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How much does a rectifier effect tone? Can a 5Y3 be a substitute for GZ34/5AR4?

Custom Deluxe
April 27th, 2010, 01:52 PM
Howdy:

Two questions:

1st: How much does a rectifier effect tone? My '66 Princeton Reverb has a no-name Chinese 5AR4. Is there really something to the quest for the Mullard or other NOS rectifiers?


2nd: Can a 5Y3 be a substitute for a GZ34/5AR4? I pulled out a nice G.E. coke bottle 5Y3 from an old radio. It test good on my little "home version" Lafayette tube tester.

Thanks all.

skeksis
April 27th, 2010, 02:04 PM
I wouldn't make that swap - save it for when you get your hands on an amp that's designed for the 5Y3... (note that I doubt you'd do any damage, but no good point).

So long as you're using the same type rectifier, I'd say it will affect tone BUT it's in the lower tier of things that matter. Why it can affect tone has to do with subtle changes in voltages, which affects how the tubes are biased, which can subtly affect your tone.... small time differences within the same rectifier types. But once you start considering different types - solid state vs 5y3 vs 5u4 vs GZ34... they can somewhat more substantially change the behavior of the amp. They're NOT necessarily interchangeable in any given amp, so do your research before swapping.

Commodore 64
April 27th, 2010, 02:08 PM
I could be wrong, but I understand the rectifier tube can be replaced with an SS component pretty easily, without as much negative effect on tone.

Weber sells a replacement for your GZ34/5AR4 for 22 bucks. http://www.webervst.com/ccap.html Its worth a try. When my NOS RCA 5Y3 gives up teh ghost, I'll use the Copper Cap replacement (I already have it, in fact).

NOS 5Y3 are pretty easy to find (30 bucks at Eurotubes), I don't know about the GZ34/5AR4 though.

ThermionicScott
April 27th, 2010, 02:21 PM
There are people who claim to hear a difference between different brands of rectifier tubes of the same type (i.e. Chinese 5AR4 versus Mullard versus JJ), but if the output voltage is close, I have a hard time buying it.

Now, as for swapping a 5Y3 for the 5AR4... the 5Y3 has more internal resistance and less current capability, so your amp will run out of steam a lot sooner with the 5Y3.

Coke-bottle 5Y3G's are rarer than the 5Y3GT's you find most places, so be a little careful with it! :wink:

- Scott

mr. lucky
April 27th, 2010, 04:02 PM
A nice sub for a GZ34 if you want a little more sag and earlier breakup is a 5R4 -- offhand I don't remember the exact specs, but it's a safe replacement for a GZ34/5AR4 as far heater current, with a significantly higher internal voltage drop.

Also makes a pretty good sub for a 5U4GB, similar performance but much lower filament draw.

I don't think I'd put a good old stock 5Y3 in a circuit designed for a GZ34, pretty big gap between them in the output rating-- might not fry immediately, but couldn't be good for it.

muchxs
April 27th, 2010, 04:14 PM
1st: How much does a rectifier effect tone? My '66 Princeton Reverb has a no-name Chinese 5AR4. Is there really something to the quest for the Mullard or other NOS rectifiers?

Answer #1: It depends. A '66 Princeton PT is a highly stressed piece of gear, don't stick a 5U4G in there. 5AR4 has a 2a filament, 5Y3 has a 2a filamant. 5U4G has a 3a filament. Don't try that one.

2nd: Can a 5Y3 be a substitute for a GZ34/5AR4? I pulled out a nice G.E. coke bottle 5Y3 from an old radio. It test good on my little "home version" Lafayette tube tester.

Yeah but why? A 5Y3 has a relatively large voltage drop. You'll hear the effect of a large voltage drop and maybe a few other little things.

I could be wrong, but I understand the rectifier tube can be replaced with an SS component pretty easily, without as much negative effect on tone.

Depends on what you mean by "SS rectifier" and what you mean by "negative effect". You go on to qualify by saying "Weber Copper Cap" which incorporates a dropping resistor to emulate a tube. It still doesn't behave exactly like a tube.

NOS 5Y3 are pretty easy to find (30 bucks at Eurotubes), I don't know about the GZ34/5AR4 though.

Thirty bucks is a princely sum for a 5Y3. I ought to go into the tube business!

I know what I need to know about the 5AR4. They're around $135 for an NOS Mullard and around half that for a small bottle GE last time I checked.