New DISPRE preamp, successor to previous popular version

[estman]

Schematics and assembly drawing now released for personal, non-commercial purposes.

Thanks Pavel, you are really great guy ! Very interesting to study

 

[PMA]

I am very sorry that I made a mistake in the BOM of Dispre 2 V3 version. The Q5 and Q6 types were swapped in the BOM of V3 version (previous version BOMs were correct). I am attaching now the corrected BOM for the V3. Q5 is BC556 and Q6 is BC546. I also tried to e-mail everyone who bought the V3 boards.

http://web.telecom.cz/macura/dispre2_v3_bom_en.pdf

 

[AKSA]

PMA,

I hardly think an error in the BOM is something to be upset about; an omission or R/C swap on your schematic would be cause for intellectual prostration, but not this.....

Hugh

 

[kestrel200]

Does anyone know a good source in the US for all these .6watt resistors?

 

[ken.berg]

Does anyone know a good source in the US for all these .6watt resistors?

try the Vishay/BC MRS25 series from DigiKey

 

[kestrel200]

Thanks! I guess it doesn't matter if the rating differs by a couple of 10ths or more.

 

[PMA]

None of the resistors dissipates higher power, and 0.25W should work as well.

 

[kestrel200]

Would this power supply be a good match for V3? I'm right in thinking that Positive over 8V is what I'd need?


http://www.at-view.co.uk/alwsr.htm

thx

 

[lineup]

ALWSR
Super Regulators

is one very good power supply
has been mentioned at same time as other very topclass regulators
like the Walt Jung & Janneman Super Regulator for example
-- if you do some search you will see this

Very good choice, I am sure, for the PMA DISPRE any version!

 

[PMA]

It should be OK, anyway you need 2 voltages, as supply is 2 x 15V. That means two PSUs in series. Probably best choice would be >8V positive and >8V negative.

 

[robmil]

Hi

I have a mic preamp that runs +/- 24 volts. Is it possible to convert DISPRE for +/- 24v or +/- 18v ?

Thanks Rob

 

[PMA]

Hi Rob, +/-18V is possible without any changes, just make sure that the servo opamp used is OK with this supply rails, recommended types are.

+/-24V would be possible with some resistor values changed, BUT a servo opamp should be OPA445 then.

 

[AndrewT]

I have a mic preamp that runs +/- 24 volts. Is it possible to convert DISPRE for +/- 24v or +/- 18v ?

Hi,
calculate the voltages and currents and dissipations for all the passive and active devices with the recommended supply voltages.
Redo the calculations for the proposed supply voltage.
Compare your results.

If one cannot do this, then one should not be considering changing the design.
Build what you are capable of, if that means copy, then copy exactly.

 

[CeeVee]

Pavel,

What changes does V4 have referenced to V3 ?.

 

[PMA]

Send me an e-mail, please, especially in case you have been my customer.

The V3 was the last I was willing to share in a public domain.

 

[CeeVee]

Ok PMA,

sent you an email.

 

[PMA]

You have the reply, Carlos.

----

Mefistofelez - I am unable to reply your e-mail today - hotmail is refusing it.

 

[robmil]

QUOTE:
If one cannot do this, then one should not be considering changing the design. Build what you are capable of, if that means copy, then copy exactly.

Hi AndrewT - go easy with the reply. I think there are many students here and that are just willing to learn. Maybe you should take a leaf out of Pavels book - check out his reply.

Rob

 

[mefistofelez]

Mefistofelez - I am unable to reply your e-mail today - hotmail is refusing it.

Interesting, it does not seem to be a problem on my end; I have been receiving e-mail - even from Czech Republic ;-). Let me check.

Thank you for letting me know.

M

 

[PMA]

" Mail rejected by Windows Live Hotmail for policy reasons. Reasons for
rejection may be related to content with spam-like characteristics or
IP/domain reputation problems."

I get this when trying to send to hotmail almost always.

It would work thru DIY audio email button, but yours is disabled.