Advice if you can. I am building a PSU for a friend. All is working fine. The PSU is fitted with an over current indicator that also limits the current. In unusual conditions ( the ones where in a car there is no hope ) the TIP 3055 might overheat. The solution is an easilly replacable wax type thermal fuse. The TIP3055 is mounted on a 2.8 deg/W heat sink. It will see worse case 1.5 A at 17V or 25 W. The 3055 is said to be 4 deg/W giving 7 total as there will be only a high grade bonding pad to fix. This would give > 200 C at the collector. Normally worse case 100 C at the collector or 50 C at the heat sink. I suspect a 72 C wax fuse is the right one to use? TIP 3055 is any big transistor, TCC5200 is the likely one ( 2SC5200 ). If asking why do it this way ? Simple, it get very good performance and as yet I have not equalled it. What I might do is set up a circuit that shuts down the circuit if overload happens for more than 1 minute. That might be easy.
Dejan. If I had one thing to say about your amps it wouild be this. Divide you PSU into two. Use 40 V 22 000 uF as many times as you like. Set V to about 35 V per section. In series +/- 70 V. If using the Quad 303 to compare you have in fact 140 V at 5500 uF if using one set of caps ( Quad is about 80V at 4000 uF , 67V regulated ). In parallel you have +/- 35 V or 70 V at 22 000 uF. A simple octal valve base could be how it is done. For close to $0 you have two amps. 50 watts or 200 . 90% of the time I suspect you would use the 50 ( 100 4R I bet ) . The beauty is it gives you all that wonderful current where you will hear it best. The other option is party mode. You could even have a fan on the party side that switches by detecting the circuit is at 70 V. Yamaha did this on the class A/AB. To be honest the AB was so good on that amp that it almost asked why bother. As for having more caps for the same money that is a no brainer. Samwa 22 000 uF screw teminals types are good.
Dejan. If I had one thing to say about your amps it wouild be this. Divide you PSU into two. Use 40 V 22 000 uF as many times as you like. Set V to about 35 V per section. In series +/- 70 V. If using the Quad 303 to compare you have in fact 140 V at 5500 uF if using one set of caps ( Quad is about 80V at 4000 uF , 67V regulated ). In parallel you have +/- 35 V or 70 V at 22 000 uF. A simple octal valve base could be how it is done. For close to $0 you have two amps. 50 watts or 200 . 90% of the time I suspect you would use the 50 ( 100 4R I bet ) . The beauty is it gives you all that wonderful current where you will hear it best. The other option is party mode. You could even have a fan on the party side that switches by detecting the circuit is at 70 V. Yamaha did this on the class A/AB. To be honest the AB was so good on that amp that it almost asked why bother. As for having more caps for the same money that is a no brainer. Samwa 22 000 uF screw teminals types are good.
I have never had problems with custom with hobby quantity. They are very tolerable and understanding people.I also used to order parts and kits a long time ago, in pre-Internet era with minimal custom duties. For bigger orders best way is to use service of local electronic shops which work with major world distributors.Prices are slightly higher , but you do not pay for postage. In this way you may get what you want , including depletion FET-s and others genuine components. For Farnell wait one week at most.
BTW choice of electronic components in our shops is not that bad.
These parts http://ww1.microchip.com/downloads/en/DeviceDoc/DN2535 B062813.pdf come from Microchip now. Microchip says they have rep and distribution that supports Serbia. I think there are one or two other vendors as well.
And the local sales rep is the KEY PROBLEM. Many companies, such as ON Semi, very dear to me, won't let me buy direct from them because they have a local sales rep. I ring them up and learn they have next to nothing on stock, but yes, I can order, it takes 3-5 weeks and I have to pay 100% of the value in advance. In ther words, they are a rep with zero operating capital, they want to make money with financing from me.
I could now write a list of such companies here. About the only thing I bought on delivery was my car. When it arrived, they phoned me up, I went there and we closed the deal in less than 30 minutes, most of which was used to fill and sign paperwork. Let's just say GM knows a thing or two about selling cars.
