Blues Jr. Rectifier Diode Question.

[Thisismyname]

Hello, I'm rebuilding a Blues Jr using an eyelet board. The original schematic uses a bridge rectifier with 1n5062 diodes. I already have a bunch of 1n4007 diodes. I'm wondering if I can just use swap the 1n5062s for the 1n4007s.

I have the datasheets for both. They are different, but I don't know enough about diodes to know what matters and what doesn't. I've used a bridge rectifier with 1n4007s before, so I feel like it should be fine, but I don't know.
I know Doug sells a cube shaped bridge rectifier for a Blues Jr, but I'm not looking to spend any more money if I can help it.

Thanks for your time and expertise.

[SEL49]

1N4007s will be fine.

[Thisismyname]

1N4007s will be fine.

Thank you.

[acheld]

In the short run, I'd agree with SEL49 and in fact I have done this on a non-production amp.

However, for an amp intended to be used for a long period of time, I think 1N5062 diodes are a better bet, or even better yet a 3A 1kV bridge rectifier.   

My own BJs typically draw about  1.2 amps.  So each diode in my bridge will pass 0.6A when turned on and allowing current to flow. For me, that's too close to the current rating of a 1N4007 for long term use.   

Edit:  That was from memory, which was incorrect.  The BJs I have owned and/or built usually consume about 0.5A from the wall, from my records and measurements.   

A 1N5062 is good for 2A, though at a lower (but very acceptable) max reverse voltage spec.

I normally use "packaged" bridge rectifiers, and spec them so that they are rated for twice my average expected (total) current without a heat sink.   The packaged rectifiers at the low end are usually rated for 1.8A or so when used without any cooling, but you can easily find them rated at > 3A as well.  Or simply use thermal glue to mount them to a small piece of aluminum plate (salvaged from your transformer cut).

These are not expensive -- a buck or two at Mouser, and you can buy them on Amazon for about $5 for two of them (though safer to buy at Mouser, Digi-Key or Farnell).   

[SEL49]

My own BJs typically draw about   1.2 amps.  So each diode in my bridge will pass 0.6A when turned on and allowing current to flow.

Maybe your bj draws 1.2A from the wall, but no 2xEL84 amp will ever draw 1.2A through the bridge rectifier. Typical B+ current draw for a 2xEL84 amp is only about 0.1A.

1N4007 are overkill.

[acheld]

1N4007 are overkill.

As I said at the outset, I agree with your statement that 1N4007s would be fine (in the short term).

Whether allowing for more current "overhead" is overkill, or not, depends entirely on your design philosophy.

In my book, packaged robust rectifiers are more compact, and are less prone to wiring errors, and while definitely more expensive than 4 UF4007s (? 40 cents) vs a package ( 55 cents to 1.21) they are worth it to me.  I build for robustness when I can.   Fender builds for "cost effective" solutions that should get their amps to the end of warranty.

Neither approach is wrong.   It's just dealer's choice.

I do want to correct my earlier statement about current draw, however.  The BJ IV sitting on my bench right now is drawing an amp, but there is an issue with it.  Looking at my records for the last 6 BJs I've owned, they do tend to run in the vicinity of 0.5A when warmed up and operating.

But I have replaced rectifier diodes for failure on two of those amps.   Maybe luck of the draw, or mistaken operator behavior, but it gives me respect for rectifiers.