I got this bad boy today!

[dak]

Not sure what you mean here. I've mostly seen full size C system converters that have 6 sets of bass reeds in which 4 sets are for stradella.

I might be overgeneralizing. Here is the layout of a Hohner Morino Artiste XD:

You get the bass reed block at the top with 12 reed chambers, and then the 3 reed blocks in front with 15/16/15 reed chambers for a total of 58 notes. The Stradella notes are just taken from those notes, the basses from the top reed block and the chord notes from a section of the 3 bottom blocks. That seemed logical enough to me that I just assumed, well…

 

[debra]

So what's the deal with the extra bass buttons?

The (C system) convertor on this accordion dates back to the period where convertors did not use one large convertor switch but used register sliders (under the reed blocks) to switch between Stradella chords and melody bass (single notes). This is similar to what a quint-convertor mechanism also uses. The extra bass buttons move the lowest few notes out of the way as they are never used for chords. It makes the rest of the setup a bit easier. (Smaller convertor accordions do not have the melody bass start with low E and thus simply do not have these lowest notes and therefore do not need the extra buttons.)
I just finished work on a large convertor accordion with this setup. Inside it has three bass blocks. The largest bass block contains the lowest octave. The next octave is distributed over the three blocks, 4 notes on each block. The third octave takes up the rest of the second block. That second block is where the magic happens. It is in this octave that the Stradella chords come into play. For each note the reed block has two holes, and under the row of holes there are two sliders. One slider opens all the holes used when playing chords and the other slider only opens the holes used for single melody bass notes. The reed plates are spaced far apart so they take up as much space as on the first reed block with the lower notes and thus larger and wider reed plates. Finally, the third block contains all the notes for all higher notes, in chromatic order. This reed block has all the reed plates with tight spacing and depending on how much space there is you can have a different number of melody bass notes. (The one I worked on has 52 melody bass notes, while most full size convertor accordions have 58.)
It's quite an ingenious system that makes the bass mechanism somewhat simpler than with the large convertor switch (that disables many levers on the bass side and enables different levers). The action of switching between Stradella and melody bass is just a simple register switch (no big "clack" or "clunk"). But... when the air and sound for a single note goes through one hole or the other hole may have a slight influence on the tuning of the note. So tuning such a convertor accordion must always be done with the melody bass, and then the notes may be slightly out of tune in Stradella mode, but that mode is less critical so you probably won't notice (and any audience you have will certainly not notice).

 

[dak]

The extra bass buttons move the lowest few notes out of the way as they are never used for chords.

You mean, "for basses in Stradella mode" rather than "for chords"? If Stradella had the lowest bass note as an A1 (typical for Italian instruments), then those buttons indeed would cover E1–G♯1. The Morino free bass instruments start at E1 in Stradella so I just didn't think of that, even though my own instrument does have a free-bass only extension down to D1.

 

[debra]

Not sure what you mean here. I've mostly seen full size C system converters that have 6 sets of bass reeds in which 4 sets are for stradella.

Modern C system convertors (with the large convertor switch) will, in Stradella mode, have the base notes open one pallet (for each note) and the chords open one pallet for each note of the chord (thus three pallets in total). That gives you a two voice bass (provided you use an LM register). They then also have an octave coupler that mechanically links the base notes to one higher octave, thus opening two pallets for four voice base notes. Larger accordions have yet another octave coupler that links the base notes to an even higher octave and when both couplers are on, each base note opens three pallets, for six voice base notes. That's where the six comes in.
In addition to this, some modern convertor accordions have copied part of the Russian bayan design which has "side-loaded" reed banks hooked up to the largest (lowest) reed block so enable a simple register switch to turn the base notes into a 4 voice setup. The four voice base notes then get their higher octaves from reeds that are not taken from the higher notes in the convertor. The extra reeds on the large block do not play at all with the chords. When Pigini copied the Russian bayan design they must have thought that just offering 4 voice base notes in a (then) top of the line Italian accordion would not be a commercial success so they added an octave coupler to give you 6 voice base notes. (The reality is that you don't really need 6 voice base notes, so people tend to not use the octave coupler.)

