Transistor equivalent

[KeepItSimpleStupid]

My take: In one of the designs there is a 10 uf, 100nf (c1,c2, C3, C4 and C9 in the supply.

The 100 nf across the diodes should be ceramic. Not in the audio path.
With all of the parallel combinations different types should be used, but a 10 uF Tantalum is way too expensive.

A mix of Tantalum, metalized film and electrolytic would be best for the filters, Ceramic has better performance at RF frequencies.

ESR, temperature and surge ratings are important int the supply. Varying the types of capacitors helps. Tantalum caps are more expensive that film caps. Usually film caps top off around 1 uf.

 

[spec]

Raking leaves between rain drops Xmas day and Xmas eave day. It's 65 F here (It's not supposed to be that hot). I got about 10 big (30 gal) garbage bags of leaves. Leaf blower broke a few weeks ago. I probably ran it without oil in the gas. Migraine blunder. I had to buy another. https://www.stihlusa.com/products/blowers-and-shredder-vacs/shredder-vacs/sh86ce/ Can't use it when the ground is wet. Leaf blower works for light snow too.
I bought a cylinder temperature gauge that should work. See: https://www.btosports.com/p/TRAIL-TECH-TEMPERATURE-METERS/option/665-0009 Battery powered. Sealed device. 5 yr estimated life. I'll have to shorten the cables. Ordered a connector and pins to do so. Mounting - not sure yet.

Asthma is triggered. Migraines are triggered.

Made Fillet Mignon wrapped in bacon using the iron skillet, (brown on stove and bake in oven method). Stuffed baked potatoes. Stir fry broccoli, carrots, mushrooms and a baked Apple tart for desert.

You are working too hard on Xmas day. Still the Fillet Mignon sounds nice.

It is incredably mild here too, the mildest since records began... in 2014. It is caused by global warming- many many people have been driving their vehicles, expecially 4x4s (SUVs), on Xmas day.

 

[spec]

2200uF-50V also available (2500VND). It is necessary to buy film caps (100nF caps in the circuits) for supply units?
I want to pass HUS High School for Gifted Students but it still very far, I must learn so hard. Four subjects need to pass: physics (of course), math, literature, English (damn my bad English)

As Keep says, use 100nF ceramic caps across rec diodes or anywhere on the transformer side of the recs. But no more ceramics to the right of the recs.

To the right use pollyprops. Use good aluminium film for electrolytics. Certain tantalum can also be used, but beware of ripple current rating of good sounding tants, like bead types.
2,500uF, 50V caps are ideal: two required for each amp = 2*3= 6 total

As I said, keep at your studies and good luck. Leave rock, booze, girls, motor bikes or any other distraction for when you are qualified, but still have fun in your spare time.

About English, there is a good little book: Penguin Guide to Punctuation (see my ETO article on references) which makes that subject clear and simple; I wish I had a copy when I was at school. Just like any subject, electronics included, there are a few simple basic rules in English writing that will get you a long way. The other advice about English, or any language, is to use it as much as possible, especially with native English speakers. Listen to English on the radio and TV, but not junk programs. Listen to audio books and read, read, read and then read some more English material: magazines, newspapers, books.

At the Saigon, a local resturant in Weston Super Mare where I live, the owner, who is from Cambodia, said that the Vietnamese people are very good at English; a waiter from Vietnam proves it. English is easy, compared to many languages

 

[spec]

Now that you have three amps in one case, especially sub, best to go for totally separate + and - supplies. Thus: 2 x transformer secondaries, 2 x bridge recs, 4 x 10mF caps (you can start with 2 x but leave space for four)

 

[KeepItSimpleStupid]

spec:

Anticipating a bridged amp for the sub? Where does one put the sub "active?" crossover?

 

[spec]

spec:

Anticipating a bridged amp for the sub?

Hi Keep,

Hoping to get away with no bridge, Instead use just three amps around 70W each.

Where does one put the sub "active?" crossover?

I have had this in mind and a preamp and any other control electronics, slow start, mute, crowbar protection, limiting indicator and such like, but have not worried to much about them because the case will have plenty of room, especially as the sub amp is now going in the same case. But any sensitive stuff will probably go in an ally/steel can, left or right by the front panel.

 

[KeepItSimpleStupid]

You are working too hard on Xmas day.

A couple of small projects. Switching PS in an old CD writer is kaput. It's been in the interior of a car for a long time. I found a replacement PS online for like $10.00 USD. Not sure what to look for in a failure. Must have bought them all. That's what happened when I wanted to replace a laptop screen.

Ordered parts (countersunk magnets) to re-mount a smoke alarm magnetically. The "mounts" break, so have to build a better mousetrap.

