MXR 118 Delay DC Conversion

[thetraintomars]

Thanks for the help from the community converting my old MXR flanger to DC. I decided to take a crack at converting an MXR 118 analog delay from the same era to DC. This is the first generation with 1 output, a later revision had a second dedicated delay out line. I'm attaching an annotated schematic. The transformer/voltage regulator section convert the input voltage to an internal 12V, so I was planning to bypass all of that and just use the 12V output on my OneSpot power supply and connect power and ground after this part. I will also use a diode on the +12V input. Does that sound like it would work or is there a reason not to bypass the built in power regulator?

 

[user 130681]

As long as your 12volts is regulated and the power supply is connected to nothing else, it seems like a good idea. If your power supply is a common power supply, it may cause instability.

 

[thetraintomars]

The power supply is this:

https://www.sweetwater.com/store/de...ow-profile-isolated-guitar-pedal-power-supply
I wouldn't be sharing the 12V output with any other pedals, so. no daisy chaining power cables.

 

[user 130681]

WOW how much? It's only a power supply!
What is it made of gold?

Overpriced for a power supply or what! I expect some sucker will buy one expecting it to be better than another, people are easily parted from their money.
Appologies if you bought it.

 

[JohnRoberts]

WOW how much? It's only a power supply!
What is it made of gold?

Overpriced for a power supply or what! I expect some sucker will buy one expecting it to be better than another, people are easily parted from their money.
Appologies if you bought it.

come on be nice...

JR

 

[abbey road d enfer]

WOW how much? It's only a power supply!
What is it made of gold?

Overpriced for a power supply or what! I expect some sucker will buy one expecting it to be better than another, people are easily parted from their money.
Appologies if you bought it.

Your post just shows your ignorance of several things.
First, it's not "only a power supply". It's a multiple floating output type (several secondaries, independant regulators).
Second, it comes with a bunch of cables and adapters.
Third, you must allow for the common multi-tier price build-up that makes a 5-cent component costing a dollar to the end-user.
If you have bought ANY manufactured product via a normal channel, apologies...

 

[user 130681]

Your post just shows your ignorance of several things.
First, it's not "only a power supply". It's a multiple floating output type (several secondaries, independant regulators).
Second, it comes with a bunch of cables and adapters.
Third, you must allow for the common multi-tier price build-up that makes a 5-cent component costing a dollar to the end-user.
If you have bought ANY manufactured product via a normal channel, apologies...

A normal channel, yes. Farnell, RS Components, Mouser etc. All of which offer better products that may be more suited to this specific use than what has been shown in this thread.
What is the purpose of more secondaries than are required. As far as I can tell, a waste of money.
This project requires ONE 12volt supply at less than 1Amp.
A switch mode, regulated wall wart, as the Americans call them, is sufficient. If there is any doubt on the regulation of the new power supply, purchase an 18volt computer power supply and connect it to where the half wave bridge diodes go, or pin 1 of the existing regulator.
Hp or Toshiba PSU less than £25, cut the plug off or fit a 2.5mm DC socket to the MXR and wire accordingly.
That gives you over $117 to spend on other stuff.
A power supply is a power supply. Nothing more.

 

[abbey road d enfer]

What is the purpose of more secondaries than are required. As far as I can tell, a waste of money.

That just proves you don't know much about pedal boards and the problems related to conducted emissions in them.
I once tended to support your opinion. Member moamps showed us why, and now I'm convinced.

This project requires ONE 12volt supply at less than 1Amp.

I agree. There are probably better choices.

A power supply is a power supply. Nothing more.

Very narrow view. You should take a holistic approach.

 

[AnalogPackrat]

A normal channel, yes. Farnell, RS Components, Mouser etc. All of which offer better products that may be more suited to this specific use than what has been shown in this thread.
What is the purpose of more secondaries than are required. As far as I can tell, a waste of money.
This project requires ONE 12volt supply at less than 1Amp.
A switch mode, regulated wall wart, as the Americans call them, is sufficient. If there is any doubt on the regulation of the new power supply, purchase an 18volt computer power supply and connect it to where the half wave bridge diodes go, or pin 1 of the existing regulator.
Hp or Toshiba PSU less than £25, cut the plug off or fit a 2.5mm DC socket to the MXR and wire accordingly.
That gives you over $117 to spend on other stuff.
A power supply is a power supply. Nothing more.

This project requires one isolated 12V supply. OP likely has a pedalboard and can make use of the other isolated outputs on this unit for his other devices. Having multiple wall-warts or bulky inline type laptop supplies under a pedalboard isn't often ideal for portability or use of limited space.

 

[user 130681]

That just proves you don't know much about pedal boards and the problems related to conducted emissions in them.
I once tended to support your opinion. Member moamps showed us why, and now I'm convinced.

I agree. There are probably better choices.

Very narrow view. You should take a holistic approach.

Everyone is entitled to their opinion, of which I respect yours but I am an engineer and rely on science not sales talk to make up my mind.
This conversation is about saving a lot of money and getting the job done.
I agree that if it were on a pedal board, a large power supply would be inconvenient, I was just using that as an example.
A power supply from a CCTV system is very small or indeed an existing multi output power distribution device may well be adequate and if already available, that will save evenmore money, save a DC socket, to plug the DC power in.

 

[JohnRoberts]

As I keep saying, Abbey is the kinder and gentler moderator.....

JR

 

[AnalogPackrat]

That just proves you don't know much about pedal boards and the problems related to conducted emissions in them.
I once tended to support your opinion. Member moamps showed us why, and now I'm convinced.

A link to that thread here might prove useful.

https://groupdiy.com/threads/isolat...hare-the-ground-plane-or-fully-isolate.79850/

 

[abbey road d enfer]

Everyone is entitled to their opinion, of which I respect yours but I am an engineer and rely on science not sales talk to make up my mind.

Isn't it the case of many members here?

I agree that if it were on a pedal board, a large power supply would be inconvenient, I was just using that as an example.

The problem is you have generalized, criticizing multiple floating output psu's as "a waste of money". A more comprehensive answer would mention that floating outputs are not necessary (even redundant) when only one output is needed.

This conversation is about saving a lot of money and getting the job done.

I don't think the OP was specifically asking for a low-cost solution.

 

[thetraintomars]

Everyone is entitled to their opinion, of which I respect yours but I am an engineer and rely on science not sales talk to make up my mind.
This conversation is about saving a lot of money and getting the job done.
I agree that if it were on a pedal board, a large power supply would be inconvenient, I was just using that as an example.
A power supply from a CCTV system is very small or indeed an existing multi output power distribution device may well be adequate and if already available, that will save evenmore money, save a DC socket, to plug the DC power in.

Oh god, can you just waddle back down into your troll hole? As was suggested earlier, I am using this pedal on my pedal board, the same one I'm using the 18V MXR Flanger that this forum helped me convert (and with way less rudeness). I'm using every output on that power supply and the 12/18V switching has been a necessary feature. I currently have no other 12 or 18V power supplies so those pedals only work on or near my board. I brought up the power supply earlier in the thread because a poster emphasized that my conversion idea would require a regulated power supply to work properly. Have I justifed something completely tangential to the thread topic, which was converting my delay pedal from AC to DC power, enough for your liking?