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Thread: Cost of producing a 20W amp with 6V6.

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    Cost of producing a 20W amp with 6V6.

    I am doing some rough calculations of manufacturing a 20W 1X12 combo in low volume. Here is my guessing with a production run of 10 and this is cost per amp:

    1) Chassis, front plate and cabinet: $250
    2) 3 transformers PT, OT and choke: $70
    3) Speaker: $50.
    4) pots and knobs: $10
    5) Tubes: $60
    6) Filter caps: $30
    7) pcb and other components: $50.

    That is $540 just for parts!!!

    You still need labor to build, test and shipping. Then you need to have profit. How do you make money? I think my guessing cost is very low for low volume production of 10 to test the market.

    Say your target price is $1000. You have to sell it to the music store for no more than say $600. You'll be building the amp for almost nothing!!!! Also, at $1000, you are competing with Fender Super Sonic and Marshall DSL40C which both are mighty amps.

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    Last edited by Alan0354; 07-22-2014 at 05:42 AM.

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    Old Timer J M Fahey's Avatar
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    Quote Originally Posted by Alan0354 View Post
    I am doing some rough calculations of manufacturing a 20W 1X12 combo in low volume. Here is my guessing with a production run of 10 and this is cost per amp:

    1) Chassis, front plate and cabinet: $250
    2) 3 transformers PT, OT and choke: $70
    3) Speaker: $50.
    4) pots and knobs: $10
    5) Tubes: $60
    6) Filter caps: $30
    7) pcb and other components: $50.

    That is $540 just for parts!!!

    You still need labor to build, test and shipping. Then you need to have profit. How do you make money? I think my guessing cost is very low for low volume production of 10 to test the market.

    Say your target price is $1000. You have to sell it to the music store for no more than say $600. You'll be building the amp for almost nothing!!!! Also, at $1000, you are competing with Fender Super Sonic and Marshall DSL40C which both are mighty amps.
    Quite accurate.

    You have to add a proper box and packaging + a printed brochure/manual + shipping (or driving to a local shop to deliver and collect) + due taxes + some extras.

    No way an unknown can compete that way , specially in price, with established brands.

    2 ways to beat that:

    1) have the amp fully made in China for an OEM price of, say, $250 tops

    2) establish yourself as a Guru , get some Guitar God to use it , specially to record a big hit or it to be very visible in the background when the equivalent du jour "Guitar Player type magazine) interviews such wonder guy.

    Then you can charge U$2600 for it.

    Surefire to waste time and money:
    spend $1200 to $1800 by building the same old tired circuits but with "first class components": expensive caps, MM iron, Bourns $20 pots, hand turned brass knobs, exotic wood cabinets, real crocodile skin Tolexing, etc.

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    Juan Manuel Fahey

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    Lifetime Member Enzo's Avatar
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    You are not competing with Marshall and Fender. You are making 10, you are a boutique builder, a cottage industry. You won't sell it to music stores from a catalog, you will sell them individually. If I wanted to sell my amp through a local music store, they are not likely to buy it from me, but they would probably sell it for me on consignment. I don't know what consignments are going for these days, is 15% still reasonable or am I out of touch? But consignment costs the store nothing, they are not buying it, your amp sits there until it sells, then they take their cut and pass the rest to you. Even the big brand names have programs like "floorplanning" where they put the product in your store, and you pay for it when it sells. That prevents the store having to pony up tens of thousands of dollars to have inventory. And that is not so different from selling on consignment, really.

    The shipping boxes and three color brochures can wait until you are a successful manufacturer.

    You will need to get the amp into the hands of potential buyers. Build some word of mouth buzz. Why does someone want your amp in the first place? Don't tell me, tell them.

