I have looked at these Hammond transformers and agree they are junk... The old ones were pretty descent...
The two main problems with the Hammond is first they are now using the lowest grade laminations in most of thier transformers to keep cost down... Transformers that use to use M6 laminations are now using M50 and M56 lams as substitute without re-working the winding geometry...This will lead to higher excitation currents and higher losses and higher operating temperatures and **** poor voltage regulation durring loading.... They removed a few turns from some of the primaries as a way of cheating to keep the voltages up durring full loading...
The second major problem is NOISE....Windings that BUZZ are common on these Hammonds....This is not a DC offset issue...It is simple 60Hz buzz due to poor potting of the windings... Hammond is not properly potting the windings... The vacuum/varnishing method is not being executed properly...there are many steps in the procedure that must be done just right...
They would be better off switching over to another more reliable method...
Many of the old time designers at hammond were retired off and it appears the young crew there now is attempting to re-invent the wheel and trying to keep cost down by any means...Typicall management practice..
cerrem
The two main problems with the Hammond is first they are now using the lowest grade laminations in most of thier transformers to keep cost down... Transformers that use to use M6 laminations are now using M50 and M56 lams as substitute without re-working the winding geometry...This will lead to higher excitation currents and higher losses and higher operating temperatures and **** poor voltage regulation durring loading.... They removed a few turns from some of the primaries as a way of cheating to keep the voltages up durring full loading...
The second major problem is NOISE....Windings that BUZZ are common on these Hammonds....This is not a DC offset issue...It is simple 60Hz buzz due to poor potting of the windings... Hammond is not properly potting the windings... The vacuum/varnishing method is not being executed properly...there are many steps in the procedure that must be done just right...
They would be better off switching over to another more reliable method...
Many of the old time designers at hammond were retired off and it appears the young crew there now is attempting to re-invent the wheel and trying to keep cost down by any means...Typicall management practice..
cerrem
Hi there, Cerrem!
This is disturbing news indeed. We now have three possibilities: (1) That others are faking Hammond transformers, (2) That Hammond themselves have two 'standards', high-end products and (say) consumer, (3) That those with good experiences might have the older Hammonds before any change took place.
We have a sole (I think) importer of Hammonds locally with whom I co-operate occasionally. It would appear that a word of warning thataway might be in order, although I doubt that fakes would easily find their way here since they correspond directly with the Hammond factory. Way ahead for us would be to carefully monitor new shipments for signs of sloppy workmanship. Return of such would be a problem though in the light of shipping cost.
Ouch.
One way out would be to engage a reliable local winder. We have one who can do three sizes of end bells, which would be an option considering the total picture.
Thanks Cerrem (but also Anatech for earlier news).
This is disturbing news indeed. We now have three possibilities: (1) That others are faking Hammond transformers, (2) That Hammond themselves have two 'standards', high-end products and (say) consumer, (3) That those with good experiences might have the older Hammonds before any change took place.
We have a sole (I think) importer of Hammonds locally with whom I co-operate occasionally. It would appear that a word of warning thataway might be in order, although I doubt that fakes would easily find their way here since they correspond directly with the Hammond factory. Way ahead for us would be to carefully monitor new shipments for signs of sloppy workmanship. Return of such would be a problem though in the light of shipping cost.
Ouch.
One way out would be to engage a reliable local winder. We have one who can do three sizes of end bells, which would be an option considering the total picture.
Thanks Cerrem (but also Anatech for earlier news).
my experience exactly, with new cores, i have to make the primary turns more by about 10~20% to keep no load current down and make the cores run cooler compared to surplus cores or cores from old tranformers, like striped core ones......the other thing is i had to use a bigger sized core to get the regulation i want....
OOPS again. No. I guess I am getting a little careless in my old age. I have never actually tried a 300 series Hammond, and as you point out the 200 series gets all the bad publicity.
As I tried to point out it takes more iron and copper to make a transformer work at 50 Hz than at 60 Hz. The 300 series are rated for 50 Hz use, and are quiet.
The Allied transformers are also rated for 50 Hz and are cheaper than the equivalent 200 series Hammond, so guess what I have been using. The Allied 6K7VG is 3/8 of an inch thicker (more core stacks) than the Hammond 274BX and is rated for less current. 150 VS 175 mA. I have run them at nearly 200 mA on 60Hz, and no buzz. They do get hot though (at 200mA)!
