And this makes your amp sound better how? Sounds like a deflection and poor comparison. 99%+ amps don't have a "transfan", so the correlation there is weak.
Could yours put out that kind of power in a rack without a fan or without taking up more Us?
How do you know your amp would even last in the environment that the Crown lives in?
If your Perreaux amp is so great why is it being repaired at all. Over here a good amp runs for over 30 years, sometimes longer, with horizontal capacitors even. Then they are "restored".
Slow down, read first.
If I said your car sounds like crap, do you think, that I think you are the owner of Yugo?
NO ...the all point about the transmotor is that is truly unic and innovative idea but still fails easier than a classic thermostatic ventilator and with catastrophic results
as about innovation this the only one exists in this Crown the rest of it is classic AB pro amp
Still you are clearly confused about the point of the thread and the ownership of Perreaux amplifier ( or company )
Last edited:
All amps will run for a lot longer if they are kept cool. The big KILLER is heat.
Heat weakens transistors.
Heat kills capacitors.
Heat eventually kills transformers.
Any good amplifier design, regardless of it being Class A, AB, B, D, T or XX will work for longer if it is kept cool.
There are two ways of keeping something cool. (1) Run it cooler or (2) Cool it.
Heat weakens transistors.
Heat kills capacitors.
Heat eventually kills transformers.
Any good amplifier design, regardless of it being Class A, AB, B, D, T or XX will work for longer if it is kept cool.
There are two ways of keeping something cool. (1) Run it cooler or (2) Cool it.
I personally laugh at the guys that are trying to make Gain Clone amps as small as possible. To me this is defeating the object.
I build Class A amps. They are naturally massive due to the heat involved. I support the OP in showing how to build a good solid amp. OK I've voiced my opinions about the numbers of push-on connectors but it still shows good construction practice.
I build Class A amps. They are naturally massive due to the heat involved. I support the OP in showing how to build a good solid amp. OK I've voiced my opinions about the numbers of push-on connectors but it still shows good construction practice.
He is doing pure provocation dear Sakis....he wants to bother you
Do not answer him...this is my suggestion... avoiding to read will be better..including in the ignore will be even much more better.
People that wants to bother..clearly is that he wants to do..already in my ignore list...because if land in my threads will not have any attention.
regards,
Carlos
Do not answer him...this is my suggestion... avoiding to read will be better..including in the ignore will be even much more better.
People that wants to bother..clearly is that he wants to do..already in my ignore list...because if land in my threads will not have any attention.
regards,
Carlos
Easy Carlos... This is a controversial thread... What is happening is natural...
Proof of the controversy is from the title itself "How to make a proper amplifier". When I read the title, I had no idea what would be written inside. This comment from Hugh implicitly describes what is going on:
It means that, from a repairman point of view, ease of troubleshooting is very important, while from others, nothing is as important as good sounding amplifier (And the Perreaux is just average).
Proof of the controversy is from the title itself "How to make a proper amplifier". When I read the title, I had no idea what would be written inside. This comment from Hugh implicitly describes what is going on:
It means that, from a repairman point of view, ease of troubleshooting is very important, while from others, nothing is as important as good sounding amplifier (And the Perreaux is just average).
Imagine another viewpoint not mentioned by Hugh, e.g. from an amp seller. It is probably the most difficult thing, to judge how much you should put more effort or production cost when you have to also judge how much increase of sales from that kind of improvement.
You want reliability without affecting sound quality? Use twice as big a heatsink, eww....
Sakis, according to this website Solid State Power Amplifier Supply Part 2 you should have 1000uf of filter capacitance per RMS ampere of current. Since my Crown will deliver a maximum 250 watts RMS into 4 ohms, my calculations indicate that a minimum of 7,905uf of filter capacitance is required for optimum operation. (sq root of 250/4) The stock amount is slightly too small, however Crown had to make this compromise to fit in capacitors that were rated to 200 volts. If you are willing to go the extra mile, you can use an amount corresponding to peak amperage by multiplying the RMS value by 1.41. This yields a value of 11146.05uf, FAR less than 60,000uf. Using more capacitance than recommended will not improve filtering performance and is honestly a waste of money.
