Vox AC15CC Schematics - Get 'em here!

robrohdeszudy · March 24th, 2008, 11:15 AM

Hey folks,

I have found it really frustrating that Vox doesn't make available the schematics for the Custom Classic amps. So I got brave and reverse engineered my lead player's Voc AC15CC. Here is the schematic in 4 parts with some notes. I truly hope it annoys Vox deeply.

Best,
--Rob

Board Numbers
Main: PCB_VX15_TYPE1_1001_A
Controls: PCB_VX15_TYPE1_1001_C

Tube locations
I numbered tubes arbitrarily with V1 nearest the output transformer (OT) and V4 nearest the power transformer (PT).

Schematic conventions

Open circles indicate off-board connections.
• “W” numbers (wire connections) are as shown on the board.
• “TT” numbers (turrets) are as shown on the board
• Connector pins are numbered, so C4:1 = connector 4, pin 1
• I think FB1 and FB2 are ferrite beads for RF shielding

British tube designations are shown. ECC83 = 12AX7, EL84 = 6BQ5

I have tried to show circuits in their “textbook form”, rather than as they appear on the PCB. For exampleVR7 and VR8 actually connect on the PCB. But it is at ground, so it is confusing to show them that way on the schematic.

Resistor wattage: The 5-watt resistors I’m sure of. I assumed the smallest were 1/4w, and the larger ones were ½ and 1 watt.

Semiconductors

IC1 & IC2: 2147D dual voltage op amp
1. A out; 2. A –in; 3. A +in; 4. V-; 5. B +in; 6. B –in; 7. B out; 8. V+

IC3: 2120D operational amplifier with switch
1. Switch control; 2. A +in; 3. A –in; 4. V-; 5. common output; 6. B –in; 7. B +in; 8. V+

MF2: LND150

TR1, TR2: C2910 – I assume this is a Sanyo 2SC2910, or some knockoff thereof

Connections to main board

W1 - V1 pin 7 [grid 1]
W2 – V1 pin 8 [cathode 1]
W3 – V1 pin 3 [cathode 2]
W4 – V1 pin 6 [plate 1]
W5 – V1 pin 1 [plate 2]
W6 – V1 pin 2 [grid 2]
W7 – V2 pin 7 [grid 1]
W8 – V2 pin 3,8 [plates 1 & 2]
W9 – V2 pin 2 [grid 2]
W10 – V2 pin 6 [plate 1]
W11 – V2 pin 1 [plate 2]
W12 – V4 pin 2 [grid]
W13 – PT pink
W14 – PT pink
W15 – V3 pin 3 [cathode]
W16 – V4 pin 9 [screen]
W17 – V3 pin 9 [screen]
W19 – blue to HT fuse (Gnd)
W20 – PT brown
W21 – PT brown (Gnd)
W22 – chassis ground
W23 – heater (V4 pin 4)
W24 – heater (V4 pin 5)
W26 – V3 pin 2 [grid]
W27 – V4 pin 3 [cathode]
W28 – V1 pin 2 shield
W29 – V1 pin 7 shield

TT5 – PT purple
TT6 – PT purple
TT8 – pilot light red
TT9 – pilot light black (Gnd)
TT7 – Red to OT C.T.

Jenix · March 24th, 2008, 12:38 PM

I'm not sure if I'll ever need this for my AC15 but I'm going to save it to my computer any way. This looks like it took a lot of work. Thanks a bunch, maybe one day it will come in handy.

NewOldStock · March 24th, 2008, 03:14 PM

Here's another from the Vox R&D department. It's a 2005 print and contains only 4 valves so it would be the AC15 Custom Classic series as well.

I edited because my pics made the thread load extremely slow-Inserted this link instead.

jhundt · March 24th, 2008, 03:40 PM

wow... thanks for the great work.

seems like Vox has added about 1000 extra little components to the good old AC-15 design. More is better... right?

It reminds me very much of how Mr Rivera "improved" the design of Fender amps by adding 500 extra parts, useless switches etc.

I built a home-brew copy of an AC-15 back in '94. It had about 30 resistors/caps in it and sounded brilliant.

How do these new Vox amps sound?

aunchaki · March 24th, 2008, 04:07 PM

Quote:

Originally Posted by jhundt

I built a home-brew copy of an AC-15 back in '94. It had about 30 resistors/caps in it and sounded brilliant.

Do you have a schematic of that? I want to do my first amp build this year. I'd be happy to build a 5E3, but the AC-15 is my favorite. I found an AC-10 schematic online, bit nothing that looks approachable along AC-15 lines...

NewOldStock · March 24th, 2008, 04:52 PM

Quote:

How do these new Vox amps sound?

It's the best sounding amp I've ever heard. Otherwise it wouldn't be sitting in my living room with my Esquire plugged into it.

I'm not compromising on sound any more. My income tax refund was around $4,500 so I could've had almost anything out there. I chose the new AC15...times 2! Got the other one sitting in my work apartment about 300 miles away. It's actually a house I rent, but I wasn't going to type "my work house" in that sentence. It'd sound like I've gotten caught.

