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Thread: Transformers: Classictone, Hammond, Mercury?

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    Transformers: Classictone, Hammond, Mercury?

    Anyone have better luck with any particular brand, for 2 valve ~20watt amp projects?

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    Supporting Member Chuck H's Avatar
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    I'm especially fond of the Hammond 1608 and have heard it in the same model amp next to two other brands. I was first put onto this model by Shea, here on the forum some fifteen years ago. He was killing it at an amp shootout being held in his area using this OT in an 18W type amp. I haven't heard the newer "easy wire secondary" model 1608a. The 1608 has an 8k primary. Good for most el84 applications. If you're planning to use 6v6's and want a different primary the only other Hammond 16XX would be the 1609 at 10k, which could also be run at 5k if you half the secondary load. Though this would change the low band -3dB I don't expect it would be a problem. I haven't heard the 1609.
    "I've heard magic defined as "a technology you don't understand". By that aphorism, the folks in this forum are practicing wizards, able to summon AND control the lightning demon, and make charms to allow others to use the demon in certain ways." R.G.

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    Quote Originally Posted by Chuck H View Post
    I'm especially fond of the Hammond 1608 and have heard it in the same model amp next to two other brands. I was first put onto this model by Shea, here on the forum some fifteen years ago. He was killing it at an amp shootout being held in his area using this OT in an 18W type amp. I haven't heard the newer "easy wire secondary" model 1608a. The 1608 has an 8k primary. Good for most el84 applications. If you're planning to use 6v6's and want a different primary the only other Hammond 16XX would be the 1609 at 10k, which could also be run at 5k if you half the secondary load. Though this would change the low band -3dB I don't expect it would be a problem. I haven't heard the 1609.

    Thanks Chuck!!

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    In my limited experience I like Classictone and Hammond a lot.

    I can't speak for everyone but to a lot of people mercury is kind of a laugh. because they're just so oozing with tone mojo
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    Old Timer Leo_Gnardo's Avatar
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    Quote Originally Posted by nsubulysses View Post
    I can't speak for everyone but to a lot of people mercury is kind of a laugh. because they're just so oozing with tone mojo
    Especially the power transformers - 'your amp just won't sound good unless you spend a premium of 50% to 400% on your PT.' What a load of codswallop!

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    I don't have them yet, but I was planning on going with ClassicTone for my Fender Concert build. They seem a good value (certainly compared to MM) and people say great things about them. Yeah, I think MM is crazy...

    Speaking of which, a local guy is selling a Peavey Classic 30 head with an MM power transformer in it for $240. That's like a $170 PT... I'm tempted to get it, but I don't really want a Peavey Classic 30 or an MM transformer. lol.

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    Well, it seems we talked you out of an MM tranny...
    I think they ooze that tone mojo only after they drain the raw life-force from your wallet and digest it...

    Justin
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    I just bought 7 50W power transformers from Magnetic Components for really cheap.

    I know it's more power than you're looking for but the price is right

    NOS-Amp-Transformers

    I live in the area and actually drove out to pick them up. I talked with one of the engineers there and we were talking about brands. He was dumbfounded there is not a spec sheet to be found on MM website......

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    Supporting Member Chuck H's Avatar
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    I can't say whether MM iron is good or not because I've never bought into their hype. I seriously doubt it's worth all the extra $$$ they cost. I may try more Edcor OT offerings in the future. I used a small SE OT of theirs recently and was impressed. Their prices are certainly right. Their shipping was stupid expensive for the small OT, but that would be offset with a larger one since they have a minimum shipping weight charge policy. I've used a few of their PT's and have been very pleased. They also made a primary wind modification to one of their 240V models to 120V for me at NO EXTRA CHARGE. And they're painted real pretty. Like that other brand, but at about a third the cost.
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    "I've heard magic defined as "a technology you don't understand". By that aphorism, the folks in this forum are practicing wizards, able to summon AND control the lightning demon, and make charms to allow others to use the demon in certain ways." R.G.

