The Royal Albert Hall Pedal

[MJ_Sound_Cubed]

Jimmy Page with his Hiwatt amplifier at the Royal Albert Hall, became an historical moment blessed by the Gods of tone.










More at soundcubed.com/the-royal-albert-hall-with-a-footswitch/

[ElectricDruid]

Nice work! How's it sound?

[Lew-Dawg]

Damnn that looks sexy!

Where did you get the schematic and the pcb? Is it a kit? Or did you scratch build it?

Lewis

[roseblood11]

It's the Catalinbread RAH, it was traced here or at "the other forum"

[mac]

See this,
https://www.diystompboxes.com/smfforum/index.php?topic=59911.0

mac

[roseblood11]

http://revolutiondeux.blogspot.com/2012/05/catalinbread-wiio-rah.html?m=1

http://tagboardeffects.blogspot.com/2012/04/catalinbread-rah.html?m=1

[Lew-Dawg]

Thanks *mouth watering * this just might be my fall/winter project.

Cheers

Lewis

[MJ_Sound_Cubed]

Damnn that looks sexy!

Where did you get the schematic and the pcb? Is it a kit? Or did you scratch build it?

Lewis

Hey man ,

Yes this  a version of a schematic of the Catalinbread RAH.

I adapted a PCB to my needs using DIY LC, and etched a 1590BB enclosure.

Nice work! How's it sound?

I think it sounds quite ok, but the EQ is insensitive.

[anotherjim]

The odd thing about that design it seems to me, is that it puts the tonestack within a negative feedback loop. Possibly that cancels some of the changes the tonestack makes? In the original amps, the tonestack is before the feedback which runs from speaker output transformer secondary back to the power stage phase splitter.

[roseblood11]

Maybe the schematic is wrong. Too many people here don't really care for detail. If it's "working" (somehow), it gets marked as "verified".

Could it be possible that the right side of R11 is connected to the wrong transistor?


This is the Hiwatt amp:
http://1.bp.blogspot.com/-8r1nNLlYNkg/T7ziBfokAbI/AAAAAAAABXE/_KWcufdOzxE/s1600/DR_Pre2InputJP.gif

[anotherjim]

It would certainly be interesting to disconnect R11. The thing might spring to life. The circuit is too simple to simulate the original NFB scheme and presence feature.

[MJ_Sound_Cubed]

Hey,

I added the schematic, PCB and enclosure transfer at the bottom of the page below:

https://soundcubed.com/the-royal-albert-hall-with-a-footswitch/

[bloxstompboxes]

Thanks. Should be able to slim this down to a 125B.

[MJ_Sound_Cubed]

Thanks. Should be able to slim this down to a 125B.

I can share the DIYLC file if you want.

[bloxstompboxes]

Thanks. Should be able to slim this down to a 125B.

I can share the DIYLC file if you want.

That would be awesome and save me a lot of time. You could put it in the DIYLC cloud if you like. I'm sure others would like that too.

[Lew-Dawg]

I'll be front row if you decide to green light the project... Keep us posted!

Cheers

Lewis

[MJ_Sound_Cubed]

Hi guys,

Its in the DIY LC cloud with the name "Royal Albert Hall by MJ".

Enjoy, and let me know about your mods. 

[bloxstompboxes]

I'll be front row if you decide to green light the project... Keep us posted!

Cheers

Lewis

I forgot that DIYLC has an issue when used with Radeon HD graphic cards. I'll do a layout but in diptrace and then I'll post a build doc with toner transfers.

[Frank_NH]

I built both the WIIO and RAH on vero a while back and was rather disappointed in the sounds from these circuits.  Maybe there are problems with the schematics.  Just last night, I decided to take a look at the RAH in LTSpice (even tracking down the BS170 spice model), and the tone stack definitely has issues and seems to be very interactive.  However, the RAH does appear to have the correct 70s Hiwatt tone stack.  Also, my LTSpice simulation showed no appreciable change in the response if you take out the feedback loop.  Maybe there's some subtle effect there.

The MOSFET stages here are rather unique in design, but I think this could be recast using the "Box of Rock" type MOSFET stages and get a similar sound while using some version of the Hiwatt tonestack.

 

[MJ_Sound_Cubed]

Still didnt try LT Spice, so cant comment on it.