About make an audio power amplifier.

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We used to demo Linn Sondeck and Rega 3 for people. Huge price difference apart from cartridge fitted. Linn won...but barely on most demos.

Linn had 3 point suspention...Rega none. Aah the days before CD's.
 
tvtech said:
Quality quality quality. You in England spec....remember Rega RB300 arm and Rega 3 Turntable?
Click to expand...
Yeah, know the Rega stuff well.

tvtech said:
I have both too...but my LP's were in storage and got damaged. Have not played a record in around 10 yrs
Click to expand...

Oh, I see. Shame about losing your vinyl. Bet you were pissed about that.

Why don't you use your computer to store FLAC audio files and play back vis USB, TOSLINK, etc into an external Digital to Analogue Converter (DAC)? Then feed the line output of the DAC into your amp?
 
tvtech said:
We used to demo Linn Sondeck and Rega 3 for people. Huge price difference apart from cartridge fitted. Linn won...but barely on most demos.

Linn had 3 point suspention...Rega none. Aah the days before CD's.
Click to expand...

Linn Sondeck and LP12 arm (is that the right reference for the arm) I hankerd after that kit for years. It still fetches big money second-hand now. I did have many hours of listening to the Linn Axis though.
 
im learning alot from this thread and am happy to have found this place
i especially enjoy the prints and engineering vocabulary.
as a new member,im greatfful
 
spec said:
Linn Sondeck and LP12 arm (is that the right reference for the arm) I hankerd after that kit for years. It still fetches big money second-hand now. I did have many hours of listening to the Linn Axis though.
Click to expand...

Hi Spec

There was a cheaper Linn in those days...don't remember the name though. Long ago.
LP 12 sounds like the arm that the Sondeck came with.

There were MC Koetsu black and reds we were running then. Got absolutely every bit of music out of an LP/Vinyl.

Detail that makes you simply start smiling for unknown reasons...hearing stuff on familiar music you had never heard before...

Those were the days. You just started smiling and could not help yourself....

Watching customers faces in a demo was the most rewarding experience ever. That I will never forget. Ever.

Whether they coughed up and bought did not matter....the amazing expressions were worth gold to me

Those were really happy days
tv
 

Hy tv,

The cheaper Linn deck was the Axis that I mentioned. It was not in the Sondeck class but was still pretty good with an Audio Technica AT-F5 moving coil pick up cartridge. I would have been one of the customers listening to the systems you were demoing- as you say, happy days

spec
 
Coming back to me now...We had an AXIS ( name still does not ring a bell)...but Planar 3 with RB300 with cheap cartridge MM...always won in a demo.

Doing some thinking here...
 
Was like a Sondeck without suspension I think? With a cheap arm??
 
Or maybe less suspension?

We never sold any that's why I cant remember it properly
 
If I remember correctly....there were people modding the Sondeck at the time to fit the RB300 arm...with brilliant results..
 
tv,

Linn Axis with LVX+ arm and Audio Technica ATF5 moving coil cartridge. The Axis arm could take the next level up, ATF3 cartridge but it was touch and go. No trouble in the Sondeck though.

This is the Axis- it is a completely different design to the Sondeck and was great value for money:

spec

 
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tvtech said:
If I remember correctly....there were people modding the Sondeck at the time to fit the RB300 arm...with brilliant results..
Click to expand...

Yeah,
There were many many mods.
When you got to that quality level it was more down to personal taste and system matching rather than absolute quality.
I was never mad about Linn cartridges, especially at the price, but lots of people raved about them
spec
 
Hello everyones. I have disappeared for several weeks just because I was start my hard study campaign for the next exam.
Return to the preamp again, I just drew power supply for it, discrete parts again! May I am a conservative man?

I believe that "T" low pass filter will smooth any ripple down to level that below what I can hear.
How many watts should the big toroid transformer have? 600W??? Total output power equal to 300W, classAB has effieciency about 50% => 600W transformer, right or wrong?
 
Nikolai Petrenko said:
Hello everyones. I have disappeared for several weeks just because I was start my hard study campaign for the next exam.
Click to expand...

Good to see you back and good that you have had your nose to the grind stone studying.

Nikolai Petrenko said:
How many watts should the big toroid transformer have? 600W??? Total output power equal to 300W, classAB has effieciency about 50% => 600W transformer, right or wrong?
Click to expand...

A 600W toroidal transformer or bigger would be excellent. Your method of choosing that size is good rule of thumb for a hifi power amplifier, but the affects of the transformer are many. One of the main objectives is to provide low ripple, low noise, low impedance supply rails to the power amplifiers.

spec
 
Nikolai Petrenko said:
Return to the preamp again, I just drew power supply for it, discrete parts again! May I am a conservative man?
View attachment 98257
I believe that "T" low pass filter will smooth any ripple down to level that below what I can hear.
Click to expand...

Nice thinking Nikolai about the preamp PSU, especially the earth lines, but afraid to say it will not do your job. If you you would like me to do a suitable discrete version let me know. Alternatively if you would like to try a revised design yourself, let me give you two clues:
(1) the bridge rectifier should feed straight into a big reservoir capacitor.
(2) you probably need to use three additional small signal NBJT transistors (BC456 for example), two as a long tailed pair and one to form a Darlington pair with the BD139.

spec
 
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Yes, like you said. After posted that circuit, I had a bath, in this time I realized that the collector of transistors are connected to 100Hz ripple voltage because I forgot to put 2200uF just after the bridge rectifiers. So my circuit lack 2 capacitor to pre-smooth voltage for the regulators.
Other mistake of my circuit is resistor are too small so zener diodes will be very hot and can be burn. I think 330Ohm will be fine, and it also increase ripple rejection.
 
Hi Nikolai,
I have captured a Rolls Royce pre amp PSU in EAGLE now. Just doing a bit of twiddling and checking and will be posting soon.

spec
 
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