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PostPosted: Wed Jul 25, 2007 8:18 pm 
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Mark III

Joined: Fri Feb 16, 2007 12:28 am
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Location: Chicago Suburb, U.S.A.
Hello all, I now own a Stiletto Deuce amps head. This is my first amp which has actual rectifier tubes.
Just for the sake of added knowledge I am wondering what people look for when buying reolacement rectifier tubes? From what I have read, there is no tone difference between rectifier tubes. If this is the case is there anything different rec tubes offer. Maybe better power distribution?
Anything else? Are there any favorites out there or does it not really matter at all with these type of tubes? Thanks much.

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PostPosted: Thu Jul 26, 2007 5:57 am 
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Mark III

Joined: Thu Mar 01, 2007 3:37 am
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You can choose, within limits, how much "sag" the rectifiers will give by changing the rectifier tube types. Sag is a certain type of compression you could say. The stock tubes give you a large amount of sag. After spending enough time getting used to the options on your amp: recto vs. diode and bold vs. spongy, you may decide that you want the tube rectification but prefer a little less sag.

The Mesa catalog lists and describes the rectifier types Mesa sells near the end.


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PostPosted: Thu Jul 26, 2007 8:34 am 
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Mark III

Joined: Fri Feb 16, 2007 12:28 am
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Location: Chicago Suburb, U.S.A.
Thanks for your help, just one more question and I hope it isnt too foolish, do rectifier tubes need to be matched at all????
Or even matched to the powertubes???

Thanks again

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PostPosted: Thu Jul 26, 2007 8:58 am 
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Mark III

Joined: Thu Mar 01, 2007 3:37 am
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No, I don't believe so. You should be safe ordering form Mesa in any event. It gives you a nice warm feeling to know that they've already done the bashing for you, right? :roll: :)


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PostPosted: Thu Jul 26, 2007 8:38 pm 
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Single Recto

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Dont have a schem for that amp so I am not sure which rectifier tube you have,but a 5AR4 (GZ34) will give you the "stiffest" or closest to a solid state or diode power supply.You will still get a little "sag" as compared to the diode,but it will give less sag than a 5U4.A tube rectifier will also give you a few less volts in the power supply than the diode,which will soften up the bass response.A 5U4 will give you lower volts than a 5AR4 as well as more "sag".


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PostPosted: Thu Jul 26, 2007 10:07 pm 
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Mark III

Joined: Fri Feb 16, 2007 12:28 am
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Location: Chicago Suburb, U.S.A.
My amp bought brand new came with two 5U4GB's installed.
Because this is my first amp with actual rectifier tubes so im a little confused at wha the difference is. I think I notice a little difference in feeling if anything. Maybe a little mushier feeling?
Anyways, since all amps have diode rectifiers, wouldnt it make the most sence to use rectifier tubes which have more slag so you will have two totally different feeling options. I guess what im saying is, if someone wants a real tight rectifier tube,,, why wouldnt they just use the diode setting???
Am I thinking correctly here or what?????


Thanks

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PostPosted: Thu Jul 26, 2007 10:21 pm 
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Single Recto

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A diode or solid state rectifier has virtually no sag.Every tube rectifier has some amount of sag,but to simplify it as just "sag"doesnt quite desribe it fully.Each different rectifier will affect the attack and response particularly the bass response.So the diode will have the "sharpest" attack,and each rectifier will get "softer" in descending order the 5AR4,5U4,5V4,5Y3 with the 5Y3 being the softest,but I wouldnt try the 5Y3 in that amp.It's not so easily defined in text,you have to experience it to get the full sense of the differences.


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PostPosted: Fri Jul 27, 2007 10:19 am 
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Mark II
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Joined: Tue Mar 06, 2007 12:30 pm
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Location: Nashville, TN
Regarding which "brand" of rectifier to get, it shouldn't matter except to your wallet. As long as they come from a reputable tube dealer, you should have no worries. Essentially, they either work or don't work. It's the quality of their construction during the manufacturing process. The Chinese Ones made by Shuguange are just as good as the Russian ones. I am using the Shuguang GZ34 in our proto amp and they have tested out comprable to the JJ's and the Sovtek's.

Regarding the sag, the GZ34/5AR5 works the amp less than the 5U4/5U3 types.


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PostPosted: Fri Jul 27, 2007 6:19 pm 
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Single Recto

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The brand will make a difference,the chinese and russian tubes wont last nearly as long as a good NOS of almost any brand,particularly the 5AR4's.
"Regarding the sag, the GZ34/5AR5 works the amp less than the 5U4/5U3 types."What is a 5U3?