So, I can order a car which costs just under €15,000 and have no problems whatsoever, but I can't order say €300 worth of electronic parts without waiting 3-5 weeks? How crazy is that?
Kamis, I don't know who you worked with, it's hard to keep tabs on everyone as there are a lot of new companies in the field, but the only two whose service I was happy with were Vremeplov and Micro Prince. Everyobdy else I tried gave me long talks explaining how they just have to work with pre finance. I don't mind making a down payment of up to say 33% of the total just so they know I'm serious about buying, but I pay nobody 100% of the EXPECTED price, with a warning that it may cost more than anticipated by the time it reaches me, and then wait 5 weeks for it.
I'll pass on that, Nige. I like simple, straightforward PSUs, no combining, no cross modes, no nothing, just plus and minus plus ground.
I am not likely to surpass +/- 56V for the current stages, or +/-61.5V for the voltage stages anyway, that allows me peak power levels of 180W/8 Ohms easily.
Practically zilch.
The country is effectively broke, demand is next to nil, required start up capital would be necessary, and the manufacturer would want an estimate of annual turnover, which I honestly cannot provide under the above circumstances.
Trust me on this, Demian, I've started up companies for others before, but they deal things I have no connection with, such as bakery additives. In fact, I was trained for starting up small companies in your neck of the woods (so to speak), Babson College, near Boston, in 1991. Different times, different circumstances by at least 100%. These days, not much economic activity in Serbia.
You can buy electronic components in shops? Where I live, the whole trade has moved to the interwebs.
The 40/35 V option is excellent . I was driving to meet some friends last night and thought it through. One is Pro Audio + builds testing gear, the other does Pro Audio and Richard a TV and anything repair man. Poor Richard now repairs vacuum cleaners to top up his income. So what did we talk about ? Mostly Simca's Ford V8 with metric bolts. And early French Morris engines using metric with Whitworth heads ( BSW ) !! That was to allow standard tools to strip the engine in the UK.
Just about got my thermal fuse question answered. 71 C, exactly as thought.
On my drive I considered the advantages of the 35/70 ( 140 total ) V PSU. Considerable.
1/ The +/- 35 V will sound better.
2/ The +/- 70 V will sell the amp
3/ No cooling fan when +/- 35 V
4/ No cooling fan will be prefered
5/ Simplicity of doing it.
Like owning a 155 MPH car the power of ownership is the pride of ownership. The reality of how it drives at 30 or 55 MPH is the quality most appreciated.
Yes, we still have the real shops with the real people where you may ask them to see and touch the components.They all have also online shops.
One thing which is becoming important is to know how simple a design can be. For example I have been testing an idea with Indian 2N3055's. I bought them for very little money. My guess is they are not quite an RCA if pushed. I also guess them to be another device in a T03 can. In the real version of this device I will not use them. Did I find them of bad performance? No. My feeling is any design can be prototyped using BD139/140 MJE340/350 MPSA42/92 2N5401/5551 BC327/337 TIP3055/2955 TTC5200/TTA1943. The latter being whatever 230 V 30 MHz gain > 50 device that is cheap. Big heatsinks have no substitute. 0.5 deg/watt seems the best value if shopping carefully ( $30 ). I dare say one made from scrap aluminium as I did when young would be OK. The mold made from polystyrene and casting sand, better still a wood pattern. My brother did a heat experiment on heatsinks. Any paint is better than none even white! He concluded that white is not white at infra red. This was his little upgrade for repaired TV's. He found the supplied heatsink when painted took the PSU transistor down to a happier temperature. The mating surface unpainted ( easier also to do that ). He used black as black is cheap and marginally better.
One thing I dislike is using very high flung ideas with no outcome. The analogy is iron pistons with 4 valves in 1920's motorcycles. Only in recent years have 4 valves made a small difference to the average driver. The reason they suceeded is a marginal advantage when trying to pass emision tests.