Just a quick note on how I solved one particular Hammond transformer issue... I had a VERY pissed customer who drove almost 4 hours to have me do a bunch of amp work for him..
The transformer was buzzing even at light load and ran hot and had poor regulation...
I heated up the lams with the torch and pulled all the plates out.... I re-stacked the core using M6 laminations... I then vacuum varnished it then baked it.... It is all quiet and running nicely now ...
That was just a one off thing I did for a good customer, not worth doing this on a regular basis...
Chris
The transformer was buzzing even at light load and ran hot and had poor regulation...
I heated up the lams with the torch and pulled all the plates out.... I re-stacked the core using M6 laminations... I then vacuum varnished it then baked it.... It is all quiet and running nicely now ...
That was just a one off thing I did for a good customer, not worth doing this on a regular basis...
Chris
Hi All,
I think I will point Ross Hammond to this thread. I have never once been mislead by anyone at Hammond, and this may be an issue that has not reached Hammond management.
From what Ross had explained to me, even the products made in China were subject to the same quality control standards that the Canadian made products were. In short, this issue should not exist, given the intentions that Hammond Manufacturing seems to have.
I will confess to being reasonably ignorant about transformer construction. I understand only the basics and have never taken one apart to adjust voltages or add secondaries. I can only go on what I am told by people I trust. What I am saying is that I do trust people here, but I also trust people like Ross Hammond.
Let's work to make this issue, a non-issue.
-Chris
I think I will point Ross Hammond to this thread. I have never once been mislead by anyone at Hammond, and this may be an issue that has not reached Hammond management.
From what Ross had explained to me, even the products made in China were subject to the same quality control standards that the Canadian made products were. In short, this issue should not exist, given the intentions that Hammond Manufacturing seems to have.
I will confess to being reasonably ignorant about transformer construction. I understand only the basics and have never taken one apart to adjust voltages or add secondaries. I can only go on what I am told by people I trust. What I am saying is that I do trust people here, but I also trust people like Ross Hammond.
Let's work to make this issue, a non-issue.
-Chris
tubelab.com said:
Although this is quite OT (I apologize) the 'made is USA' or 'made in Canada' label is definately applied to products where the majority of the MONEY spent on such product is from USA or Canada. Marketplace (a consumer-focused investigative TV show in Canada) did a show on seafood products sold at supermarkets where they say made in canada (like superstore) where actually they were products of Russia, Vietnam, China, etc. But they spent more than 50% (probably 50.00004%) of the total value on the product (due to shipping, packaging, 'testing', wages, etc) in Canada, so they are allowed to label it Made in Canada.
I am sure this is the case with your company's 'made in USA'-Maylasian-made product. Sigh. I dont like how companies are allowed to do this (fault of law-makers), but it happens all the time.
anatech said:
(Again off topic, and a little late in the post, but I must respond!) But this might be of interest to some of you, about these old scopes. I have done some experiements with CRO's lately (ones without any graticules or timebases, just a basic CRT with voltage inputs for the deflection plates) and I am sure 'researchers of the past' would have done such tests as well to calibrate thier scope.
Basically there is a formula to fill your info into. To get the deflection of the beam = (2Va)(L/D)(D+0.5L)(Vd) where Va is accelerating voltage, L is length of deflection plates, D is distance to the screen from plates, and Vd is applied voltage to the plates. (Few!! Hope you are still with me.) This info is found by looking up the specs of the CRT you are using. But it is easier just to take some measurements and graph it (excel or whatever you like). ( but in the old days, do it by hand, of course)
But basically you apply differing voltages to the plates, and note the change in position, and graph the data (deflection vs voltage) and the inverse of the slope will give you, tada!, volts per cm!! (the slope gives the sensitivity of the CRO) The certain scope I used gave me 13.7 Volts per cm for vertical deflection, and 23.1 Volts per cm for horizontal deflection.
I know this has NOTHING to do with hammond transformer quality issues, but I rarely see any actual technical information given in most threads.
As far as Hammond transformers go, I havent had much problems with them. No one has mentioned about designing the amplifier with the voltages the tranny gives you. Does anyone actually have the transformer for testing before you finish the design of the amp, before you start construction? Or is it more like..here is a schematic for an amp to build, buy these parts, build it and then you will have perfection?
I just think taking these higher voltages into acount into the initial design of the amp would be a good way to go. Or else publish your own underload tests of different models (on diyaudio) so everyone knows what to expect (unless Hammond should publish this)
I dont know, but I am sure you can make a compromize.
