Heyboer & Pacifc - Transformer Vibration & Hum in a

[plook]

RJ, that information about the types of hum is really interesting and makes me think of how it was all getting mixed together when i was trying to diagnose the problems with my TW build using the problematic Heyboer export power transformer. There was clearly a physical - what i called hum but we now know as vibration - coming from the transformer, but i also had hum, which was from a combination of bad ground locations, strip lights in my workshop and worst of all - sitting too close with my guitar. All of the hum was fixed with the help of guys here - especially Geetarpicker's advice about it being on 'lead' all the time, a high gain amp, but the physical 'vibration' remained. I ended up taking that power transformer out of the chassis and with only the primaries connected it still vibrated. If i squeezed the bells it would change tone but not get quieter. I tightened the bolts to within a hair of snapping but this didn't make any difference. I should point out though that the transformer although clearly making a vibration noise - was not as loud as when on the chassis, so the chassis in my estimation was amplifying or working like an acoustic guitar body on the vibration coming from the transformer.

I contacted Heyboer and they very gracefully said that there had been some issues with the TW style transformers and that i was welcome to return it for fixing, which is not really an option as i am in UK and the shipping would be more than the value of the transformer, or i could open up the transformer and tighten the copper band after putting high temperature silicon sealant underneath. This is a very easy thing to do and if you can build a high voltage amplifier without killing yourself you could do this with your eyes closed. I took up 5mm on the copper band and the action of bolting the bells back on make it very tight. I gave it a few days to dry while i was away and powered it up outside the chassis on just the primaries. It was almost silent, if you put your ear close to it you can hear and feel it to the touch, then put the legs on the chassis and it was noisy, not as bad as before but still noisier than any tube amp i have, even 50 and 75 watt amps. Once wired back in and inside the cabinet head, when i turn the power on (standby still off) i can hear a 'vibration'. With background noise it's not an issue, but you wouldn't be able to record with it and it would probably make it difficult to sell. I have secured everything in the chassis, silicon sealed under any components i consider as potential sources of amplifying the vibration, but it really comes down to the transformer vibrating and anything touching it amplifying it. I can't say i'm happy with it, but i have to live with it because of the costs involved in changing it.

[xtian]

Sounds like you're sick of tinkering with this one. But in case you're not…

After you fixed that copper band and found that you had improved the vibration, you then bolted the tranny to your chassis, and now the chassis is acting as a resonator for the vibration. If you isolate the tranny mechanically, like with rubber bushings, the chassis should transmit far less vibration, and hopefully it would be quieter.

[plook]

Sounds like you're sick of tinkering with this one. But in case you're not…

After you fixed that copper band and found that you had improved the vibration, you then bolted the tranny to your chassis, and now the chassis is acting as a resonator for the vibration. If you isolate the tranny mechanically, like with rubber bushings, the chassis should transmit far less vibration, and hopefully it would be quieter.

Hi, because the tranny resonated when i touched it down on the chassis i knew it needed some rubber under there, so i put thick rubber grommets (the type you put on a chassis to pass through tranny wires) under the feet. It didn't make a lot of difference. Maybe i should try something softer like neoprene.

[Colossal]

Hi, because the tranny resonated when i touched it down on the chassis i knew it needed some rubber under there, so i put thick rubber grommets (the type you put on a chassis to pass through tranny wires) under the feet. It didn't make a lot of difference. Maybe i should try something softer like neoprene.

Plook,

That is a lot of vibration if you have to go to these lengths...out of curiosity, have you scoped your AC mains?

[plook]

Hi, because the tranny resonated when i touched it down on the chassis i knew it needed some rubber under there, so i put thick rubber grommets (the type you put on a chassis to pass through tranny wires) under the feet. It didn't make a lot of difference. Maybe i should try something softer like neoprene.

Plook,

That is a lot of vibration if you have to go to these lengths...out of curiosity, have you scoped your AC mains?

No, do you mean using an osciloscope? I don't have one and i wouldn't even know how to use it, though i do fancy learning.

I have a bunch of other amps though with Heyboer transformers and they are all silent, like Sewell Wampus Cat, Tweed Champ, Deluxe, and i have a couple of Fender 75 amps and they are silent too. Three years ago i sourced Heyboer transformers to make a Dumble Overdrive Special clone and that was silent too, so i think it's just this tranny or a a certain batch of them.

[Colossal]

No, do you mean using an osciloscope? I don't have one and i wouldn't even know how to use it, though i do fancy learning.

Yeah, I was just wondering about the AC there. But that doesn't seem to be an issue.

