pics over the next few days and try to verify the entire schematic from them and your feedback. Then, (hopefully) we'll have another circuit we can call: CONFIRMED (in the lexicon of MythBusters).

DEH

[jaysg]

I can't get the scheme to load. Must be doing something wrong.

I've had some trouble with specific .gif and .pdf files. I was able to right click and save picture as on this one. I couldn't open it in IE.

[d95err]

I can't get the scheme to load. Must be doing something wrong.

I've had some trouble with specific .gif and .pdf files. I was able to right click and save picture as on this one. I couldn't open it in IE.

I suspect that it is because of the bracket (#) symbol in the filename. The bracket symbol must be escaped properly to work. Apparently some browsers manage anyway though.