Touch-up (artist's brush) on a screen door latch I epoxy painted and re-installed

 

[spec]

About subs:

I know the theory, but have no practical experience at all.

As a policy, with me and others, filters in the audio chain are a big no no. Of course, you do need filters for a sub amp, so what I am thinking about is, going down in frequency, to roll-off the L & R amps on a single slope around 70Hz and roll on the sub amp at the same frequency, also on a single slope. The cross-over frequency can be tailored to suit the actual l, R, & sub speakers on the day.

How do you view this?

 

[spec]

Nikolai,

Just getting the basics of the new amp sorted. I am thinking about plus and minus 40V supply lines for all three amps: L, R, and sub. This will give a comfortable 70W RMS which, in my opinion, is the sweet-spot for home hifi. It will allow you to drive most commercial or home-made speakers well and will not be too expensive or complex to build and get running reliably. It will also form a good platform for future upgrades without having to modify the 'foundations', as we now say. Do you like this approach?

 

[Nikolai Petrenko]

Nikolai,

Just getting the basics of the new amp sorted. I am thinking about plus and minus 40V supply lines for all three amps: L, R, and sub. This will give a comfortable 70W RMS which, in my opinion, is the sweet-spot for home hifi. It will allow you to drive most commercial or home-made speakers well and will not be too expensive or complex to build and get running reliably. It will also form a good platform for future upgrades without having to modify the 'foundations', as we now say. Do you like this approach?

Cool! But 70W RMS contain 2x20W satellite and 30W subwoofer? (I think it is 80W)
Use 2x10000uF caps now, if I upgrade it will need 4x?

 

[spec]

Cool! But 70W RMS contain 2x20W satellite and 30W subwoofer?

3 x 70W amps: l, R, & sub

... I think it is 80W...

Not sure what you mean, but don't worry all will be well

Use 2 x 10,000uF caps now, if I upgrade it will need 4x?

Start with 2 x 10mF capacitors, one for each supply rail, if you want. Then add a further 2 later to finsh the job. (total = 4)

 

[Nikolai Petrenko]

Well but seem be ratio of L-R-Sub is 1 : 1 : 1 not fit for me-guy that like heavy bass
I think 1 : 1 : 1.5 or 1 : 1 : 2 will be more suitable

 

[Tony Stewart]

Always wondered how disk drives worked so reliably... and fast... and so accurate- a real feat of engineering.
Tell me, have you had any experience of Hitachi HDDs. I am advised that they are one of the best types and have always used them.

UPDATE
I now remember there was two types of servo loops, but can't recall more at the moment, One of the guys published a book about it all. I had a copy of the book but it got lost along the way.

HDD's have many servo loops, My guess about a dozen servo loops or more. for servo acceleration, velocity, position, clock recovery, spindle speed
Most sophisticated electro-mechanical, magnetic mature reliable products in the world in a small package at low cost. without exception.

My first exposure to Hitachi was Nippon Peripheral Limited (NPL) with their (dont laugh) 6MB 5.25" HDD in early 80's. They were a subsidiary of Hitachi and the design used stepper drive motors.
Unlike many newbie questions today about BLDC and stepper motor design, they already were using steppers with variable speed to accelerate to max speed and used a viscous ring damper around the motor shaft to eliminate resonance. If anyone wants to learn about how to design the best stepper-servo design, go back 30 yrs and reverse engineer these drives. It outperforms what they do today with 3 axis milling machines, 3D printers etc in terms of optimum stepper speed control and accuracy.

When we got into 100MB 5.25" HDD qualifications, Hitachi was one of the potential sources. They flew from Japan to do a show and tell. Very professional and advanced in HDD contact start stop reliability. For example at that time when 14" HDA's lasted maybe 5k to 10kh MTBF, their products were >50kh. They were insulted when I asked how did they verify their quality and reliability.
Toshiba and Fujitsu on the other-hand were also good but more in tune with western communication. I knew all the companies and contacts in sales and Engineering and the learned the designs by reverse engineering and DVT test plan I created, in order to qualify the best for purchase in large qty.

Today the best rank in any order depending on specific models ; price, performance and application. My rank today is: Hitachi, WD, Seagate.

The newer the technology, the higher the density and more reliance on error correction, on-the-fly (ECC) and the less warning to the user... before "click of death" ( loss of servo signal)

Great advances in lower surface roughness on glass vs burnished alum. in old days since vertical recording is std. now resulted in flying height which can be measured in atoms instead of u" It still relies on an aerodynamic no-contact flying over the surface 30~100kph.

 

[spec]

Well but seem be ratio of L-R-Sub is 1 : 1 : 1 not fit for me-guy that like heavy bass
I think 1 : 1 : 1.5 or 1 : 1 : 2 will be more suitable

Nikolai, you will be able to have base as heavy as you like- more heavy than even you could take. just say how much, or even set it yourself. You are not understanding how it all works.

