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Reducing line voltage

danalog
By danalog
in Hobby Electronics
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Go to solution Solved by iamdarkyoshi,

There's actually a considerably easier solution, one you likely have already. A buck transformer configuration.

 

Take the output of a transformer, say maybe a 12V AC transformer from a wall wart, and put the OUTPUT in series with the mains, out of phase. It will subtract 12V AC from the mains voltage.

 

I've done this for a few of my old pieces of gear and it works a treat. Need less of a drop? Use a transformer with a lower voltage output, and it'll subtract less voltage from the mains.

 

I've seen my house's mains voltage as high as 128V, so knocking that down really does help keep my older gear running cool.

 

As always, please be careful with mains voltage and tube equipment, there's a real risk of hurting yourself if you don't know what you're doing.

Posted

I work on a lot of old tube radios from the 50s and 60s designed for a 110v line voltage. My house puts out 120-125 depending on time of day and, considering even a 3v increase can cause the premature death of every tube, I certainly don't want to feed 15v extra into the circuit. 

A potential solution I thought of was purchasing an AC motor speed control. These are readily available under $20 and would allow me to in theory pick a precise voltage to send into the set. From research though, I've heard that these work by converting AC to DC, modulating the DC voltage, then converting it back to AC and my question is if this would be safe to use on anything OTHER than a brushless AC motor? I have never worked with AC voltage, I only deal with repairs after the rectifier in the circuit so do excuse my ignorant question. 

Other cheap option is an incandescent lamp dimmer. Could find one for like 10 bucks BUT a lot of them seem to use MOSFETs, which from my understanding would switch the power on and off quickly to dim a lamp... which would be horrible for the tubes.

 

Any suggestions would be appreciated!

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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5 minutes ago, Electronics Wizardy said:

Variac seems like the goto here.

 

Can you show a example of that motor speed controller? A lot of those have pretty junky output power as motors don't really care about ripple. Same with light dimmers.

Variac is absolutely the go-to but price wise not very feasible. 

 

One of these.. I was figuring their output wouldn't be very clean for audio use but it was worth an ask.

image.jpeg.55684190c43a8c5c233515e023b12b26.jpeg

 

 

I might go the resistor array route... I have some old HAM radio resistors that aren't anywhere near spec but could handle AC line voltage and, with a few, I could drop 125v down to 115. Thought it was worth a shot asking about other inexpensive methods though.

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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1 minute ago, danalog said:

Variac is absolutely the go-to but price wise not very feasible. 

 

One of these.. I was figuring their output wouldn't be very clean for audio use but it was worth an ask.

image.jpeg.55684190c43a8c5c233515e023b12b26.jpeg

Variacs don't seem that bad price wise, so Id relly look towards those. Not sure how that 

 

 

 

Also 110v is often the nominal voltage, I wouldn't be surprised if they have 120v back then, and 120v is probably within the +-10% which is the common spec for line voltage.

22 minutes ago, danalog said:

Could find one for like 10 bucks BUT a lot of them seem to use MOSFETs, which from my understanding would switch the power on and off quickly to dim a lamp... which would be horrible for the tubes.

A lot of dimmers use Triacs that basically chop off a chunk of the waveform as thats the most efficient way to dim devices on AC. Its get a ugly waveform though.

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Posted

Vevor makes a knockoff variac, because of course they do. I can't speak for how good it is, but it sure looks like an old, dumb coil of wire transformer.

 

https://www.amazon.com/VEVOR-Variable-Transformer-Regulator-Industrial/dp/B0CYZHPVVZ?gQT=2

 

You can find the real deal on eBay for less though.

 

https://www.ebay.com/itm/316896600502

I sold my soul for ProSupport.

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Posted
  • Solution

There's actually a considerably easier solution, one you likely have already. A buck transformer configuration.

 

Take the output of a transformer, say maybe a 12V AC transformer from a wall wart, and put the OUTPUT in series with the mains, out of phase. It will subtract 12V AC from the mains voltage.

 

I've done this for a few of my old pieces of gear and it works a treat. Need less of a drop? Use a transformer with a lower voltage output, and it'll subtract less voltage from the mains.

 

I've seen my house's mains voltage as high as 128V, so knocking that down really does help keep my older gear running cool.

 

As always, please be careful with mains voltage and tube equipment, there's a real risk of hurting yourself if you don't know what you're doing.

Donate your unused computer resources for cancer and other research. For Zinsey ❤

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