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Post by Lefty on Dec 30, 2006 14:13:02 GMT -7
OK I have used 5U4GB's in RT 66's and I really liked the bloom and almost tweed like characteristic it gave the amp. Lowered power and headroom but increased sustain.
Now time for a little rectifier primer by DR.Z.
A 5U4 is the toughest rectifier on the amps Power Transformer. The filaments of a 5U4 are 5 Volts AC @ 3 AMP. Most designers cheapen out on this section of the PT and use a lower rating for say a 5AR4 and save copper ( i.e. CASH ) .
ALL the PT I designed and use in my amps have 3 AMP Rectifier Filament taps from the 5001 in the Ghia to 9001 in the Delta 88.
So a 5U4 can be safely used in any Z-Amp. Just remember it will lower plate voltage so on FIXED biased Z-Amps Bias will need to be re-adjusted.
The 5U4GB sounds best in a 6L6/KT 66 amp IMHO, not so good in a EL-34/EL-84 based amp, but YMMV.
Hint the new EVAN DR.Z 6L6 amp has a 5U4GB in it right now and do like what I'm hearing, this may change in the final release or not.
I like 5V4's as they are in between the dynamic and higher powered 5AR4 and the spongy 5U4.
I would use them more but they are hard to find these day's and no one makes a GOOD replacement.
I like 5V4's in EL-84/EL34 amps especially for smooth BLUES tones.
OK 5Y3's they supply the least amount of Voltage and Currant. A 5AR4 SHOULD supply 250 mA a 5Y3 supplies 125mA. The draw of 4 EL-84's is typically 120 mA at idle so NO room is left for any other tubes in the amp.
In a 2 EL-84 or two 6V6 amp a 5Y3 is fine just be careful ,too much sag and too much heat. A 5Y3 tube heats up a lot as it's internal voltage drop and dissipates that drop as HEAT.
As you can see all my amps are tube rectified, even the plug in SS amps Delta 88, KT 45 and 6545 are wired for and can except a tube rectifier as a plug in. I find that changing the rectifier type can make the biggest difference in an amps tone for the smallest amount of money. Just remember all changes in TONE are not for the best in all applications.
Happy New Year
DR.Z
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Post by skydog958 on Dec 30, 2006 14:33:59 GMT -7
Thanks Lefty for posting this here. Very useful information!
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Post by Lefty on Dec 30, 2006 16:01:39 GMT -7
I figured it's a FAQ, might as well make it easy to find
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Post by mooretonerocks on Dec 30, 2006 22:46:32 GMT -7
Yeah, thanks for this. I have been reading a lot about tubes lately and just read the TQR 2006 sample issue about NOS tubes. This just adds to the pot something new about all of this that is new to me. I am new to tube amps and my Maz 18 Jr will be delivered next week.
How are JJ rectifiers?
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Post by dei305 on Jan 2, 2007 7:54:01 GMT -7
mooretonerocks, Welcome and congrats on the new Maz Jr. IMO the JJ rectifier is a bit stiff compared to the Sovtec. The Sovtec gives the amp a great feel and not expensive to replace. The Sovtec really complements the amps' performance. I've tried old mullards..with similar results as the JJ. I have found the GT EL-84's to sound wonderful. You may want to experiment with different preamp tubes. I really like the GT12AX7M in V1 and in the PI spot as well. Also have having great results with TAD 7025's. Of course, you can experiment with different speakers as well. Your investment in a Dr Z amp will pay you back huge dividends! Check out this thread. drzamplifiers.proboards41.com/index.cgi?board=tubes&action=display&thread=1161629869Enjoy! Rick
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Post by dock66 on Jan 2, 2007 12:57:14 GMT -7
Lefty,
Thanks for the helpful info.
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Post by nitehawk55 on Jan 3, 2007 18:15:37 GMT -7
Thanks Doc , gonna try a 5V4 in my Maz 18 . Lots of NOS 5U4 GB's available at good prices yet and supply seems pretty good but is sure to change someday .
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Post by guitarstan on Jan 4, 2007 11:48:40 GMT -7
Thanks Lefty, I got a lot to learn about tubes.
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jaamz2
Full Member
^Those have come here to hate should leave now, for in their hatred they only betray themselves.....
Posts: 195
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Post by jaamz2 on Aug 17, 2007 14:50:43 GMT -7
anyone out there tried a 5v4 in a maz 38? whats the difference from stock rec?
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Post by mikekca on Aug 18, 2007 7:36:13 GMT -7
anyone out there tried a 5v4 in a maz 38? whats the difference from stock rec? A 5V4 would give you lower B+ and plate voltage, less brightness, earlier breakup, more sag, and looser low end.
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Post by fisholot on Aug 18, 2007 10:45:31 GMT -7
Thanks Doc , gonna try a 5V4 in my Maz 18 . Lots of NOS 5U4 GB's available at good prices yet and supply seems pretty good but is sure to change someday . Did you ever find one and try it out??? Just wondering, The Phillips 5AR4 sure is nice...