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    Senior Member km6xz's Avatar
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    Manufacturing whiz bang hand built amps is something hobby builders dream about but it is just a pipe or bong dream. Manufacturing is hard to do because almost none of the skills needed to do it successfully has anything to do with music or sound. And in the simple dact that any of those skills that might be lacking, even once, can sink the company. I got into manufacturing in 1970 starting with 4 friends, 2 were ee's, another was a marketing guy and 2 were money types but basically all hippies in a big interesting warehouse. We made a line of line amps and eq for broadcast and recording studios. We made everything ourselves even the rack mount chassis pc boards knobs and shipping boxes. they were priced at $250 . We lucky because a distributor liked them and bought 25 and then 50 and got them written up as a review in NAB. Even with that good luck we barely broke even when all the components only cost around $50. We made about 700 total over a couple years and they got great reviews but we needed much bigger volume to make living wages.
    I calculated that Behringer had a FOB cost of about $8 invested in boxed and tested 19" compressors that were sold for $125 in the US and a landed final cost of $16 after shipping and duties.. That is why even "American" companies have everything built in China. I had a few thousand wireless audio systems built in China for our tour company of my own design and with shipping non-retail boxing they were $25 each. If I committed to 10,000 the price would have dropped to about $9. We use them on our guided tours plus rent the others put for $3/ Day ship port call but that includes fresh aa cell batteries and disposable earbuds. To build them here it would cost me $85 each using $9/hour labor.
    Manufacturing is a lot harder than it looks from the outside and much riskier than sales or services.

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    Thanks guys, I just want to do some calculations. I figure it is bad, I did not realize is that bad!!!! I think I'll just continue to use old amps and gut the inside and put in my design as hobby. At least I can tell my big boss that I might sell amps one day to justify spending money to buy parts!!!

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    ToneOholic! big_teee's Avatar
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    Take whatever you think it's going to cost, and double it. lol
    Not with a mojo ready made cab.
    But, you end up with an amp that sounds good that can be easily serviced and repaired.
    T

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    Old Timer J M Fahey's Avatar
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    Quote Originally Posted by km6xz View Post
    Manufacturing whiz bang hand built amps is something hobby builders dream about but it is just a pipe or bong dream. Manufacturing is hard to do because almost none of the skills needed to do it successfully has anything to do with music or sound.
    True.
    Personally I have been relatively successful, at least always lived out of this , including keeping Family alive, buying (cash, never on credit) different houses along the way, cars, travelling, etc. and never ever had another job, no matter what.
    And yet , what baffles customers when they ask it, I am not an Electronics Engineer but an Industrial Engineer who happens to make an Electronic product, not the same.
    And one big difference beteween Industrial Engineers and all others, is that they are the only ones totally commited to make the cheapest product which meets specs, with the least effort possible, as fast as possible.
    While all others tend to design the best in their own field and let others worry about cost.

    And in the simple fact that any of those skills that might be lacking, even once, can sink the company.
    I got into manufacturing in 1970 starting with 4 friends, 2 were ee's, another was a marketing guy and 2 were money types but basically all hippies in a big interesting warehouse. We made a line of line amps and eq for broadcast and recording studios. We made everything ourselves even the rack mount chassis pc boards knobs and shipping boxes. they were priced at $250 . We lucky because a distributor liked them and bought 25 and then 50 and got them written up as a review in NAB. Even with that good luck we barely broke even when all the components only cost around $50. We made about 700 total over a couple years and they got great reviews but we needed much bigger volume to make living wages.
    True and let's do some math. (sorry Big Tee but 2X *parts* cost is not enough, there's a Ton of extra fixed and hidden costs which must be paid by the product sales ):
    $250-50=$200 gross profit ... if parts and assembly time was the only cost .
    What about renting the place, keeping at least a couple staff (supposing the 5 partners actually built them with their own hands) , light/water/etc. plus local Tax, delivering (in which vehicle?) , etc.
    *Just* considering above gross profit without all the other ones, it means:
    700 units x 200$=140000$
    In 24 Months=5833$
    Given there's 5 partners and hippies were idealistic friendly guys, it would evenly split into 5 x $1166 checks.

    Not much, and that ignoring all other costs I mentioned before.

    In practice I doubt any partner got much more than 20/30% of that ... and this is being very optimistic.

    Doubt even seasoned Hippies can live on meager $200 to $300 a Month.

    Of course, it was probably a side business and they also had some other cash source but on its own .....
    I calculated that Behringer had a FOB cost of about $8 invested in boxed and tested 19" compressors that were sold for $125 in the US and a landed final cost of $16 after shipping and duties.. That is why even "American" companies have everything built in China. I had a few thousand wireless audio systems built in China for our tour company of my own design and with shipping non-retail boxing they were $25 each. If I committed to 10,000 the price would have dropped to about $9. We use them on our guided tours plus rent the others put for $3/ Day ship port call but that includes fresh aa cell batteries and disposable earbuds. To build them here it would cost me $85 each using $9/hour labor.
    Manufacturing is a lot harder than it looks from the outside and much riskier than sales or services.
    Amen Brother.