    "...less ear-friendly but handy for jazz." Leo_Gnardo

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    I take back everything I said about MM I found this on their site and theyre obviously legit

    The Phenomenon of Ear Fatigue

    Did you know... that ear fatigue is related to poor transformer quality? If while playing (or listening to someone play) through an amp you find yourself tiring easily, or the experience seems unpleasant… you are experiencing the tell-tale signs of ear fatigue. It is nature's way of telling you that something's wrong. In nature all sounds are composed of layers of frequencies producing all sorts of harmonics and distortion. Ear fatigue is caused by information commingling with non-musical, unnatural noise that "beats up" your internal mechanisms. The mechanisms that make your hearing possible are working overtime trying to separate the desirable from the less desirable sounds. It's the output transformer's job to emphasize the even-order harmonics and make tones more musical, appealing, and less fatiguing. There's no short-cut to building a quality transformer. The result is less effort by your ear to receive this information.
    No wonder they are the best. Their transformers are based on the magical principle of being a tone pass filter. all those shabby unpleasant distortion artifacts are nullified.

    Undesirable tone/sounds be gone!!!

    I've experienced ear fatigue but I always thought it was because I was trying to adjust the tone of my 100W amp while standing two feet away

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    Supporting Member Chuck H's Avatar
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    Quote Originally Posted by nsubulysses View Post
    I just bought 7 50W power transformers from Magnetic Components for really cheap.

    I know it's more power than you're looking for but the price is right

    NOS-Amp-Transformers

    I live in the area and actually drove out to pick them up. I talked with one of the engineers there and we were talking about brands. He was dumbfounded there is not a spec sheet to be found on MM website......
    I worked with them on a project once. It never went into development, but they were super easy to work with and offered attractive prices. I'd call them again as a potential proprietary manufacturer if it ever comes up. I couldn't even work out a "bulk deal" worth my time and effort with Hammond.
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    "I've heard magic defined as "a technology you don't understand". By that aphorism, the folks in this forum are practicing wizards, able to summon AND control the lightning demon, and make charms to allow others to use the demon in certain ways." R.G.

    "...less ear-friendly but handy for jazz." Leo_Gnardo

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    I know, right? Edcor's shipping is insane. Not a bargain for individual transformers. If you buy multiple transformer, shipping as a percentage of the order total drops quite a bit, which I guess is the minimum shipping weight charge you were discussing Otherwise their prices are good and I've heard nothing but great things about their transformers... Haven't gotten one yet, though.

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    Hammond transformer rule IMO but unfortunately I think you have to do orders of 25 or more to get a deal.

    Magnetic does 12 run minimums for special orders and they try to avoid small runs. They say that's the reason they have the classictone line. They made a kind offer even though they couldn't accomodate my small run of 3-5 PT/OT. They said if a classictone transformer fits my needs they will pull a few off the production line before it gets the "classic tone" stamp. They offered to add my art work to the transformer for a one time $30 set up fee. I don't have a logo though. The NOS transformers I bought from them are blank, which I like. And of course you can't beat the price.

    Heyboer will make whatever you want, even 1. Supposedly if you order 3 or more you can get 20% off or so. Chuck would know better than me. I've only bought a few transformers from them and it was never multiples.

    Well, except for when PRS was selling Heyboer 50W OTs on ebay recently. $75 each or best offer. I offered $310 for 8 and they accepted........let the good times roll

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    Quote Originally Posted by nsubulysses View Post
    I just bought 7 50W power transformers from Magnetic Components for really cheap.

    I know it's more power than you're looking for but the price is right

    NOS-Amp-Transformers

    I live in the area and actually drove out to pick them up. I talked with one of the engineers there and we were talking about brands. He was dumbfounded there is not a spec sheet to be found on MM website......
    I thought that very odd as well. I think there are only one or two links to weak specs on their site (not complete at all). I had to email them many time to get spec sheets, and they are not all complete.
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    I've got a special order Heyboer OT for a Trainwreck sitting on a shelf. Supposed have a good low end response. Gonna get to that one day...
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    Quote Originally Posted by nsubulysses View Post
    I just bought 7 50W power transformers from Magnetic Components for really cheap.

