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

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

@thom_mackris

I noticed you said if looking for Med to High Power Tube Amp look at VAC. A lot of people can't afford VAC. What other company would you recommend looking at? Would Primaluna be a consideration?

I noticed you said if looking for Med to High Power Tube Amp look at VAC. A lot of people can't afford VAC. What other company would you recommend looking at? Would Primaluna be a consideration?

I wish I could responsibly advise you on this. 

Most of my recent exposure has been to low power triode amplifiers - 2A3, 300B, 845 and such, and it's only serendipitous encounters with both Kevin Hayes and VAC in general that led me to bring them up.  Indeed, they occupy more of the ARC price tier and not Prima Luna's.

Prima Luna appears to make many intelligent design compromises (to meet a price point), but without hearing them I'd hesitate to say, other than to recommend an audition.

Cheers,
Thom @ Galibier Design

Thanks for the write up btw. Appreciate your time.