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Another Maggie Tympani-1D rebuild thread

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The left tweeter is 10.1 ohms which means 1 run is open circuit inside tweeter panel.

I have placed an order for a replacement from magnepan .

@buddyev I agree the best I have heard @djb speakers.

The top end is now excellent 

With 4 Bass trap panels fitted their is no more boomy bass it is much tighter.

Kick drum and double bass sound a lot more realistic.

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15 hours ago, andyr said:

Excellent - look forward to hearing it soon.

Not a good idea, IMO, Russ.  :(

 

To avoid 'lobing', as there are 2 frequ ranges where 2 drivers are both contributing output (over the bass/mid XO and mid/tweeter XO regions), these driver pairs should be adjacent to each other.

 

IOW, the tweeter should be next to the mid panel - and it should be next to the bass panel.  Exactly as it is now!  :thumb:

 

Putting the AMTs on the outside of the bass panels would result in the bass panels being positioned in between the tweeter and the mid panel - a very bad thing to do.

 

Of course, @djb could swap the L panels for the R panels - which would mean that the AMTs would:

  • be on the outside, for maximum soundstage width.
  • and would maintain correct positioning of B, M & T drivers.
  • but IMO would have several bad consequences:

 

  1. the bass panels would no longer get the side-wall reinforcement they do now.
  2. the tweeters would not sound their best, being crammed up against the side walls.
  3. yes, the soundstage would be wider than at present ... but David would have inferior instrument placing - within the soundstage, as a result.

 

Andy

 

Hi Andy,
 

If you have the multi panel maggies like the Tympani range you do have to rearrange the panels accordingly if you have intentions of moving the tweeter either from the inside or the outside.

Simply moving the tweeter panel is not sufficient.

In terms of outcome I dare not comment because when I came to Davids place my immediate impression was that it would not work.

I was wrong. 

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10 hours ago, ghost4man said:

Hi Andy,
 

If you have the multi panel maggies like the Tympani range you do have to rearrange the panels accordingly if you have intentions of moving the tweeter either from the inside or the outside.

Simply moving the tweeter panel is not sufficient.

In terms of outcome I dare not comment because when I came to Davids place my immediate impression was that it would not work.

I was wrong. 

You seem to have misunderstood what I was talking about, Ozzie.

 

(Hint - turning a 2-way (albeit with 2 differently-tuned bass panels each side) into a 3-way.)

 

Andy

 

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You seem to have misunderstood what I was talking about, Ozzie.
 
(Hint - turning a 2-way (albeit with 2 differently-tuned bass panels each side) into a 3-way.)
 
Andy
 
Andy I think you will find that the position of the AMTs outside or inside is perhaps not as problematic as some would suggest.

But you will form your own opinion when you listen to it.

I'm thinking Peter has XO to the HF at the higher end as per your suggestion and yielded a very good result. So I hear from the underground planar movement

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Very enjoyable afternoon at[mention=106551]djb[/mention] 's , I was keen to hear the differences with the Maggies paired with the AMT and tweaking done by[mention=141230]gonefishing999[/mention].

Certainly more sparkle in the top end since last visit and as Russ mentioned better punchy bass with less bloat .

 

After switching from CD's to a vinyl copy of Janis Ian - Breaking Silence , I could more clearly discern improvement with excellent vocals in the mid although question mark on the lower mid frequency range - perhaps the AMT needs to be dialled down slightly (?).

Soundstage was also noticably better , I could hear more even balance .

 

Unsure on how the AMT will integrate visually, (of little importance to David!), but more in how it can be slotted in more permanently and seamlessly.

 

Question is it better to stay with matched and get 2 new tweeter panels?

With 3 panels each side in a less than large room , not much space to play with!

 

 

 

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On 4/13/2018 at 8:28 AM, gonefishing999 said:

The left tweeter is 10.1 ohms which means 1 run is open circuit inside tweeter panel.

 

For those that are not familiar wth the T-1D ... the tweeter panel has 2 runs of wire on the mylar, connected in parallel.  Each run measures ~10 ohms - which delivers a combined load of 5 ohms.  And that is terrible!  :angry:  These T-1D tweeter panels were repaired by Bill McLean's tech - at a not inconsiderable expense - they should be working correctly!

 

On 4/13/2018 at 8:28 AM, gonefishing999 said:

With 4 Bass trap panels fitted their is no more boomy bass it is much tighter.

Kick drum and double bass sound a lot more realistic.