    I know it's more power than you're looking for but the price is right

    NOS-Amp-Transformers

    I live in the area and actually drove out to pick them up. I talked with one of the engineers there and we were talking about brands. He was dumbfounded there is not a spec sheet to be found on MM website......
    OhhHoooo kid in a candy store, wish I could get a few for future use.

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    Most of my transformers have come from organ pulls and unfortunately most have been 18W (either 6V6 or EL84 PP amps). I'm done stripping those, at least for now. I'm keeping my eyes out for stuff with bigger iron in it, though. Just not as many of those available for free...
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    Better Tone thru Mathematics bob p's Avatar
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    Quote Originally Posted by Chuck H View Post
    I can't say whether MM iron is good or not because I've never bought into their hype. I seriously doubt it's worth all the extra $$$ they cost.
    I can answer that question with an anecdote -- I'm a MM dealer, I used to buy from them in 25-unit quantities, and I have refused to place any order with them since c.2003.

    I used to buy from MM back in the days when they were a little known custom winder serving the magnetics industry, long before they started directly targeting end users with all of the marketing hype, BS claims and the predatory pricing strategy. Back in the 90s there wasn't that much in the way of internet sales and there weren't a lot of options available if you had an oddball vintage amp that needed an authentic iron replacement. Back then they sold a good product at a not unreasonable price. If you were a dealer back then buying Mercury iron was actually cheaper than buying the equivalent Hammond. Those were the days.

    I signed-on as a dealer and I placed my first order with them for 25+ units. I received several very heavy boxes of very nice iron. When it was time to place a follow up order for 25 more units, I called Paul Patronete (sales) on the phone, he took my order, and a few days later I received a several more very heavy boxes of iron... but this time the contents were disappointing. Being generous, what I received could best be described as fugly factory seconds and QA rejects.

    My second shipment of transformers from Mercury was absolute garbage --

    * I received OT that had only one lead on the secondary side.
    * I received transformers with leads that had started off as 10" but had been clipped down to 3", and then the short leads were spliced and shrinkwrapped to yield 10" overall length. These were obviously used transformers that had had their leads clipped and had been accepted as returns. Instead of removing the endbells and soldering on brand-new leads, they took the shortcut of just splicing the external leads to make them longer. They looked like crap.
    * I received some transformers that were obvious scratch and dents.
    * I received some transformers that were varnished on one side of the laminations but not on the other.
    * I received some transformers that I had paid extra for teflon wires, but the teflon insulation was not adequately proected during shipping. As a result the teflon jacket had cold-formed off of the wire under pressure, leaving exposed wires in the middle section of the leads.

    All 25 of the transformers that I received were so bad that I couldn't use them in custom builds as I knew my customers would have rejected them, and my reputation for quality would have taken a hit because of them. They were all defective in one way or another and I decided to reject them. I called Paul Patronete, my sales contact, to complain. He told me that they would gladly accept all of the items back for a refund, but if and only if I paid the shipping charge back from Chicago to California. Think about this -- they made the mistake of sending me substandard garbage, and they refused to cover the return cost for their defective shipment. They expected me to cover the return shipping costs on their defective shipment. What would it cost to ship a box of 25 transformers rated for 50 or 100 watt amps all of the way from Chicago to California? We're talking about a 200-lb. freight charge that they expected me to pay to cover for their "mistake."

    Realistically speaking, I don't think it was a mistake at all. I think that when I signed-on as a dealer, they gave me a great fill for my first order, to build my confidence and to encourage me to place a subsequent order. Then, when it came to place my second order, they knew that they already had me on the hook. In my opinion they filled that order with all of the rejects, seconds, useless doorstops and other shop garbage that they had accumulated and were waiting to unload. Then they shipped all of the crap to somebody far away, and refused to take it back unless he paid the freight both ways. They had to know that the return freight on 200-lb of iron would be cost prohibitive, so dumping it on a customer was a safe bet for them.

