Model 22 vs Model 22A

[Robthomp]

Hi,

Today I just bought a pair of Model 22's from a guy on CL. The cabinets are in beautiful condition and they sound great.   When I got home I realized that one is a 22 and one is a 22A.   He advertised them as 22A.    Does anyone know what the A designation is for and is there any difference?   I can find references online to both but no mention of the difference, if any.

The tweeter on the 22 is mounted on a white cardboard ring, the tweeter on the 22a is mounted on a black plastic ring.  The woofer cones are slightly different colors. The particle board backs have  slightly different colors.   The cabinets and grills are absolutely identical but I don't know if the grills are original or if the cabinets were ever refinished.  The serial number on the 22 is 23519 and on the 22A its 45037.

Rob

 

[Robthomp]

Also, the letter "A" on the back plate isn't part of the original lettering on the plate - it looks like it's stenciled on or something.

[ra.ra]

All of these KLH model numbers confuse me, but those two appear to be virtually identical from the exterior. Maybe, just maybe, there might be a slight revision on the inside?.....but enough to necessitate a change in model number? Despite your suspicions about the stenciled "A" on the back plate, the serial number sticker also features the "A", so there is some yet-to-be-determined differentiation between the two. You'll probably have to take a peek inside - -  meanwhile here are a few threads which might offer some ideas. From this first link, I suspect what you have is the original grille cloth.

http://www.classicspeakerpages.net/library/klh/klh_22_klh_model_twenty-two/klh_22_photos/klh_22_front.html#previous-photo

http://audiokarma.org/forums/index.php?threads/klh-22a-speaker-score.720273/

 

[Robthomp]

Well, I opened the Model 22 and Model 22A.   The crossovers are different:

 

1)   The drivers appear to be identical.  The Model 22 drivers are stamped with 1968.  The Model 22A doesn't have a date stamped on the drivers, but there is a stamp on the baffle board which contains the line STY 5 21 70, which I am guessing is a 1970 date?

2)  The Model 22 tweeter is housed in a cardboard enclosure, the 22A tweeter is housed in a plastic one.

3)  The woofer on the 22 is sealed with the usual bead of white putty seal, but the woofer on the 22A is NOT sealed with that stuff. Under the rim of the aluminum frame there is just a thin ring of foam stripping.

4) The Crossovers:  the Model 22 has a simple first order crossover - a 4 muF capacitor in series with the tweeter, and a coil in series with the Woofer ( I do not know the inductance of the coil, it doesn't appear to be printed on it.)  The Model 22A on the other hand in addition to the coil,  has a 16 muF capacitor in parallel with the woofer, and an 8 muF capacitor and a 3 Ohm resistor in series with the tweeter.  I have attached drawings I made of the schematics. 

I am learning a little bit about crossover design and I'm very interested in knowing what the effects would be of this crossover upgrade and why KLH went to it.   Is it possible to generate the frequency response plots for these two crossover designs, assuming identical drivers, and compare them?  Is the modified crossover in the 22A related to the fact that the woofer didn't seem to be sealed as well? Or is the woofer on the 22A supposed to be sealed but KLH just cheaped out by using a flimsy foam strip instead of the airtight putty?

How good would your hearing, or listening training, have to be to hear the difference between these two crossovers?

 

Rob

 

 

 

[Robthomp]

Hi,

 I think I can ask a better question: I'm recapping these speakers.  Should I replace the crossover in the 22 with the same one that's in the 22A?   If the drivers are in fact identical, then presumably KLH decided the second crossover was an improvement, otherwise they wouldn't have put it in.  On the other hand, if the drivers do not have the same electrical characteristics (even though they look the same to my untrained eye) or if the inductors have different values, then modifying the crossover in the 22 might be a bad idea.

Rob

 

 

[boreas]

I know I'm a little late to the party on this thread (okay, a lot late)  but I just restores a set of Model Twenty-Fours and a set of Twenty-Four Series II speakers.  These speakers are identical to the Model Twenty-Twos.  As near as I can tell, the Twenty-Fours were simply Twenty-Twos repurposed and renamed for inclusion in the Model Twenty-Four compact stereo.

The difference between the two version of the Twenty-Four, like the two versions of the Twenty-Two,  is in the crossover.  The Twenty-Four has the same inductor and 4uF cap as the Twenty-Two and the Twenty-Four Series II has the same inductor, 8uF & 16uF caps and 3 ohm resistor as the Twenty-Two A.  One other difference between the two types of Twenty-Four not found in the Twenty-Twos is that the Twenty-Four Series II has RCA plugs instead of binding posts.