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 Post subject: Rectifier tubes?????
PostPosted: Tue Oct 09, 2007 7:35 am 
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Mark IV

Joined: Fri Oct 05, 2007 11:39 am
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Location: Park City, UT
I have some experience with different types of rectifer tubes in my amps. The 5y3, 5v4, and 5ar4/gz34 has a 2 amp heater draw, the 5u4 and 5r4 use 3 amp heaters. The idea is that if your amp comes with a 2 amp heater tube and you wish to experiment then it would be best to sub a tube with similar heater rating, to avoid overloading the 5 volt windings in the main power tranny.l 5y3 is weakest in transmitted current, 5ar4 is most in 2 amp heater types, 5r4 is stronger than 5u4 in 3 amp heater tubes.

Regarding vintage old stock 5ar4/gz34, prices have doubled in the last year on ebay. A spendy mullard, siemens, telefunken, philips, or real amperex can set you back a ton of cash and while they have the reputation of lasting longer than you will on this planet, remember that that life is different to tubes placed in a combo amp. Frankly, I'd not put a real expensive vintage rectifier tube in a powerful combo amp and let it get shaken to death prematurely. I would, however, put an inexpensive vintage tube in a combo amp and not worry so much.

5v4's have an output fairly close to 5ar4 and are much less expensive. Have had great luck with Sylvania and GE. 5r4 has more oomph than a 5u4, and some, notable the Cetron military "potato masher" have a very massive glass bottle and base. If you have a tube clamp as part of your socket, they won't fit. Other 5r4 tubes have similar size and shape as 5u4. The great thing about vintage 5u4/5r4 is that they are relatively inexpensive and plentiful.

The Mesa/sovtek 5ar4 is a copy of the Mullard sawtooth 5ar4 and is a relatively decent tube, and not expensive.

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PostPosted: Tue Oct 09, 2007 6:03 pm 
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Single Recto

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A 5R4 has a 2amp heater.There is more to rectifier tubes than the heater current.When experimenting with various tube rectifiers you must also consider the max plate current.If you put a 5Y3 in a circuit designed for a 5U4 the 5Y3 wont last 5 minutes.


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PostPosted: Tue Oct 09, 2007 9:34 pm 
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Mark IV

Joined: Fri Oct 05, 2007 11:39 am
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Location: Park City, UT
Just looked up the data on Frank's tube data pages on 5r4, Stokes is right. 5r4 is 2 amp heater.

Stokes is also right on max plate current draw as being important on choice for application. I agree 100%. His 5y3 example is right on.

Finally, on the military 5r4 potato masher type, brand name should be Chatham, not Cetron. Cool looking tube, massive is size and weight, very shock/vibration resistant and it is a more beefy sub for 5u4, will deliver less sag.

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PostPosted: Wed Oct 10, 2007 9:05 pm 
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Single Recto

Joined: Sun Feb 19, 2006 11:43 am
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Location: NYC
Another thought on the 5R4,if you look at the data sheets,they recomend a 20uf input cap.I have found this to be very conservative.I did some tests and went up to a 220uf input cap and had no issues with arcing when hit with full voltage.I installed one in a 5E3 type build with a 100uf input filter I have in my studio that gets a lot of use and so far the tube has stood up for almost a year being used 3-5 days a week at least 2 hours each session.Very durable rectifier.I got 6 NOS JAN RCA's for a song on ebay,dont remember exactly what I paid but it was less than $50 for the lot.Dont be afraid to use this tube in almost any application.


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PostPosted: Sat Oct 13, 2007 8:11 pm 
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Single Recto
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Joined: Fri Apr 21, 2006 9:06 pm
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Location: Newcastle , Australia
i just re tubed a tripe rec with JJ GZ34's and they sound amazingly tight..strongly recomend..

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PostPosted: Thu Oct 18, 2007 8:58 pm 
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Mark III

Joined: Fri Feb 16, 2007 12:28 am
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Location: Chicago Suburb, U.S.A.
Another question that comes to mind here is I keep seeing people say say how tight their rectifier tubes sound. From what ive gathered here, a rectifier tube compared to a silicon diode rectifier is somewhat slaggy.
If thats the case then wouldnt it be wiser to find a rectifier tube with more slaggy characteristics so you have the best of both worlds seeing that the silicon diode rectifier is the tightest?

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