which of both runn the amp to work less hard?

Discussion in 'Cabinets & Speakers' started by Reginald, Oct 15, 2009.

  1. Reginald

    Reginald Member

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    which of both will running the amp to work much less hard?

    and What's the difference ? both are 16ohms?
    them look wiring in different way...I don't know
    I think that one is a vintage wiring and that one is a modern wiring......does they run the amp in different way or not?
     

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  2. T-Bird

    T-Bird New Member

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    Hi.

    Looks a lot like a normal series/parallel wiring on both to me.

    Regards
    Sam
     
  3. Reginald

    Reginald Member

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    they are both 16+16 parallel 16+16=32parallel32=16ohms
    or they are 16 parallel 16+16 parallel 16 = 8+8=16ohms ?


    they look the same ,,but they're not the same.....look
     

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    Last edited: Oct 16, 2009
  4. Wilder Amplification

    Wilder Amplification New Member

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    The second pic is hard to tell what it is cause I can't tell whether it's full parallel or if it's parallel series. But the first cab is wired series parallel, which with four 16 ohm speakers will be a total 16 ohm load. This is because for each pair that's in series, the impedance is additive so you end up with 32 ohms for each pair. Then when you place the pairs in parallel with each other, that cuts the 32 ohms in half back to 16 ohms.

    As far as which one "works the amp harder"...neither. This is what the ohms selector switch is for...to ensure that your valves always see the same load and the speakers consume the same amount of power no matter which speaker config you're running. The ratio between voltage and current will differ from one load value to the next, but the power out will be the same.

    On a 50 watt amp assuming you're running at max clean power at one frequency -

    4 Ohm Load - 50 Watts = 14.14 Volts @ 3.54 Amps

    8 Ohm Load - 50 Watts = 20 Volts @ 2.5 Amps

    16 Ohm Load - 50 Watts = 28.28 Volts @ 1.77 Amps

    On a 100 watt amp assuming you're running at max clean power at one frequency -

    4 Ohm Load - 100 Watts = 20 Volts @ 5 Amps

    8 Ohm Load - 100 Watts = 28,28 Volts @ 3.53 Amps

    16 Ohm Load - 100 Watts = 40 Volts @ 2.5 Amps

    As you can see, as the load impedance increases, the voltage drop across the speaker also increases while current draw decreases. Also, if you look at the 4 and 8 ohm values for the 100 watt and compare them to the 8 and 16 ohm values for the 50 watt, you'll see that the voltages are the same on these loads with double the current on the 100 watt. You'll also notice that the 8 ohm load on the 100 watt is the same current draw as the current draw through a 4 ohm load on a 50 watt, but double the voltage on the 100 watt. The 100 watt produces double the voltage on the bigger load because the 8 ohm speaker on a 100 watt can pull more current than it can from a 50 watt simply because the current is there to pull. The more current flowing through a given resistance/impedance (i.e. the speaker), the higher the voltage drop across it (resistance to current flow creates voltage, just as resistance to water flow creates pressure).
     
  5. Reginald

    Reginald Member

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    So,if a 100W amp will run to 16ohm ,it will work much more hard because it produce much more Volts ,while 4ohms makes it work much less hard because the amp will produce less Volt...
    I think about the Output Transformer ....it will work much less hard to 4ohms.
    it's correct? or it's the opposite?
     
  6. Wilder Amplification

    Wilder Amplification New Member

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    NO!

    Read the post again...NEITHER WILL MAKE IT WORK HARDER! Higher voltage/lower current doesn't make it work any harder than lower voltage/higher current. It's all about POWER, which is voltage and current combined.

    POWER is a measurement of WORK PERFORMED, so since you're putting out the same power in every configuration, your amp is not working any harder with a 16 ohm load than it would with a 4 ohm load. A 4 ohm load isn't gonna make the transformer live any longer than a 16 ohm load. When the impedance selector is set accordingly and you're running a matched load, the valves see the same load regardless of speaker cab impedance and will pull the same amount of current through the primary side of the transformer. Only the voltage/current ratio will be different on the secondary side.

    The ponit is, you have to run a matched load, i.e. set the selector to 16 ohms for a 16 ohm load and set it to 4 ohms for a 4 ohm load.

    Voltage is just the force created by a charge difference between two points when you have more electrons available on one side of a circuit than the other. Current is the actual flow of electrons. Combine the two and you have Power.

    Make sense?

    Besides...treated right and ran with a matched load at all times an output transformer will virtually last forever. A lot of vintage amplifiers are still running their original output transformers they came with over 40 years ago and believe me, every one of them you can pretty much guarantee back then was being ran flat out cranked so that should tell you something about how well they hold up under proper operating conditions.
     
  7. thrawn86

    thrawn86 Well-Known Member

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    Jon, I think Reggie's asked this question like a billion times already. :naughty:
     
  8. Wilder Amplification

    Wilder Amplification New Member

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    Wow...that's one of my biggest pet peeves is when person A asks a question, person B who has the knowledge takes the time to type something out that took him time to learn in very simple terms, and then person A responds and it's evident that person A didn't read 1 word that person B just took the time out of his day to figure out how to relate it in simple terms and type it out. If you're not even gonna take the time to read the answers to your question, why even post the question?

