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#7,261
It has too much hysteresis, try and see the specifications on arc welding transformers, the open voltage is about 120V, and on load about 85-90V with a standard 10 SWG arc welding rod, IIRC.
Those coils are made with thick wire or at times flat strips, and will not be very good above 1 kHz, I think.
 
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#7,263
I just bought the new 16 core ryzen 5900XT to revamp my Good ole AsRock X370 MB,
It is a newly designed chip just for this purpose, So, We'll see how it goes....................
Been running on a R1800x since the month the whole series Debuted !! 😉
😀
And about 3-4 weeks ago an Octa Core Banana Pi Bpi-F3 RISCV board showed up on my doorstep to play with.................
A very early 4/16 GB version to boot !!!!
Now you can get one with 8GB or 16GB of ram, and are now available since it was released just a few months ago !!! 🙂

:cheers:

jer 🙂

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🙂
 
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#7,264
130A and 34V is probably open circuit volts.
Would need many power transistors to get a high output current at that voltage.

And some are designed for a low duty cycle, and continuous high current would cause heating. Also, heavy windings for arc strike load, and a lower load during the actual weld.
I would not load it at beyond 10% continuous, which is a fair load, and it would possibly be bulky for an amp.
 
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#7,266
kevinkr said:
More Toshiba JFETs, specifically 2SK170BL and 2SJ74BL, could have bought them back in the day, but was into tubes and could not conceive I would ever be interested in designing with them, now I get to pay through the nose (although in truth I am not paying much more for them than for devices from Linear Systems)
Click to expand...
If you don't mind the fact that they're SOT23-5 SMD, 2SK2145BL from Mouser is a fraction the price of 2SK170BL. And if you connect the two devices in a 2SK2145BL in parallel, the resulting device has very similar Cdg and DC characteristics to a 2SK170C but is 1.7dB quieter. Adapter PCBs are easily found for SOT23, but check pricing as some vendors are "imaginative" on pricing.
 
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#7,267
NE WAY said:
Well I actually bought a vintage arc welding machine (and I went out to buy two more because I was so pleased with this one) aaand trying to use it as the transformer for audio amplifier 🤣

It is capable of 130A, and deliver 34Vrms when connected to 1 ohm load.
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NareshBrd said:
130A and 34V is probably open circuit volts.
Would need many power transistors to get a high output current at that voltage.

And some are designed for a low duty cycle, and continuous high current would cause heating. Also, heavy windings for arc strike load, and a lower load during the actual weld.
I would not load it at beyond 10% continuous, which is a fair load, and it would possibly be bulky for an amp.
Click to expand...
Is that a military surplus welder? Very nice in any case!
 
#7,268
EC8010 said:
If you don't mind the fact that they're SOT23-5 SMD, 2SK2145BL from Mouser is a fraction the price of 2SK170BL. And if you connect the two devices in a 2SK2145BL in parallel, the resulting device has very similar Cdg and DC characteristics to a 2SK170C but is 1.7dB quieter. Adapter PCBs are easily found for SOT23, but check pricing as some vendors are "imaginative" on pricing.
Click to expand...
That is a great tip - thank you. 😀 The design in question was a one off for a specific purpose, but provided it performs to expectation (it measures well) I do plan to replace the 2Sk170BL with SMD parts in my next design. I am very comfortable working with SMD components and prefer them in most situations to TH parts.
 
#7,269
My last order from Fair Radio - several of each item.
Too bad they are closed up now, in preparation for their in-person and online auction scheduled for August 15th-17th. Just saying, it may be worth a look to builders and experimenters for general parts, one of a kind, and whatnot. I have no doubt the bulk of items are still there because I've seen pictures of recent "tour" of buildings full of non-catalog stuff and it's way more than in the catalog. This isn't an ad, just a tip for a huge pile coming up.

Anyway I mess with carbon microphones and they have 3 different transformers for those.
The ribbon inductors BTW have some white oxidation spots on the aluminum spool, which needs cleaned off without scratching it. I don't know how to do this, but ya just can't get these any more and if you have the 180 series tuners you may need one.
 

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#7,271
DRONE7 said:
Denon POA-S10. Just the one for subwoofer duty. Hoping it survives shipping as I have no control over packaging and multiple courier hand-offs :-(
Plan is to use the Rod Elliot project-48a controller and feed to the Denon thence to a Monitor Audio Silver 12 which I picked up for a song as the crappy plate amp was dead.
However..the best laid schemes of mice and audiofools Gang aft agley,
Tomorrow will tell if I have a boat anchor or fun.

https://sound-au.com/project48a.htm
https://sound-au.com/project48.htm
https://reverb.com/item/43947392-de...plifiers-extremely-rare-audiophile-grade-amps
https://www.monitoraudio.com/en/product-ranges/silver-series-7g/silver-w-12-6g/
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Yes! works wonderfully. Rod Elliot has nailed it with his project48a.
This works very well with the MA-Silver12 and it's dead crappy plate amp removed and driven externally.
I looked to find some amp that was both affordable and would compliment the current main amp.
The Denon POA-S10 fits the bill and has drive to spare too.
Current system = RPi4>MoOde Audio>DIYinHK USB to i2c>AKM 4137>ProtoDAC TDA1387 X8 project>Perreaux Amplifier>pre-out to-Denon-POA>MonitorAudioS10>Silver12 (and mains=Shahinian ARC)

Happy as a Suidae in ordure.
 
#7,272
5 1/2 digit DMM. I've always wanted something a bit more accurate than my handhelds. I continue to be surprised by how inexpensive test equip is today relative to my college years. Less for this 5.5 digit (although probably more like a 4.5 digit true accuracy) than the Fluke the lab I worked in college bought which was a 4.5 digit. I think the fluke was over a grand and I picked this up from rigol for less than 400 with free shipping.
 
#7,273
Closed yesterday. I have a porch with a view. 1.19 Acres, half wooded, two car garage (read that workshop, I will add a steel car port for the vehicles), 100sq-ft root cellar, and 100 sq-ft canning room. It needs a bunch of work. The only utility is electricity. it has a 350' deep well for water. Water quality report was very good. pH 7.5, 15pts hardness, zero bacteria count.

I am going to be very, very busy for the next 6months to a year.
 

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#7,275
TheGimp said:
Closed yesterday. I have a porch with a view. 1.19 Acres, half wooded, two car garage (read that workshop, I will add a steel car port for the vehicles), 100sq-ft root cellar, and 100 sq-ft canning room. It needs a bunch of work. The only utility is electricity. it has a 350' deep well for water. Water quality report was very good. pH 7.5, 15pts hardness, zero bacteria count.

I am going to be very, very busy for the next 6months to a year.
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Lovely view! Congratulations!
 
#7,276
NareshBrd said:
130A and 34V is probably open circuit volts.
Would need many power transistors to get a high output current at that voltage.

And some are designed for a low duty cycle, and continuous high current would cause heating. Also, heavy windings for arc strike load, and a lower load during the actual weld.
I would not load it at beyond 10% continuous, which is a fair load, and it would possibly be bulky for an amp.
Click to expand...
Thanks for mentioning that it was designed for low duty cycle. I don’t think that the welding machine would last very long at 130A if operate continuously for hours.

I did not test it for 130A, 130A is closed circuit.

I connected all my 56 100 ohm, 50W resistors in parallel.

The voltage at o/c was 65V, at 1.8 ohm it dropped to 34V.

At least now I know it is good for 600VA😊
 
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