One thing I dislike is using very high flung ideas with no outcome. The analogy is iron pistons with 4 valves in 1920's motorcycles. Only in recent years have 4 valves made a small difference to the average driver. The reason they suceeded is a marginal advantage when trying to pass emision tests.
As we both know, a lot things were not mentioned, it would simply take too long to exoplain how and why.
That's why I called it a short list. I believe even that short list will sound like a script for a horror movie, the only difference being that they will only watch it, while you and I live it.
Nige, that sounds awfully like Hitachi's switching amps, like 5300. Double output stage, normally driven at low voltage, as required also on higher voltage, I think they called it Class H. It failed to impress me sonically, although it's well built.
I don't like switching tricks anywhere in the amp, other than power ON/OFF. I have yet to hear any such system which would justify the time and trouble against a classic, beefed up system.
Dejan I reallly have to build it now I have thought it through. The switching is the problem . This 35/70V is ideal. Naim 250 was 40 V . 70 V +/- is the limit of 2N5401/5551 and realistically so for 5200/1941 . I would use 12 output devices per stereo amp. I might use FET drivers for simplicity. Fetlingtom with 0R22 feedforward. 8 amps should drive 3 pairs nicely and have some to drive the speakers.
Sad thing is Rapid had the Samwa 22 000 uF computer grade very cheap. I bought 2!
Sad thing is Rapid had the Samwa 22 000 uF computer grade very cheap. I bought 2!
I have been working all week on a problem and mostly going backwards. No solution worked. Reading the complex world problems here I went to have a bath. The bath is allso a mini holiday with winter firmly here ( Cyprus 23 C today ). Then it came to me how to solve my electronics problem. It's the weekend so I should do it Monday. One hour later it worked perfectly. The word excellent would be best ( that's not about me , excellent is how it works). Every internet solution was complex and frought. 0.1% resitors for those solutions. That's a result.
I told my girlfriend my life is better than most peoples. My life is about sucess and learning. Other peoples lives like her life is about conflict. She has become a boss, the respect she gets is greater now. I notice the very hard work she does is not the killer problem. It's other people. I think Jean Paul Satre said " hell is other people ".
I heard whilst in the bath a lady say on the radio " I knew my son was Autistic when he wanted to know about the wheels on a train and not about Thomas the Tank Engine and his friends" Opps that's me. Ringo Star read the stories. If you don't know it here is a link. My two kids are Autistic and doubtless me too.
The other quote I liked was " I was in the car with my dad, we were listening to the Smiths. I knew he got it as he was nodding in agreement to the words and not the tune ".
https://www.youtube.com/watch?v=tTCEjQ1SpsQ
I told my girlfriend my life is better than most peoples. My life is about sucess and learning. Other peoples lives like her life is about conflict. She has become a boss, the respect she gets is greater now. I notice the very hard work she does is not the killer problem. It's other people. I think Jean Paul Satre said " hell is other people ".
I heard whilst in the bath a lady say on the radio " I knew my son was Autistic when he wanted to know about the wheels on a train and not about Thomas the Tank Engine and his friends" Opps that's me. Ringo Star read the stories. If you don't know it here is a link. My two kids are Autistic and doubtless me too.
The other quote I liked was " I was in the car with my dad, we were listening to the Smiths. I knew he got it as he was nodding in agreement to the words and not the tune ".
https://www.youtube.com/watch?v=tTCEjQ1SpsQ
The majority of people are unable to identify the source of all issues
because they are being under influence not to become aware of it.
Just watch the wrong movies and it will become more evident.
What do actors do in a movie when they have issues ? Light a cigarette,
drink liquor and feel sorry for themselves. Way to go, yeah right!
because they are being under influence not to become aware of it.
Just watch the wrong movies and it will become more evident.
What do actors do in a movie when they have issues ? Light a cigarette,
drink liquor and feel sorry for themselves. Way to go, yeah right!
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