Solid Solid State Power Amplifier

[PMA]

Thanks for your kind words, Hugh, Michael and mlloyd1.

Regarding VAS mosfets - there are several reasons for me to use them, but let me not reveal all of them

One of the reasons is VAS current 20mA (in the bigger amp version) and supply voltage 2 x 58V - I guess you can see the dissipation of these parts.

Best regards,

 

[PMA]

Several small mods ....

 

[Federmann]

Nice work.

 

[bogdan_borko]

Several small mods ....

Hi PMA what speaker relays you use, and are ~15mF per rail enough?

 

[Bonsai]

Very nice result Pavel - Kudos to you.

 

[jacco vermeulen]

Tesla Vrsovice also manufactured foil caps (47nF-2% ) ?

 

[Upupa Epops]

No Jacco, Tesla Vrsovice was mainly manufacturer of complete custom equipments for other Teslas ( mainly for Tesla Roznov, which was here something like our " silicon valley " ). They did not made discrete devices...

 

[jacco vermeulen]

Pavel (One and Only unique),

I thought tubes/valves are still considered discrete parts ?
=> HISTORIE FIRMY TESLA ELECTRONTUBES S.R.O.

So who made/makes the flashy Tesla capacitors in Pavla2's amp ?

 

[PMA]

Hi PMA what speaker relays you use, and are ~15mF per rail enough?

Hi Bogdan, it is a Finder relay, rated current 30A, peak current 50A.

Regards,

 

[PMA]

Tesla Vrsovice also manufactured foil caps (47nF-2% ) ?

Not Tesla Vrsovice, but Tesla Ostrava. Now ES Ostrava:

Electronic components Ostrava - components, capacitors, potentiometers, trimming resistors, suppression chockes

Regards,

 

[PMA]

Nice work.

Very nice result Pavel - Kudos to you.

Thanks

 

[Upupa Epops]

Here is little bit mishmash in postTesla factories, Jacco... it is for very long talking and I mean, that all is not very intererestig for you....

 

[PMA]

After one year and a half of tests and evaluation, there is some small upgrade to this amplifier. The new version is no. 6, and it is called PA4_V6. It is rated at 2 x 150W/8 ohm and 2 x 300W/4 ohm. It has true balanced input now, discrete, without opamp. The amplifier is quite fast, and does not suffer from any cross-conduction problem, as seen from 100kHz/8 ohm measurement. Please also note perfect behavior when clipping.

 

[PMA]

This is the last and final version of this amplifier. The specs are 2 x 150W/8ohm, 2 x 300W/4ohm. It measures 2 x 190W/8ohm and 2 x 330W/4ohm. It has a discrete JFET balanced input and also a single-ended RCA input, selected by a switch at the rear panel.

 

[Bonsai]

Very nice Pavel. I have the same case you have (modushop). How did you stop the base p anel where your transformers are mounted from bending?

 

[Upupa Epops]

Bottom plastic base of transformers make with bottom housing sandwich, so deflection isn't great...

 

[Mooly]

Hi Pavel... I was trying to make out whether you had used your SS speaker relays in this ?

I suspect not from what I think I can make out... nice bulid

 

[PMA]

Hi all,

thanks for your kind words.

There is no problem with transformers, as they have wide plastic circular base and there are two plates - perforated mounting plate and solid bottom plate in a distance of some 4mm, so the whole thing is quite solid and does not bend.

Output DC protection is made with power relays. I am quite conservative in case that the amplifier goes to a customer. I still plan to evaluate MOSFET protection for several weeks (at least) before it will be released.

Cheers,

 

[Federmann]

This is the last and final version of this amplifier. The specs are 2 x 150W/8ohm, 2 x 300W/4ohm. It measures 2 x 190W/8ohm and 2 x 330W/4ohm. It has a discrete JFET balanced input and also a single-ended RCA input, selected by a switch at the rear panel.

I see that the amp came to perfection.

 

[PMA]

Hi,

I hope it is not too bad .

Regards,