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    Are there any subs for 5AR4

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    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Are there any subs for 5AR4

    Post by Frank111 on Mon Mar 23, 2015 12:17 pm

    I can't seem to find an answer, so I'm asking. Can anything like 5V4, 5AS4, 5R4, or 5U4 be used in place of a 5AR4? Of all of the tubes I have, I don't have one 5AR4! Thought I did.
    I'm talking about a simple plug in without any wiring changes.

    Frank.

    peterh

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    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Are there any subs for 5AR4

    Post by peterh on Mon Mar 23, 2015 12:45 pm

    No, they all differ in various ways.
    Depending on amp topology and transformer capacity some might work in some amps, but
    you never told us what amp.

    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Mon Mar 23, 2015 12:47 pm

    The amps are M-125 mono blocks.

    peterh

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    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Are there any subs for 5AR4

    Post by peterh on Mon Mar 23, 2015 1:49 pm

    Frank111 wrote:The amps are M-125 mono blocks.
    You should in emergency be able to use 5u4. But wait fpr Mr Latino for the definitive answer.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Are there any subs for 5AR4

    Post by sKiZo on Mon Mar 23, 2015 2:32 pm

    Seems to me a 5U4 has too much voltage drop for the monoblocks to be comfortable. Same goes with the 5R4's. I tried one of those Phillips 5R4GYS that are advertised as good subs, but managed to kill it pretty quickly.

    Either a GZ33 or GZ37 should work well. Both can flow a lot more current as well. I've got a Mullard GZ37 driving a quad of KT120's in my ST120 ...



    Granted ... they're not cheap, and that's if you can find them. But ... it may just be the last rectifier you'll ever buy as they tend to be pretty bulletproof.

    Also ... you should consider investing in a a pair of Copper Cap solid state rectifiers. Those can take a lot of punishment and are inexpensive. Good to have around at least as a spare, and lots of folk are happy using them full time. The WZ34 is listed as a direct sub for the 5AR4, but most go with the WZ68 - a direct plug in with double the current handling, at the same price!

    (Not as purty as a big bottle though) cheers

    http://www.webervst.com/ccap.html

    Frank111

    Posts : 83
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    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Mon Mar 23, 2015 3:54 pm

    Sounds like 'there is no substitution for a 5AR4'....

    I think I'm going to order some of the copper cap solid state rectifiers for now. I will be ordering a set of 8 KT-120 Tung-Sol's and that's almost $400.00. Gotta watch cash flow!

    Frank.

    deepee99

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    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Are there any subs for 5AR4

    Post by deepee99 on Mon Mar 23, 2015 4:32 pm

    Hard to beat the old Mullard GZ-33s but the copper-caps come pretty close. They just don't look as cool on a dark winter night.

    sKiZo

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    Join date : 2013-04-01
    Location : Michigan USA

    Re: Are there any subs for 5AR4

    Post by sKiZo on Mon Mar 23, 2015 4:32 pm

    Sounds like a plan.

    You're gonna like those KT120's and the WZ68 copper caps should drive them nicely.

    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Mon Mar 23, 2015 5:25 pm

    I think that'll solve the problem. I like what I'm hearing about the KT 120 Tung-Sols, and my fear of new tubes is lessened. NOS ones are pretty expensive! I'll get theWZ68 as advised.

    I can't resist - is the 'Monarch' labeling on the amp from a '76 Mercury Monarch? I remember when they were new, and I was a kid working at a local dealership. The sticker price for a new one was around $5,200.00. You can pay that for tubes now!

    Frank.

    deepee99

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    Location : Wallace, Idaho

    KT-120s

    Post by deepee99 on Mon Mar 23, 2015 7:38 pm

    I'm not on his payroll, but get your KT-120s from Jim McShane. Good guy.

    skriefal

    Posts : 116
    Join date : 2011-09-20
    Location : Utah, USA

    Re: Are there any subs for 5AR4

    Post by skriefal on Mon Mar 23, 2015 7:49 pm

    Yes, www.mcshanedesign.net.  Good place to buy burned-in, matched tube sets.

    sKiZo

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    Location : Michigan USA

    Re: Are there any subs for 5AR4

    Post by sKiZo on Mon Mar 23, 2015 8:41 pm

    Frank111 wrote:
    I can't resist - is the 'Monarch' labeling on the amp from a '76 Mercury Monarch? I remember when they were new, and I was a kid working at a local dealership. The sticker price for a new one was around $5,200.00. You can pay that for tubes now!

    Yah ... the emblem is from the dash of a '79 ESS.



    Don't see many of them around anymore. Those and the Granada rotted real bad after about 10 years.

    Can't find any pics of the "Monchero" version. I eventually hacked up the back half of the car and stuck in a bed from a Subaru Brat, and finished that up with a nice bed liner. I also converted the side window louvers into working air scoops on the hood, and added a push bar from a Ranger. That had four amber spots, and three and a half Japanese flag decals on the top bar. Scared the crap out of any Honda or Toyota I pulled up behind ...

