5U4G vs. 5U4GB Rectifier Tubes?

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Kiss My Axe

5U4G vs. 5U4GB Rectifier Tubes?

Post by Kiss My Axe » Sat Feb 23, 2008 5:36 pm

I just found out that I have to change the Rectifier tubes in my Tremoverb. Right now it's using 5U4G's, the big bottle ones. Could I swap them for 5U4GB's? What would be the difference in feel/sound?

stokes
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Post by stokes » Sat Feb 23, 2008 11:50 pm

Wont make any appreciable difference at all.The GB has a bit more max current capability,but either one is more than enough for your amp.Any difference in the feel/sound that you notice is imagined.

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Post by edgarallanpoe » Sun Feb 24, 2008 1:56 pm

Stokes got it right, I would also add the following.

Get a pair of NOS rec tubes. They aren't that much more and will probably outlast the amp. LOL!!!

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Post by stokes » Sun Feb 24, 2008 5:08 pm

edgarallanpoe wrote:Stokes got it right, I would also add the following.

Get a pair of NOS rec tubes. They aren't that much more and will probably outlast the amp. LOL!!!
I agree 100% on the NOS,in fact,if I ever mention any tube,it goes without saying I mean NOS.

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Post by edgarallanpoe » Mon Feb 25, 2008 11:58 am

I agree 100% on the NOS,in fact,if I ever mention any tube,it goes without saying I mean NOS.
I agree completely, but unfortunately much of our Boogie brethren can't afford NOS power and pre tubes. Rec tubes are a different story though, and there really is no reason why people shouldn't invest the small difference in those tubes. You can pick up 5u4gbs for around $25 a piece. Spending 50 bucks on something that will give me peace of mind is money well spent IMHO. It won't have the effect on tone that the other tubes will, but having good NOS rec tubes is having one less thing to worry about.

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Post by stokes » Mon Feb 25, 2008 6:36 pm

You can find NOS 5U4G's or GB's on ebay for less than $25.

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Post by edgarallanpoe » Mon Feb 25, 2008 9:15 pm

You can find NOS 5U4G's or GB's on ebay for less than $25.
Yup...I was using a worst case scenario price if someone was leery about buying tubes from an e-bay seller.

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Re: 5U4G vs. 5U4GB Rectifier Tubes?

Post by Timbre Wolf » Mon Feb 25, 2008 10:54 pm

Kiss My Axe wrote:Right now it's using 5U4G's, the big bottle ones. Could I swap them for 5U4GB's? What would be the difference in feel/sound?
I've heard definite differences between 5U4G and 5U4GB, but only to the same degree I hear differences between different manufacturers' tubes. That is to say, there is as much of a difference between, say, RCA 5U4G and Ken-Rad 5U4G, as there is between the Ken-Rad 5U4G and Sylvania 5U4GB. I don't have a Tremoverb, though.

For what it is worth, I prefer the Ken-Rad 5U4G, for its superior dynamic clarity. I've tried RCA and National Union 5U4G and find them quite similar. I actually much prefer Tung-Sol 5U4GB to any other 5U4 type (except the Ken-Rad), though even the lowly Sylvania 5U4GB is preferable to a new-production version, in my opinion.

- Thom

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Post by Kiss My Axe » Tue Feb 26, 2008 3:01 pm

So there should be no problem with putting 5U4GB's in my Tremoverb? I'll probably just go with those then, since that's what Mesa is using now.

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Post by Timbre Wolf » Tue Feb 26, 2008 3:16 pm

Kiss My Axe wrote:So there should be no problem with putting 5U4GB's in my Tremoverb? I'll probably just go with those then, since that's what Mesa is using now.
Absolutely no problem using the GB instead of G - that is to Boogie's design spec.

I do highly recommend NOS Tung-Sol 5U4GB. It is the top of the heap, in my opinion.

- Thom

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Re: 5U4G vs. 5U4GB Rectifier Tubes?

Post by stokes » Tue Feb 26, 2008 8:03 pm

Timbre Wolf wrote:
Kiss My Axe wrote:Right now it's using 5U4G's, the big bottle ones. Could I swap them for 5U4GB's? What would be the difference in feel/sound?
I've heard definite differences between 5U4G and 5U4GB, but only to the same degree I hear differences between different manufacturers' tubes. That is to say, there is as much of a difference between, say, RCA 5U4G and Ken-Rad 5U4G, as there is between the Ken-Rad 5U4G and Sylvania 5U4GB. I don't have a Tremoverb, though.