The old Parts Connection ST 40 (their version of the ST 70) is notorious for the Hammond sourced power transformer failing - now you know why the new Parts Connexion sells replacements (unfortunatly the replacements are also apparently from Hammond). Same goes for the Sonic Frontiers Power 2 amp - the original Hammond sourced power transformers had field failures - which reduced when they had Electronic Craftsman build the next batch.
Hi deyjavont,
Actually, in North America, the "Made in ..." sticker has guidelines. Basically, wherever the final assembly takes place is where the thing is made for the record. So any transformer manufacturer could buy wire from Taiwan and steel sheet stock from China. As long as they put it together here, it's made in Canada.
Watch out for investigative reports. They often get the facts wrong, and often represent an industry by look at one player. My brother's girlfriend was killed by a nut bar (they got him). In the reports in print, they got his name wrong several times and didn't state his job correctly - ever. On top of that, they tend to sensationalize their stories. The printed accounts on that story were so far out in left field, I was silly. One phone call to the place my brother worked would have given them the correct name and job description. The details of the crime were reported in the same way. A total joke.
I have seen many other examples of poor and inaccurate reporting several times over the years. You are further ahead listening to the gossip. BTW, a few of our customers were large seafood brokers and a couple small ones, a couple meat packing / slaughter houses and more. From what I have seen printed about them, I can say that reading news stories is almost a complete waste of time.
Anyway, you can not fault the transformer manufacturer for these field failures. You want to know who actually did make poor quality transformers? Counterpoint. They made their own. Later, Michael spec'd Plitron transformers too light. Same error years later by the same guy. Those Plitrons run too hot in his stuff. It's not Plitron's fault.
The people selected to build a transformer for a production run has more to do with price than anything else. Remember, we are dealing with Chris Johnson here. There is always a different reason why these things happen than what people in the affected company are willing to share. Possibly Hammond refused to deal with Sonic Frontiers after some mud slinging? I have no clue, but this is a possibility as well.
-Chris
Actually, in North America, the "Made in ..." sticker has guidelines. Basically, wherever the final assembly takes place is where the thing is made for the record. So any transformer manufacturer could buy wire from Taiwan and steel sheet stock from China. As long as they put it together here, it's made in Canada.
Watch out for investigative reports. They often get the facts wrong, and often represent an industry by look at one player. My brother's girlfriend was killed by a nut bar (they got him). In the reports in print, they got his name wrong several times and didn't state his job correctly - ever. On top of that, they tend to sensationalize their stories. The printed accounts on that story were so far out in left field, I was silly. One phone call to the place my brother worked would have given them the correct name and job description. The details of the crime were reported in the same way. A total joke.
I have seen many other examples of poor and inaccurate reporting several times over the years. You are further ahead listening to the gossip. BTW, a few of our customers were large seafood brokers and a couple small ones, a couple meat packing / slaughter houses and more. From what I have seen printed about them, I can say that reading news stories is almost a complete waste of time.
It was underrated. My wife worked there for a bit. Not a Hammond fault. When you spec a transformer for a piece of equipment, you have to tell the manufacturer what the ambient is, the amount of air flow and your acceptable temperature rise. If you give the design team the wrong numbers, guess what happens? Also, the transformers did not burn out, but the thermal fuses did open. Canada reduced the temperature of the thermal fuse in the transformer by 10 °C, in the 80's I think. Could have been later. Many brands had transformers coming back. I remember that Yamaha was hit hard by this.
Anyway, you can not fault the transformer manufacturer for these field failures. You want to know who actually did make poor quality transformers? Counterpoint. They made their own. Later, Michael spec'd Plitron transformers too light. Same error years later by the same guy. Those Plitrons run too hot in his stuff. It's not Plitron's fault.
The people selected to build a transformer for a production run has more to do with price than anything else. Remember, we are dealing with Chris Johnson here. There is always a different reason why these things happen than what people in the affected company are willing to share. Possibly Hammond refused to deal with Sonic Frontiers after some mud slinging? I have no clue, but this is a possibility as well.
-Chris
Chris,
A M E N
I thought we were the only country where matters were this bad.
Yes, specs are a bugger, even among knowledgable folk. As a researcher in my working days, having to design and make instrumentation; brother, did you have to argue with the 'director' and bean-counters of some companies to convince them what they needed. And when one could not succeed and the instrument did not work up to expectations ... I will not insult your intelligence by asking where the blame went.
