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Dynaco A-50 tweeter help needed?


Guest landcruisergeek

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Guest landcruisergeek

Hello, first off, I am a newbie to this forum and a newbie to Dynaco, I just picked up my first set today! I should also note that I am a speaker novice.

After hooking up my newfound A-50s, I noticed one of the tweeters just didn't sound right. On a close ear listening test I detected a consistent faint "buzz" as opposed to crisp actual sound.

Any ideas on what the problem might be or if a novice can even diagnose and repair? Is this a drop in tweeter replacement? I removed the screws on the cover ring, but can't figure out how to actual get the tweeter out. My only other speaker repair was a direct screw out/screw in on a set of Polks...is it much more involved on these Dynacos?

Thanks in advance for any help and suggestions!

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>Hello, first off, I am a newbie to this forum and a newbie to

>Dynaco, I just picked up my first set today! I should also

>note that I am a speaker novice.

>

>After hooking up my newfound A-50s, I noticed one of the

>tweeters just didn't sound right. On a close ear listening

>test I detected a consistent faint "buzz" as opposed

>to crisp actual sound.

>

>Any ideas on what the problem might be or if a novice can even

>diagnose and repair? Is this a drop in tweeter replacement?

>I removed the screws on the cover ring, but can't figure out

>how to actual get the tweeter out. My only other speaker

>repair was a direct screw out/screw in on a set of Polks...is

>it much more involved on these Dynacos?

>

>Thanks in advance for any help and suggestions!

Hi John;

First, a very wise purchase for an authoritive speaker system.

First turn off the stereo, do not disconnect the speaker lead wires, turn the treble control to maximum, and lay the questionable speaker cabinet on it's back.

By gently prying under the rim on opposite sides with small standard screwdrivers, the tweeter will pop up out of the hole.

The tweeter is held in by a very pretty but sticky goop substance.

Use extreme care to avoid puncturing the woofers cones or the tweeters dome.

After removing the tweeter, lay it dome up on the cabinet front, turn on the amp and using white noise, interstation hiss or similar, at very low levels, to hear if the tweeter is producing any output the same as the other A-50 tweeter.

Wiggle the tweeters soldered leads to see if there is any change in volume level.

If you should have a spare tweeter or any cheap small driver, attach a pair of leads in parallel with this tweeter.

See if that cheap driver has the same or increased output when connected to the tweeters leads.

This should be done at low levels.

Let us know what has happened at this point please.

Don't just start cutting wires or removing the woofers and tinkering just yet.

It would be a good idea to fuse these speakers after your project is over any ways.

If the tweeter should be in need of replacement, there is oodles and oodles of the Seas versions on ebay for example, usually running $15.00 - $25.00+/- US each.

The tweeter is the standard classic 8 ohm, 1 1/2" dome.

The 1" version, which is also available on ebay, is not exactly the same but is more efficient by a few dB, there is the look-a-likes also but they are different.

The same Seas tweeter was used in most all of the classics, A-10, A-25, A-35 and the A-50, they are all 8 ohm tweeters.

A similar but different tweeter Dynaco also used, was the Scan version, less readily available then and now, which may or may not sound the same.

I would not buy just one of the Scan versions for fear that they are noticebly different, you would need to pick up a pair if you were to decide that the Scan version was acceptable to you.

Either 8 ohm version definitely will do if matched by manufacturer.

The A-50 is a very good classic speaker system with clean equipment, good musical sources and fused.

More help to follow, if needed.

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Guest landcruisergeek

Vern, thanks again for your suggestion. I was able to remove the tweeter, it was pretty snug in there. There is sound coming out of the suspect tweeter, but it does not sound equal in volume as the other one. The difference in volume is very slight.

I had an old tweeter laying around and connected that in parallel with the suspect tweeter, and the volume sounds the same as the suspect tweeter.

Thoughts/suggestions?

I might add that even though I posted this as a tweeter issue, I suppose there is the possibility that my ears could deceive me and this could be one of the other drivers (though it did sound like the missing/hissing/buzz was coming from the tweeter.

Thanks again if you can suggest anything more! John

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Hi John;

I was assuming that the tweeter level control on both speakers are set at maximum.

Set the amp/pre-amp/receiver to mono output, then see what the tweeter levels are like.

If you can, try to have your head between the two enclosures and try the test again to see if the tweeter output is equal or not.

Is your tweeter a Seas and is the other one a Seas as well?

There is a paper label on the side of the magnet, a photo of it please.

If, very carefully now, you can lay the grille cloth frame over the woofers area with perhaps a towel cover to eliminate too much woofer interference with our test.

The tweeters usually are hissy and spitty sounding.

