Unique PROTON D540 Integrated Amplifier has entered the Listening Room. Part TWO

Gentle reader,

I previously wrote about my buying a PROTON integrated stereo amplifier because it was genetically related to my Dynaco Stereo 200 power amplifier here:
The Robb Collections: Unique PROTON D540 Integrated Amplifier has entered the Listening Room 

Here it is, in situ as they used to say in Latin:

It now resides where the Dynaco power amp once sat. I moved the JVC 3-head cassette deck to the location the preamplifier usually sits as it's interconnect cables would not reach. This left an empty slot, so I stacked the Yamaha and Dynaco and slid them as seen below:

Yes, this photo IS different than the one above. I found that what I thought were plastic sleeves on the Nakamichi speaker terminals must not be. Two would touch and trip the amp's protection. So, I redid it all, as you can see.

What I have been able to do, finally, is use it as PROTON intended as an integrated amplifier instead of as a preamplifier as I had been. If you've read the previous post (linked above) you will know that PROTON invented a unique way to have tremendous power on demand, AKA: as needed, while still having it play in Class A mode most of the time.

Why I had to wait was because this integrated amp's speaker terminals, like the huge Technics integrated amp that I had also written about previously, are what appears to be 3-way binding/banana posts. I wrote about those type of termianls and some neat braided speaker wires I found here:

The Robb Collections: Budget option for Kimber Kable 4TC plus 3-way binding posts explained. 

Here is a photo of them, empty. Note, no metal tube inside the holes.

Here are two photos from previous blog posts showing 2-way binding/banana speaker terminals. Why 2-way? Because they also will not accept spade lugs:

The photo above is a close-up of the amplifier at the bottom in the photo below. The one on top, is of course my Dynaco power amp. Clearly you can see the metal tubes I wrote about that accept banana plugs which are my favorite speaker cable/wire terminals.

Since copper can oxidize, I don't like using it bare. So I needed pin plugs, but not straight ones. Ones that I could only get directly from China. Here they are below in two photos.

The reason they are bent is to fit around the curved post and make better contact.

Now, here is a view of the speaker terminals from a higher angle showing the opening on the top-right portion of the black plastic behind the red and black plastic "nuts" that tighten down.

One unscrews the plastic nuts, they don't come all the way off, and slides the wire, or in this case, fancy bent pins into the opening sliding the curved portion (think the letter j) in and down then tightens the nuts. Below shows them attached to the braided wires. I went ahead and used the banana terminals on the other ends of these wires. So much for those spade lugs.

Those banana terminals came from the ends of these huge Monster Cable M-Series speaker cables that I use as jumpers to the speaker switch.

Below shows all eight terminals in place. Kind of annoying that they stick up, but I found out they break easily. Yes, I did.

Let's talk about, OK, let ME write about, conductor girth. No, not orchestra director's size, the diameter of wires as they conduct the signal or electricity from one end to the other.

These braided wires, which sound fantastic, are comprised of six 18 gauge wires cleverly braided to resist RF interference and also get the music dizzy on it's way to the speakers. I jest. When I stripped them and twisted them together, they were still quite thin. 

I had bought brand new, two reels of Monster Cable speaker cable and wrote about them here:

The Robb Collections: Some tweaks to the Den stereo system + Monster Cable MCX

I had found that they lacked bass significantly. An A/B comparison with the thicker cable as seen above, clearly showed that. So, I bought used Monster Cable Z-Series which is their top of the line, and sold the small stuff on eBay.

Despite these braided wires thinness, I have not found any lack of bass. So far. So perhaps Monster Cable miscalculated something. Fear not, I intend to listen critically as time permits.

So, this last photo shows the PROTON D540 fully loaded and ready for use:

All of the interconnects in the image above except the lighter blue ones, which are the last of the Liberty Cable units and the black ones which connect the cassette deck, are various Monster Cable units. NOTE that the Liberty Cable ones replace the simple U shaped pins that connected the preamp portion to the power amp portion of the D540.

I redid the speaker switch as mentioned at the top of the post. I made feet from Blu-Tak to secure it to the top of the amp which also prevents it from letting the amp breathe and cool itself.

I now have all four pairs of speaker cables attached electronically to the amp most via the switch. The black cables are the Monster Cable Z-Series cables which are my default littlest speakers. If I wish to listen to other pairs, I slip the black ones out of the switch's inputs and choose #1 or #2. The big Cerwin Vega! LS-12 speakers are attached to speakers "A" and gray jumpers are attached to speakers "B". I continue to really enjoy the new braided wires.

 

So, how does it sound all by itself? At first, I wasn't sure. This was last night and I couldn't turn it up much because my wife was watching TV and reading in the living room. So, rather than making a rash decision. I put in a really well made CD and listened exclusively to the smallest speakers and the subwoofer. 

The design works and it doesn't generate heat. Crescendos were loud and crystal clear, bass was excellent, wide, deep and high soundstage. I could point to unique musicians locations. Since I hadn't played a cassette in a long time, I chose a MCA HQ cassette of Acoustic Alchemy performing their first album called Red Dust and Spanish Lace.

There was one piece where it was just the two of them (both play acoustic guitars, one has steel strings, the other nylon) playing something very Flamenco like and I was hearing echoes and really felt like I was IN the recording room as they played. I have NEVER experienced that without some form of surround speakers and multi-channel playback. 

Does this mean I am going to pass on the Dynaco Stereo 200 power amplifier? No, but maybe the Yamaha preamp will find a new steward to house it.

Thanks for looking,

Scott