Pay attention to the Vox cabinet design from the Jennings period. The combo amp was almost closed back, which seems to aid the Celestion Blue a lot to produce solid bass. I found this out because the cabinet was furnished and was a Fender Tweed style, but was made from 2 special woods. When I played the amp, it sounded thin. I plugged it into my 1, 12 cab, closed back Blue loaded and the bottom end thickened up as It should. He made 2 back panels thicker and larger and we installed a thicker Birch Speaker Baffle and it worked and sounded correct.
Output Transformer I have tried. I used the newer easier to wire Hammond, Good! Mercury is expensive for a lot of folks (the Mercury Toneclone is $255 and sexy and you can put the Mercury Badge on the amp. Mercury has branded the "Best" transformers according to most players and provide Mojo and it WILL help sell the amp. The markup is insane, but I like it since I get a huge discount. The 18 Watt OT Doug has in his store sounds really good! Classictone is where most going, but if you want your voltages to run close to the original it will have a grainer sounding distortion when you run it hard. I use one, one time. Amp is still loved by the owner, so I cannot say the sound is bad, just different some. If you asked me what is the best all around OT for the build considering price and performance os the 18 watt OT Doug sells. The NEW Sensor Tweed Deluxe works great too. There is some argument over the reflected impedance of the old AC15. Classictone builds 6K for the tubes to see, the Hammond is 7.8K, The Heybour Doug Sells is 8K, So is Mercury and after the initial Radiospares OT's that were used that leaked, got too hot it was finalized to be an 8K. I measured an original 1962 and it is 8K.
Mistake to increase filtering any as it stiffens up too much. Builds easier using Xicon caps, especially the Tremolo/Vibrato. I actually use ceramic caps. Mine, I did use yellow SOZO everywhere because they were free for me. This board has a lot on it and you appreciate the ease of future repairs and so will another tech that may have to work on it down the road. Also, the original wiring of the foot switch is annoying. Change it permanently as waiting for it can seem long at times.
I removed the cap from the board that the Brilliance Switch varies capacitance. On mine, I used a 12 position switch so I can actually allow lower frequencies to pass. I felt it was overkill while I was doing it and a 6 position will give you all you need in reality, but All the ones sold except the combo used 12. I prefer 12 as this makes it so I do not have a guitar sounding muddy, but have access to pass more bottom end. Great aid for Telecaster and Strat Bridge pup.I built him 4. Delivered on a Tuesday and all were sold by Saturday. Remember now, this guy is a Vox guy and has Vox Friends. This helps. He asked for 4 more and I agreed only to these.
He is bugging me now for more, also another AC30 Version and a Top Boost Version. Since the Korg Vox amps do not have that Pentode channel, players seem to take on an immediate infatuation.Since I have had experience with this build, I thought I would share some of the drama of the learning curve, but also what I learned building these. It is much easier to get what I think of as the Vox sound with the AC15 and built the same way, but in AC30, 4 tubes, sounds almost the same with the AC30 version being thicker.
I have also installed NEGATIVE FEEDBACK just to see if Dick Denny was right. He is and none of the amps sold except the combo have reverb and none get NFB.This has been such a successful layout and build that Sluckey and Bnwhit began discussing years ago. When I saw the old thread I got Sluckey interested in it again. He had me blocked from PM to him, as he will do. He only does this so he can make fun of you before you learn, sit back and write where is your schematic? If you draw one and ask him to check it and miss something, he writes stuff like "That is going to be one quiet amp." Didn't tell me why. This amp was different. When I started getting information together, they had Filter Caps in a Doghouse and no Ground Scheme. He told me he was too busy with his garden, but would help me with it when he could.The next day he had revised the drawings and added a ground scheme! He now knew it was going to happen and made sure his name was on it. What happened to me is I understood how the components work and what they do. Gain is not distortion and you can afford to own an AC15.
Thanks Steve, Happy New Year!
Topic: SLuckey's AC-15 build - second time around (Read 5981 times)