With your ears on the tweeters axis, and same distance from them, there should be no noticeable difference between the tweeters output, particulary in mono.

Check out your speaker cables and connections for integrity as well.

Lastly for tonight, shut off the amp and reverse the left and right speaker wire connections and have another listen.

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Guest landcruisergeek

Hello Vern, I set the stereo to Mono, isolated the tweeters by covering the woofers with towels...and listened to both speakers at equal distance to my ears and close up as well. They both sound the same, with same volume,s imply emitting a "hiss" sound for the white noise I had running.

I have included a few photos of the suspect tweeter. It is labeled only with two label tags that have the following number(s) respectively.

A7046

A0005

I believe another label fell off, that I saw inside the cabinet with seems to read Scan Seaker or Sneaker?

I also tried reversing the speaker connections and gave a listen..sounds the same.

I have not yet pulled the other speaker's tweeter to see if it is the same. I will have to do that tomorrow.

Thoughts based on the above? Thanks again Vern for your assitance, I appreciate it. John

p.s. I hope the pictures post correctly.

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post-20-1168493896.jpg

post-20-1168493897.jpg

post-20-1168493898.jpg

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Vern knows more about the guts than I do, but it looks like your A-50s have SEAS woofers and Scanspeak tweeters. Scanspeaks were the tweeters used in the earliest A-25s. They're good tweeters, quite similar to the later SEAS tweeters. I've had about 25 pair of A-10s, A-25s and A-35s pass through my house over the past year, and I've never encountered a bad Scanspeak OR SEAS tweeter. So my hunch would be that any problem would be earlier in the circuit. I did encounter one "cold solder" problem near the capacitor in the tweeter circuit of one speaker and it was pretty easily remedied. Taking out the woofer (without disconnecting it) gave me access to the crossover network (wear gloves--that fiberglass fill is nasty), but I'll let Vern take back over before suggesting that you poke around where the tweeter wires connect to the crossover.

--Horse

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Guest landcruisergeek

Thanks Horse...good to know about my tweeters and woofers. I don't know anything really about these..except that one of the speakers sounds really really good! :) I hope to issue ends up being minor and easily repairable. We'll see.....

Thanks! John

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Guest landcruisergeek

Hello Vern,

I did another listening test this morning...but have yet to pull out the tweeter from the other "good" speaker. I did pull the outer ring off and it looks the same as the other tweeter from the outside. Please suggest if I should go ahead a pull to verify it is indeed the exact same tweeter...the scan speak

In the listening test today...I connect another tweeter in parrallel with the suspect tweeter, and better isolated the woofers from the suspect tweeter. What I observed is that the suspect tweeter does put out some sound, but it is definitey not as loud nor as clear as the tweeter in other good Dynaco...nor is it as clear or as loud as the spare tweeter that I connect in parrallel. The sound it puts out is very faint and not very legible..compared to the normal and spare/in-line.

Again when you listen to both speakers in mono to a normal song...the bad tweater emits a hit and miss, faint crackle/buzz/"tiss-tiss-tiss" sound...did I just say that? :)

Thanks again for any suggestions, or if I should pull the good tweeter?

John

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>Hello Vern,

>

>I did another listening test this morning...but have yet to

>pull out the tweeter from the other "good" speaker.

>I did pull the outer ring off and it looks the same as the

>other tweeter from the outside. Please suggest if I should go

>ahead a pull to verify it is indeed the exact same

>tweeter...the scan speak

>

>In the listening test today...I connect another tweeter in

>parrallel with the suspect tweeter, and better isolated the

>woofers from the suspect tweeter. What I observed is that the

>suspect tweeter does put out some sound, but it is definitey

>not as loud nor as clear as the tweeter in other good

>Dynaco...nor is it as clear or as loud as the spare tweeter

>that I connect in parrallel. The sound it puts out is very

>faint and not very legible..compared to the normal and

>spare/in-line.

>

>Again when you listen to both speakers in mono to a normal

>song...the bad tweater emits a hit and miss, faint

>crackle/buzz/"tiss-tiss-tiss" sound...did I just say

>that? :)

>

>Thanks again for any suggestions, or if I should pull the good

>tweeter?

>

>John

Hi again John;

Removing the ring threw me off.

If they both have the rings they are both Scan versions.

You have the less common Scan tweeters.

I do not mean inferior in any way, just less common.

This was the earliest tweeter also with the less seen Scan woofer.

I don't know the Scan/Seas start and finish story yet.

Dynaco switched suppliers mid-stream early on, and I don't know why or when, and do not know their relationship.

They are physically interchangeable with the later and much more common Seas tweeter version.

Sonically I do not know if they are the same, to replace one it may be best to replace both with the same Seas or Scan tweeters to be certain.

