Allen&Heath Zed R16 Linear Power supply Upgrade/Modification

 The story goes like this….

I got  A&H Zed R16 brand new over 10 years ago, it was my first serious piece of gear and at the time first class seat into music production world.

If you want to find out more about ZED R16, take a loot at great under the hood review by Mike Rivers.

My first studio setup was made of few Shure SM 57 dynamics, pairs of Audio Technica 4040 and 4041 condensers, CAD e100 condenser, Yamaha HN 5 monitors and Apple Mac Mini Server.  Affordable  setup for recording  professional sounding music without breaking the budget. 

This is great example of recordings made back then (all preamps, EQ's and summing were ZED R16, the only plug-in was Logic stock reverb). 

In over 10 years of use I never had any issues or need to service Zed R16, though, the sound quality gap in between new outboard gear in my studio from well known brands like  Neve, Spl, Phoenix Audio, Mytek, Summit Audio and Zed R16 was obvious. As gear modification master mind Jim Williams once said "it sounds good until you hear better", I started looking for a ways to somehow improve performance of ZED R16 and catch up with the rest of the gear in studio. There were some users on A&H Zed R16 firewire mixer page on Gearspace forum who managed to get more out of ZED R16 by recapping stock SMPS as well some other modifications (bypassing/de-coupling op-amps) but as I know no one really did external LPS mod. 

 

Linear power supply I used for this mod is Yamaha PW8, think these LPS goes cheap these days because it was used for discontinued Yamaha IM8 consoles as redundant power supply and no ones needs it anymore. I got it in local store, it was listed as stock clearance. Yamaha did great job with design and they didn't cut cost with chep parts, great buy and dirt cheap. .

 DC outs are perfect match for Zed R16 power consumption.

Just to make sure that everything is going to work and that it will be worth investing in PW8 I dropped a message to Mike  from A&H, the designer of Zed R16. Not that he was so kind to reply and send me confirmation that PW8 is good match for ZedR 16 he event went step further and send me all details instructions with photos how to execute modification!! At the top of it he helped me sort out all connectors and cables needed to connect new power supply with console …. well beside being brilliant analog gear designer Mike is as well living legend …. customers support doesn’t get better that … AWE to A&H!!

 

Back to power supply modification ….

As it turned out, executing the mod wasn't that complicated at all … to take out stock SMPS all it needs is to remove few screws and unsolder few wires. Empty AC socket makes perfect candidate to fit Hirose JR21RK-10S Pin connector.

Next step is to solder  wires from power distribution PCB to connector and you are ready to go, simply as that!

Mod instructions from A&H:

Lift bottom cover from ZED R16, distribution PCB is accessable right underneath.
I’d recommend keeping the green wire from the distribution PCB to the rear panel and wiring the new PSU to the distribution board after the old wiring is removed... 

for example - take out brown, red, blue and yellow wires from psu to distribution pcb. Then wire to distribution pcb:

Brown = +10 (or 12)

Red = +15

Blue = -15

Yellow = +48

PSU 0v can go to the rear panel or the 0V on the distribution pcb, but ensure at least one green wire exists from the rear panel to the distribution pcb 0V. 

I'm planing to recap old stock SMPS and put it in new metal chassis add  JR21RK-10S Pin connector and use it as external PSU for mobile works(SMPS weights less that 1kg, PW8 11kg!) and as back up if PW8 fails.

 Here is replacement capacitors list someone posted on GS forum

Original					Replaced with below
QTY	uF	Voltage	Company		uF	Voltage	Digi-Key #	MFG #
5	470	25	Samxon		470	50	P15378CT-ND	EEU-FR1H471B
1	330	10	Jamicon		330	50	493-6975-ND	UHW1H331MPD
2	120	63	Samxon		120	63	P15404-ND	EEU-FR1J121
2	100	25	Suscon		100	50	P14454-ND	EEU-FR1H101
2	68	400	Aishi		68	400	493-5879-ND	UCS2G680MHD
2	47	63	Jamicon		47	100	P10773-ND	EEU-FC2A47
1	47	50	Jamicon		47	100	P10773-ND	EEU-FC2A47
1	10	50	Suscon		10	100	493-11505-1-ND	UPW2A100MED1TD
1	1	63	Aisi		1	100	493-11368-1-ND	UPW2A010MDD1TD

Conclusion

There isn’t a piece of audio gear that won’t benefit from a better power supply.

A better power supply will reward you with:

• A lower noise floor
• Not as susceptible to EMI and RFI 
• Much quicker transient response 
• Better isolation from mains
  
• Improved timbre

I can tell that there are improvement in bottom to top frequencies, more natural soundstage and clarity. Zed R16 was my tracking/monitoring tool for over a decade, my ears got used to that  sound, have to give some more time to digest these changes and come back here to update this post.

 

Thanks for reading, stay tuned for more!