    And for a (chilling) real account on manufacturing problems, by a guy who created KILLER guitar amps, among others the excellent LAB amps, used by Guitar Gods, just read:
    http://www.gearslutz.com/board/attac...ps-history.pdf

    Keep some tissue paper close because you'll want to weep.

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    That is so true, Sell amps is about advertizing, meeting with musicians, going to shows, getting endorsements. It is the business end that make or break the business.

    I am just doing a simple calculation here and it doesn't even look good. I have not put in any cost of labor, packaging, shipping, returns, production problems. Then comes the fun stuffs.............Rent, utilities, insurance...........AH!!! That's the biggie, you build products with dangerous voltage, people always have a way to sue you. Then Cost of marketing and advertizing. My friend that is getting successful in pickup business has to go to NAMN twice a year, just the booth is over $3000. Then he has to travel all over to meet with musicians to get endorsements. These are all money and more important, time.

    That's why I am just playing business!!!! I had my whole career already. I had been a musician for over 10 years and I really not interested in the scene again.

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    Further update on my new build. This is a proving of the design and done with better, cleaner layout.....with the final components. Not only all the difficulties we talked above. I encounter parts problem.

    1) The Weber PT I order had wrong turning ratio and the two HV taps ( it's an old style center tap winding like the old Fenders) are not balanced. One has 40V higher than the other. I had to email them and they are sending me a replacement right away.......should be arriving tomorrow.

    2) The Form 2C DPDT relay I ordered has error on the data sheet, the pin out are wrong. I had to write to Digikey to find out. Luckily this is still a hand wired chassis, if I were to layout the pcb, that would have been a big issue.

    3) The pilot light is intermittent, how can you go wrong with the pilot light?? They have to send another one to me!!!

    I am sure you guys experienced these before!!!

    That's why, unless miracle happens, I am just playing business and use this as an excuse to my big boss to spend money!!!

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    Last edited by Alan0354; 07-24-2014 at 07:11 PM.

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    Old Timer J M Fahey's Avatar
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    Welcome to the Real World

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    Juan Manuel Fahey

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    Another update

    I received the second PT from Weber, this time I was wise, I power the transformer out of the box without putting into the amp. IT MEASURE WRONG AGAIN. I asked them to check before ship. Just wrote another email to them telling them the way I measured so they can comment. The stupid PT is not balanced. with the center tap as reference 0V, the two side of both sets of wires are not the same voltage, off by 44V!!! ie: one Red wire measured 312, the other red wire measure 356.

    There you go again. That will be another week delay. My amp sounds really good, the power scaling works beautifully, just need that stupid PT to close it up!!! Can you imagine if I were one of you guys that waiting for this part to ship to customers, I'll be having a heart attack!!!!



    The one in the amp measured wrong too, but I am surprised it does not give me any hum even it is not balanced. The problem is instead of getting about 380VDC after rectification, I only got 330VDC under load. The tap is supposed to give 540VAC which when used in center tap, should give me (540V/2) X 1.414=381VDC with no load, say about 360VDC under load. I loss 30VDC and that reduced the power output.

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    Last edited by Alan0354; 07-26-2014 at 12:22 AM.

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    'I received the second PT from Weber, this time I was wise, I power the transformer out of the box without putting into the amp. IT MEASURE WRONG AGAIN'

    Wow, that's deju vu all over again.
    I've been through the exact same thing with Weber, got a handful of near useless DR PTs to prove it.
    Eventually they got a good batch from their supplier and sorted me out with a good one.
    That was in 2005!

    Yes, the main hassle with the unbalanced ones was a much higher differential between unloaded / fully loaded VB+.
    Pete

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    Quote Originally Posted by pdf64 View Post
    'I received the second PT from Weber, this time I was wise, I power the transformer out of the box without putting into the amp. IT MEASURE WRONG AGAIN'

    Wow, that's deju vu all over again.
    I've been through the exact same thing with Weber, got a handful of near useless DR PTs to prove it.
    Eventually they got a good batch from their supplier and sorted me out with a good one.
    That was in 2005!