    I also had the "devil car" horns on it ... BWA BWA ... BWA BWAAAAAAAAAAAAHHHHH!

    Bob Latino
    Admin

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    Location : Massachusetts

    Re: Are there any subs for 5AR4

    Post by Bob Latino on Tue Mar 24, 2015 7:53 am

    peterh wrote:
    Frank111 wrote:The amps are M-125 mono blocks.
    You should in emergency be able to use 5u4. But wait fpr Mr Latino for the definitive answer.

    You can use a 5U4 rectifier in the VTA M-125 but the amp WILL lose power. A 5U4 has a higher forward voltage drop than a 5AR4 and your B+ DC voltage will be significantly lowered.

    You can use a 5AR4 successfully in a VTA M-125 monoblock IF ..
    1. Your room isn't too large
    2. Your speakers are of average or above average efficiency
    3. You don't play music at very high volumes

    My opinions below but other's could have a different take on these ....

    1. If you like tube rectifiers, a GZ33 or a GZ37 do a better job driving the amp than a GZ34 at higher volume levels. The downside is that GZ33's and GZ37's are not made anymore and are expensive ($100 and up)

    2. A Weber WZ68 (IMHO) is the BEST rectifier that you can use in the M-125's and at $22 each + shipping, they are not that expensive. A Weber WZ68 can flow 450 milliamps if necessary. 450 milliamps is beyond the current level that an M-125 may use even when playing loudly. Another benefit of the Weber rectifiers is that they do not use the 5 volt AC heater voltage that a tube rectifier would use. Theoretically this should make it easier on the power transformer because one winding is not being used ..

    3. The Weber WZ68 does get HOT after it has been on for a while. Don't assume that because it is not a tube that it doesn't heat up. If you touch the Weber when it's hot, you can burn your hand.

    4. Do not remove the Weber when it is hot. Over and above the "you can burn your finger" thing, the copper tube on the top is connected to the tube base by some adhesive that softens with heat. If you try to remove the Weber when hot, the copper tube can come away from the base.

    5. You don't really need the TDR if you use the Weber rectifiers. The Weber WZ68 has a short 3 to 5 second delay built in. Through experience, I have found this short delay to be enough to allow the output tube filaments to come on before the B+ comes up. As an aside .. The TDR is nice to have if live in an area that has frequent power interruptions, thunderstorms etc. When the power goes off the TDR will not allow the amp to restart for 17 seconds if you have one of those quick ON/OFF/ON situations on your AC power. As most know > A quick ON/OFF/ON on a tube amp can take out the rectifier. The "diode mod" mentioned in the sticky above can help with a situation like this ...

    Bob

    Frank111

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    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Tue Mar 24, 2015 8:32 am

    Bob, thanks for the above info. I'm going to print it and keep it with my other documents for the M-125's.  For now, I'll get the Weber WZ68's. I am sort of leaning towards getting 8 KT-120's, and they run around $400.00. That mix should be a nice solution for me. I guess you buy the Weber's from them directly? Will need to spend some time later searching vendors for these items.
    The boards for my amps are nearing completion, so time is coming near where I'll need the tubes and rectifiers.

    Frank.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Are there any subs for 5AR4

    Post by sKiZo on Tue Mar 24, 2015 9:47 am

    $400 does sound like a lot, but one nice thing about the KT120's - you won't be working them as hard as you would a KT88, and they should last forever. The VTA amps are simply incapable of stressing them if working properly. Just don't go into it thinking you'll get the max power out of the tubes - you should see a comfortable 7-10% increase over a KT88, but it'd take a complete redesign to really push them.

    If it helps any, I just recently spent more per tube for a matched quad of TAD tubes. Those are modeled after the old production British MOV KT88, heavy glass and all, and have turned out to be quite tasty. The KT120's are currently my backup set.



    (nice backup set, right?) clown

    PS ... good thread going a while back that covers some of the other options ...

    http://dynacotubeaudio.forumotion.com/t2336p15-no-love-for-the-kt-90

    PPS ... Bob mentioned the "quick power blip" problem and how it can kill amps. The TDI board gives you a delayed start up and allows the caps to discharge properly instead of creating a destructive surge. Another option - a NON-LATCHING (that's the important part) GFCI adapter ...

    TRC 90033 Shockshield White Portable GFCI Plug with Surge Protection



    The GFCI part isn't important here. Truth be told, that feature probably doesn't even work on a two prong plug - not that I've ever tried a direct short to see what happens. The NON-LATCHING feature means it stays off until you manually reset it. That allows you to let it rest for a couple minutes before restoring power.

    I got mine for around $20 ...


    Last edited by sKiZo on Tue Mar 24, 2015 10:08 am; edited 2 times in total

    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Tue Mar 24, 2015 9:56 am

    From what I can find, the KT-120's are supposed to be good reliable tubes. Hopefully New Sensor has things under control with them.

    Have you ever dealt with a place called Upscale Audio?

    http://www.upscaleaudio.com/KT88/

    Frank.

