Considering switching from Audio Research to PrimaLuna, troube with VS115 amp


Hello everyone, I have question that I hope some of you either can answer or have an opinion on. Ever since I was 17, I have always wanted to own Audio Research equipment. I’m 56 now, and finally was able to fulfill my life long dream. My first acquisition was an ARC LS15 pre-amp bought here used in mint condition. I paired it with a Vincent 331MK hybrid amp also bought here used in mint condition. The resulting sound was impressive. After that, I started looking for an ARC amp I could afford. The resulting search found me an ARC VS115 amp also here in used, awesome condition. This is where my problems and my doubts started. Upon hooking up the amp to my system, a tube in the left channel arced and blew a resistor. I had to take the amp to an ARC dealer and he installed a new resistor and suggested I buy all new tubes from ARC for the amp. I did and when I got back home, I again hooked up the amp and immediately upon turning the amp on, I started to hear thumping sounds coming from my left speaker, then, two left channel output tubes started to glow a very bright orange, and then white smoke started to rise from one of the tube sockets. I immediately turned the amp off. I called the dealer and he suggested I mail the unit back to ARC. I did and I am now waiting to see what they say.

During this time, I started to search out other brands and came across one called PrimaLuna. I have watched their videos and seen them compared to ARC equipment. Their build quality seems to be superior to ARC and the reviews are over the top. I am looking at their Dialogue Premium HP amp and their Dialogue Premium pre-amp. For what they cost, considering how they are built and supposedly sound compared to units costing 3 to 4 times their price, they almost seem too good to be true. Anyway, my bubble has been burst, and in simple terms, I am considering jumping ship and going with another company instead of ARC, despite all those years of drooling and waiting.

My main question is this, is there anyone out there that either owns PrimaLuna or has had experience with the equipment and can give me their opinion on owning and using it. Then, my second question is how does PrimaLuna really compare to other high end equipment such as ARC. Kevin Deal in his videos on PrimaLuna makes a very compelling case for the equipment. In one video, he compares an ARC LS17SE to the PrimaLuna pre-amp.

My last question is in regards to my ARC VS115 amp problems. Anyone have an opinion on what is going on with my amp or a VS115 in general. For those of you who want to know what else is in my system, I am using KEF 104ab speakers, a Cambridge Azur 752BD Blu-ray player as my CD player, Morrow Audio Cables and I am considering getting the Sony HAP-Z1ES music player for my digital files.

I greatly appreciate all who take the time to comment and give their opinions. I will be glad to answer any questions you may ask or provide additional. Thanks for your help. Steve.


128x128skyhawk51
"anyone what were the driver and gain tubes used for this comparison? I assume stock Primaluna 12au7 for both the Premium and HP?"

samzx12-box stock tubes  Kevn was hesitant to use KT150.Plumbing was Nordost Heimdall II. I think speaker cables were Valhalla

Thanks tablejockey. Can't say I blame him for using KT150 as the HP version was running stock tubes. 
fsonicsmith you are da man.  What a fun journey.   Someone asked me today if I was ready to retire.  Hell no.  I'm having more fun now than ever.  I still collect vintage receivers.  

I'm going to be at the Focal factory in France next Tuesday and will be taking a few videos.  I hear it's incredible.  Which ones were you thinking about? 
I need either standmounts or small floorstanders. i have a dedicated room but its on the small side.

Greetings all,

As an amplifier manufacturer, I want to tread lightly on this topic. Please bear in mind that the following are my biases. Others clearly differ. Note that I didn’t have time to get through this entire thread, so perhaps some of this has been covered. I caught a few references to PCB vs. point to point however, and some misconceptions prompted my reply. Finally, I’d consider taking a look at VAC Amplification if you’re looking for a medium to high powered tube amplifier (http://www.vac-amps.com/pages/statement.html).