    Yes, the main hassle with the unbalanced ones was a much higher differential between unloaded / fully loaded VB+.
    Pete
    Wow, so I am not the first one. I really questioned what I did wrong. I wrote to them in detail what and how I measure and even took pictures. They are not very good!!!! I did ask them to measure before shipping.

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    Old Timer J M Fahey's Avatar
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    Please post which exact model is that transformer.
    Thanks.

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    Click image for larger version. 

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    Quote Originally Posted by J M Fahey View Post
    Please post which exact model is that transformer.
    Thanks.
    WO25130INT

    Here is the data sheet: https://taweber.powweb.com/store/025130intsch.jpg

    It is a very good transformer....if it works!!! It has 540V CT and 680V CT. Spec for 150mA. You use SS, you can use 6L6 and get something like 30W.

    Problem is this is the THIRD holdup. Notice the data sheet shows with vertical chassis mount? IT is NOT. It said in the site that you have to buy the bell housing for that. They did willing to send me for free if I buy something else, which I did. I attach a picture so you can see what I meant, the housing cannot be mount on the chassis as is. The wires are coming out on both sides as shown in the picture, you cannot lay it down without having the wires sticking out on one side.

    Then the first PT has wrong voltage, then the second PT still have wrong voltage. 3 Weeks delay.......3Weeks on this stupid PT!!!!

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    Last edited by Alan0354; 07-26-2014 at 02:06 AM.

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    Don't forget the joker g1's Avatar
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    Could they have mixed up the colour coding on the CT and the blue/red? It is supposed to be 45V and you said the voltages were off by 44V.

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    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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    Old Timer J M Fahey's Avatar
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    40V difference between 2 officially equivalent windings is ABSOLUTELY UNFORGIVABLE ....... PERIOD......

    It is a GROSS error, means the presumanly chinese OEM winder misread a spec or something and that Weber does NOT check what they sell, not even a single sample.

    Makes me shudder about other hidden errors, as well as how on Earth other builders have not noticed that and complained.

    What does Weber say about the first 2 ones?

    Did they measure them?
    Do they confirm or deny your findings?

    Or they simply tossed it in a future "SALE !!! 2x1 offer !!!" labelled box?

    We are not talking an acceptable error of 1 or 2 turns possible because of digital counter last digit resolution but some 100/200 turns.

    Thatīs why I suspect a misread or misunderstood winding table or spec, the blue collar worker does not know or care about the design, why each winding uses such and such wire, turns, whatever, he just follows instructions.

    Note: I calculated it to put it into numbers.

    Thatīs a 3.1 Turns/volt core @ 50 Hz.
    You could use 80% of that for 60Hz-only designs and save a couple bucks but itīs good practice to design for 50Hz so the transformer (and amp) work anywhere.

    Back to the transformer, 40V error means 40x3.1=124 turns error.
    NO WAY a modern counter will err that much.

    I remember when I was poor and attached a cassette recorder counter to my winder , I *could* have 1 or 2 turns error with that crude method, but not higher (which anyway was less than 1 VAC error).

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    Quote Originally Posted by g-one View Post
    Could they have mixed up the colour coding on the CT and the blue/red? It is supposed to be 45V and you said the voltages were off by 44V.
    I did, that's the first thing I did on both PT. They measure the opposite!!

    Meaning if I measure Red1 at 356V and Red2 at 312V using the Red/Yellow as CT. If I use Blue/Red as CT, Red1 measured 312V and Red2 measured 356.

    So there is no center tap, they both off.

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    Last edited by Alan0354; 07-26-2014 at 05:46 AM.

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    Lifetime Member Enzo's Avatar
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    I don't know just which transformer this might be, but some time ago, Weber was selling a PT and it had something like two taps in the middle, but not center. You had to pick one as your "center tap" then use the other for your bias winding, leaving the grossly mismatched winding ends for your B+.

    Imagine a straight 700v winding with a 45v winding in the center made with taps. In other words, if there were a center tap is would have these two middle taps 22v either side, but there isn;t one, so you have to slide the whole winding one direction or the other, and there is your 45v difference.

    Imagine trying to use this one:
    https://taweber.powweb.com/store/PTGPsch.jpg

    Click image for larger version. 