    I spoke to the business owner, Sergio Hamernik, about this and I got nowhere. When I complained about being sent items with spliced leads, he offered me some sort of nonsense excuse that because he had spliced the wires using silver solder, the transformers would have special mojo that made them better than unspliced leads and I should want keep them. Obviously, if there were any truth in that then every transformer that Mercury sells would have extra mojo-enhancing splices on the leads and their marketing department would be hyping it.

    I ended up ebaying off most of the defective iron at a loss. I have kept in contact with them every now and then just to assure that my account is still open, just in case I'm desperate for something special and I'm forced to buy from them in an emergency. Needless to say Mercury hasn't received another penny from me in the past 14 years.

    I've had much better luck dealing with local iron shops like Magnetic Components/Classictone. Their service and technical support are great, and they're close enough that I can do pickups instead of shipping. Mojotone also has some great pricing on high quality products if you have a dealer's account.
    Last edited by bob p; 07-13-2017 at 10:23 PM.
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    Supporting Member Chuck H's Avatar
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    Heyboer was great too. They made the custom OT's for the amps I brought to the NAMM show in 2009. Then I ordered another single custom OT about five years ago and I accidentally stiffed them for about a hundred bucks. I swear I thought I'd paid them. Then I found the Check in it's stamped envelope addressed to Heyboer ABOUT TWO YEARS AGO. I wrote another referencing the invoice and sent it off. I haven't ordered from them since. I guess I'll see how it goes whenever it comes up
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    "I've heard magic defined as "a technology you don't understand". By that aphorism, the folks in this forum are practicing wizards, able to summon AND control the lightning demon, and make charms to allow others to use the demon in certain ways." R.G.

    "...less ear-friendly but handy for jazz." Leo_Gnardo

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    Quote Originally Posted by Justin Thomas View Post
    Well, it seems we talked you out of an MM tranny...
    I think they ooze that tone mojo only after they drain the raw life-force from your wallet and digest it...

    Justin
    For me, the extra ~200.00 usd for the set (PT, OT, CHoke) is hard to justify, esp when so many of you who do lots of build/repairs have good things to say about Hammond and Classictone.

    Ive read a few posts on other blogs from people who had bad performance (over heating 'could cook eggs', bad sound, short life ...) from mostly no brand name xformers. There's an amp parts supply web site that has xformers for sale, with no brand on them, and they refuse to tell me who makes the transformers! They said "that is proprietary and we WON'T tell you". Hah.

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    Supporting Member Chuck H's Avatar
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    About the only times when I can say that transformer were responsible for bad tone would be the cheapest examples of some factory amps (both vintage and modern). Some of the OT's made overseas are noticeably poor sounding, but certainly not all of them. Almost anything you buy from a respected manufacturer will be snuff, and nearly always better quality (and tone) than any manufactured amps use. That said, there is a small difference in tone between the vendor products. Small. And since tone is subjective, well... There was a video floating around where someone swapped something like four different OT into the same amp and played the same guitar track at the input with each one. The makers were the usual as I recall. MM, Weber and I can't even remember the other two, but you'd recognize the brands. The consensus here was mixed. Some couldn't discern any significant difference. Others had a preference, but the favorites were different for everyone with very little in the way of an overall "winner". I said very little. It's possible that Mercury actually did come out a little ahead. YMMV. I'll see if I can locate the thread and if the video attachment is still present.

    EDIT: I found the thread. As it happens there wasn't a consistent track at the amp input. But as I recall it was well replicated by the player anyway. Unfortunately the link in the thread no longer hosts the audio clips.
    Last edited by Chuck H; 07-14-2017 at 03:01 PM.
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    "I've heard magic defined as "a technology you don't understand". By that aphorism, the folks in this forum are practicing wizards, able to summon AND control the lightning demon, and make charms to allow others to use the demon in certain ways." R.G.

