Introduction

Bruinsma

Member
2008-04-14 12:18 pm
Hello, my name is Bruinsma,

I am new at this forum. I like to introduce myself.
I live in the Netherlands, a small country at the western side of Europe.
I was already infected by the Audio virus when I was eight. During that time (some years after World War 2) in comparison with what we have nowadays, the possibilities on the audio field were very limited. We had tubes, resistors, capacitors some transformers and bad kinds of wires. Often military surplus. So (mono) amplifiers than were always equipped with tubes. But unfortunately not always of good quality.
Later on I studied electronics engineering. But tubes were still the most important active components than. When the transistor arrived in the sixties everybody including myself expected that we would come in heaven with those components. The reality however appeared less perfect. Only many years later the quality of solid state components became at a real professional and reliable level.
I worked many years in the telecommunication and power cable industry. I developed several systems and instruments for production control, inspection and measurements of cables and related equipment. I am retired now.
About twenty years ago I discovered Nelson Pass and his philosophy of less is more and the simpler the better. After having build his A75 design I went on developing power amplifiers, pre amplifiers and phono pre-pre amps, all based onto MOSFETS.
To my opinion the more recent Pass XAxx.5 developments with the use of JFETS (hard to find) are extremely interesting.

Regards.
 

Bruinsma

Member
2008-04-14 12:18 pm
Designs

Hello Mr. Pass,

This thread did not accept the size of my design drawings. I.e. I did not succeed in it.
So I will try sending you later some design information to your Pass Labs e-mail address.
In general:
All my designs (power amps, pre-amps, pre-pre-amps etc.) are 3-phase mains supplied. In the Netherlands in almost each house a 3-phase mains cable is brought in. Advantages are less ripple (even without electrolytic supply capacitors* compared to single phase rectified power supply) and much less noise and interference from the power line. You can also choose for 6 pulse, 12 pulse or even more pulse rectification.
Some next plans are CFP (complementary feedback pair) input circuits, exclusively with MOSFETS, input circuits based onto (power) JFETS (unfortunately P=channel power JFETS do not exist yet as far as I know) and phono pre-pre with zero input impedance (current input), RLC RIAA/IEC correction.

*In less ideal designs the power supply electrolytics are in the secondary signal path. In better designs (symmetrically class A) the signal is kept within the signal circuit.

Regards,
P.J.B.
 

Jaac

Member
2002-10-30 8:58 pm
Amsterdam
Re: Designs

Bruinsma said:
Hello Mr. Pass,

This thread did not accept the size of my design drawings. I.e. I did not succeed in it.
So I will try sending you later some design information to your Pass Labs e-mail address.
In general:
All my designs (power amps, pre-amps, pre-pre-amps etc.) are 3-phase mains supplied. In the Netherlands in almost each house a 3-phase mains cable is brought in. Advantages are less ripple (even without electrolytic supply capacitors* compared to single phase rectified power supply) and much less noise and interference from the power line. You can also choose for 6 pulse, 12 pulse or even more pulse rectification.
Some next plans are CFP (complementary feedback pair) input circuits, exclusively with MOSFETS, input circuits based onto (power) JFETS (unfortunately P=channel power JFETS do not exist yet as far as I know) and phono pre-pre with zero input impedance (current input), RLC RIAA/IEC correction.

*In less ideal designs the power supply electrolytics are in the secondary signal path. In better designs (symmetrically class A) the signal is kept within the signal circuit.

Regards,
P.J.B.

Let me guess; Your amps have wooden housings ?