Plexi MSG Project...(Inspired by the Royal Amp)

[playloud]

I've never actually thought of that before! It makes sense now you say it, but then I also wonder why they give separate DC/AC maximums in the datasheets? But surely potential is potential to a cap though...

It's a bit of a complex subject I believe. There are absolute dielectric limits (which are related to peak voltages) and long-run durability limits (which are related to RMS voltages), and then frequency/ripple-dependent aspects. As a general rule of thumb, if you know the DC voltage limit, I'd imagine you want (actual DC voltage) + (peak signal voltage) < (DC voltage limit) at the very least.

 

[Gianbirra77]

The Alpha 'D' pot could mean a different audio taper than the standard 'A' which is 10%. Your typical Marshall log pot from this era (1969) had a 10% - 15% taper from what I've seen.

So would a log A pot be suitable for the Volume 1 - Volume 2 - Bass positions?

 

[Gianbirra77]

Spay the pots with some Deoxit D100...That should take care of the crackling.

I tried but without great results, I'll try again

 

[Gianbirra77]

Marshall used both linear and log pots for the Middle & Treble positon depending upon what Radio Spares had on hand at the time.

If so which one do you recommend, log or lin?

 

[TAZIN]

So would a log A pot be suitable for the Volume 1 - Volume 2 - Bass positions?

Yes, Alpha's 'A' log pot (standard 10% taper) is fine for Volume & Bass pots.

If so which one do you recommend, log or lin?

It really doesn't matter since both types of achieve the same results just at different dial positions. Personally, I tend to use the linear pot for the Middle & Treble,

 

[Vegas strip]

Can i ask you guys what preamp tubes came with these Royal amps and what you suggest for the best Jimmy Page tone?

 

[Gianbirra77]

Can i ask you guys what preamp tubes came with these Royal amps

Hi
In RoyalAmp MSG the factory installed pre-amp tubes are JJ ECC83/12AX7

Can i ask you guys what preamp tubes came with these Royal amps and what you suggest for the best Jimmy Page tone?

Personally have never tried the JJ's but they speak very well of them out there.
I have tried Sovtek WA and RCA Red,I currently have Mullard Blackburns and I think I have found the best for me.

 

[Vegas strip]

Hi
In RoyalAmp MSG the factory installed pre-amp tubes are JJ ECC83/12AX7

Personally have never tried the JJ's but they speak very well of them out there.
I have tried Sovtek WA and RCA Red,I currently have Mullard Blackburns and I think I have found the best for me.

Sweet. Is that your royal amp?

 

[Gianbirra77]

Sweet. Is that your royal amp?

Hi
No,I found the pictures on the web.
I am modifying my former 1987x to RoyalAmp MSG specifications,I am gathering all the components for now and in a few weeks I should start working on it.

 

[Vegas strip]

Hi
No,I found the pictures on the web.
I am modifying my former 1987x to RoyalAmp MSG specifications,I am gathering all the components for now and in a few weeks I should start working on it.

That's sweet. How long does it take to learn how to DIY the mods on amps?

 

[tallcoolone]

Did this for a guy in another Royal MSG thread--thought it was relevant:

 

[Davetheampguy]

Who on earth would mod a circuit board amp like this? Build a kit or something. Total waste of time on a shitty reissue circuit board turd.

 

[tallcoolone]

The 1987x is far from a “turd”, although for what they charge us here in the US for it it should be turret board constructed

 

[Gianbirra77]

Did this for a guy in another Royal MSG thread--thought it was relevant:

Wooww great tone Page style
Another question... where can I find the backing tracks without guitar from the live show at M.S.G.?

 

[Gianbirra77]

Who on earth would mod a circuit board amp like this? Build a kit or something. Total waste of time on a shitty reissue circuit board turd.

Who wants specs closer to the old historic Plexi?
Who wants to test different capacitor and resistor values? With PCBs it is more complicated.
The 1987x is a great amplifier, but it is a jumble of different specifications from various periods of Plexi.
Here's who would modify a PCB amplifier like this