Calor amp 40watts Class A !

[umut1001]

Has anyone built this amplifier???.I am curious.Thank you

> Average output power--------40W/8 ohms (without exiting class A!)
> Power Bandwidth-------------11Hz - 135kHz
> Small signal frequency BW --- 2,5Hz - 450kHz
> THD----------------------------<0.008% (20Hz-20KHz/80%power)
> Phase shift --------------------up to 2,5� in the range 20Hz-20kHz
> Slew rate----------------------85V/uS
> Dumping factor---------------->750

[juma]

The autor, boraomega, is a member of this forum and I'm sure he'll be glad to answer your questions.

[boraomega]

Hello “umut1001” !
As far as I know, no one built CALOR except me. It is an excellent amplifier by all means, but for now, you will have to either wait for somebody else to build it and report results and impressions, or to believe me!

[umut1001]

What are your experiences?my friend suspect that it has so much slew rate and damping factor.He does not completely believe the specifications.But i believe you.Can you explain how it sounds ?

[boraomega]

Neither you nor anyone has to believe me anything. Build it and see for yourself my friend - that is the best option. I am probably the last person to be asked for description of how one amp sound, if for nothing else but for the fact that it is my design and I will probably be quite biased no matter how hard I try not to be. That is the question for reviewers of HiFi magazines, they developed a convenient vocabulary.

Thanks to two of my old friends (audiophiles, not builders), prototype has been listened one evening alongside one nicely done DIY Hiraga and my old HK 6600. To me, CALOR performed clearly more pleasant and I was glad to hear the same impression from both of those friends.

Only THD is a simulation result (I don’t have instruments to reliably measure such low distortion) but other parameters were measured on prototype. My apologize for omission of measurement frequency for Dumping factor – that has been measured on 200Hz.

[Samuel Jayaraj]

Dr.Bora, the IC appears to be an NE5534 but it is not mentioned anywhere. Do you think that the use of a different and more modern opamp may improve the sonics of the amp? I found that NE5534 is very good and pleasant sounding but a little too laid back in the mids; generally, a more forward mid presentation is desirable and most Class A amps have this character.

[boraomega]

Yes Samuel it is NE5534AN and YES, I tried several other high class modern OPAMP-s but without any noticeable improvement!

[Samuel Jayaraj]

Thanks, Dr.Bora for the reply.

With so many amplifier offerings on your site, the choice is difficult without knowing what the characteristics of each are. I am gazing at Calor-Gold, Lambda, DOGC-Mk3, CroSer, T-Reference and Modus as likely candidates for a reference amp to drive a pair of Fostex FE168EZ and Fountek Ribbon Tweeters. At the moment I am using a modified Quasi-NMOS and want to hook up the Stochino amp which needs final assembly. The latter is a great amp which I made several years ago and gave away to a friend.

Which of your designs would you say is the most musical, detailed and engaging amp? That is not a question you might want to answer but how about listing the strengths of each amp eg., I read that Modus (Techno) is a very good alrounder with particularly great bass performance or that Studio has a wide and deep sound stage? Thanks for your yeomen service to the DIY community.

[RSK]

Originally Posted by Samuel Jayaraj

Thanks, Dr.Bora for the reply.


Which of your designs would you say is the most musical, detailed and engaging amp?

I would go for DOGC-H.

Raj

[umut1001]

Originally Posted by boraomega

Yes Samuel it is NE5534AN and YES, I tried several other high class modern OPAMP-s but without any noticeable improvement!

Hi Bora.I admire your designs.It seems ne5534 makes 10x gain.Maybe opa637 gives better sound.Why did not you try discrete components instead of opamp?Maybe the sound quality improves then(I am sure it sound goods now indeed)Thank you