    "...less ear-friendly but handy for jazz." Leo_Gnardo

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    Better Tone thru Mathematics bob p's Avatar
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    Quote Originally Posted by mikepukmel View Post
    They said "that is proprietary and we WON'T tell you". Hah.
    If there's not an EIA code on the endbell then you can bet it's been manufactured by the lowest bidder in China.

    I've seen several online stores that sell their own store branded iron where the EIA code points to an unknown Chicago supplier.

    marvel-pt.png
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    Old Timer Leo_Gnardo's Avatar
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    Quote Originally Posted by mikepukmel View Post
    There's an amp parts supply web site that has xformers for sale, with no brand on them, and they refuse to tell me who makes the transformers! They said "that is proprietary and we WON'T tell you". Hah.
    It's not so much they refuse to tell, it's they can't pronounce the manufacturer's name, something like Hsieh Xiang Qa'lin Zhiu. And sons... Do I get an egg roll with that?
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    I've dealt with both Heyboer and Edcor. If you need a one-off custom transformer wound, I had great experiences working with Heyboer. They offered competitive pricing with no minimum order, with prompt and pleasant correspondence back and forth. My output transformer was exactly what I wanted from them. The only problem I had on my power transformer could have been a communication error, in that, I gave them secondary voltage specs under a stated load and they ended up winding them as no load secondary voltages. But I found this out fairly recently and need to give them the heads up about it see what may have happened to be fair to them. They have been great to deal with in the past so I'm sure we can work it out.
    Edcor is tough to beat for value if you can find a particular transformer that meets your needs, but they build to order and mine took about 4 weeks from order to shipping date. If you need something custom wound, hey have a minimum order and design fee. Someone mentioned them having ridiculous shipping charges, but I paid $19.56 to have one output transformer shipped from New Mexico to Massachusetts. I don't think that's unreasonable. I've packed and shipped several transformers, and I wouldn't charge under $10 to ship a heavy piece of iron that is packed well enough to protect it from damage.
    Last edited by SoulFetish; 07-15-2017 at 04:59 AM.
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    Quote Originally Posted by Chuck H View Post
    I'm especially fond of the Hammond 1608 and have heard it in the same model amp next to two other brands. I was first put onto this model by Shea, here on the forum some fifteen years ago. He was killing it at an amp shootout being held in his area using this OT in an 18W type amp. I haven't heard the newer "easy wire secondary" model 1608a. The 1608 has an 8k primary. Good for most el84 applications. If you're planning to use 6v6's and want a different primary the only other Hammond 16XX would be the 1609 at 10k, which could also be run at 5k if you half the secondary load. Though this would change the low band -3dB I don't expect it would be a problem. I haven't heard the 1609.
    Whatever happened to Shea anyway? He had a lot to contribute.

    Greg

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    Better Tone thru Mathematics bob p's Avatar
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    IMHO... To me a PT is a PT. It either puts out the correct voltages at the necessary current or not. There are a lot of clone (ish) amps being made in China, Indonesia, etc nowadays. Their sources seem to be making more transformers than they need and are now showing up in containers to various mom and pop distributors in the USA. Especially here on the left coast. I just bought a couple for $5 apiece. One for a 2 x EL84 amp and one for a 4 x El 84 amp. Also 2 chassis with both the PTs and the OTs, tube sockets, pots, jacks, etc. Unless you are a purist it pays to check CL and EBay, Google, etc. There are lots of bargains out there. Granted.. they aren't Hamonds, Mojos, Heyboers, whatever. But they do the same damn thing. I build a 20 watt 2 channel amp for $50 this way. Sounds great.
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  28. #28
    Better Tone thru Mathematics bob p's Avatar
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    Quote Originally Posted by olddawg View Post
    IMHO... To me a PT is a PT. It either puts out the correct voltages at the necessary current or not. There are a lot of clone (ish) amps being made in China, Indonesia, etc nowadays. Their sources seem to be making more transformers than they need and are now showing up in containers to various mom and pop distributors in the USA. Especially here on the left coast. I just bought a couple for $5 apiece. One for a 2 x EL84 amp and one for a 4 x El 84 amp. Also 2 chassis with both the PTs and the OTs, tube sockets, pots, jacks, etc. Unless you are a purist it pays to check CL and EBay, Google, etc. There are lots of bargains out there. Granted.. they aren't Hamonds, Mojos, Heyboers, whatever. But they do the same damn thing. I build a 20 watt 2 channel amp for $50 this way. Sounds great.
    Some amps sound best with cheap iron because that's what they were built with to begin with, and our ears are trained to love that tone. Look at the Tweed Deluxe. The original transformers for that amp were very cheaply made, spiral wound, and they sound great. To properly reproduce the tone of those amps, an expensive boutique transformer is not required. You can get great tone out of a cheap transformer. I think it was Bruce Collins who was the first on this site 15-20 years ago to tell people not to go spending huge sums of money on a boutique 5e3 OT because something like the Hammond 125E was commonly available, dirt cheap and sounded great.