Begin rant …

I’m a big fan of the turret board / tag strip construction technique. Designed correctly, it can have as short of a signal path as point to point, but with far more robust construction (immunity to shock and shipping damage), ease of maintenance, and sample to sample consistency. Know that (along with point to point) it’s much more expensive to manufacture, requiring more time and a skilled labor force, which I’ll expand on below.

If carefully designed, the signal path can be as short as point to point, although many examples of this technique don’t reflect this (short signal path) as a priority of the designer. I can understand why, because it’s tedious work. It took me over 4 months to lay out our new NiWatt amplifier, achieving a total wire length on the positive side of the circuit of only 4” from input jack to speaker binding posts. Sometimes, longer isn’t better ;-)

The term Point to point is freely bandied about by marketing departments. If you look at the Prima Luna site, you’ll note that their construction technique is in NO WAY point to point construction. It’s a mix of tag strip/turret board (I like that!) with quite a few printed circuit boards thrown in for good measure (meh!). I certainly prefer this construction to a pure PCB construction, but for my tastes, it’s not all the way “there”.

In fairness to them, an amplifier as complex as the Prima Luna would be a nightmare to manufacture and service if it were fully point to point (or tag strip/turret board) construction. This calls into question whether this complex of a design has any sonic benefits vs. sonic costs ... a discussion for another day. The fact however, is that this is not point to point construction.

Here’s a gut shot of their amplifier: http://www.primaluna-usa.com/dialogue-premium-hp-power-amplifier.

This Wikipedia page has some photos of true point to point construction: https://en.wikipedia.org/wiki/Point-to-point_construction

Here’s an example of a beautifully executed turret board/tag strip construction (a Thoress phono stage): http://www.thoeress.com/images/thoeress-phono-enhancer-03.jpg.

See the differences?

Comment: I’d like to see a shorter signal path on the Thoress, as these “ladder” (parallel) component layouts tend to add quite a few more inches of wire into the equation, but I wanted to call out the elegance and robustness of the construction technique. As I mentioned above, you can achieve a short signal path with this technique, but it won’t look quite as neat as the Thoress.

A couple of definitions and additional comments …

Point to Point:

All components are soldered to each other or to terminals (e.g. tube sockets, binding posts, input jacks, transformer terminals, etc.). An occasional wire is necessary on the hot side of the circuit (to bridge some longer distances), and some sort of ground bus (wire) is used on the negative side.

Vintage components (i.e. Marantz, Scott, Fischer, etc.) are wired this way. Looking at them, the components appear to be a chaotic rat’s nest. There’s a lot to be said for this from a sonic perspective (parallel wires are your enemy). Duplicating the construction from sample to sample can be quite difficult however, and it requires a highly skilled labor force (expensive), because lead dressing differences (component and wire length and routing) can result in sample to sample sonic differences if attention isn’t paid to this.

Tag Strip / Turret Board:

This is the evolution of point to point and the precursor to circuit boards. It’s typically a mix of some point to point wiring combined with some form of “support” for many components by use of intermediate terminals or turrets to which some components are soldered. It’s typical of vintage guitar amplifier construction and can withstand the abuse of roadies throwing the gear around carelessly. The tags/turrets tend to fix the layout quite a bit more than point to point, so it’s quite a bit easier to maintain sample to sample layout and lead-dress consistency (less QC required on the back end than pure point to point).

Circuit Board:

We all know what this is. It’s the least expensive manufacturing technique, and you can get by with a much less skilled workforce. It offers lowest manufacturing cost (by far) and a better assurance of sample to sample consistency with less QC required at the back end.

High quality circuit boards can withstand the abuse of parts replacement, but ask any tube amp tech which architecture he’d like to repair, and I’d expect them to say point to point or tag strip / turret board.

The circuit board material (glass/epoxy) is inherently capacitive (a bad thing) and you can’t control the quality of your “wire” (the circuit traces). You can’t specify silver, 6-nines copper, etc. for your circuit board traces.

Again, the above are my biases and by no means universally agreed upon.  Rant off ...

Cheers,
Thom @ Galibier Design