After rebuilding the crossovers in both pairs, I gave each pair a careful listen.  I found the  Series IIs to be slightly smoother and more balanced than the first generation Twenty-Four so I redid the crossovers in the Twenty-Fours to  Series II specs.  They're quite good speakers and have surprisingly good bass, considering the size of the woofer. 

[Stephen 59]

This is weird. I just bought a set of KLH 22A today. At least that's what I thought! The black metal plates at the speaker terminals both say Model 22A but the "A" on both do look like they were post added at the factory. The paper serial number sticker on one says M-Twenty Two A 034098. The paper serial number sticker on the other one says Model 22A SPKR A 041496. The differences in tweeter mounting (one is mounted on white cardboard, the other is on black plastic) and the woofer surround colorations mimic exactly what Robthomp posted several years ago. The only difference between his experience and mine is that both of my pair have the odd looking stencil "A" on the metal plates and his only had it on one speaker. Is this common? I'm new to the forum. I had a pair of KLH bookshelf speakers back in the mid seventies (not sure what model) and bought the 22A's on a whim, as I'm getting back into vintage gear. I haven't even had a chance to listen to them yet. 

[RoyC]

KLH had many 2-way models, and variations within them.

Earlier specimens used a clay-like material ("Mortite") as a driver gasket material, and later used foam gaskets. It's nothing to be concerned with. If you are so inclined, it would be interesting to see the crossovers...and if you do open them up, it would be prudent to replace the notoriously crappy KLH capacitors. On the other hand, if they sound good to your ear don't worry about the details.

Roy

[Stephen 59]

Both speakers have the same woofer gasket material (not foam ) but one is light beige color and one is nearly black. I hooked them up last night for a listen, and unfortunately one tweeter has no output at all, so I'm dropping them off at my local speaker tech to test them and figure it out. No surprise that 50+ year old speakers would need service! At least the cabinets, grilles etc. are in excellent condition.

[Stephen 59]

They non-functioning tweeter was caused by two blown capacitors, so they were replaced and the speakers sound great! Can anyone tell me how to know when the woofer surrounds need re-doping?  

[RoyC]

3 hours ago, Stephen 59 said:

They non-functioning tweeter was caused by two blown capacitors, so they were replaced and the speakers sound great! Can anyone tell me how to know when the woofer surrounds need re-doping?  

Well, that's good news! Old KLH capacitors are often troublesome.

Regarding your question...Depress the woofer cone while the woofer is installed in the cabinet. It should return relatively slowly as compared to its action outside of the cabinet. If there is no discernible difference, the surround should be treated. It is not unusual for KLH woofers to require additional treatment.

Roy

[Stephen 59]

RoyC, I see on other forum pages that you are the supplier of the proper surround dope. Do you have any made up and available for purchase?

Thanks,

Stephen 

[RoyC]

4 hours ago, Stephen 59 said:

RoyC, I see on other forum pages that you are the supplier of the proper surround dope. Do you have any made up and available for purchase?

Thanks,

Stephen 

I do. PM sent.

Roy

[Andrew Wood]

Hey guys, just starting to recap some klh model 20’s. I got great info here on which caps to buy. But the speaker goo, I still need, RoyC I read that you sometimes have some made up, any chance of obtaining some?

[RoyC]

3 hours ago, Andrew Wood said:

Hey guys, just starting to recap some klh model 20’s. I got great info here on which caps to buy. But the speaker goo, I still need, RoyC I read that you sometimes have some made up, any chance of obtaining some?

Andrew,

Yes...PM sent.

Roy

[JackAlterman]

Hi RoyC,

I, too, am interested in the sealant mixture you create. Can you please PM me about it?

Thanks!

Jack

[RoyC]

1 hour ago, JackAlterman said:

Hi RoyC,

I, too, am interested in the sealant mixture you create. Can you please PM me about it?

Thanks!

Jack

Hi Jack...PM sent.

[D.Bachtel]

Roy, your cloth surround dope for KLH 17s is something I need to restore my speakers. How can I purchase some?

Thank you,

Don Bachtel 

Nipomo California

[RoyC]

On 3/25/2023 at 3:10 PM, D.Bachtel said:

Roy, your cloth surround dope for KLH 17s is something I need to restore my speakers. How can I purchase some?

Thank you,

Don Bachtel 

Nipomo California

Just sent you a PM, Don.