    Furthermore...valve amps have gotten a very bad rep over the years. Misconceptions about them being fragile and finicky and blowing up all the time. This is not the case...there are just some simple rules you have to follow with them. As long as you're running matched or close to matched loads, the bias is adjusted properly and the tubes aren't worn out, these things can more than handle being pushed to the absolute limit and live to do it repeatedly. I ran my Super Lead clones weekend after weekend flat out cranked through a Power Brake for 3 years straight...transformers so hot you couldn't comfortably place your hand on them for a good 20 minutes after a 4 hour gig...and never once did I have a failure. I even had a backup Super Lead clone head on the ready in case of one, but I never had to use it. As long as you replace your tubes when the amp starts "losing its tone", the bias is set properly, and your matching your loads properly and not running the amp without a speaker hooked up to it, these things are a lot more durable than you think...a lot more than solid state amps IMHO. Try running a solid state amp like this and see how long it lives.
     
  9. Reginald

    Reginald Member

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    well,I'm afraid
    the fact is that I've got my first vintage amp and I've fear to damage it.
    I'm a unknowing boy ,so I make many questions for surely,you know.
    listen this:
    Is the filter caps value correct here?Or is it possible to upgrading it?
    A repairman has replaced filter caps.
    About tubes....theese ugly,smaller,lower Sovtek tubes will the amp work good? or the Output Transformer would work less hard with the NOS GEC KT88? the same question is also about the filter caps...May I let on theese
    or better repalce them with upgrading ones? you consider this question also about Sprague Atom black caps into circuit....thanks so much
     

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  10. Reginald

    Reginald Member

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    theese others are some shots after the replacement ...
     

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  11. Reginald

    Reginald Member

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    black Sparague Atom caps into the preamp-circuit...is it possible upgrading all theese caps and filter caps...or I should leave the world for itself?
    sorry if some shots are unfocused...but two blue F&T filter caps are 100+100uF and the third (near power tubes) is only 50+50uF....the two black Epcos near the Mains Transformer are both 470uF ...and about into the preamp-circuit the Sprague Atom are 50 it seems ..instead the two into the power circuit are only
    10.................what,which of all them should I upgrading? about to replace theese ugly tubes?does the Output trans. would work worse with theese ugly Sovtek tubes instead NOS GEC?
     

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  12. Wilder Amplification

    Wilder Amplification New Member

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    OK...just so you know -

    Get the whole "what makes the output transformer work more/less hard" idea out of your head. This is simply not a problem unless you set the ohms selector on the back panel of the amp wrong for the cab you run. One tube doesn't work it harder than another, different cabinet configurations between 4, 8 and 16 ohms don't either. You just have to make sure you set the ohms selector to 4 Ohms if running a 4 ohm cab, 8 ohms when running an 8 ohm cab, and 16 ohms for running a 16 ohm cab.

    When everything is set up properly, VOLUME is the only one thing that will work the transformer "harder". The more you crank up the amp/the louder you play, the harder you work the output transformer. But that goes for the valves, the power transformer...pretty much every component in the amp, not just the output transformer. And it doesn't matter what valves you have, what speakers you have, etc etc. The louder you play, the harder the amp has to work regardless of anything else. That is the ONLY thing that will work the amp harder is how loud you play it.

    However, as I mentioned before, if the amp is set up correctly with good tubes, biased properly, and the ohms are matched to the cab you're running, this simply is not a problem. Transformers are a lot more durable and robust than most give them credit for. Unless you have something hooked up wrong between the amp and the speakers, or the ohms selector is set wrong, or the valves are biased too hot, this is just not a problem at all.

    Also, if I were to buy any used amplifier, I would have the valves replaced with new ones and rebiased by a tech.

    Those filter caps are not only not the original caps, but they're not even the same value. Electrically, this is fine, but if you want the early sound that that amp originally had, I would consider getting those replaced with ones that are the correct value. The ones inside of the amp are fine...you don't need to mess with those. But the ones on top of the amp chassis next to the tubes I would consider definitely replacing those with the correct value.

    BTW, what country are you in?
     
  13. Reginald

    Reginald Member

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    Those filter caps are not only not the original caps, but they're not even the same value. Electrically, this is fine, but if you want the early sound that that amp originally had, I would consider getting those replaced with ones that are the correct value. The ones inside of the amp are fine...you don't need to mess with those. But the ones on top of the amp chassis next to the tubes I would consider definitely replacing those with the correct value.


