The most advanced GainClone amp yet

[Peter Daniel]

It seems like more serious players are entering chip amps field now: http://www.6moons.com/industryfeatures/gill/gill.html

To keep up with the Jonses, I designed an integrated amp that pushes the envelope even further.

Starting with custom made toroids that have special windings and amorphous cores and dual mono design to the bridged amps output and TVC integrated volume control.

From the outside, the chassis is stylized by Levinson reference DAC and transport.

[Peter Daniel]

From the inside, I was really influenced by Connoisseur preamps layout

The front end consists of S&B102 TVC mounted on rubber dampers into Mardone Burl side panels. A stepping motor coupled to higher grade Elma switch allows remote volume control. The transformers act as phase splitters as well, allowing either balanced or single ended inuts and feeding the amps with balanced signal only.

The amps are basically Pateks in bridged configuration with a usual bypass scheme. The heatsink is made of bronze. Not a best material heatwise, but sonically better than other alloys.

[Peter Daniel]

The rear panel is pretty straightforward with dual signal sockets, which can be either configured for both RCA and XLR inputs, or one input and one output from the preamp, allowing preamp operation only.

[Peter Daniel]

What is interesting though, the rear panel is decoupled from the rest of the chassis with special, aircraft rubber grommets. This allows for the main heatsink assembly to be rigidly supported in one point only, with a cone, reducing unwanted chassis infuences. The other two points of support are of a semi-flexible type.

[Peter Daniel]

Here's the bottom view, showing 4 main cones supporting the chassis and the 5th cone, just for the heatsink. That cone is using special disc dumper support disk (you can also see it in a first picture) that further improves the sonics.

[Peter Daniel]

Here you can see that disk under the amp. The front panel is not finalized yet, it will be made out of copper.

[Peter Daniel]

A close up of the inside with top cover removed (as usually made of perforated aluminum for low mass).

I'm running the amp presently with 4 ohm speakers. In bridged mode it gets pretty hot and clips at louder levels. Eventually it will be used with 8ohm rated Fertins, but also as a headphone amp with AKG1000.

Regarding the TVC configuration, I opted for +6dB connection with a single primary, it sounds better this way.

What is interesting I have only 0.1uF coupling caps in my DAC and the bass is terrific, no loss at all.

Some of you might be curious how this compares to resistor based volume control I used previously. Well, not bad at all.

With that amp, the buffer after the DAC didn't work well. I much prefer direct input to TVC for more cleaner and pure sound.

The buffer worked really well with resistor based attenuator. Overall that setup had a bit more air extention, however it may also seem that it had some artifacts that were not completely natural. The current setup with TVC is very pure and natural. A bit highs shimmer is missing, but I enjoy both setups equally well (for now).

[Netlist]

Very nice Peter. Remember, there are many types of bronze, I can't give you the details for now but my neighbour is an artists, working with bronze all day. He searched many years to find the good alloy for his work.
http://www.dirkdekeyzer.com/english.html
A bit off topic but a Gainclone of yours would fit nicely near one of those sculptures.

/Hugo

[sinski]

Very nice amp !

Hi Peter,
I have some questions

1. What power and voltage have those toroids ?
2. I noticed some bigger caps on the rectifier PCB ???

This weekend i finished Your premium kit , it works great but i want more !



It is a prototype and both pcb are mounted in such a way, that i can play with some components. Later i will put it in one nice case.

Now i am inspired and thinking about two monoblocks.

Could You post some more technical details ?

Cheers, Tomek

[Peter Daniel]

Originally posted by sinski
This weekend i finished Your premium kit , it works great but i want more !

This looks like Shigaraki amp.

Toroids are 300VA, 2 x 22V AC, single primary wounded over secondaries.

There are only 100uF caps beside the chips, the ones at the rectifiers are 1000uF.

Not to create further consternation between more technically oriented guys, I will not mention what brand it is.