I have a bunch of other amps though with Heyboer transformers and they are all silent, like Sewell Wampus Cat, Tweed Champ, Deluxe, and i have a couple of Fender 75 amps and they are silent too. Three years ago i sourced Heyboer transformers to make a Dumble Overdrive Special clone and that was silent too, so i think it's just this tranny or a a certain batch of them.

Good to know that you have lots of other amps as a baseline for PT hum. I seriously think that the PT in question has some issues. It should not be resonating on the chassis like that, so much so that you need to dampen it.

[M Fowler]

Heyboer said one of my PT's had loose flux band and the unit was improperly built. Either they repaired the PT or sent a new one because no more hum after that.

Mark

[plook]

Heyboer said one of my PT's had loose flux band and the unit was improperly built. Either they repaired the PT or sent a new one because no more hum after that.

Mark

Well, Heyboer are a great set of people and i like there transformers more than any others, which is why i always try to get them when i'm on vacation in the states. they would change this one or repair it in a flash, but it's not really cost-effective to do so and it would be very unreasonable of me to expect them to send a replacement because of the cost of shipping.

I might try getting this one re-varnished and baked in Chesterfield at Trans-tronic where i get my trannies when i can't get Heyboer.

[eazilyled]

I think I've got some mechanical hum in my export Heyboer PT (as soon as I flip the power switch), but it's not that bad and I can live with it. I notice mine more when I put the inverted chassis on a wooden desk (e.g. during biasing). The PT and the desk make good contact and the wood in the desk amplifies the vibration.

Plook, I hadn't heard of Trans-Tronic out before. Chesterfield isn't too far from where I live. I notice they have some 6.6K toroidial OTs.

[plook]

I think I've got some mechanical hum in my export Heyboer PT (as soon as I flip the power switch), but it's not that bad and I can live with it. I notice mine more when I put the inverted chassis on a wooden desk (e.g. during biasing). The PT and the desk make good contact and the wood in the desk amplifies the vibration.

Plook, I hadn't heard of Trans-Tronic out before. Chesterfield isn't too far from where I live. I notice they have some 6.6K toroidial OTs.

Trans-Tronic are good, they make the VOX JMI, HiWatt transformers. I told Philip Pickering there that i have a faulty Heyboer mains transformer and he said it probably needs to be varnished under pressure, so i might try that if i can muster up the energy to pull the transformer out again.

Buxton eh, just over the hill. What amp have you got? Home build?

[eazilyled]

That's good to know about Trans-Tronic.

My amp is a home built Express from a Ceriatone kit using Heyboer trannies. Yours is a Liverpool isn't it?

Whereabouts are you? Maybe we can meet up and compare vibration / hum levels some day!

[plook]

That's good to know about Trans-Tronic.

My amp is a home built Express from a Ceriatone kit using Heyboer trannies. Yours is a Liverpool isn't it?

Whereabouts are you? Maybe we can meet up and compare vibration / hum levels some day!

Yes, i went for the Liverpool, but i'm wondering if i should have gone for the Express. I built it up myself using Heyboer transformers (i always use them or Trans-tronic).

I'm in North Sheffield where i have a little workshop in my garage with lots of lovely amps, you'd be welcome to try them.

[eazilyled]

Cool. I could do with getting myself an amp cave!

I used to work in Sheffield for a spell but don't get there too often these days. I'll drop you a line if I'm over your way.

Your Liverpool sounded great on that YouTube video. I really need to do one of mine.

[plook]

Cool. I could do with getting myself an amp cave!

I used to work in Sheffield for a spell but don't get there too often these days. I'll drop you a line if I'm over your way.

Your Liverpool sounded great on that YouTube video. I really need to do one of mine.

That guitar player in that clip is really good and i might get him to do more. I have a 15inch Weber speaker in a Sewell combo that soinds great with the Liverpool, so might get him to try that. The recording is really limited by the compact digital camera though.

[mauiboy81]

I'm bringing this thread back because I am having a problem with vibrating power transformers. I recently had some power transformers wound by Heyboer that are supposed to be like the stancors but with different high voltage secondaries and they all have a vibration hum/buzz. I am trying to determine how much is acceptable and whether or not I need to have them fixed/rewound.

When I connect the pt unloaded to the AC line it vibrates and has a hum. I can feel the vibration and in a quiet room can hear it from several feet away. The chassis acts like a sound board and amplifies it. I have compared them with other transformers and they are louder than all the others I have. The others do have some noise but I have to put my ear near them to hear it.

I have a feeling it is because of the 7.5A 6.3v filament winding on the small stancor size core.

I don't know if I'm being too picky but it doesn't seem right to me. How much of this mechanical noise do you live with?