Model 19 crossover schematics

[Todd W. White]

Regarding the little black piece -

1. The Model 19's phase plugs are orange.
2. If the control knobs are still present on the crossovers, my guess is the button is not from the Model 19.

Regarding the large L-pads -

Iconic's replacement crossovers will have them on the direct replacements, but the improved ones will be fixed...

And, yes, once the caps settle in, the Model 19 sure sounds GREAT!!!

[run]

Hi All,

Martin, you say you replaced the top Lpad with a 10 ohm/5 watt resistor? What did you replace the bottom Lpad with? How did you decide on the values?

Regards,

Pat McDermott

[Hornluvr]

Hi Pat,
my LPads both have a ring label where an "optimum"
setting is marked, for the upper Lpad (labelled
H.F. Level) this setting is fully clockwise,for
the lower Lpad (M.F.Level) the "optimum" is in the
10 o`clock position. After intensive listening I
have come to the conclusion that these proposed
settings are indeed the best. So I measured the
resistance of the LPads in this setting , and they
were 0 ohm for the H.F. Lpad and 10 ohm for the
M.F. Lpad. I first simply joined the wires leading
to the HF Lpad, making them as short as
possible. When I listened again, I found a very
noticable reduction in distortion, obviously the
Lpad was internally corroded after all these years, causing distortion despite its 0 ohm setting.
I then replaced the MF Lpad with five 47ohm,1 Watt metal film resistors wired in parallel,
resulting in a 5watt, 9.4 ohm virtual resistor,thus
avoiding the higher impedance of a wirewound
resistor. Again, another drop in graininess and
distortion, the 19 now sounds like an electrodynamic speaker, you would not guess this
is a horn speaker! I encourage you to try it out,
the effect is truly stunning, cost is next to nothing, and it can easily be undone.
Best regards, Martin Wunderlich

[run]

Hi Martin,

I think I'm going to try your suggestion, however, I have reservations about the values of the resistors you are using for my application, as I have a solid state amp and a very "live" room. I usually listen with the HF Lpad at 12 o'clock and the MF in the middle of the optimal setting.

What are your room acoustics like and what is the size of your room? Have you ever driven your speakers with a solid state amp?

Regards,

Pat McDermott

[Hornluvr]

Hi Pat, my room is rather large, 70 square metres
(I live in Europe)and a bit on the boomy side.
I have driven the Model 19 with a solid state
Revox B251 that I keep for reference, and the Lpad
settings I had chosen with my vintage tube amps
turned out to be just right with the Revox too.
My suggestion: Turn your LPads in your favourite
position, unsolder one wire on each, and measure
their resistance. Then you have your personal values, they may well be different from mine.
Regards, Martin

[Hornluvr]

Hi Pat, my room is rather large, 70 square metres
(I live in Europe)and a bit on the boomy side.
I have driven the Model 19 with a solid state
Revox B251 that I keep for reference, and the Lpad
settings I had chosen with my vintage tube amps
turned out to be just right with the Revox too.
My suggestion: Turn your LPads in your favourite
position, unsolder one wire on each, and measure
their resistance. Then you have your personal values, they may well be different from mine.
Regards, Martin

[run]

Hi Martin,

I took your advice and purchased two 10 ohm resistors and ran the horn without any resistance. I found that (as you said) the speakers became more immediate and much like electrostatics (without the shortcomings of that design). I tried setting my lpads to appropriate settings and then measured their resistance. The lpads sounded best with the horn at no resistance and the bass at 10 ohms. However, I found the horn too revealing when I bypassed the lpad and ran the horn with no resistance. The lpads have a huge effect on the sound (they veil it).I purchased a number of resistors and found that in my very "live" room a 3 ohm 12 watt resistor sounded the most balanced and "smooth".

A friend who does a lot of diy stuff cautioned me against using a 5 watt resistor in a crossover and recommended at least 10 watts. I used a 10 ohm 12 watt resistor on the bass driver and I think I'm finally finished with this madness. These speakers are insanely good!

Thanks for your help,

Pat McDermott

[Hornluvr]

Hi Pat, I`m glad I could be of some help. Yes,
getting those pesky lpads out of the signal path
seems like the thing to do, they have long since vanished from modern speaker design, and for good
reason. Consider all your music travelling thru
a tiny and probably corroded contact patch, this
must cause some serious deterioration.
Best regards, Martin

[run]

Hi Martin,

I've been tweaking the old horns again and I was wondering if you remember what the lowest amount of resistance was on the MF L-pad? I know you settled on a 10 ohm resistor in that position. I took my l-pads out all together and I don't have them any more. Could it be as low as 3 ohms or even lower?

Regards,

Pat McDermott

[Altec Best]

I've been tweaking the old horns again

Hi Pat, Wow !!! This is a old thread since your last post have you found any new upgrades for the 19,Xo, anything I would be most interested in any.But for the most part mine sound really good after XO rebuild but always interested in any upgrade that maybe available Regards