Mod your Beresford 7520

[DaveK]

Ding-a-ling is obviously going the extra mile to try and comply with the basic requirements of being a valued member of the forum. I vote that in future we leave him COMPLETELY alone in his own little world.
Cheers,

[HighFidelityGuy]

Hi Stan,

I've been doing a bit research into the Murata 7805SR-C and I've noticed that it's maximum output current is 500mA but the existing L7805CV has a maximum output current of 1.5A. Will the Murata be able to supply enough current for use in the 7520?

Thanks.

[leo]

Hi Stan,

I've been doing a bit research into the Murata 7805SR-C and I've noticed that it's maximum output current is 500mA but the existing L7805CV has a maximum output current of 1.5A. Will the Murata be able to supply enough current for use in the 7520?

Thanks.

Its more than enough, yes

BTW, Don't mean to keep jumping in, just tell me to bog off

[HighFidelityGuy]

Thanks Leo, definitely don't bog off.

From what I can make out from comparing the data sheets between the L7805CV and the 7805SR regulators, the latter should be a drop in replacement for the former. I'm going to order a 7805SR from Farnell soon and try it out, so I'll report back with my findings.

I'll then start looking into swapping the KIA7810A for a 7812SR but that's going to require a lot more research.

[StanleyB]

I'll then start looking into swapping the KIA7810A for a 7812SR but that's going to require a lot more research.

Borrow a variable power supply and set it on 15V. I use one of those PSU that has a LCD display and shows V and A. But don't go over 16V!! The electrolytic capacitors in the DAC are rated at 16V working. So you don't have much room to play with.

Stan

[leo]

I have a 3pin socket soldered where the regs go just temporary , it allows for quick and easy swapping out of the regs, once I'm happy the sockets are removed and the chosen regs will be soldered top the pcb as normal

The sockets look the same type of thing used on the 7520 front pcb that the audioboard slots in

[HighFidelityGuy]

I have a 3pin socket soldered where the regs go just temporary , it allows for quick and easy swapping out of the regs, once I'm happy the sockets are removed and the chosen regs will be soldered top the pcb as normal

The sockets look the same type of thing used on the 7520 front pcb that the audioboard slots in

Yeah, I noticed your little blue socket in your photos in the "collection of mods" thread, it's a clever idea.

Have you noticed much change to the sound quality between different regs?

[HighFidelityGuy]

Borrow a variable power supply and set it on 15V. I use one of those PSU that has a LCD display and shows V and A. But don't go over 16V!! The electrolytic capacitors in the DAC are rated at 16V working. So you don't have much room to play with.

Stan

Thanks Stan, I've been fancying investing in a bench power supply for a while, I'll look into it.

On the subject of voltage ratings, is the big power input cap the only component before the reg that's likely to blow over 16V?

For example, if I swapped the big cap for a 20V model, would I then be able to go over 16V input or would other components start to fry?
I'm just trying to get an idea of what the limiting factors are.

Thanks.

EDIT: Just for clarification, I'm not thinking about supplying the 7520 with more than 16V, it's just that I'm a little worried about running the input cap so close to it's rating. So if swapping this cap for a 20V model would mean that no components were likely to blow at 16V I'd look into this as a safely feature. I'm sure that finding a 10,000uF 20V cap small enough to fit in the case will be trick though.

[leo]

Yeah, I noticed your little blue socket in your photos in the "collection of mods" thread, it's a clever idea.

Have you noticed much change to the sound quality between different regs?

Yes, the results vary depending on the reg type used, some sound slightly different, others can sound quite a bit different, some can be worse than the standard 78** type fitted

We first see if they measure better , then try the listening test

[HighFidelityGuy]

Yes, the results vary depending on the reg type used, some sound slightly different, others can sound quite a bit different, some can be worse than the standard 78** type fitted

We first see if they measure better , then try the listening test

Hmm, I see. So fitting a Murata SR isn't a sure fire way to getting better sound quality. Have you tried one of the Murata SR's or anything similar yet?

Thanks.