For what it is worth, I prefer the Ken-Rad 5U4G, for its superior dynamic clarity. I've tried RCA and National Union 5U4G and find them quite similar. I actually much prefer Tung-Sol 5U4GB to any other 5U4 type (except the Ken-Rad), though even the lowly Sylvania 5U4GB is preferable to a new-production version, in my opinion.

- Thom
You've got some ears!The only difference in "tone" I can say I've ever noticed between rectifiers is more sag from a lower power rect., or say if I have 2 5U4's,if one is weaker than the other causing a bit more sag.A rectifier is not in the signal chain and should have little if any effect on the tone.Like I said,if one is somewhat weaker,there may be a noticeable difference in response,but it will hardly be noticeable to most people.

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Re: 5U4G vs. 5U4GB Rectifier Tubes?

Post by Timbre Wolf » Tue Feb 26, 2008 10:49 pm

stokes wrote:You've got some ears!The only difference in "tone" I can say I've ever noticed between rectifiers is more sag from a lower power rect., or say if I have 2 5U4's,if one is weaker than the other causing a bit more sag.A rectifier is not in the signal chain and should have little if any effect on the tone.Like I said,if one is somewhat weaker,there may be a noticeable difference in response,but it will hardly be noticeable to most people.
I hear the challenge in your question, and, to clarify, I did not speak about "tone" differences. I use that "t" word for amplitude differences in frequency bands: more/less bass, low-mids, upper-mids, etc. That is not the kind of differences I am referring to.

We may be discussing the same thing - what you call "sag" may be what I'm noticing between different rectifiers. But what I hear is not dependent upon "weak" or "strong" electronic capacity - a weak testing Tung-Sol 5U4GB is closer in character to a strong Tung-Sol than it is to a weak or strong Sylvania 5U4GB.

For the Ken-Rad 5U4Gs, for instance, I note more clarity/definition (or, perhaps, less compression) than the RCA 5U4Gs I've tried. Weaker, or stronger, the sonic character remains. Some prefer the RCA because of this character, some prefer the Ken-Rad - it is a matter of taste. 5U4G and 5U4GB tube types are spec-ed a little differently, with GB having slightly less voltage drop, yet I've noted much more compressed murkiness from stronger Sylvania 5U4GB.

Maybe I've got great hearing (it tests very well). Or maybe I just care to pay closer attention to this phenomenon, which most of the world couldn't really care less about.

- Thom

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Post by stokes » Tue Feb 26, 2008 11:44 pm

Okay,it does sound like we are talking about the same thing,I use sag as a broad description.I guess I misread your first post to mean tone,reading your second post as well as reading the first again,I see it clearer now,I'll agree there are some differences but I think you are either more sensitive to them,or they just strike me as being more subtle.You are probably more critical ,and I dont mean that in a negative way at all,in the way you listen and compare tubes.Again we come to the subjectivity of the matter,and we all hear things a little different,or in this case,to me the differences are so subtle they arent worth mentioning,but I will agree they are there.But I still think the average Joe aint gonna hear it,or like you say,care less.

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Post by Timbre Wolf » Wed Feb 27, 2008 12:25 am

stokes wrote:You are probably more critical
Let's put it this way - I make my OCD work for me.
stokes wrote:to me the differences are so subtle they arent worth mentioning
More subtle than changing to a different material or thickness of pick - that's for sure. Don't get me started on that, though.

- thom

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Post by Elpelotero » Tue Mar 04, 2008 5:24 pm

I hear much more sag (less tightness) with the 5u4gB than with the big 5u4G, which I find to be much tighter. That's the only real difference. I tested both types of tubes in the same amp several times and that was the conclusion I drew.

Mesa actually posts a similar description in their tube catalog.
'92 Dual Recto Rev. D, Volume mod
'84 Mark IIC+ Coliseum
'85 Mark IIC++ DRG, V1 mod
Mesa Standard 4x12
1980's EV Thiele
Sold:
'92 Dual Recto Rev. C
'92 Dual Recto Rev. E
'05 Dual Recto 3ch
'84 Mark IIC+ DR
http://www.TheBoogieArchives.com

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