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    Look at the diagram. I could see an ignorant winder looking at this one and thinking the 50v winding was centered and not a tap side of center. We naturally assume there is a center tap, but someone not familiar with our tube circuits, just knows winding, might interpret it different, after all hte drawing does not specify center tap, just has 50v in the middle. NO, I am not defending it, just trying to understand how it happened.
    https://taweber.powweb.com/store/022756sch.jpg

    Click image for larger version. 

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    Last edited by Enzo; 07-26-2014 at 04:53 AM.
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    Quote Originally Posted by J M Fahey View Post
    40V difference between 2 officially equivalent windings is ABSOLUTELY UNFORGIVABLE ....... PERIOD......

    It is a GROSS error, means the presumanly chinese OEM winder misread a spec or something and that Weber does NOT check what they sell, not even a single sample.

    Makes me shudder about other hidden errors, as well as how on Earth other builders have not noticed that and complained.

    What does Weber say about the first 2 ones?

    Did they measure them?
    Do they confirm or deny your findings?

    Or they simply tossed it in a future "SALE !!! 2x1 offer !!!" labelled box?

    We are not talking an acceptable error of 1 or 2 turns possible because of digital counter last digit resolution but some 100/200 turns.

    Thatīs why I suspect a misread or misunderstood winding table or spec, the blue collar worker does not know or care about the design, why each winding uses such and such wire, turns, whatever, he just follows instructions.

    Note: I calculated it to put it into numbers.

    Thatīs a 3.1 Turns/volt core @ 50 Hz.
    You could use 80% of that for 60Hz-only designs and save a couple bucks but itīs good practice to design for 50Hz so the transformer (and amp) work anywhere.

    Back to the transformer, 40V error means 40x3.1=124 turns error.
    NO WAY a modern counter will err that much.

    I remember when I was poor and attached a cassette recorder counter to my winder , I *could* have 1 or 2 turns error with that crude method, but not higher (which anyway was less than 1 VAC error).
    I wrote to them very detail like this:


    > INPUT: Wall AC to Black and
    > Blue.(120VAC)
    >
    > 1) Measure with the black probe of the meter on RED/YELLOW
    > wire:
    > a) Measure RED/WHITE
    > wires: 242VAC and 286VAC resp.
    > b) Measure RED wires:
    > 311VAC and
    > 353VAC resp.
    > c) Measure BLUE/RED
    > wire: 44VAC
    >
    >
    > 2) Measure with black probe of the meter on BLUE/RED wire:
    > a) Measure RED/WHITE
    > wires: 285VAC and 242VAC resp.
    > b) Measure RED wires:
    > 356VAC and
    > 312VAC resp.
    > c) Measure RED/YELLOW wire: 44VAC


    When I email to them the first time, they did not contest, they just sent me the second one. I still have the first one in my amp!!! The problem is with the wrong winding, I only get 330VDC on the 540V taps. I am using it as if I already have a little power scaled down!!!

    As you can see, it's not just mixed the Red/Yellow and Blue/Red.

    I just email them today, it's after 5pm E.S.T. So I have not got a reply back from them. We'll see what they are going to do this time. I have the second one packed up ready for them to have UPS pickup.

    Man, it would not be funny if you guys run into this kind of problem. Can you imagine customer calling and ask for their amp and you get this?

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    I thought Weber sell high quality stuffs. Their speakers and attenuators have received a lot of praises.

    I bought a lot of caps and resistors, so far, nothing gone wrong.

    Watch out when buying cloth wires, the Black and White colors are multi strands, but the Yellow, Blue, Green are solid strand.

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    Old Timer J M Fahey's Avatar
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    Alan, in post #18 you state:

    If I use Blue/Red as CT, Red1 measured 312V and Red2 measured 312.
    which is fine (at least itīs symmetrical):

    but in post #20 you state:
    > 2) Measure with black probe of the meter on BLUE/RED wire:
    .....
    > b) Measure RED wires:
    > 356VAC and
    > 312VAC resp.
    Which of these 2 contradicting statements applies?
    Thanks.

