Metropoulos Forum

Had a Mark A Mod 5 for a few years now and decided to take a look under the hood today.
Haven't played it much either but plugged in today and that thing sounds awesome plugged straight in.



From what i can see it only looks like a few parts are changed. The preamp filter on top is a 32/32 F&T and all changed coupling caps are Mallorys. Looks pretty simple but Mark had the touch.

If Mark did this why No Mustard caps? and who did that service W. Dunne It still is cool

Mark(rip)basically used the pre white Mallory caps (yellow) from what I've seen. On the pcb board amps he modded (like in these pics) he changed very little. Looks like a older Mallory and some new white one's. If I'm not mistaken, Mark was using alot of new Mallory and Sozo caps towards the end. Forum member White Noise is the 'Rockstah Mod5' expert. He has several examples of Mark's actual work/amps.

If you still have the amp open,what value is the bright mix cap (the black cap paralled to 470k mix resistor)? 100pf or 500pf? On my mod5 I have a 500pf. I tried both for shits and giggles and 500pf seems to make the most sense in my amp.

In the specs for mod5, it lists it as 100pf but I have seen mostly 500pf. At least I think I'm seeing 500pf caps.

Tone Slinger wrote:Mark(rip)basically used the pre white Mallory caps (yellow) from what I've seen. On the pcb board amps he modded (like in these pics) he changed very little. Looks like a older Mallory and some new white one's. If I'm not mistaken, Mark was using alot of new Mallory and Sozo caps towards the end. Forum member White Noise is the 'Rockstah Mod5' expert. He has several examples of Mark's actual work/amps.

Andy, thank you for the kind words.

This is definitely an amp that Mark modded, it is written all over it.
I would love to hear a clip of the amp if you have one.

Andy is absolutely correct about the Mallorys and the Sozo's.

As far as a Mod 5 that Mark did replacing original caps with Mustards, I haven't seen one (not to say he didn't if someone requested he use them) other than his personal amp ('78 JMP MKII Superlead - testbed amp) and that is the Mod 6 on that one.

The W. Dunne service sticker is probably from someone who serviced the amp prior to Mark modding it.

Wow, the guy (whitenoise) that could legitimately answer my question completely ignores my post..... Nice....

echoplexi1974 wrote:If you still have the amp open,what value is the bright mix cap (the black cap paralled to 470k mix resistor)? 100pf or 500pf? On my mod5 I have a 500pf. I tried both for shits and giggles and 500pf seems to make the most sense in my amp.

In the specs for mod5, it lists it as 100pf but I have seen mostly 500pf. At least I think I'm seeing 500pf caps.

Sorry wasn't trying to ignore your post.

I can't say what is in Lbrown3743 amp for the bright mix cap as i cant see from the pictures, Lbrown3743 would have to tell us.

As far as specs for the mod 5, there is no one set of specs, there are general specs, I have seen the 100pf, 500pf and even higher values that were used for the bright mix cap.

I think that it was what Mark was hearing for that particular amp is why he used a certain part.

the bright cap is a 500pf. There is only a few changes to the amp but it sounds awesome.

Lbrown3743 wrote:the bright cap is a 500pf. There is only a few changes to the amp but it sounds awesome.

More than just a few, I counted over 20 changes from the stock circuit.

Do you have a clip of the amp?

Thanks guys, I appreciate it It's funny, out of all the pictures that I've seen of real mod5s (including mine) I've never seen the 25uf v2a being used. I'm not sure who came up with that mod5 component list, but it is really misleading. Mark really did tweak by ear. There seems to be no set formula for the mod5 as most of us know around here.

One thing that I noticed that is really important for the mod5 sound is the volume bright cap. I can hear it in most of Mark's clips. It's like he set the volume right at the point where you barely hear the bright cap in the circuit. Just enough to make the amp cut.

white noise wrote:

Lbrown3743 wrote:the bright cap is a 500pf. There is only a few changes to the amp but it sounds awesome.

More than just a few, I counted over 20 changes from the stock circuit.

Do you have a clip of the amp?

clip.

https://soundcloud.com/lbrown3743/rocks ... jul-2015-1

Efraser's Rockstah modded Jcm 800 has a similar component selection as this one. The clip though is proof enough that Mark did the mod

Sounds pretty good Thanks for posting pictures..What is the blue cap on the volume pot?

I cant tell what value the cap on the volume is. I cant ready what's on it.

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