Hi
I am new here and I am interested in building a SS power amp. I have been an EE for a long time and designed guitar electronics before, but I absolutely know nothing about audiophile electronics. My first question is about power supply.
1) What is the requirement of the power supply other than the obvious reason to supply power?
2) Is regulated power supply good for audiophile amp or you want to add some sag like in guitar amps?
I know this is kind of stupid question, in guitar amps, people don't like stiff supply, they want sag. So I don't want to take for granted one way or the other.
Thanks
I am new here and I am interested in building a SS power amp. I have been an EE for a long time and designed guitar electronics before, but I absolutely know nothing about audiophile electronics. My first question is about power supply.
1) What is the requirement of the power supply other than the obvious reason to supply power?
2) Is regulated power supply good for audiophile amp or you want to add some sag like in guitar amps?
I know this is kind of stupid question, in guitar amps, people don't like stiff supply, they want sag. So I don't want to take for granted one way or the other.
Thanks
I believe there are no audiophile amplifier. Sometime amp with 0,1% THD called udiophile amp, but amp with 0,01% THD called hi-fi amp. Even, amp with 1% THD using exotic components can called audiophile.
I know THD is not only a parameter that determine the quality of an amplifier.
1) Use regular power supply for class AB. Use capacintance multiplier for class A. You should consider using cap multiplier on amp that using CFA topology.
2) No need using regulated power amp, it is not efficient. Better using capacitance multiplier.
Thanks for the reply. What is CFA means?
Is capacitance multiplier using a pass transistor to buffer a filtered voltage using some resistor divider? It's is half way of a regulated supply and it's without negative feedback?
Hi Alan 0354,
you could get many answers in getting and reading the following books :
Bob Cordell : Designing Audio Power Amplifiers, copyright 2011
Douglas Self : Audio Power Amplifier Design, sixth edition
Randy Slone : High-Power Audio Amplifier Construction Manual
IMHO this last one is the good one for somebody that wants to build his first amp without getting too much problems. The others are more advanced and also very, very precious books
, very well written, with plenty of informations !Welcome here, don't forget to look at some of the best diy amp that have been proposed, like the SymAsym from Michael Bittner, or the SymAsym TO3 from Rudi Ratlos. There are many other very good amps you might build here, look around ...
I wish you to have great success
in your builds.Best regards
rephil
"Audiophile" describes the category of listener - a discerning type who strives for the impression of high quality - i.e. everything that sounds rich, engaging and detailed in the music programme. Despite protest from engineering and professional audio circles, this is a higher listening priority to them, than relying on faithfulness to the original signal input to be the the judge and jury of the most entertaining listening experience.
Put another way, it's subjectivism V precision as design goals.
If you design and build for either camp, you'll wind up with quite a different set of parts, construction priorities, materials and costs. In commercial products, the price differential can be staggering with the normal priorities of $/watt and least distortion often being totally reversed and clients comparing the component quality, fittings and feel of controls etc. This is a different world.
BTW, you are right about capacitance multipliers, often used to improve the PSRR of the front end of all types of linear amplifier.
CFA (we have lots of acronyms) means Current Feedback Amplifier as opposed to the regular designs which are Voltage feedback types, though this is a misnomer in the traditional distinction since the meaning of CFA now applied, derives from the IC Opamp terminology.
An example is the VSSA amplifier by Lazy Cat
Put another way, it's subjectivism V precision as design goals.
If you design and build for either camp, you'll wind up with quite a different set of parts, construction priorities, materials and costs. In commercial products, the price differential can be staggering with the normal priorities of $/watt and least distortion often being totally reversed and clients comparing the component quality, fittings and feel of controls etc. This is a different world.
BTW, you are right about capacitance multipliers, often used to improve the PSRR of the front end of all types of linear amplifier.
CFA (we have lots of acronyms) means Current Feedback Amplifier as opposed to the regular designs which are Voltage feedback types, though this is a misnomer in the traditional distinction since the meaning of CFA now applied, derives from the IC Opamp terminology.
An example is the VSSA amplifier by Lazy Cat
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Thanks
I guess I said audiophile to mean I am looking for higher quality than the normal quality. So far, I have an Acurus 200W per channel power amp and I consider it is the very low end of the audiophile. I really like the YBL amp that was over US $4000 back in 1998. I have a pair JM LAB top of the line Focal floor speaker, which I consider middle of the road audiophile speaker, no where close to the Utopia line. This is how I call it. I bought the Acurus amp when I had a pair of Kef that was about US $1000 at the time, so it is not matching to the JM Lab and it really showed when I A/B the YBL amp. So my goal is to build an amp that match the JM Lab, BUT not over the quality because it is only middle of the road. I don't want to build any exotic amp that I will run into the speaker not matching up to the amp.