    For the most part, almost all of the classic fender transformers were "cheaply" made in that they used quality components with simple winding formulas. That kind of wind is easy to reproduce and does't cost much, so it's pretty easy to get a decent sounding OT for a fender amp.

    On the other side of the coin, there are OTs that DO sound different because of the way that they're wound. Whether or not a transformer is interleaved with a complex formula has a definite impact on it's production cost, and that can have a huge impact on tone.

    Way back in the day SpeedRacer was one of the first people to realize the market value of the more complex OT winding formulae on tone. He was one of the first people around here to pay close attention to winding specs on Plexi and AC30 type transformers via destructive forensic analysis of rare/valuable original units. 20 years ago Obsolete Electronics was one of the pioneers in the field and you didn't have many other options if you wanted an authentic sounding Woden or a Haddon OT for an AC30. They are different ... in a corksniffing sort of way.

    The same could be said for the some of the vintage Marshall type OTs. I think that the authentically wound RadioSpares JTM45 and the Plexi type repro OTs do sound different than the rest of the current production iron on the market for those applications. Some of this has to do with variations in the turns ratio and the effective primary impedance, along with the complexity of the interleave formula. Some of these things can make a huge difference, though I have to admit that the amount of hype that has ensued in the marketplace is just ridiculous.

    It's interesting that the Chinese knock-offs are coming along so cheaply. That's sort of a problem when you're a guy who does expensive destructive analysis of an original specimen to obtain a blueprint for a design, and then have a foreign contract manufacturer who has no respect for your intellectual property rights begin backdoor production. That's an inherent risk in manufacturing anything in China -- they openly steal peoples' designs and then enter the marketplace as their own customer's competitor, undercutting them on their own designs. It's hard to respect the business model that openly steals intellectual property.

    It'd be interesting to know whether the cheap iron that you speak of is just the knocking-off of cheap transformer designs, or if they're also knocking off some of the more complex formulae, in which case that amounts to selling stolen IP.

    Got links?
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    Senior Member Enzo's Avatar
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    olddawg was discussing PTs. And I would counter that there is more to it than voltage and current. There is breakdown voltage, will it arc over if the mains goes up 10v? And temperature. Juan has pointed out wire types here. Ther is no-strip enamel, you can solder through teh coating. But if you wind a transformer with that, it gets hot enough, your wire coating evaporates.
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  30. #30
    Old Timer olddawg's Avatar
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    Quote Originally Posted by Enzo View Post
    olddawg was discussing PTs. And I would counter that there is more to it than voltage and current. There is breakdown voltage, will it arc over if the mains goes up 10v? And temperature. Juan has pointed out wire types here. Ther is no-strip enamel, you can solder through teh coating. But if you wind a transformer with that, it gets hot enough, your wire coating evaporates.
    All this is true Enzo. But honestly if the PT is made for use in an amp sold in the USA, I assume it meets minimum safety specs. And as you always say. Fuses are there to prevent fires. Lol. Honestly... OTs are a bit of a crap shoot to me. My favorite build has a giant old black Zenith OT. I never bothered to spec it out. I just know it's louder and has a better low end response than my other EL84 18watt Marshall clones to me. But who knows? My point is simply bargains are out there to build stuff. You aren't necessarily limited by traditional choices on individual builds.

