Laney AOR 50 Series II to 2204 w/ PPIMV
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neptoess
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Laney AOR 50 Series II to 2204 w/ PPIMV
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Last edited by neptoess on Sat Jun 14, 2014 3:20 pm, edited 1 time in total.
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gldtp99
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
The 2204 schematic you linked to is the early non-cascaded 2204 ----- this is not the circuit that most think of when building a 2204------ here's a great 2204 schematic: http://www.mhuss.com/MyJCM/JCM800_2204.pdf.
I have a Laney AOR 50 watter that's been a "test mule" for many different circuits after i removed the stock PCB and went with a turret board--- it has been a Krankenstein, AFD #39, and others----- currently it's a hi-gainer with ideas borrowed from many sources (SLO/5150/Dual Rec basic topography)---and some of my own ideas.
The stock Laney iron has served well for all these different circuits--- the amp has been a great learning platform---plenty of room inside and many stock chassis holes to support a wide variety of circuit features.
My Laney AOR has a non-centertapped PT so i used a Full Wave Bridge rectifier for the HT and i used the stock Laney Bias Tap to run the Bias circuit-------other that that a 2204 turret board build isn't all that hard----the zero loss FX loop should be pretty simple to install---plenty of room in the chassis.
The Lar/Mar PPIMV is a nice addition----- there should be plenty of room to add a Resonance control, too---simple to do and another nice feature..............................gldtp99
PS--- then after you get the stock 2204 build done you might want to add #34 mods to the stock 2204 circuit---not too involved and completely reversible
I have a Laney AOR 50 watter that's been a "test mule" for many different circuits after i removed the stock PCB and went with a turret board--- it has been a Krankenstein, AFD #39, and others----- currently it's a hi-gainer with ideas borrowed from many sources (SLO/5150/Dual Rec basic topography)---and some of my own ideas.
The stock Laney iron has served well for all these different circuits--- the amp has been a great learning platform---plenty of room inside and many stock chassis holes to support a wide variety of circuit features.
My Laney AOR has a non-centertapped PT so i used a Full Wave Bridge rectifier for the HT and i used the stock Laney Bias Tap to run the Bias circuit-------other that that a 2204 turret board build isn't all that hard----the zero loss FX loop should be pretty simple to install---plenty of room in the chassis.
The Lar/Mar PPIMV is a nice addition----- there should be plenty of room to add a Resonance control, too---simple to do and another nice feature..............................gldtp99
PS--- then after you get the stock 2204 build done you might want to add #34 mods to the stock 2204 circuit---not too involved and completely reversible
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neptoess
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
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Last edited by neptoess on Sat Jun 14, 2014 3:20 pm, edited 1 time in total.
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neptoess
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
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Last edited by neptoess on Sat Jun 14, 2014 3:21 pm, edited 1 time in total.
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gldtp99
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
Loads of tube amp info here: http://www.freewebs.com/valvewizard/
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rcol1325
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
Nevermind
Last edited by rcol1325 on Sun Apr 24, 2011 9:45 pm, edited 1 time in total.
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neptoess
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
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Last edited by neptoess on Sat Jun 14, 2014 3:22 pm, edited 1 time in total.
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neptoess
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
Oh yeah, I also want a PPIMV, but once the circuit is a 2204, that's hilariously simple to install since SDM has the tutorial on his site
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neptoess
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
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Last edited by neptoess on Sat Jun 14, 2014 3:22 pm, edited 1 time in total.
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gldtp99
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
I suppose that almost anything is possible---- but i didn't realize that you wanted to keep the orig Laney PCB and switch in/out a stock 2204 circuit--- not the way i'd approach it but then i didn't like the orig AOR circuit in mine----so i removed it and went with different circuits built on a new turretboard.....................gldtp99
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neptoess
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
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Mr Fixit
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
It is not clear from the first post if the amp is a head or combo or what the specific aim of the modification is i.e. to get a smoother distortion sound at low volumes or just to build a Marshall 2204 clone as closely as possible. There were a number of versions of the AOR circuit over the years with alterations in some components which give significant differences in tone between the AOR30/50 and AOR100 models.
The AOR circuit is very similar to the 2204 but the extra (4th) 12AX7 preamp tube in the first stage does give much increased gain over the 3 stages of the 2204 (just like putting a booster pedal infront). By definition these very high distortion levels contain a lot of extra harmonic content which can sound buzzy under some circumstances. Please note however that the AOR circuit does not use any solid state components to generate the distortion. The opto-couplers and op-amps are used only for channel switching, effects loop buffering, and as input/output from the reverb spring unit. The diodes are not involved in signal clipping (as in some Marshall amps) but provide certain voltage levels to the switching circuits and as a bridge rectifier.
The low input on the AOR is as for the 2204 but the high input goes to the additional tube stage. The more gentle high level input of the 2203 (compared to the AOR high i/p) is within the AOR circuit and can be accessed as the input of the second tube stage is wired the wiper of the first (preamp 1 gain) potentiometer. So if you are really sure you will never use the additional gain from the first stage (or use a booster overdrive pedal as is common with the 2204 for additional drive) the shielded cable from this wiper can be moved to the AOR amp high input socket.