    Hi,I'm an italian boy..
    listen...you wrote about I should replace the caps on the chassis.. in old blue filter caps ,I don't able to read the value ...now ,I've not more them,for permit to see their value..
    You intend for all 5 caps on the chassis,or only that two near the Power Transf.?
    could you write the original value of theese five caps and suggest me a very good(the best) quality brand of them?what's the name of the old gold filter caps brand?they seem lower value compare theese ones black Epcos....previewusly you wrote about filter caps that if they are bigger value they are good....old gold caps were only 200uF ,while theese ones are 470uF..I don't understand because I should put in a smaller value.....yes,if I would the same original sound it would be so,but the ones bigger caps value is better for the best amp working.....isn't it?or not?
    original gold filter caps are only 200uF,while the present ones are 470
    so,they can fill more stored electrons compare the old ones
    about others three near Output Transf. i don't know the old caps value because I don't wasn't able to read it for cause of a masking,scotch-tape covering them.
    What's the old all filter caps value on the chassis in this amp? you know also the original caps value into circuit boards?
     
  14. Wilder Amplification

    Wilder Amplification New Member

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    Ok, I don't speak Italian, but I used a translator program to translate what I want to say hoping that it will be easier for you to understand so here goes.

    Bene, senza sa che l'anno che l'amp era fatto io non può dirla. Hanno usato dei valori diversi da ‘62 -' 68. Da ciò che vedo in uno delle sue immagini, il pannello per circuito somiglia a un prima modello.

    Per quanto "i cappucci di valore più grandi sono migliori" ...that è all'altezza di ciò che sembra lei ama. Il più grande il valore di cappuccio di filtro, il più "stretto" l'amp sembrerà. Il più basso il valore, il più "sciolto" sembrerà. Dipende da appena che le sue orecchie amano.
     
  15. MartyStrat54

    MartyStrat54 Well-Known Member

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    Wow, something about Ohm's Law and a cup of coffee in Italian.:rofl:
     
  16. Reginald

    Reginald Member

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    Wow,thank you ,for your italian translation,but it don't necessary you translate in italian your answers...don't matter.I speak english very bad,but if when I read english of yours,slowly,I understand enough...the problem is that I've no a computer with Internet,so,I use that one of council library.
    they leave me to use it for only 30 minuts at day....so ,I can't read all things of yours.
    About theese caps....you wrote smaller (as in old amps) you obtain a 'free' ,loose sound ,while bigger filter caps is equal to a tight sound....it's right?
    I think I understand.....a bigger filter caps are a short of rectifier valve,is it so?
    I think I should have get for english lessons,soon.
    don't worry to reply in italian ,reply in english....I can use a on-line dictionary....and if you write in italian ,others people will don't understand nothing........and I woldn't learn ever the Enghlish as well
     
  17. Wilder Amplification

    Wilder Amplification New Member

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    No problem, you're doing fine.

    As far as filter caps, no they're not a rectifier valve. They're a reserve of electrons. When the amp is being driven hard, it will have to draw a lot of current. The lower the filtering you have, the less electrons you have in reserve for the amp to draw when the amp needs them. Eventually the amp reaches a point where it's drawing enough current to load the power supply down and the power supply voltage will drop because it can't supply the current that the amplifier is trying to draw, dropping the headroom of the amp, and causing the amp to sound and feel "looser".

    The higher the filtering, the more electrons available to draw when the amplifier needs them. Thus, the amplifier will not load the power supply as much, causing less of a power supply voltage drop, resulting in more headroom and a "tighter" sounding/feeling amp simply because more electrons are available to draw when the amp starts drawing them.

    In other words, it's about supply & demand. When the amp DEMANDS the current, the power supply has to SUPPLY it. When the DEMAND exceeds the SUPPLY due to low filtering, the amp will sound and feel "loose". When the SUPPLY exceeds the DEMAND, it will sound/feel "tighter".
     
  18. Reginald

    Reginald Member

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    in another thread by MajorNut 1967 on 'Blackmore tone?'thread(let's talk vintage) ..he say that Majors tend to be like a bomb and break down their OT because have a sh*t OT....is it true?
     
  19. MartyStrat54

    MartyStrat54 Well-Known Member

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    This doesn't have a thing to do with your amp. Did you understand that? Your amp is not a Marshall Major. Your amp does not use an ultra-linear output transformer. You are taking bits and pieces from other posts and then you are asking questions that make no sense.

    I don't think a boy should be working on a 220V amp in Italy. It sounds really risky.
     
  20. Reginald

    Reginald Member

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    In italy the standard voltage power line (from the wall ) is 220V....What's risky.....I'm obligated to set any amp so....220 is the voltage power line....do you think I could fry the amp? I set it at 220 because from the wall is 220.
    About major of mine,
    you're wrong....my amp is a Major....(sorry the unclean nail of mine...I was working?)
    So,what's a ultra-linear OT and why is it 'crappy'?
    what's the difference between a 100W OT and a ultra-linear Major OT?
    I own this Major but I not play it because I haven't time...

    supposing I set to 10 of volume and I play a '70 100 Superlead and a '70 Major (like of mine) for 10 consecutive hours ....which of their OTs will blow up,break down at first...and why?
     

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