Not all 5Y3's are alike...

[bitsandvolts]

Well, I know this issue has been discussed before...but I've just had some first hand experience...I thought it would be worthwhile mentioning it to you guys.

As some of you know, I had an amp (think the last letter of the alphabet and an old volkswagon) here that was running a little hotter than I expected. The B+ was expected to be 305v...and this amp was running at 338v.

The rectifier I had in the amp, was a Sovtek 5Y3GT. The going line on these tubes is that they don't drop the expected 50volts of a 5Y3, instead only dropping about 20v. (30 volts difference) It makes sense, if I expected the circuit to give me a 305 B+ and I was getting something roughly 30volts higher.

So today, I get my hands on a NOS Jan Phillips 5Y3....sure enough, B+ comes out at 308. As a result, amp is now sounding and playing as intended....all is good.


Regardless, if you guys decide on using a 5Y3 for any of your builds, be warned of the Sovtek 5Y3GT.

[rjgtr]

This seems to be true of most modern rectifier tubes. None of them seem to have as much voltage drop. And for many that is an improvement! The fact that most of the common rectifiers are still available at a reasonable $$$ in NOS, keeps me selecting them when I can.

[phsyconoodler]

It's not just the sovtek,it's any modern made 5Y3.They have less internal resistance and are not really 5Y3's.The NOS versions are true 5Y3's.You can tell a couple of ways.One the internal structure is different looking.Two, most of them have only 4 pins.A true 5Y3 has 5 pins.And most 5y3's have the glass coming right to the edge of the base.There are exceptions to this rule,but it is true with most.I don't like using them for that reason.It's getting harder to find NOS 5Y3's,so an alternative is needed desperately.Most of the time I just get a transformer that accomodates a 5AR4 instead.

[novemberrain]

HARD TO FIND NOS 5Y3s?! Maybe 100 years from now! I suggest you look a little harder, if ya can't find any maybe I'll buy the hundreds I see in my travels, mark 'em up a buck or two and pass 'em on!

[sgtoverdrive]

man that is the gospel truth . kids sell 5y3s in front of markets here! i dub this the worlds sloppiest full wave rect! can anyone tell me where the voltage drop chart is!! im trying to tame overall voltage a bit ! heres a pic of 4500 tubes i picked up on tuesday.yea and most of em were 5y3s ive got enough to rectify all the ac current in los angeles to dc for a decade!

[gene]

Nice haul, Sarge!

Gene

[bitsandvolts]

Sarge,

Looks like the limiting factor is your trunk.

Time to trade in that car for a standard issue Humvee....this way you can haul more than 5Y3s!

-F

[DutchMarco]

Apart from the NOS 5Y3s, you could use a WY3 from Weber. Due to no glass they're less mechanically fragile as well (in so far as that's a problem), and the tolex won't peel off due to the heat.

Now, you could always use a Sovtek 5Y3 (very cheap) if you wanted to raise the voltage a bit.

I've ordered a 5E3 kit from Ceriatone, looks like I've just been forewarned about the rectifier tube! I might still get an el-cheapo Sovtek, for above reasons. Thanks for the info guys!

--edit: whoops a bit enthusiastic - I hadn't seen the posting dates!

[bitsandvolts]

Ted Weber has a great product with the copper cap...but I hate using, because most of the PTs out there are really over engineered...and need a bit of load to be happy.

I have a build with a hammond 270FX...and I really need 3-5 more tubes in that thing before it acts as per spec. Even though at that stage, the difference between a weber copper cap and a real tube recto wasn't that great, it was significant enough for me to want to stay with the tube recto and give the PT something more to fight....

[DutchMarco]

So what you're actually saying is that the WY3 also isn't close enough to a real 5Y3? That would be rather silly. Well, to be fair it is of course very difficult to duplicate tubes with non-tube technology. Heck, it must be the reason Line6 haven't produced their own 8- and 9-pin DigiTubes!

But Line6 amps are modeling amps, not guitar amps...

[bitsandvolts]

No, my statement about the WY3 has more to do with power draw. The WY3 doesn't draw any power from the PT...and you can either hook up the 5v tap or not, depending on what kind of mood you're in.

Obviously, a real 5Y3 will draw the standard 5v tap required for the heater element of the tube...and this is a minor draw on the PT...In the case of some PTs, they're really a tad overkill..and the PT could use the extra draw to make it operate a little more as expected.

The advertising line that Ted Weber uses for the copper caps is along the lines of 'your pt will thank you'....implying that it puts less strain on a PT. Which is true....but some of these PT s we use *need* the strain.

[aphekgreg]

So has anyone found any current (no pun intended) production 5Y3s that perform the way they're supposed to?

[bitsandvolts]

I dunno....but I found a JAN Phillips one from some online tube dealer for roughly 13 bucks....it was no different, price wise than the sovtek I got....and far better, in terms of voltage drop...

-F

[Mooncar]

Repeat question but it's been a while.

Has anyone found a current 5y3 with the same draw as the old ones?

I have a Penta 5y3 that I got from somewhere that seems to have the same draw but I can't remember where it came from.

Anyone have the skinny on Penta tubes?

Ken