The cabinets are not plywood so care must be used in screwing in the woodscrews.

If a screw hole strips, you can dip a wooden match in glue and sort of plug the large hole, or, sharpen a wooden dowel the size of a pencil and sharpen the end with a pencil sharpener and also dip it in glue and tap it into the hole and cut it off flush.

The woofers are also different.

Most all woofers have horns, a protrusion at each screw hole, and these are the most common.

If a woofer speaker was to have a round perimeter woofer basket and a horned version was obtained, then each horn projection must be slightly knotched for.

The reverse is not needed.

A putty, a non-hardening type, should be used around the holes under the flanges perimeter to re-seal the driver openings, as you tighten the screws the excess may ooze out slightly but that is ok.

At this time I see no reason to remove the other tweeter.

It does sound like your tweeter may be sick with a damaged voice coil, this is not repairable but a used replacement tweeter is a realistic and reasonable option.

There is look-a-like tweeters with different lower impedances, if you were to buy a 3 ohm version it would be a few dB louder than the stock 8 ohm tweeter.

The typical printing for your tweeter will be 4 - 8 ohm rating not 3 ohm.

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Guest landcruisergeek

Thanks again Vern. As mentioned I am a novice on this stuff, so bear with me...

When you wrote about the wood screws and filling the holes, notching, and putty, etc...it sounds as if you are talking about the process to replace one of the tweeters? Is that right?

Is your suggestion to replace the faulty tweeter? Or shall I replace both? Or are is there something else you would suggest?

I don't suppose there is any hope of finding just one Scan tweeter out there huh?

Again, thanks for much for your assistance Vern.

All the best,

John

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>Thanks again Vern. As mentioned I am a novice on this stuff,

>so bear with me...

>

>When you wrote about the wood screws and filling the holes,

>notching, and putty, etc...it sounds as if you are talking

>about the process to replace one of the tweeters? Is that

>right?

>

>Is your suggestion to replace the faulty tweeter? Or shall I

>replace both? Or are is there something else you would

>suggest?

>I don't suppose there is any hope of finding just one Scan

>tweeter out there huh?

>

>Again, thanks for much for your assistance Vern.

>

>All the best,

>John

Hi again John;

The mention of the knotching was of course not for the tweeters or your particular horned woofers.

It was a comment for those that have a round perimter and buy a horned version woofer.

You have the horned woofers that are most common.

I try to add other bits of knowledge when I write, not just the specifics.

Your woofers are actually 16 ohm each woofers as well, for some more information for you and other owners.

All other Dynaco classic woofers are 8 ohms, but, as a caution, there is other look-a-like wookers as well with different impedances as well.

The hole plugging is in case you or someone else has stripped a wood hole out, very common.

Usually a person might just turn the driver a few degrees and start all new holes as well.

The putty sealant is for any acoustic suspension type driver, removed from a cabinet and re-mounted, cabinet seal, otherwise the air can leak through that gap.

To find and buy a Scan 8 ohm tweeter is not as common as a Seas tweeter and will take more patience.

You can search ebay as I have seen Scan tweeters every so often, but the Seas is much more common.

You will need to do a Dynaco search rather than a Scan search for best results.

If you can wait for a Scan to come along you will only need one, but if you would like to rush the repair, then I would suggest buying a pair of Seas.

Anticipate $15 - $30.00 each roughly plus S&H, obviously a pair of Seas will cost you less from one seller.

There is usually a dozen listed at any one time, sometimes individually, but more often in pairs.

My previous experience at the local Dynaco warantee depot left me with a few memories, the A-25 went through a lot of burnt out woofers, the tweeters seemed to be almost indestructible by comparison.

By all means fuse them when completed.

I just hopped over to ebay for a lookie loo.

A single Seas tweeter just went for $15.00 plus $10 S&H USA.

The same seller has another pair up for auction now.

This is the ballpark price you should anticipate paying.

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Guest landcruisergeek

thanks for all your insight Vern. I have ordered a set of new Seas tweeters. looks like I need to do some research to fine out what "fuse" them means....like I said, I am a novice - but this is real interesting stuff to learn about. Thanks again! John

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Before putting in your new tweeters, I'd recommened removing ONE woofer in the "troubled" speaker, removing the foam stuff inside, and wiggling all wires at the crossover network in that speaker. Your tweeter could be toasted, but it COULD also be that one of the connections has become questionable. Sometimes you can just wiggle all the wires at the crossover and get a better connection. Use work gloves when you remove the foam stuff inside...it can get under your skin and be an irritant. Vern, are you with me on this? I'm thinking "cold solder" problem. My cold solder problem was at the capacitor in an A-25. I think I addeed a bit of solder, but slightly moving the capacitor was actually all that was necessary to yield a good connection. If that doesn't work, then replace both tweeters....