 

[debra]

You mean, "for basses in Stradella mode" rather than "for chords"? If Stradella had the lowest bass note as an A1 (typical for Italian instruments), then those buttons indeed would cover E1–G♯1. The Morino free bass instruments start at E1 in Stradella so I just didn't think of that, even though my own instrument does have a free-bass only extension down to D1.

What I meant to say is that the lowest notes do not feature in the chords in Stradella mode.
Let me tell you what happens in the accordion I used (probably exactly what happens on the Petosa/Giulietti/Zero-Sette).
When you use stradella. the lowest octave of the melody bass still plays melody bass. That means the following: if you go up the base notes on Stradella the G# is the last one that still has all the chords, and the D# still has major, minor and seventh but has no diminished chord. Where the diminished chord should be is D# from the lowest octave in melody bass. So the whole lowest octave in melody bass is always melody bass. There is no switch to turn these notes into chords. By moving the lowest octave "partly" out the way only a few rows of Stradella are affected.
In Stradella the base notes still use the lowest octave completely, so the lowest base note in standard bass is still the low E.

 

[dak]

What I meant to say is that the lowest notes do not feature in the chords in Stradella mode.
Let me tell you what happens in the accordion I used (probably exactly what happens on the Petosa/Giulietti/Zero-Sette).
When you use stradella. the lowest octave of the melody bass still plays melody bass. That means the following: if you go up the base notes on Stradella the G# is the last one that still has all the chords, and the D# still has major, minor and seventh but has no diminished chord. Where the diminished chord should be is D# from the lowest octave in melody bass. So the whole lowest octave in melody bass is always melody bass. There is no switch to turn these notes into chords. By moving the lowest octave "partly" out the way only a few rows of Stradella are affected.
In Stradella the base notes still use the lowest octave completely, so the lowest base note in standard bass is still the low E.

Ok. Too bad converters didn't become en vogue in the West while Morino was still around. I doubt he would have stood for this kind of construction… On the Artiste D series with bass buttons and treble buttons filling a rectangular region, all buttons are operative even if that means that I get the nominal A2 in the treble just in the fourth row, and even if it means that you get a somewhat weird mixture of where chord and bass buttons run out on the bass side. What is there will do what you expect it to do. Given the thorough job the déclassement coupling mechanism does on the treble side ot the old Morinos, I think he would have been up to designing working converters.

Idle speculation and hero worship, of course of course. Sue me.

 

[dak]

(The reality is that you don't really need 6 voice base notes, so people tend to not use the octave coupler.)

Well, I can get 8 and 10 voice bass notes on my instrument (10 voices from A to C♯, 8 voices from D to G♯) and the thing with those is that they don't sound all that bassy because of all the high reeds, they eat a lot of air, and in character they are actually close to pulling quite a few stops on an organ. They don't work all that well for the typical final chord of an organ piece in full sound (that reverberates around the church after it ended) because a fortissimo chord of that length will use more air than the bellows will provide in one breath.

I did play the Mendelssohn Wedding March (from the Midsummer Night's Dream) with that registration. Builds character.

 

[micahcowan]

Sounds like a beast, but I cannot see Petosa selling many of these at Gola prices... a base level Gola with no Free Bass today *starts* at $60,000 US, add in those modifications you are looking at over $100,000 for a Gola of those specs.

I've been looking into getting a Cathedral Super Bayan in C griff from Petosa, they've been quoting me on the order of $25,000, so perhaps not quite the same class of pricing. Super jealous, @breezybellows ! Even if it's not a CBA like I'm looking for. Fantastic find!

(If anyone's curious on a bit more detail, it's 25% deposit to get the instrument started, and they're saying up to a couple of years wait time I think. Petosa claims to be about the only ones still doing bass mechanics whose manufacturer is paid by the hour (to maximize quality), rather than per-completed-machine, in their Petosa-brand converter instruments)

 

[breezybellows]

I've been looking into getting a Cathedral Super Bayan in C griff from Petosa, they've been quoting me on the order of $25,000, so perhaps not quite the same class of pricing. Super jealous, @breezybellows ! Even if it's not a CBA like I'm looking for. Fantastic find!