Furthermore, I believe you are incorrect on the fanformer. I spoke with a crown technician who noted that the fan will only turn on when the internal temperature of the amplifier reaches a certain point. In fact, I replaced broken thermistors (that controlled the fan) in one of my amplifiers because they had failed. Instead of blowing out the amplifier, this failure tripped the protection circuit and the amplifier was saved. I have never seen a Crown of this era failing catastrophically. In fact, I purchase broken ones with an assumption that I WILL get them working again.
No matter how many amplifiers one works on, there is no replacement for math to ensure that that you get everything right.
i agree with the math ..i also agree that a 60 W amplifier in class AB that uses 200.000 mfd is a complete waste of money .
Still i will disagree that if you want clean power at the range of 250w times 2 equals to 500W a total of 20.000 mfd will not be enough to preserve regulation or to respond fast enough and provide enough power for 500 non clipped Watts ...The math cannot tell you much about mixed audio signal and static calculation also
For example techno music will be far more demanding in power than some classic music
Also this type of calculation can be a rule of thumb and also survive in real life tests since your amplifier includes VI limiters and input limiting ....
That will define your amplifier as a classic pro amplifier and reduce the needs for output transistors/power supply transformer /and capacitance All that in exchange of lower quality music
So may both amplifiers are basically class AB amps one BJT and the other mosfet but the concept is far more different and also the duty is far more different .....
As about the transmotor if the ones you have work with a thermostat we talk about different model of crown state the model please ..i d like to take a look on the service manual
Still i will disagree that if you want clean power at the range of 250w times 2 equals to 500W a total of 20.000 mfd will not be enough to preserve regulation or to respond fast enough and provide enough power for 500 non clipped Watts ...The math cannot tell you much about mixed audio signal and static calculation also
For example techno music will be far more demanding in power than some classic music
Also this type of calculation can be a rule of thumb and also survive in real life tests since your amplifier includes VI limiters and input limiting ....
That will define your amplifier as a classic pro amplifier and reduce the needs for output transistors/power supply transformer /and capacitance All that in exchange of lower quality music
So may both amplifiers are basically class AB amps one BJT and the other mosfet but the concept is far more different and also the duty is far more different .....
As about the transmotor if the ones you have work with a thermostat we talk about different model of crown state the model please ..i d like to take a look on the service manual
When we ran Bryston amplifiers in the 80's (4B) I had requested them to increase PSU capacitance by double , they refused citing science , Julius at Audire responded and guess which ones drove and controlled the woofers better @2ohms , worst the brystons would develope PSU noises after 14-16 months and we would send them back to Bryston for recapping ( at their expense) and still they refused to increase the capacitance , citing more than enuff ...
We eventually moved them off the bass units running all Audire stuff on the bass, where they had no issues and easily outperformed the 4B's. So IMO the science is LAB junk , crowns are lab junk ( thrown out enuff to say so) successful audio products are the ones applying science with real world application , Big PSU rules in my world with my cash and I totally abhor dinky toy amps ....
Errr just saying ....
We eventually moved them off the bass units running all Audire stuff on the bass, where they had no issues and easily outperformed the 4B's. So IMO the science is LAB junk , crowns are lab junk ( thrown out enuff to say so) successful audio products are the ones applying science with real world application , Big PSU rules in my world with my cash and I totally abhor dinky toy amps ....
Errr just saying ....
Last edited:
Have a look at profusions power supply considerations here:
http://www.profusionplc.com/images/data sheets/ecf10-demo.pdf
http://www.profusionplc.com/images/data sheets/ecf10-demo.pdf
marvelous article i only copy that :
Power supply considerations.
The power supply should be capable of supplying the
module with D.C. equivalent to 150% of the RMS
output power.
The power supply capacitors should be at least
2,000mF per amp drawn from the supply rail. This will
yield approx 1 volt p-p of ripple, which is a good
compromise between cost and performance. For
applications where the sound quality is of prime
importance, the capacitance should be increased to 2
or 3 times this value.
The mains transformer should be sized according to
expected usage. Hi-fi amplifiers use a transformer
rated at approx 1.5 x the total output power (in VA).
For a stage or P.A. amplifier the factor should be
2 - 2.5 times the output power.
Oversize power transformers will also enhance the
sound quality.
The rectifier can be made from discrete diodes or a
bridge rectifier. Remember that bridge output ratings
are given at relatively low case temperatures, and
should be rated accordingly. Leaded diodes dissipate
much of their heat through their leads, and require
large PCB lands to achieve their full ratings.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.