prototype preamplifier

[jonstanza]

Dear sirs

I put a topic here, something I had in mind for some time already, but for professional reasons, was always limited by the lack of time.

The question is a personal project, which personal and professional knowledge I decided to build an active preamp (solid state) that has lasted eight years your development

With the help of software Auto-CAD in conjunction with our imagination is possible to create a housing with a personal designer.

The housing material is aluminum. Has two RCA inputs and two input xlr. Has one RCA output and one xlr. The front panel has an input selector and one attenuator. On the right side is the standby button.

The pot attenuator is an ALPS modified. Inside, Teflon is used to dampen the vibrations of the box..

The supporting foot are stainless steel. 3 foot is used at strategic points to reduce the resonance.

I enclose photos. then inform details of the preamp circuit and power supply

note: my English is somewhat bad, there may be some errors. I'm sorry.
jon

[jonstanza]

the pieces were made on my specifications in company specializing in aerospace.

[Junie]

that's a serious DIY in there Jon, a very detailed construction and well planned project huh. Well done and good luck with your build mate.

[gk7]

Looks fantastic. But it´s rather expensive, I believe, no ?

[jonstanza]

Originally Posted by Junie

that's a serious DIY in there Jon, a very detailed construction and well planned project huh. Well done and good luck with your build mate.

thanks junie

[AndrewT]

Mention of aerospace and it must be more than rather expensive!
Or someone repaying a big favour. Friends help sometimes.

Between 30 and 46years ago I got three little jobs done in Ferranti.

I await further details, both pics and description/specification

[jonstanza]

Originally Posted by gk7

Looks fantastic. But it´s rather expensive, I believe, no ?

yes it is a "little" expensive

best regards
jon

[jonstanza]

pcb layout

The software used for the design of the board is the Altium Designer... excellent, sophisticated and with a margin of error "null". The best that has passed through my hands.

Link:
http://products.live.altium.com/#r10/explore/bd-PcbLevelDesign



regards
jon

[ide2003]

very nice Jon, I admit this is the first time I see a roller bearing used in the amp ..and I have made many custom amp chassis...

best, TeguhPS

[jonstanza]

Power supply

Consists of two bus (positive) and (negative). Each bus has four diodes ultrafast, 15 A, 35 ns (MUR1520) of ON Semiconductor, the capacitor are the from Nichicon KG (Gold Tune), totaling in all 47200 uf . (four 6800UF and two 10000uF).

The regulation this based on JFET (PN4393) Fairchild, (do not use 2sk170 because of counterfeits) and also I had better response with this model.

In series with the JFET this a zener (1N5250). From this point of reference there is an amp that goes to the output transistors of the power supply. (ECX08N16-Z) positive rail and (ECX08P16-Z) negative rail.

To prevent vibration the transformer is suspended on shock absorbers to neoprene

There is also a small circuit in the power supply that is responsible for the mute / standby. In reality the whole circuit is designed to be connected to the current 24 hours per day.

regards
jon