Archive for the ‘Schematics’ Category

B15VB Schematic (2010)

May 15th, 2010 No comments

Here is a schematic of my B15NC amp project.  It is based on the Ampeg B15NC schematic but reflects changes I have made to the circuit.

B15VB Schematic 5/10 (PDF)

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B12NF/B15NF Schematic (1965)

October 19th, 2009 No comments

I forgot I had this – it’s a 1965 B15NF schematic that I redrew.  It’s pretty much the same as the 1966 version I posted previously.  However, I did notice some differences with the speaker cable wiring, as well as the Treble pot on channel 1 being shown as 4 Meg, instead of 1 Meg.  That seems odd to me, but who knows?  There may be other subtle differences that I didn’t catch.  I’ve included a photo of the preamp section of the schematic that I used as a reference.

B15NF Schematic 9/65 (PDF)


9-65 B15NF preamp schematic

9-65 B15NF preamp schematic

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B12NC/B15NC Schematic

October 18th, 2009 No comments

I finally got around to redrawing my B15NC schematics, something that I have been wanting to do for quite awhile.  I have redrawn 3 different versions of the NC schematic, which are shown here.  These drawings are based on originals that I have, and I have tried to replicate the original’s appearance as closely as I could.

The first is dated 1/64.  This is an early NC schematic and does not have circuit voltages shown on it yet.

B15NC Schematic 1/64 (PDF)

The second is dated 11/64.  It has various voltages shown in the circuit, and there have been a few capacitor additions and deletions.

B15NC Schematic 11/64 (PDF)

The third is dated 9/64.  It is the same as the 11/64 schematic except for the center tap on the hum control pot.  Rather than attaching to point “K”, this symbol has been marked over by hand and changed to a ground symbol.

B15NC Schematic 9/64 (PDF)

Because of the size of the original schematics, these drawings are formatted to be printed on 8.5″ x 14″ paper.  When printed, they should be the size of the originals, as long as no resizing occurs within Adobe Acrobat.

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B15NC eyelet board layout

October 15th, 2009 No comments

Here is a drawing I did of the eyelet board in my B15NC.  It just shows the components on the board; it does not show any of the control wires, etc. that also connect to it.

1964 B15NC Eyelet Board (PDF)

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B12XT / B18X Manual (includes schematic)

September 29th, 2009 2 comments

This is a service manual for the B12XT and B18X Portaflex amplifiers.  I have redrawn it from a photocopy and have tried to match the look of the original as best as I could.

B12XT/B18X Service Manual (PDF)

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B12NF/B15NF Schematic (1966)

September 29th, 2009 No comments

Here is a schematic of an Ampeg B15NF, dated 1-66.  I redrew it from an original I have and tried to closely match its appearance.

B15NF, 1-66 (PDF)

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Oliver Powerflex P502

September 29th, 2009 No comments

Here are some schematics I have for the Oliver P502.  I realize that this is not a Portaflex amp, or even an Ampeg amp.  However, since it was Jess’ new twist on his original Portaflex concept (after starting his own company), I think it’s appropriate that it’s included.  The first file is a schematic of the amplifier itself.  I redrew it from a photocopy but tried to closely match the appearance of the original.

P502 Schematic (PDF)

The second is a schematic of the cabinet wiring.

P502 Cabinet Wiring Schematic (PDF)

The third is more of a logical diagram of the cabinet wiring and is meant to more closely resemble what is actually seen inside the cabinet.  Please note that the wire colors shown are based on the wiring of my particular cabinet, and may not match others.  According to Jess Oliver there was not a strict color-code followed when wiring the cabinets.

P502 Cabinet Wiring Diagram (PDF)

(Update, 12/18/09 – I just realized that the P502 Cabinet Wiring Diagram PDF that was posted here was incorrect.  It was a duplicate of the P502 Cabinet Wiring Schematic.  The correct file is now posted)

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