Telelicious · March 24th, 2008, 06:20 PM

Heres an AC15 schematic from the Webber Amp book:

March 24th, 2008, 11:15 AM	#1 (permalink)
robrohdeszudy Tele-Meister Join Date: Dec 2007 Location: Madison, Wisconsin, USA Age: 37 Posts: 255	Vox AC15CC Schematics - Get 'em here! Hey folks, I have found it really frustrating that Vox doesn't make available the schematics for the Custom Classic amps. So I got brave and reverse engineered my lead player's Voc AC15CC. Here is the schematic in 4 parts with some notes. I truly hope it annoys Vox deeply. Best, --Rob Board Numbers Main: PCB_VX15_TYPE1_1001_A Controls: PCB_VX15_TYPE1_1001_C Tube locations I numbered tubes arbitrarily with V1 nearest the output transformer (OT) and V4 nearest the power transformer (PT). Schematic conventions Open circles indicate off-board connections. • “W” numbers (wire connections) are as shown on the board. • “TT” numbers (turrets) are as shown on the board • Connector pins are numbered, so C4:1 = connector 4, pin 1 • I think FB1 and FB2 are ferrite beads for RF shielding British tube designations are shown. ECC83 = 12AX7, EL84 = 6BQ5 I have tried to show circuits in their “textbook form”, rather than as they appear on the PCB. For exampleVR7 and VR8 actually connect on the PCB. But it is at ground, so it is confusing to show them that way on the schematic. Resistor wattage: The 5-watt resistors I’m sure of. I assumed the smallest were 1/4w, and the larger ones were ½ and 1 watt. Semiconductors IC1 & IC2: 2147D dual voltage op amp 1. A out; 2. A –in; 3. A +in; 4. V-; 5. B +in; 6. B –in; 7. B out; 8. V+ IC3: 2120D operational amplifier with switch 1. Switch control; 2. A +in; 3. A –in; 4. V-; 5. common output; 6. B –in; 7. B +in; 8. V+ MF2: LND150 TR1, TR2: C2910 – I assume this is a Sanyo 2SC2910, or some knockoff thereof Connections to main board W1 - V1 pin 7 [grid 1] W2 – V1 pin 8 [cathode 1] W3 – V1 pin 3 [cathode 2] W4 – V1 pin 6 [plate 1] W5 – V1 pin 1 [plate 2] W6 – V1 pin 2 [grid 2] W7 – V2 pin 7 [grid 1] W8 – V2 pin 3,8 [plates 1 & 2] W9 – V2 pin 2 [grid 2] W10 – V2 pin 6 [plate 1] W11 – V2 pin 1 [plate 2] W12 – V4 pin 2 [grid] W13 – PT pink W14 – PT pink W15 – V3 pin 3 [cathode] W16 – V4 pin 9 [screen] W17 – V3 pin 9 [screen] W19 – blue to HT fuse (Gnd) W20 – PT brown W21 – PT brown (Gnd) W22 – chassis ground W23 – heater (V4 pin 4) W24 – heater (V4 pin 5) W26 – V3 pin 2 [grid] W27 – V4 pin 3 [cathode] W28 – V1 pin 2 shield W29 – V1 pin 7 shield TT5 – PT purple TT6 – PT purple TT8 – pilot light red TT9 – pilot light black (Gnd) TT7 – Red to OT C.T.

March 24th, 2008, 12:38 PM	#2 (permalink)
Jenix Tele-Meister Join Date: Feb 2008 Location: Illinois State University Age: 19 Posts: 303	I'm not sure if I'll ever need this for my AC15 but I'm going to save it to my computer any way. This looks like it took a lot of work. Thanks a bunch, maybe one day it will come in handy. __________________ USA Ovation * (Big Baby Taylor - SOLD) MIM Telecaster * Vox AC15CC Takamine Classical G series Martin 000C-16RGTE Aura Some people sing in the shower, I play guitar...

March 24th, 2008, 03:14 PM	#3 (permalink)
NewOldStock Tele-Holic Join Date: Mar 2003 Location: Northern Minnesota Age: 36 Posts: 560	Here's another from the Vox R&D department. It's a 2005 print and contains only 4 valves so it would be the AC15 Custom Classic series as well. I edited because my pics made the thread load extremely slow-Inserted this link instead. Last edited by NewOldStock; March 24th, 2008 at 05:00 PM.

March 24th, 2008, 03:40 PM	#4 (permalink)
jhundt Friend of Leo's Join Date: Mar 2003 Location: Netherlands Age: 54 Posts: 3,008 9 Photos	wow... thanks for the great work. seems like Vox has added about 1000 extra little components to the good old AC-15 design. More is better... right? It reminds me very much of how Mr Rivera "improved" the design of Fender amps by adding 500 extra parts, useless switches etc. I built a home-brew copy of an AC-15 back in '94. It had about 30 resistors/caps in it and sounded brilliant. How do these new Vox amps sound?

March 24th, 2008, 06:20 PM	#7 (permalink)
Telelicious Banned Tele-Meister Join Date: Nov 2007 Location: Seattle Age: 44 Posts: 403	Heres an AC15 schematic from the Webber Amp book: