ADA8000 +/-18V regulator swap: lower heat dissipation?

[Gene Pink]

In particular the buck transformer method gets you a big improvement with minimum modification.
PUTTING 18 volts ON YOUR TLxxx IS NOT A GOOD IDEA!!!

Agree with both of these statements.

However, the solution to adding a buck may actually be quite easy. In another thread referenced in this one, the power transformer is a toroid, correct? If so, and it is not potted solid like a hockey puck, you can just add a buck winding of well-insulated wire (not magnet wire) by hand to the toroid. No external transformer needed this way.

In essence, this extra winding goes in series with the primary for more primary turns, dropping the volts/turn ratio, and lowering all the secondary voltages by the same ratio.

If interested, I can elaborate, been there, done it. But not with a toroid, that would be way easier than threading 40 turns of insulated "bell" wire  through just enough space on an I-E transformer.

Gene

 

[nevercroak]

Gonna use this as an example and not adress everything individually as it would be: "Has been said" or "I know".

Why dont you go back and read that thread, [...]

Please everybody, don't tell people to read if you obviously aren't either.  Everything (nearly, see below) in the last posts has been said before.

There is another thread about this where people discuss at great length various ways of improving the situation, but no, you have to be different!  Why dont you go back and read that thread, and DO WHAT THEY SUGGEST!!!

Yeah, "them" are always right and there is no need to think for yourself... may do me the favor and project this to politics - you know what this leads to.

Clear enough for you?

Clear enough that with a world full of people with the same attitude we would all use sticks to make fire...

If so, and it is not potted solid like a hockey puck, you can just add a buck winding of well-insulated wire (not magnet wire) by hand to the toroid.

Transformer includes shielding and is filled with resin in the middle, so not possible.


I don't know if anybody is really taking valuable information from this after this point. There is not even discussion on topic. So if some mod sees this and feels the need to close - feel free. Possibly spares some people some of their time, when feeling like you have to answer.

-Arne

 

[s2udio]

I don't know if anybody is really taking valuable information from this after this point.

The person requesting the information is yourself , you seem too avoid or disrespect any information or idea  given.

There is not even discussion on topic.

The topic has been discussed at length in many passed threads/posts, by some very competent techs and engineers
unfortunately for someone who has recently joined Group DIY,  your behaviour is quite bizzare and disrespectful,
With foolish ideas that are quite honestly stupid.
I belive its call "Trolling" and  seems the normal dictat on the internet nowadays.
You will not get information discussed here with that childish attitude.
Maybe GS would bee the more appropriate platform for a troll.
Your type makes my blood boil

 

[JohnRoberts]

In particular the buck transformer method gets you a big improvement with minimum modification.
PUTTING 18 volts ON YOUR TLxxx IS NOT A GOOD IDEA!!!

Agree with both of these statements.

However, the solution to adding a buck may actually be quite easy. In another thread referenced in this one, the power transformer is a toroid, correct? If so, and it is not potted solid like a hockey puck, you can just add a buck winding of well-insulated wire (not magnet wire) by hand to the toroid. No external transformer needed this way.

In essence, this extra winding goes in series with the primary for more primary turns, dropping the volts/turn ratio, and lowering all the secondary voltages by the same ratio.

If interested, I can elaborate, been there, done it. But not with a toroid, that would be way easier than threading 40 turns of insulated "bell" wire  through just enough space on an I-E transformer.

Gene

I am apprehensive about advising people to do things I wouldn't do myself... Messing with a transformer primary could inadvertently degrade the protective mains insulation. Be very careful doing things like this. 

JR

PS: I know some here are experienced with rebuilding transformers, most are not.

 

[JohnRoberts]

I don't know if anybody is really taking valuable information from this after this point.

The person requesting the information is yourself , you seem too avoid or disrespect any information or idea  given.

There is not even discussion on topic.

The topic has been discussed at length in many passed threads/posts, by some very competent techs and engineers
unfortunately for someone who has recently joined Group DIY,  your behaviour is quite bizzare and disrespectful,
With foolish ideas that are quite honestly stupid.
I belive its call "Trolling" and  seems the normal dictat on the internet nowadays.
You will not get information discussed here with that childish attitude.
Maybe GS would bee the more appropriate platform for a troll.
Your type makes my blood boil

Try to relax a little...

It is the nature of web forums for the same or similar questions to get asked over and over again.

JR

 

[s2udio]

Try to relax a little...
It is the nature of web forums for the same or similar questions to get asked over and over again.
JR

Sorry for the outburst........Its just that life ie "world" in general...not just web forums, .. seem to be overun with stupid people,
Who think they are capable of anything , with little or no experience, and discard practical and seasoned advice from those who are,
Without even being polite, and then discard said advice like so much trash.

Maybe its the time of year, or Maybe its the time of Man.

Now chilled with a beer 

 

[JohnRoberts]

Try to relax a little...
It is the nature of web forums for the same or similar questions to get asked over and over again.
JR

Sorry for the outburst........Its just that life ie "world" in general...not just web forums, .. seem to be overun with stupid people,
Who think they are capable of anything , with little or no experience, and discard practical and seasoned advice from those who are,
Without even being polite, and then discard said advice like so much trash.

Maybe its the time of year, or Maybe its the time of Man.

Now chilled with a beer 

If I got angry every time somebody ignored my advice (or called me boring), I'd stay angry.

I don't think the OP is stupid, (maybe because he listened to me some).

Different people communicate differently,  Life is short and beer is good.

Not beer o'clock here yet.

JR

 

[nevercroak]

I did not want to offend anybody with this - except maybe once...

There is a long general discussion about how to get these units cool down and more reliable. I specifically did not want to repeat this. Possibly I should have appended this to an existing thread but they have all been quite old so I decided against it.
I hoped to get discussion on the question: "What could it do for one to swap these regulators? In this specific unit." (a bit generalized now as it shifted throughout) as I could not find any discussion on it. Quite a few replies did not address this, but things discussed before, what was not my intent and I hoped to communicate this in my third post.
Further I don't see why this gets hated so much as this could be a possible solution (one of many) for the main reason these are dying (at least in Europe as the transformers don't seem to die here), too hot regulators and these located too close to the filtering capacitors. As I see it, there is only one technically optimal solution and this is to replace the transformer. All other solutions are in a way tradeoffs - what is a good and what is a bad solution depends on the factors involved and how you weight them.

I am grateful for all the replies on the topic as they make you think about it, and made me think about it. Even after all these mostly "negative" replies I am still willing to try it someday when I get the time. Frying your unit while trying to make it not fry itself is possibly a bit weird, but I don't really care about it - my fault and I learned from it, everybody else may learn from it as well. (And few people can say: Told you so!) If there is a specific topic I value discussion on it and not getting many comments like "But there already is this and that..." pointing somewhere else. Even if the topic may seem stupid at first. And this counts for everybody asking questions, not only me, at least from my perspective. All this and the "fear" of making this another (unnecessary!) general thread may have made me a little pissed and weary.

-Arne

 

[PRR]

> in mechanical engineering and safety margins are in most cases quite a lot higher there

Well, this is a key point, isn't it?

Bridges fall down. Mechanical engineers hate to see their names in the news. So they over-design.

Record players smoke. Get a new one. Or in my case my Dad identified a 1 Watt resistor cooked open, put in a 2 Watt part. I asked "Why, daddy?" Of course the first answer was that the part-price difference was 5 cents, but the time/trouble was worth $5, so he wanted it to never fail again. Then he got his slide-rule and figured we'd had 1.1 Watts of dissipation in that 1 Watt part. I said "that's bad, right?" and he said just what you are saying: electronic engineers don't use the safety margins that mechanical guys do.

Looking back: the resistor was probably rated 1W for 1,000 hours. The amplifier was sold on 30 day warranty. You can't rack-up 1,000 hours in 30 days even 24/7. And most buyers would not run 24/7. So the "design" was "safe" from the point of view of warranty costs. Incidental liabilities were probably excluded, and nobody died when the record player quit.

Dad also said that electronics "mostly" has well-specified parts and loads. Whereas all wood and much steel is prone to hidden defects. And anything you can put weight on, someone will put too much weight on.

In houses the floor load goal is about 3X what any "normal" floor will see. Or it figures full solid with people face-face. (Stadiums aim for solid people with zero face space and jumping.) Meanwhile the wood is also derated 3X from what clear wood can stand to allow for knots and splits and nail-stress. Even these rules slip: an older house had a party upstairs, the upstairs pancaked down to the ground floor. In this case it was "detail": the joists held, but were supported on 2-story studs with ledgers nailed on. The ledger nailing was inadequate. But had stood for 80 years of normal use; it took crazed college students to find the weakness.

Back to your whatsit. I missed key details like the raw supply volts. And why re-heatsinking is not a first response. Shifting strain from regs to opamps does kinda sound like "rearranging the deck chairs on the Titanic", or the patchwork crack-patch on the building in New Zealand which fell down. Well-burned rubble-shifters hate to find such "fixes".

However I would not fret about a *measured* 18.00V on the opamps. Just as that party house would not have pancaked if _I_ had inspected the nailings. Mass-production (or unsupervised carpenters) you have to keep a healthy margin. And FWIW, I have run 125% of "Max voltage" spec on analog chips and observed ~~1,000 hours mean time to failure. 5% overvolt (regulator tolerance) may not be wise, but is not sure to be early death. And if you are avoiding the labor to add proper heatsinks, then you sure can put a good DMM on there and verify <1% tolerance.