  31. #31
    Senior Member Enzo's Avatar
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    Oh, I am fine with repurposing things.

    But to assume something made for 120v meets all safety specs is not good. Does it carry a UL sticker? Nothing says it has to. If the maker is in China, there is no way a liability problem could ever reach them.
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  32. #32
    Better Tone thru Mathematics bob p's Avatar
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    Quote Originally Posted by Enzo View Post
    olddawg was discussing PTs.
    oops. somehow i read OT when i was reading that post. nevermind.

    emily-litella.jpg.
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  33. #33
    Old Timer olddawg's Avatar
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    Quote Originally Posted by Enzo View Post
    Oh, I am fine with repurposing things.

    But to assume something made for 120v meets all safety specs is not good. Does it carry a UL sticker? Nothing says it has to. If the maker is in China, there is no way a liability problem could ever reach them.
    Well... the VHT amps in the same pallet pile that used the same parts did. They don't get warm or smell and there is no leakage to the bells or chassis. I see stuff from other brands too from time to time without really looking. Bugera, Blackstar, and others. I'm getting into your age territory Enzo, trying to finish my projects and downsize. It's hard to walk away.
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    the Tweed DeLuxe used a gapped core.

    this means that they did not stack the core with, say, 3 lams going this a way and 3 lams going that a way like most push-pull transformers are laced these days.

    it is laced just like a choke or SE Champ xfmr. why? maybe Triad wanted a universal xfmr that could be used with balanced DC of the P-P amps, or unbalanced DC like the Champ. kind of a "one size fits all" approach to marketing.

    what does this air gap do? in addition to preventing DC saturation (B= 1.25 X AMP-TURNS) it stabalizes the permeabillity of the core which stabalizes the primary inductance.

    the gapped xfmr changes the sound. don't ask me why. maybe a rolloff thing, maybe the speaker-transformer-tube transfer function changes,

    the gapped core for the Tweed DeLuxe will need more turns of wire to make up for the loss in permeabillity, so you might have 3000 turns instead of 1000. and even with the additional turns, your Henries will still be lower than the Lap 3 stack. this is because gapping a core will bring the perm down to around 500, instead of your typical 10,000 for GOSS core. that is a factor of 20 to 1, but inductance is quadratic in turns, in other words going from 10 turns to 20 will increase your inductance by 2^2 = 4. so 3000 turns instead of 1000 will increase the pri ind. by 3^2 = 9.

    so you get 9 times the inductance which gets divided by 20 for the gapped core so figure 1/2 the pri. ind. for the Tweed DeLuxe. that will translate into less bass which might save those old Jensen speakers,

    there is also more DC resistance in the 3000 turn wind which will shift the phase angle at the bottom end (arc tan DCR/XL) and add compression.

    with the addition of more wire, capacitance will go up, especially with the lack of layer insulation on that scatter wound coil. this will roll off the top end.

    so decreased hi and lo end are the result of the gap in the 75 EI lams.
    Last edited by cjenrick; 07-20-2017 at 06:40 AM.
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  35. #35
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    Quote Originally Posted by bob p View Post
    Some amps sound best with cheap iron because that's what they were built with to begin with, and our ears are trained to love that tone. Look at the Tweed Deluxe. The original transformers for that amp were very cheaply made, spiral wound, and they sound great. To properly reproduce the tone of those amps, an expensive boutique transformer is not required. You can get great tone out of a cheap transformer. I think it was Bruce Collins who was the first on this site 15-20 years ago to tell people not to go spending huge sums of money on a boutique 5e3 OT because something like the Hammond 125E was commonly available, dirt cheap and sounded great.
    +1.

    My last 5E3 build has Hammond iron and does the rounds with pro players, including Bill Kirchen who loves it. If he can't tell a good 'Tweed' then no-one can.
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