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Are there any subs for 5AR4

    Post by sKiZo on Tue Mar 24, 2015 10:13 am

    I got mine from the Tube Depot ...

    Funny story - they put these ridiculous big blue labels on those shiny chrome bases. Tried peeling one and it started shredding. Emailed them to ask them how to get their silly stickers off the tubes, and they huffed 'n puffed back about how their stickers aren't silly. I replied with "Well ... then how do I get these silly tubes off your stickers?" ;-}

    Short version - the labels peel off fine when they're warm ...

    zx

    Posts : 194
    Join date : 2011-08-05

    Re: Are there any subs for 5AR4

    Post by zx on Tue Mar 24, 2015 10:27 am

    Jim McShane..... matchs tube the right way....An his prices are vary fair.. same $$ as others.
    An he helps us on the fourm out with info from time to time.....why not use him....Anything I should know about Jim an his tubes??
    Thanks




    Thanks For the site Bob....................

    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Tue Mar 24, 2015 11:56 am

    I'm just new at buying these kind of tubes, and am out there reading some sites. Pretty much
    doing some comparing right now. I contacted Weber about the copper caps and emailed them about
    buying two WZ68's. Waiting to hear back from them.

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Are there any subs for 5AR4

    Post by deepee99 on Tue Mar 24, 2015 12:18 pm

    I wouldn't go to anyone but Jim McShane for new Russian tubes. He has good relations with the parent company, New Sensor. He's also got a stash of NOS tubes, as does Andy Bowman at Vintage Tube Services.
    Tell you a McShane story. I stupidly pulled the glass off of a brand-new KT-88 of his; he put a replacement in the mail the same day, happy to trust me for payment a week later. Nice guy and quality product line.
    As to the Webers, you can buy a fist-full of the 68s for the price of a single NOS GZ-33. As Bob L mentioned, even though s/s/ they are very tube-like in the heat department. Troy (tmadden on this board) has some mods for the Webers to deal with the heat issue. Talk to him.
    I have dealt with Kevin at upscale audio. He's OK, but more of a promoter than a tube guy.




    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Tue Mar 24, 2015 1:41 pm

    Finally made a little progress today. I now have two WZ68's coming.

    Next is to get the KT-120's ordered. You guys have given me some measure of confidence in dealing with Jim McShane. I appreciate your help on that. Does anyone have a phone number to contact him? I can't find one on the web site, and would prefer to talk with him first.

    Also want to thank all of you for your input!  Feels like a club here Smile

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Are there any subs for 5AR4

    Post by deepee99 on Tue Mar 24, 2015 1:43 pm

    Don't have a phone, but
    jimmcshane@prodigy.net
    will get you guys in touch.

    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: Are there any subs for 5AR4

    Post by Frank111 on Tue Mar 24, 2015 1:49 pm

    Email sent to him to call or give me a number to call.

    We'll see how it pans out.......

    mantha3

    Posts : 298
    Join date : 2010-11-10

    Re: Are there any subs for 5AR4

    Post by mantha3 on Wed Mar 25, 2015 8:19 pm

    Bob,

    Will a 5U4G from Emission Labs work in an ST120 having only the voltage drop issue?


    http://www.emissionlabs.com/datasheets/EML5U4G.htm

    When you say "the amp WILL lose power" do you mean the Watt Per Channel will be reduced at that is the only issue?

    Cubdriver

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    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: Are there any subs for 5AR4

    Post by Cubdriver on Wed Mar 25, 2015 8:36 pm

    sKiZo wrote:PPS ... Bob mentioned the "quick power blip" problem and how it can kill amps. The TDI board gives you a delayed start up and allows the caps to discharge properly instead of creating a destructive surge. Another option - a NON-LATCHING (that's the important part) GFCI adapter ...

    TRC 90033 Shockshield White Portable GFCI Plug with Surge Protection



    The GFCI part isn't important here. Truth be told, that feature probably doesn't even work on a two prong plug - not that I've ever tried a direct short to see what happens. The NON-LATCHING feature means it stays off until you manually reset it. That allows you to let it rest for a couple minutes before restoring power.

    I got mine for around $20 ...

    sKiZ - the GFCI should work with or without a ground connection.  It operates by sensing the current going out and the current coming back, and trips if the difference is more than a few milliamps.  They actually sense by using the two power leads as primary windings for a transformer.  Since during normal operation, I out = I in, the magnetic fields generated by the two wires cancel one another out (same current flowing in opposite directions means equal and opposite magnetic fields which effectively equals NO magnetic field) and there's no voltage output from the transformer.  

    If there's a ground fault, some of the current that's flowing out finds its way to ground through an alternate path - you, for instance.  When that happens, there's less current flowing 'back' through the return conductor, and the magnetic fields generated by each one in the transformer primary no longer cancel completely.  This means that there now IS a magnetic field in the transformer primary, generating a voltage across the secondary which the circuitry in the GFCI senses.  When it exceeds the amount equal to that few milliamp threshold, the device then trips and opens the circuit.

    -Pat

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