As for the CFA amp you show, is the feedback is from the 1K to 47ohm from the output to the two emitter of the two input transistors?
Thanks
Yes, that's correct, for both polarities.
CFA designs have speed advantages as you suggest but the interest is for subjective reasons. Many have believed for decades that incredible bandwidth leads to great improvements in subjective audio performance. Several postulations linking this to low IMD and TIM have been floating around just as long. There are massive threads and long, bitter professional exchanges over the subjects.
There is another view that the higher level of distortion in simple practical amplifiers like this one is "nicer" sounding than a similar performing VFA design typically produces. This can be measured and appreciated, as we read the enthusiastic comments in the construction threads. I can much more easily accept this reason, given the wide support of the DIYs themselves, over some years now.
Thanks, you lead me into another question: Do you need some amount of distortion for the amp to sound good? An amp that has no distortion sounds clinical?
Is IMD = intermodulation distortion? What is TIM?
Low noise (from the rectifiers and mains), low impedance (meaning low load-induced noise).
Yes, provided the regulator's up to snuff (not always a trivial task to achieve low noise and low impedance with active circuitry). Otherwise passive filtering (CLCLC....) is going to sound better probably.
Switching supplies can make great poweramp supplies, but there are noise challenges to overcome. They also tend to need a large value of output capacitance in order to provide the peak current requirements of amps. High capacitance, when composed of many paralleled small caps also provides excellent filtering when combined with series inductors.
Build up a simple linear NON Regulated Power Supply Unit (PSU).
This consists of:
mains transformer
bridge rectifier
smoothing capacitor/s
If you want a single polarity supply, then a single secondary transformer and one capacitor are sufficient.
If you require a dual polarity supply, then a dual secondary, or centre tapped secondary is required and two capacitors.
Learn how to wire that up safely.
Learn how to connect a circuit to that safely
From that decide if you need anything better than that.
This consists of:
mains transformer
bridge rectifier
smoothing capacitor/s
If you want a single polarity supply, then a single secondary transformer and one capacitor are sufficient.
If you require a dual polarity supply, then a dual secondary, or centre tapped secondary is required and two capacitors.
Learn how to wire that up safely.
Learn how to connect a circuit to that safely
From that decide if you need anything better than that.
I have been an EE for 30 years designing analog, digital and RF electronics. I designed my own Guitar amp already. I am new to audiophile electronics, but I am pretty sure I can build any complicate circuit. I just want to know what is important and what's not.
As I posted before, I already have an Acurus 200W per channel power amp, anything I want has to be better than that, preferably something in YBL, Krell type of quality.
Anyone can give me link to power amp kit that is in the ball park of YBL and Krell quality? That will really save me time.
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With an interest in high-end products but probably not the price ticket (like most of us here) you probably want to look at cloning the popular icons of the big name brands - and there are plenty of threads here covering almost every revered model there is. Simply search here or Google your favourite model and follow any promising threads. You wind up here for most DIY either way.
Maybe a thread begins with showing a build or using a PCB that's available and that makes life so much easier. It will cover the specific design aspects that may concern you and make that journey into your own design a more certain process. I believe it is a good beginning to start with a clone to get a feel for how commercial products are designed, constructed and the high reputations established. That way you don't wind up with a mediocre creation founded on the wrong priorities.
Parts sourcing, hardware and the major problem of obsolete designs and components for old products are still down to you, like any real DIY is. We can help with group buys on current threads and occasionally members have sources and will trade at the swap-meet and commercial forums, if you need to.
Easiest start is follow a thread or two of your favourite models and see what's going on - maybe rekindle interest of others in a dead thread, who have already been there and have something worthwhile to share about it.
Maybe a thread begins with showing a build or using a PCB that's available and that makes life so much easier. It will cover the specific design aspects that may concern you and make that journey into your own design a more certain process. I believe it is a good beginning to start with a clone to get a feel for how commercial products are designed, constructed and the high reputations established. That way you don't wind up with a mediocre creation founded on the wrong priorities.
Parts sourcing, hardware and the major problem of obsolete designs and components for old products are still down to you, like any real DIY is. We can help with group buys on current threads and occasionally members have sources and will trade at the swap-meet and commercial forums, if you need to.
Easiest start is follow a thread or two of your favourite models and see what's going on - maybe rekindle interest of others in a dead thread, who have already been there and have something worthwhile to share about it.
Yes, money is the biggest concern, but electronics is my hobby also. I am retired, so going out and spend $5000 for a power amp is a little steep!!! I have no issue building amps at all, or even design something.
What do you mean by available pcb? Is there any generic pcb I can buy for power amp?
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