A M E N
I thought we were the only country where matters were this bad.
Yes, specs are a bugger, even among knowledgable folk. As a researcher in my working days, having to design and make instrumentation; brother, did you have to argue with the 'director' and bean-counters of some companies to convince them what they needed. And when one could not succeed and the instrument did not work up to expectations ... I will not insult your intelligence by asking where the blame went.
Hi Johan,
Most average people who have never dealt with things like this have little to no understanding of the realities. I have a pretty good idea who was blamed from my own experiences.
What I do know is that most manufacturers who build quality products do their very best to continue with that same high quality. They do not have any power to enforce a good decision from a customer of their products. When a customer does something stupid, all you can do is document your warning and wait for the sparks to fly. Unfortunately for the rest of us, people who tend to ignore good advice prepare a scape goat, or are loud enough to destroy a supplier - customer relationship. They can not admit to an error for some reason.
I make mistakes. Not once has it cost me more than a red face. In fact, I have been able to really cement a good relationship by being honest, working out a plan to get around the issue, and reporting to concerned parties with suggestions for moving forward. When working as a project manager and a sub errs, mitigating the losses for everyone (including the sub) and continuing forward with minimal impact gave me a group of subcontractors that gave me 110%. It also gave me an honest group that will work for me as a priority. Doesn't sound like being honest is a bad way to go, does it?
-Chris
Most average people who have never dealt with things like this have little to no understanding of the realities. I have a pretty good idea who was blamed from my own experiences.
What I do know is that most manufacturers who build quality products do their very best to continue with that same high quality. They do not have any power to enforce a good decision from a customer of their products. When a customer does something stupid, all you can do is document your warning and wait for the sparks to fly. Unfortunately for the rest of us, people who tend to ignore good advice prepare a scape goat, or are loud enough to destroy a supplier - customer relationship. They can not admit to an error for some reason.
I make mistakes. Not once has it cost me more than a red face. In fact, I have been able to really cement a good relationship by being honest, working out a plan to get around the issue, and reporting to concerned parties with suggestions for moving forward. When working as a project manager and a sub errs, mitigating the losses for everyone (including the sub) and continuing forward with minimal impact gave me a group of subcontractors that gave me 110%. It also gave me an honest group that will work for me as a priority. Doesn't sound like being honest is a bad way to go, does it?
-Chris
First of all apologies for resurrecting an old thread.
Due to living in New Zealand our freight costs are almost as much as a transformer is worth so it pays to carefully selecting a transformer before ordering.
About seven years ago I build an amplifier and used the Hammond 370FX. Three years ago I build another amplifier and used the Hammond 370KX. The 370FX performed according to specifications, the 370KX did not and ran very hot as well.
I'm now embarking on another build and wonder what the recent experiences with Hammond Power transformers are.
Thanks in advance.
Due to living in New Zealand our freight costs are almost as much as a transformer is worth so it pays to carefully selecting a transformer before ordering.
About seven years ago I build an amplifier and used the Hammond 370FX. Three years ago I build another amplifier and used the Hammond 370KX. The 370FX performed according to specifications, the 370KX did not and ran very hot as well.
I'm now embarking on another build and wonder what the recent experiences with Hammond Power transformers are.
Thanks in advance.
I used Hammond 1650P output transformers in my last amp build. I have also used the equivalent Edcor transformers. The Edcor transformers were good to about 15 Hz, while the Hammonds were limited to about 25 or 30 Hz. In exchange, however, the Hammond transformers had noticeably better high frequency performance. This made tweaking the feedback loop considerably easier. I consider this to be worth sacrificing performance below 30 Hz.
I have not tried any Hammond power transformers made in the last 25 years. The old stuff was excellent.
For power transformers, if you can deal with a toroid, I really recommend Antek. I have used them in several projects and they are overbuilt and very high quality.
As a side note, I have had issues with the finish on the end bells of Edcor transformers. About 6 months after arrival they started to corrode underneath the paint, which to me indicates a prep issue given that my shop has a dehumidifier in it.
I have not tried any Hammond power transformers made in the last 25 years. The old stuff was excellent.
For power transformers, if you can deal with a toroid, I really recommend Antek. I have used them in several projects and they are overbuilt and very high quality.
As a side note, I have had issues with the finish on the end bells of Edcor transformers. About 6 months after arrival they started to corrode underneath the paint, which to me indicates a prep issue given that my shop has a dehumidifier in it.