You will need a seat belt fitted to your armchair- you can fit one? You can get one from a scrap car, but make sure you bolt it securely to the framework of your armchair!

 

[spec]

HDD's have many servo loops, My guess about a dozen servo loops or more. for servo acceleration, velocity, position, clock recovery, spindle speed
Most sophisticated electro-mechanical, magnetic mature reliable products in the world in a small package at low cost. without exception.

My first exposure to Hitachi was Nippon Peripheral Limited (NPL) with their (dont laugh) 6MB 5.25" HDD in early 80's. They were a subsidiary of Hitachi and the design used stepper drive motors.
Unlike many newbie questions today about BLDC and stepper motor design, they already were using steppers with variable speed to accelerate to max speed and used a viscous ring damper around the motor shaft to eliminate resonance. If anyone wants to learn about how to design the best stepper-servo design, go back 30 yrs and reverse engineer these drives. It outperforms what they do today with 3 axis milling machines, 3D printers etc in terms of optimum stepper speed control and accuracy.

When we got into 100MB 5.25" HDD qualifications, Hitachi was one of the potential sources. They flew from Japan to do a show and tell. Very professional and advanced in HDD contact start stop reliability. For example at that time when 14" HDA's lasted maybe 5k to 10kh MTBF, their products were >50kh. They were insulted when I asked how did they verify their quality and reliability.
Toshiba and Fujitsu on the other-hand were also good but more in tune with western communication. I knew all the companies and contacts in sales and Engineering and the learned the designs by reverse engineering and DVT test plan I created, in order to qualify the best for purchase in large qty.

Today the best rank in any order depending on specific models ; price, performance and application. My rank today is: Hitachi, WD, Seagate.

The newer the technology, the higher the density and more reliance on error correction, on-the-fly (ECC) and the less warning to the user... before "click of death" ( loss of servo signal)

Great advances in lower surface roughness on glass vs burnished alum. in old days since vertical recording is std. now resulted in flying height which can be measured in atoms instead of u" It still relies on an aerodynamic no-contact flying over the surface 30~100kph.

Thks Tony- very interseting. On advice, I have always chosen Hitachi HDDs. Seems like the advice was good. Amazing stuff you have done- way above my head- dozen servo loops!

 

[Nikolai Petrenko]

Nikolai, you will be able to have base as heavy as you like- more heavy than even you could take. just say how much, or even set it yourself. You are not understanding how it all works.

You will need a seat belt fitted to your armchair- you can fit one? You can get one from a scrap car, but make sure you bolt it securely to the framework of your armchair!

How funny you are! I know if my subwoofer fire to the ground, it can cause an earthquake. Maybe my bad subwoofer has poor sensitivity so it need a lot of power to blow (old subwoofer from junk yard). I ever seen some tube amps with sensitivity speaker play very loud despite output power only 2W.

 

[audioguru]

Don't you know that if you double the power from an audio amplifier that is feeding a speaker then the sound level is only a little louder? You might not notice the small difference between 1 times or 1.5 times the power. 10 times the power sounds twice as loud.
Your subwoofer speaker might not even play low frequencies. What is the speaker size? Did you measure its resonant frequency in its enclosure? Is the enclosure sealed or ported?

 

[Nikolai Petrenko]

Don't you know that if you double the power from an audio amplifier that is feeding a speaker then the sound level is only a little louder? You might not notice the small difference between 1 times or 1.5 times the power. 10 times the power sounds twice as loud.
Your subwoofer speaker might not even play low frequencies. What is the speaker size? Did you measure its resonant frequency in its enclosure? Is the enclosure sealed or ported?

don't know yet. I not buy yet. But I think I will buy type for ported, I will contact to seller to receive information about this subwoofer.
I also ask how to make potentiometer more linear (less logarit)? Linear pot not availabe or to luxury for me. I asked my brother he said add a resistor in parallel with value approx 20% of pot. maxium value but I fell it only more linear a little (I calculated then drew a graph and result this graph only more linear than old graph of pure pot. a little)

 

[audioguru]

Our hearing's sensitivity to loudness is logarithmic not linear so we can hear very faint sounds and very loud sounds. Therefore a volume control should also be logarithmic. Connecting a resistor from the slider of a linear pot to ground helps a little.
I do not know why you cannot buy a common logarithmic volume control.

 

[Nikolai Petrenko]

Connecting a resistor from the slider of a linear pot to ground helps a little.
I do not know why you cannot buy a common logarithmic volume control.

Of course, resistor from "output" of pot. to the ground.
I can buy normal volume control easily and cheap, I have 4 dual 100K and 1 single 10K and 1 dual 50K. But ALPS pot. too expensive and hard to buy.