Crites 3636 autoformer vs 3619 and the ALK crossover?

[Rolox]

Hi everyone,

 

I was just wondering: how come my ALK Universal crossovers, with 3619 autoformer, has many different attenuation taps when it's supposed to have only -3, -6, -9 and -12dB? There must be something I don't understand..

Also, and that's the main question, could I put a Crites 3636 in place of the 3619 without having to change the circuit (I know I would have to add some wires for the additional entry taps, if I want the full flexibility, but I don't wanna change the rest of the circuit). Doable?

Thanks a lot!

[mboxler]

Once you get away from labeling the taps "db", it becomes clearer.

 

Each tap connects to a specific winding of the autoformer.  The ratio of the input connection to the output connection dictates the voltage change.  On a T2A, the ratio of taps 4 - 0 to 5 - 0 is .68, so the output voltage is 68% of the input voltage, or -3.35db.

 

There is no reason why one can't connect the input to 5 - 1 (75% of the windings) and the output to 4 - 1 (43% of the windings).  .43 / .75 = .573, so the output voltage is 57.3% of the input voltage, or -4.84db. 

 

Since the T2A exposes only four of the internal windings, the number of input to output ratios is limited.  The other autoformers allow access to more windings, and therefore allow for more input to output ratios.

 

Yes you can swap any autoformer with any other autoformer on your crossover, as long as you realize that each will have unique attenuation possibilities.

 

Mike

[Rolox]

15 hours ago, mboxler said:

Once you get away from labeling the taps "db", it becomes clearer.

 

Each tap connects to a specific winding of the autoformer.  The ratio of the input connection to the output connection dictates the voltage change.  On a T2A, the ratio of taps 4 - 0 to 5 - 0 is .68, so the output voltage is 68% of the input voltage, or -3.35db.

 

There is no reason why one can't connect the input to 5 - 1 (75% of the windings) and the output to 4 - 1 (43% of the windings).  .43 / .75 = .573, so the output voltage is 57.3% of the input voltage, or -4.84db. 

 

Since the T2A exposes only four of the internal windings, the number of input to output ratios is limited.  The other autoformers allow access to more windings, and therefore allow for more input to output ratios.

 

Yes you can swap any autoformer with any other autoformer on your crossover, as long as you realize that each will have unique attenuation possibilities.

 

Mike

It is still unclear in my head how ALK manages to have so many different outputs on a 3619 when the input connections are fixed. Does that mean with a 3636 I could actually get MORE attenuation possibilities than the announced 1dB steps from -1dB to -12dB (sorry I'm still using dBs because I just don't know how to calculate the ratios), possibly in-between steps as well? Sorry if I ask dumb questions, I've been using autoformers in my crossovers seemingly forever, I mean for as long as I've been playing with big Klipsch and now with similarly "horny" speakers - but I've never really wondered how those actually work, not in details at least. 

 

Thanks! 🙂

[mboxler]

6 hours ago, Rolox said:

It is still unclear in my head how ALK manages to have so many different outputs on a 3619 when the input connections are fixed. Does that mean with a 3636 I could actually get MORE attenuation possibilities than the announced 1dB steps from -1dB to -12dB (sorry I'm still using dBs because I just don't know how to calculate the ratios), possibly in-between steps as well?

 

You can get 26(?) possibilities with the 3636 when the inputs are on taps 5 - 0, and 15 possibilities with the 3619.

 

6 hours ago, Rolox said:

Sorry if I ask dumb questions, I've been using autoformers in my crossovers seemingly forever, I mean for as long as I've been playing with big Klipsch and now with similarly "horny" speakers - but I've never really wondered how those actually work, not in details at least. 

 

Thanks! 🙂

 

No need to be sorry.  We're all learning.  If it weren't for LTspice, I never would have fully grasped how autoformers work.

 

I'm having trouble finding my docs for these, but if you go to Al's website under Universal Economy, and scroll to the bottom of the page, you'll find the 3919 tap settings.   Think of the left value under Ratio as the output voltage if the input voltage is 1 volt.  Plug those two values into this calculator to get the attenuation in db.  For example, input 1 volt output .6452 volt results in -3.8db if the output taps are 2 - 5.

 

http://www.sengpielaudio.com/calculator-amplification.htm

 

Hope that helps!

 

Mike

 

 

 

Mike

[Deang]

A 3636 in that early design of the Universal gains you nothing except some additional settings that you don’t need.

[geoff.]

On 1/18/2023 at 11:58 PM, Rolox said:

Hi everyone,

 

I was just wondering: how come my ALK Universal crossovers, with 3619 autoformer, has many different attenuation taps when it's supposed to have only -3, -6, -9 and -12dB? There must be something I don't understand..

 

 

@Rolox, 

 

Those (0), -3, -6, -9, -12 settings would have been based on the T2A autoformer used in Klipsch crossovers.

 

Al sourced the 3619 for many more attenuation options.

 

As Dean said, the 3636 provides many more options than the T2A as well, but many are redundant, ie. different combinations yield the same or .1 of a decibel difference. Looks like about 6 of the 28 combinations are redundant, and 4 of them are above -18db of attenuation which I cannot fathom ever needing. So each of them has 18 useful combinations?

 

I have never been privy to a 3619 autoformer, but I know my OCD would prefer it’s even 1 db steps.

 

 

 

[Rolox]

12 hours ago, Deang said:

A 3636 in that early design of the Universal gains you nothing except some additional settings that you don’t need.

With much respect, Dean, how can you know if I don't need more / different attenuation settings without knowing what drivers I use?  I'm not using Klipsch speakers. As a matter of fact, with my current tweeter / midrange I always wish there was an intermediate position between -3,8dB and -5,5dB. Between mids and bass I'm using an active crossover so it really is a matter of finely balancing the midrange on the tweeter.

[Deang]

Yes, I made an assumption. Sorry. 
 

You have a PM.