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    Juan Manuel Fahey

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    Quote Originally Posted by J M Fahey View Post
    Alan, in post #18 you state:


    which is fine (at least itīs symmetrical):

    but in post #20 you state:


    Which of these 2 contradicting statements applies?
    Thanks.
    Trust post #20 in blue color. I straight copy from the email that I sent today to Weber on the second PT. It was a typo in #18. I corrected it.
    In order to be exact, this is the number I sent to Weber a week ago on the first transformer:

    1) With Red/Yellow grounded:
    a) Measure the two Red wires, readings are 320VAC and 366VAC resp.
    b) Measure the two Red/White wires, readings VAC 250VAC and 294VAC resp.

    2) With Blue/Red ( 45VAC) grounded:
    a) Measure the two Red wires, readings are 366VAC and 320VAC resp.
    b) Measure the two Red/White wires, readings are 294VAC and 250VAC resp.



    Hey, I notice the two transformers is not exactly the same!!!! Don't ask me, I just measured that. I can only assure you that I measured both in no load condition and the same wires. AND measured by the same....one and only one meter!!! Unless my AC main is different, you might even read something into this also!!!

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    Last edited by Alan0354; 07-26-2014 at 05:49 AM.

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    Old Timer J M Fahey's Avatar
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    Cool off, this is not a personal attack.
    I wanted clarification on 2 contradicting posts, one of which showed a perfectly normal transformer (312/312VAC).
    Thanks.

    Quote Originally Posted by Alan0354 View Post
    Trust post #20 in blue color. I straight copy from the email that I sent today to Weber on the second PT. It was a typo in #18. I corrected it.
    In order to be exact, this is the number I sent to Weber a week ago on the first transformer:

    1) With Red/Yellow grounded:
    a) Measure the two Red wires, readings are 320VAC and 366VAC resp.
    b) Measure the two Red/White wires, readings VAC 250VAC and 294VAC resp.

    2) With Blue/Red ( 45VAC) grounded:
    a) Measure the two Red wires, readings are 366VAC and 320VAC resp.
    b) Measure the two Red/White wires, readings are 294VAC and 250VAC resp.



    Hey, I notice the two transformers is not exactly the same!!!! Don't ask me, I just measured that. I can only assure you that I measured both in no load condition and the same wires. AND measured by the same....one and only one meter!!! Unless my AC main is different, you might even read something into this also!!!

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    Juan Manuel Fahey

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    Any chance this is supposed to be used with a bridge rectifier?, and we're assuming the red/yellow wire is a center tap? When you look at it that way your measured voltages are close to the predicted values. If you measure across the red/whites and the reds do you get about 540v and 680v respectively?

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    After looking at the WPTGP maybe W025130INT is supposed to be used in the same way, its just that someone screwed up the drawing. So maybe if you want 300 something volts you would choose the red and the blue/red or the red/yellow as your primary voltage and use a bridge. If you started with the red at the bottom and called that 0v what do you measure at each tap moving up to the top red? I know its labeled as a replacement and red/yellow is labeled CT, but, well, what we could have here is a failure to communicate. In other words if you threw out the drawing and just found a primary you liked, could that work?

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    Lifetime Member Enzo's Avatar
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    That would be fine if one of the taps were actually in the center. But none of them are here.

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    Don't forget the joker g1's Avatar
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    Looks like they may have finally figured out they have a problem, the website is showing it as "temporarily out of stock".
    I wonder how many of them got sold and put into use without the problem being noticed.
    Years on down the line we could be hearing about people solving their mystery problem of low B+. These are supposed to be a direct replacement for Fender 025130, fairly common in many models.

    Edit: Sorry, it's the domestic version that is out of stock, not the international.

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    Last edited by g1; 07-26-2014 at 06:11 PM.
    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

  29. #29
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    Quote Originally Posted by J M Fahey View Post
    Cool off, this is not a personal attack.
    I wanted clarification on 2 contradicting posts, one of which showed a perfectly normal transformer (312/312VAC).
    Thanks.
    No, I did not take it as personal attack at all. I wasn't offended or anything. I made bigger fond to get your attention that there is another inconsistent in the reading even between two transformers. One has higher voltage than the other. The only thing I can think of that can make two identical transformers to have different reading is if the two phase of the AC main in my house has different voltages.( is that possible?) AND if I plugged in one phase for one measurement and the other phase for the second measurement. I measured the first one in the work room, the second one in the kitchen area.

    It is a good PT according to spec, but this really kills it.

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    Last edited by Alan0354; 07-26-2014 at 08:13 PM.