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Post by nitehawk55 on Sept 5, 2007 20:36:57 GMT -7
Thanks Doc , gonna try a 5V4 in my Maz 18 . Lots of NOS 5U4 GB's available at good prices yet and supply seems pretty good but is sure to change someday . Did you ever find one and try it out??? Just wondering, The Phillips 5AR4 sure is nice... Yes I did Erik and I use one in my Maz jr all the time and prefer how it breaks up a bit smoother then with the GZ34 . You will be able to try one out soon too , nudge - nudge
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Post by fisholot on Sept 6, 2007 11:22:14 GMT -7
Yes I did Erik and I use one in my Maz jr all the time and prefer how it breaks up a bit smoother then with the GZ34 . You will be able to try one out soon too , nudge - nudge I see that now... One for each amp.... ;D Thanks
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Post by ledkreplin on Sept 10, 2007 8:09:32 GMT -7
For Nitehawk:I have nos rca 5v4's also a maz 38 and a maz 18 using 5v4's a bias ajustment is not needed for either amp?
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Post by nitehawk55 on Sept 10, 2007 13:55:06 GMT -7
For Nitehawk:I have nos rca 5v4's also a maz 38 and a maz 18 using 5v4's a bias ajustment is not needed for either amp? Since the Maz 18 and 38 amps are cathode biased no rebiasing is needed to switch to the 5V4 tube so you are good to go . Let me know how you think they sound compared to the GZ34/5AR4 . I use a 5V4 in my Maz 18 and really like it .
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Post by play4jc on Sept 11, 2007 4:27:31 GMT -7
I have a brand new 18w jr w/ reverb, in a nutshell, i heard to replace the rect. tube and keep stock as a spare, what should i look for and where do i get a good 1?, Mike at kantos is closed till later on this month thanks
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Post by Stylemaster on Sept 13, 2007 1:06:34 GMT -7
I have a brand new 18w jr w/ reverb, in a nutshell, i heard to replace the rect. tube and keep stock as a spare, what should i look for and where do i get a good 1?, Mike at kantos is closed till later on this month thanks I'm wondering the same. I had to replace the sparking, fuse blowing Sovtek 5AR4/ GZ34 in my MAZ Sr. head and grabbed the rectifier that's been in my '64 Tremolux. It's got the GE logo on it and it has "Made in Great Britain," printed on the glass. Hmmmm, it's from the '60's, made in Britain and looks just like a Mullard. Do you think........?
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Post by janinedoubly on Sept 14, 2007 10:47:51 GMT -7
Almost every GZ34 I've run across that has a US brand name on it from the '60's is a "Made in GB". I don't think there were very many GZ34's ever made here in the US. I've got two "Mullard" GZ34's, neither of which are "real" Mullards.
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Post by dnoseworth on Mar 13, 2008 16:19:13 GMT -7
Thanks Lefty. Nothing like some good reading
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Post by deaconblues on Jul 5, 2008 8:27:56 GMT -7
Any thoughts on replacing the rectifier tube in a Ghia for a bit more headroom?
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Post by detuned on Sept 18, 2008 19:53:02 GMT -7
I gots to get me one of those Weber copper caps - just in case.
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Post by god2710 on Nov 26, 2008 15:27:22 GMT -7
somebody know if I can use a 5Y3 instead of gz34 I heard it break-up early Thanks
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Post by myles on Dec 2, 2008 17:55:49 GMT -7
somebody know if I can use a 5Y3 instead of gz34 I heard it break-up early Thanks These are not a good idea in a GZ34/5AR4 stock equipped amp ... the voltage is lower which is fine but the current is too low for the amp design and that can cause problems. To soften things up in a GZ34 rectified amp use a 5V4.
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Post by eggman on Apr 13, 2009 20:53:14 GMT -7
Howdy,
Would a Russian 5V4 be "OK" for use in my Carmen Ghia? What affect would it have on tone? Would it be necessary to re-bias? Eggman
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Post by myles on Apr 14, 2009 8:39:09 GMT -7
Howdy, Would a Russian 5V4 be "OK" for use in my Carmen Ghia? What affect would it have on tone? Would it be necessary to re-bias? Eggman I would not use a Russian 5V4 in any amp .... they have a difficult enough time producing the common rectifiers.
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Post by eggman on Apr 14, 2009 12:06:34 GMT -7
Myles,
Thanks! Eggman
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Post by myles on Apr 14, 2009 14:16:44 GMT -7
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Post by upfrontguitars on Jan 15, 2010 15:11:22 GMT -7
KOS Tubes has some good NOS 5V4 tubes priced from around $25-$40. Seeing how long the older NOS stuff lasts, this is a good deal. If changing to a 5V4 in a fixed bias amp like the Z28 you will need to check the bias and possibly adjust. Follow the directions on the Z website and it is very easy. All you need is a decent multimeter (Radio Shack has some good ones) and a little screwdriver.
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Post by upfrontguitars on Jan 15, 2010 15:13:29 GMT -7
DUH - I meant KCA NOS tubes. I word-mashed that in my last post.
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Post by Albert on Feb 12, 2010 16:27:06 GMT -7
What about 5R4GY tubes can they be used in a Maz Jr ?
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