[Dreamslacker]

Some ****:

RC filtered + Filtered zener power supply:

One channel of the amp. Currently testing the sound of AD843's. Otherwise, I'd be using the OPA627's in the amp. They run hot (60'C) but I'd only heatsink them once I decide which opamp I want to use.

Paired up with my DT931's:

Borrowed a pair of SR-225's from a friend for auditioning (fantastic synergy here):

 

[pabbi1]

Cool case.. part # and vendor?

 

[Dreamslacker]

Quote:

Originally Posted by pabbi1 Cool case.. part # and vendor?

I bought it at a local (Singapore) shop selling electronics and electrical parts. I believe it's an el'cheapo, generic case that's made in Taiwan/ China. I do not know if you're able to get it online.
It at least comes with a 2mm thick, black anodised aluminium faceplate.

 

[comabereni]

Nice-looking amp. Nice case. Great photos. How does it sound?

Just one thing wrong with it--it's not mine.

 

[Dreamslacker]

Quote:

Originally Posted by comabereni Nice-looking amp. Nice case. Great photos. How does it sound? Just one thing wrong with it--it's not mine.

I prefer it to every other amp I've heard so far including but not limited to:
Antness KGCA V1 & V2, Headroom Airhead, MF X-cans (with Pinkfloyd mods), Corda HA1-MKI (with and w/o Blue mods), HA2, Prehead, entire Creek line, Naim Headline, maxed out META42's...

For the Prehead/ HA2 and the HA1 with similar mods to the Corda Blue mods, they're actually very fine sounding but it boils down to personal preference. I don't feel the Prehead is inferior in any way. It just has a subtly different type of sound.

 

[rayofsi]

nice amp =P
lhz told me about the first version

 

[flecom]

wow awesome case! its like a mini-rackmount

any idea who makes it i would love to make a lil mini rack of audio components for my pc

also why are your opamps runnign so hot

 

[was ist los?]

Schematics?

 

[digi01]

good p2p work.

 

[chillysalsa]

What design is it? I second the call for schematics!

 

[av98m2]

Quote:

Originally Posted by chillysalsa What design is it? I second the call for schematics!

Its his own original design. So you're probably not going to see any schematics.

Here's a look at an earlier version of the Big Ben that Dreamslacker built, which I ended up buying.

Signal section. That's a pretty big heatsink for the 4 opa627bp opamps. Yeah, I know, everything's hidden by the heatsink.

Close-up of the coupling caps(Hovland Musicaps). Look carefully under the board you can see a film cap peeking out. There are 4 of them under the board. 1 for bypassing each opamp.

Close-up of the 2 Neutrik combi-jacks. 5N (99.999%) teflon insulated silver wire is used for the entire signal section.

The power supply section. Transformer is a Talema encapsulated model.

Close-up of the power supply caps.

DT880s plugged into the twin Neutrik combi-jacks. You can also drive 2 headphones with normal 1/4inch plugs.

One final look at the signal and psu sections side by side. Both are separately cased and connected via XLR jacks on the back.

 

[Dreamslacker]

Quote:

Originally Posted by flecom also why are your opamps runnign so hot

Try biasing opamps with 10mA or more of current and see if they run hot..

 

[Dreamslacker]

Quote:

Originally Posted by chillysalsa What design is it? I second the call for schematics!

Took me 1 year of R&D to come up with the design.. Naturally, I can't throw it all away. It's a basic design, Class A, global feedback loop with a few tricks thrown in. All tricks taken from META42, PPA, CHA47, HA1-MK I, XP7 etc..

A good mix & match of designs and experience was what it took to come up with this.

 

[yongchao]

i see 4 opamps there..
is it something like CH47, opamp buffered by another opamp, and biased into class-A??

but interesting class A biasing circuit, 2 Fets and a VR (I think so). good idea..

anyway, the pic is not clear. can you show us the class A biasing method you used?

 

[Dreamslacker]

Quote:

Originally Posted by yongchao i see 4 opamps there.. is it something like CH47, opamp buffered by another opamp, and biased into class-A?? but interesting class A biasing circuit, 2 Fets and a VR (I think so). good idea.. anyway, the pic is not clear. can you show us the class A biasing method you used?

It's not quite as simple as that. =)
I've built a CHA47 before, it doesn't match up.. FYI, opamps buffered with opamps can also be seen in Corda amps.

The Class A biasing is the same as in the PPA. Cascode Jfets.



I believe how the amp ultimately sounds like is a reflection of the builder. The design, layout, method of connection and parts used all affect the sound of the amp.
The end-state is, if you're going to use the cheapest parts possible, it's not going to do a good design any justice. In fact, such a practice would be an insult.