(If anyone's curious on a bit more detail, it's 25% deposit to get the instrument started, and they're saying up to a couple of years wait time I think. Petosa claims to be about the only ones still doing bass mechanics whose manufacturer is paid by the hour (to maximize quality), rather than per-completed-machine, in their Petosa-brand converter instruments)

What was the spec for $25k?

 

[micahcowan]

What was the spec for $25k?

We were speaking fairly generally at that stage, I believe, so you could consider it to "start" around there, I imagine. I definitely specified that I wasn't necessarily looking for the "Grand Concert" version, with the extra-extra-expensive materials, mute, and such.

 

[Xiane]

We were speaking fairly generally at that stage, I believe, so you could consider it to "start" around there, I imagine. I definitely specified that I wasn't necessarily looking for the "Grand Concert" version, with the extra-extra-expensive materials, mute, and such.

I definitely want to hear that one when you get it.

 

[micahcowan]

I definitely want to hear that one when you get it.

Lol, "and if"!

 

[Xiane]

Lol, "and if"!

What would happen if you walked into Petosa and said "Gimme the most expensive accordion you can make!"

I'll admit I've only done that with Starbucks "free drink" coupons.

 

[debra]

What would happen if you walked into Petosa and said "Gimme the most expensive accordion you can make!"
...

That would be interesting, because they do not actually make any accordions (they get Zero Sette to make the accordions for them). So I wonder whether they will pretend to make accordions...

 

[Xiane]

That would be interesting, because they do not actually make any accordions (they get Zero Sette to make the accordions for them). So I wonder whether they will pretend to make accordions...

I'd imagine for enough money they'd fly someone from Castelfidardo to make you one on the spot.

But their sort of branding is a time honored tradition in accordions, right? It's not as if Zero Sette is a bad manufacturer..,

 

[breezybellows]

That would be interesting, because they do not actually make any accordions (they get Zero Sette to make the accordions for them). So I wonder whether they will pretend to make accordions...

It's not as black and white as that. Petosa have had a partnership with zero sette since 1945. This has been the operating procedure for all American manufacturers. Excelsior, Guerrini, Italo American, PAN, Petosa, Bell, Giulietti and the likes moved their manufacturing to Italy. Petosa has a dedicated team that works only on Petosa Accordions in the factory. Of all these American brands, Petosa is the only one that has continued to operate as a business and it has been owned by the same family.

So this is very different from a new boutique brand that just purchases something from a factory and rebadged it. From my understanding, Petosa operates from inside of zero sette and there are no like-for-like models from the Bugari, zerosette or Giulietti (brands that are made in the same factory). There is only one AM-1100. There might be shared components (like guidobaldi reeds) but the design and the sound of a Giulietti Super is very very different from an AM-1100.

In fact, a Petosa accordion bought today is more definitively a Petosa as opposed to a Scandalli, Excelsior or other brands that are now owned by completely unrelated companies (sometimes acquired right to the brand decades after the original company ceased to exist).

I've attached a picture that shows a comment from the president of Zero Sette while talking about how a Petosa compares to a zerosette accordion.

 

[breezybellows]

That would be interesting, because they do not actually make any accordions (they get Zero Sette to make the accordions for them). So I wonder whether they will pretend to make accordions...

I also remember reading that the original zero sette factory went bankrupt and then was restarted. Not sure how accurate this information is but I vaguely remember reading it somewhere. So I'm not sure how much has changed from the open days to today. But from several Accordions I've owned and played, I have nothing but the best things to say about their products and service.

 

[Ventura]

he parroted the party line
"Petosa has a dedicated team that works only on Petosa Accordions in the factory."

bullshit

they do not even have unique body forms anymore

 

[Jaime_Dergut]

Excellent find. It looks like a AM-1400ESM model but I can't tell for sure, if it has free bass.

 

[breezybellows]

he parroted the party line
"Petosa has a dedicated team that works only on Petosa Accordions in the factory."

bullshit

they do not even have unique body forms anymore

I shared what information I was aware of (and my personal experience with the products). If you have a contradicting view, you can share the relevant information.