IMO it is better to leave the extra gain stage but to carry out a number of mods to tame it a little. The output of the first two tube stages goes via a green wire to one side of the low input socket. When the guitar is plugged into the high socket this green wire is connected to the third tube stage (the one with the 10k cathode resistor) via the second potentiometer (preamp 2 gain). Compared to the AOR50 (and AOR30) the AOR100 has an additional 470K resistor between the with 470pf treble peaking capacitor added on the high end side of the second potentiometer (preamp 2 gain). For further gain reduction the 100K resistor feeding the high end side of teh first (preamp 1 gain) potentiometer can be increased up to say 470k. Please remember that as this resistance value goes up the tone becomes darker so the distortion is smoothed. A treble peaking cap e.g. 470pf can be added across this resistor if desired.
The hign levels of bass boost vs treble boost can be also be controlled. The boosts are passive and "borrow" some of the amps total volume at lower volumes. On the AOR50 (and AOR30) the boosts interact with the level of the master volume potentiometer (as a kind of loudness control in hi-fi amps) and become less pronounced as the level is increased. To prevent the volume getting too loud overall I recommend wiring the AOR level poentiometer permanently into the circuit by connecting the low end to ground. Since it actually comes after the M/V control it now becomes the actual master volume control) and lets you set the tone boost sound you want on the original M/V control at the volume you want using the AOR level potentiometer. Remove the blue wire already there which goes to the opto-coupler switching i/c and tape it up safely. The AOR level control is usually effective only when the AOR boost switch is on. The AOR100 is different as separate master volumes for the AOR/non AOR channels.
In another post I will show how to use this now unused blue wire to make the AOR a true channel switching amp with seperate gain controls for each channel (there are already two controls but they are both on at the same time).
The AOR circuit is very similar to the 2204 but the extra (4th) 12AX7 preamp tube in the first stage does give much increased gain over the 3 stages of the 2204 (just like putting a booster pedal infront). By definition these very high distortion levels contain a lot of extra harmonic content which can sound buzzy under some circumstances. Please note however that the AOR circuit does not use any solid state components to generate the distortion. The opto-couplers and op-amps are used only for channel switching, effects loop buffering, and as input/output from the reverb spring unit. The diodes are not involved in signal clipping (as in some Marshall amps) but provide certain voltage levels to the switching circuits and as a bridge rectifier.
The low input on the AOR is as for the 2204 but the high input goes to the additional tube stage. The more gentle high level input of the 2203 (compared to the AOR high i/p) is within the AOR circuit and can be accessed as the input of the second tube stage is wired the wiper of the first (preamp 1 gain) potentiometer. So if you are really sure you will never use the additional gain from the first stage (or use a booster overdrive pedal as is common with the 2204 for additional drive) the shielded cable from this wiper can be moved to the AOR amp high input socket.
IMO it is better to leave the extra gain stage but to carry out a number of mods to tame it a little. The output of the first two tube stages goes via a green wire to one side of the low input socket. When the guitar is plugged into the high socket this green wire is connected to the third tube stage (the one with the 10k cathode resistor) via the second potentiometer (preamp 2 gain). Compared to the AOR50 (and AOR30) the AOR100 has an additional 470K resistor between the with 470pf treble peaking capacitor added on the high end side of the second potentiometer (preamp 2 gain). For further gain reduction the 100K resistor feeding the high end side of teh first (preamp 1 gain) potentiometer can be increased up to say 470k. Please remember that as this resistance value goes up the tone becomes darker so the distortion is smoothed. A treble peaking cap e.g. 470pf can be added across this resistor if desired.
The hign levels of bass boost vs treble boost can be also be controlled. The boosts are passive and "borrow" some of the amps total volume at lower volumes. On the AOR50 (and AOR30) the boosts interact with the level of the master volume potentiometer (as a kind of loudness control in hi-fi amps) and become less pronounced as the level is increased. To prevent the volume getting too loud overall I recommend wiring the AOR level poentiometer permanently into the circuit by connecting the low end to ground. Since it actually comes after the M/V control it now becomes the actual master volume control) and lets you set the tone boost sound you want on the original M/V control at the volume you want using the AOR level potentiometer. Remove the blue wire already there which goes to the opto-coupler switching i/c and tape it up safely. The AOR level control is usually effective only when the AOR boost switch is on. The AOR100 is different as separate master volumes for the AOR/non AOR channels.
In another post I will show how to use this now unused blue wire to make the AOR a true channel switching amp with seperate gain controls for each channel (there are already two controls but they are both on at the same time).
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k-man
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Re: Laney AOR 50 Series II to 2204 w/ PPIMV
I would be very interested in this mod. Thanks.Mr Fixit wrote:In another post I will show how to use this now unused blue wire to make the AOR a true channel switching amp with seperate gain controls for each channel (there are already two controls but they are both on at the same time).