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    Quote Originally Posted by Loogie View Post
    Any chance this is supposed to be used with a bridge rectifier?, and we're assuming the red/yellow wire is a center tap? When you look at it that way your measured voltages are close to the predicted values. If you measure across the red/whites and the reds do you get about 540v and 680v respectively?
    Yes, You get 540 and 680. Just the center tap is not correct. In the data sheet, it called Red/Yel to be CT.

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    Quote Originally Posted by Loogie View Post
    After looking at the WPTGP maybe W025130INT is supposed to be used in the same way, its just that someone screwed up the drawing. So maybe if you want 300 something volts you would choose the red and the blue/red or the red/yellow as your primary voltage and use a bridge. If you started with the red at the bottom and called that 0v what do you measure at each tap moving up to the top red? I know its labeled as a replacement and red/yellow is labeled CT, but, well, what we could have here is a failure to communicate. In other words if you threw out the drawing and just found a primary you liked, could that work?
    I kind of prefer CT. Maybe I am not correct, I think it is easier for transformer to run as CT as each side of the winding only work 50% of the time ( the negative half of the cycle does not drive anything). But maybe that's not important.

    Ha ha, I don't think they are interested in getting the transformers back. They never asked to send back the first one. I might just do that using it in a new build. I am not selling it, it's just my pretend play business!!!

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    Last edited by Alan0354; 07-26-2014 at 08:21 PM.

  32. #32
    ToneOholic! big_teee's Avatar
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    They cost a little more, but wouldn't the ClassicTone PTs made near chicago be a better investment?
    I've had real good luck with the ClassicTone Transformers.
    Fender Power Transformer, Deluxe, Deluxe Reverb, Tweed Tremolux, 125P23B, 025130, 041316, 120V
    T

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    Terry

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    Quote Originally Posted by big_teee View Post
    They cost a little more, but wouldn't the ClassicTone PTs made near chicago be a better investment?
    I've had real good luck with the ClassicTone Transformers.
    Fender Power Transformer, Deluxe, Deluxe Reverb, Tweed Tremolux, 125P23B, 025130, 041316, 120V
    T
    At the time, Weber has the highest current spec of 150mA and 540V and 680V option. If it is correct, it's better. But at this point, yes, you are right.

    Also, I read a lot of raving reviews of Weber speakers and attenuators. I guess that doesn't imply to their other stuffs.

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    ToneOholic! big_teee's Avatar
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    I bet you get it all worked out.
    I put this one in the converted 18 watt chassis, was a near drop in.
    Fender Power Transformer, Vibrolux, Vibrolux Reverb, Tremolux, 022723 & 125P26A, 120V
    It really did a nice job with 2 - 6L6s. I ended up with about 450v loaded.
    I used the bias tap, I didn't need the 5 volt tap, so I used it to power the 6 Volt pilot lamp.
    That worked out slick, and the lamp was still bright enough, but not too bright, and didn't put any additional load on the 6v tap.
    Don't know if anyone else here has tried running the pilot on 5v or not?
    T

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    Terry

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    Quote Originally Posted by big_teee View Post
    I bet you get it all worked out.
    I put this one in the converted 18 watt chassis, was a near drop in.
    Fender Power Transformer, Vibrolux, Vibrolux Reverb, Tremolux, 022723 & 125P26A, 120V
    It really did a nice job with 2 - 6L6s. I ended up with about 450v loaded.
    I used the bias tap, I didn't need the 5 volt tap, so I used it to power the 6 Volt pilot lamp.
    That worked out slick, and the lamp was still bright enough, but not too bright, and didn't put any additional load on the 6v tap.
    Don't know if anyone else here has tried running the pilot on 5v or not?
    T
    That would be my choise the next go around. I use the 5V winding for relay and pilot light. But I did use Schotky rectifier to get 6V DC.

    I my Bassman platform, I use a few 5W zeners to drop the +B to 400VDC to adapt to 6V6, then bypass the zener for 6L6.

    I should have gone to Classic Tone. I have good experience with their Vibrolux OT. My amp would have been all buttoned up already.


    You have experience with the Classic Tone Marshall 50W OT? My next project will be to rip out the Marshall JCM900 Dual reverb and put in something of a modified 2204 ( definitely with slightly more gain, the original one barely break up). Or do you think the 100W OT in the Dual Reverb is good enough?

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