--H

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Guest landcruisergeek

Vern, one more quick question if you please...

When putting in new tweeters, will I also need more of the black goop adhesive to seal it? If so, what is that black goop stuff? Thanks! John

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>Vern, one more quick question if you please...

>

>When putting in new tweeters, will I also need more of the

>black goop adhesive to seal it? If so, what is that black

>goop stuff? Thanks! John

Hi again;

Of course follow Colins advice, it is very good advice.

I am sometimes very tired when I write and do not always think of everything.

Your previous commentary that the tweeters between cabinets have very close to the same output kept me from suggesting going inside the enclosure.

If you should remove the woofers be certain to wear vinyl gloves or equal for the fiberglass insulation and a face paint mask with safety glasses.

When you say you have ordered 2 new tweeters, what do you mean?

The original tweeters have not been manufactured for over 25 years.

A replacement tweeter manufactured recently would very likely be a mismatch compared to an old used OEM Scan tweeter.

Any non-hardening and non-staining putty will do for the seal, just roll a strip about the size of a pencil and lay it around each perimeter flange.

The low crossover point is an important issue, most tweeters cannot go as low as the Dynaco speakers need with it's superior power handling capabilities.

Go to the, "other forum", and read all that is written under, "fast blow fuses".

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Guest landcruisergeek

thanks. I ordered these tweeters http://www.madisound.com/cgi-bin/index.cgi....18492&pid=1002

I was told they were the replacement tweeters as recommended.

Thanks again for all the assistance.

Colin, thanks for your suggestion. Since I connected a spare tweeter to the same pos/com lines in the faulty speaker and the spare tweeter worked good, I assumed connections were good. But perhaps I should give your suggestion a try. thank you.

John

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Hi again;

I believe you wrote earlier that the two Scan tweeter outputs are very close in sound level.

Those tweeters at that link are rated at 6 ohms, not 8.

They are also rated at 91 db which I believe is higher (louder or brighter sounding) than the OEM tweeters.

I may be wrong but I believe that the A-50 has a 1khz crossover.

That tweeter is rated at 1.5khz - 25khz.

If I am correct there would possibly be a sonic hole on the 1khz - 1.5khz range.

Colin please correct me if I am wrong.

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Guest landcruisergeek

Vern, I did write earlier that the bad tweeter and good tweeter sound somewhat equal in volume, but upon better isolation of the woofers and further testing I think the bad tweeter is not putting out much volume, and definitely not equal compared to the good tweeter. When I connected a spare tweeter in parrallel it was equal in volume to the good Scan tweeter.

Interesting note on the sonic hole from the tweeters I ordered...that would be interesting.

According to Madison, their retrofit recommends a tweeter very similar to the one I purchased, perhaps I ordered the wrong one by one letter differnce in the parts

I ordered the Seas 27TDFC

there website recomends the 27TFFC for the A-25.

Hmmm. What to do, perhaps return the ones I ordered for the others? I have not checked the specs to compare the two, and honestly I don't know that I would be able to decifer what the spec differences are anyways.

I lifted their recommendation from this page:

http://www.madisound.com/retrofits.html

thanks again! John

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Hi John;

I went to that site to see what they had written.

There is 2 recommendations.

One from Seas and one re: Morel.

I would opt for the Seas if an OEM is not available, but either new one is an option.

I would have searched for a Scan OEM or Seas OEM before I would have bought new but at least you will have identical new tweeters.

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Guest landcruisergeek

thanks Vern. I was confused because I had seen some for sale that were 1.25 inch and others that were 1.5 inch. I was not sure which size tweeter went with which model Dynanco.

Thanks, John

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>thanks Vern. I was confused because I had seen some for sale

>that were 1.25 inch and others that were 1.5 inch. I was not

>sure which size tweeter went with which model Dynanco.

>Thanks, John

Hi John;

You will see 2 different sizes of Dynaco/Seas tweeters being sold on ebay alone.

Mis-informed sellers use the same advertising words whether it is the 1" or 1 1/2" tweeters.

The 1" tweeters were for the later XL models, not truly backwards compatible with yours because of the lower db output of your tweeters.

I cannot stress enough, to be cautious about the photos used because there was other manufacturers of speaker enclosures that used the same brand drivers but different impendances, so these are not truly interchangeable as well.

Even these ones are sometimes incorrectly headlined with the Dynaco name.

If you should ever ask a question similar to your original one, wait at least a week or two for everyone to see it before making any decisions.

Timing, timing, timing, John.

I just hopped over to ebay now and there is a single Scan tweeter being offered for sale.

Search under Dynaco or Scan or Scan Speak.

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