 

Yes, the panels sound nice and tight (I was there this afternoon).  :)

 

On 4/7/2018 at 8:21 AM, gonefishing999 said:

MG-3.5/R is 3 way TR xo at 1.7k.

 

On the MG-3.5R factory spec sheet that Magnepan faxed to me on Mar 18, 1997, the bass LP is 3rd order (but in fact less than an 18dB slope); component values are: 5.6mH / 1.7mH / 275uF.

 

There is a 115uF cap in series with the feed to (and an 8.5mH coil across) the internal (mid/ribbon) XO ... which is a 2nd-order HP for the mid panel.  The remaining filters are as follows:

  • mid LP - 3rd order; component values are: .355mH / .318mH / 50uF.
  • ribbon HP - 2nd order; component values are .397mH / 17uF (or 15uF - the sheet shows a different value in 2 different places).

Putting these values into lspCAD shows the ribbon LP is 2600Hz (-3dB point) if you take the ribbon resistance as 3 ohms (using the 15uF value) - and 5000Hz if you take the ribbon resistance as 2 ohms.

(I'm not sure whether the 3.5 had the 2 ohm ribbon or the older 3 ohm ribbon - but I suspect it was the latter.)

 

So I don't know where you get your 1.7kHz roll-off point from?

 

On 4/11/2018 at 4:42 PM, gonefishing999 said:

What are the circuit values ?

 

See above.

 

On 4/12/2018 at 10:24 AM, Point source said:

Reading this thread with interest, excellent tech discussion going on here. I will drop in at @djb when I get back from Hols. One suggestion though, the AMT is being used to ‘fill’ the very high freq roll off coz there is no ribbon. Keep the crossover to the AMT as high as possible. The existing TIV tweeter (non ribbon) panel is a superb transducer and sounds  better than the AMT to me.

 

I don't know what the AMTs are being rolled off at but I didn't get any sense of "better treble" with the AMTs in the mix, this afternoon.  But maybe my ears are influenced by their spec sheet?  (What I read said the AMTs are only rated to 20kHz - which is the same as the T-1D tweeter.)

 

On 4/12/2018 at 6:02 PM, VanArn said:

The inductor is listed as .687 mH and the capacitor as 35 mFd.


Actually, the T-1D factory spec-sheet which I have says .68 - .70mH, with 35uF.

 

On 4/12/2018 at 6:02 PM, VanArn said:

For a 6 dB per octave crossover, the -3dB for the bass/mid section would be at 926.6 Hz and for the tweeter panel it would be 1136.83 Hz. This is of course for precise value components and 4 ohm resistive loads.

 

Xept they're not both 4 ohm loads.  The 2x ~10 ohm tweeter 'coils' come out to ~5 ohms and the 2x bass panels are ~8 ohms each ... which delivers ~4 ohms.

 

Using the average mH value, 35uF and 4 ohms for the bass / 5 ohms for the tweeter, lspCAD delivers:

  • 990Hz bass LP
  • 900Hz tweeter HP.

 

On 4/12/2018 at 6:02 PM, VanArn said:

If it is the intention to improve the  midrange and treble dispersion of the Tympani system to suit the small lounge room, then replacing the tweeter panel with dual  Bohlender Graebener Neo 8S units and implementing these to run from a 300 to 400 Hz crossover point with the bass panels and up to  a 1.2 kHz xover with the ESS Heil AMT would be a worthwhile option to consider.

The people on the Planar Asylum who have implemented Neo 8s in place of a standard Maggie mid-panel have used 6x Neo8s a side (to get as long a line-source for the mid, as the rest of the speaker) ... which makes this an expensive exercise!  :(  They have then crossed over to the (true-ribbon) tweeter at 4kHz or more, to keep the mid-tweeter XO above the vital 3kHz range.

 

Andy

 

 

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The people on the Planar Asylum who have implemented Neo 8s in place of a standard Maggie mid-panel have used 6x Neo8s a side (to get as long a line-source for the mid, as the rest of the speaker) ... which makes this an expensive exercise!    They have then crossed over to the (true-ribbon) tweeter at 4kHz or more, to keep the mid-tweeter XO above the vital 3kHz range.
 
Andy
 
 
Andy in answer to your statement re tweeter and XO point for 3.5 I can only go off the following b4681750e90d95a29d17f2c7528fe7ae.jpg

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40 minutes ago, andyr said:

I don't know what the AMTs are being rolled off at but I didn't get any sense of "better treble" with the AMTs in the mix, this afternoon.  But maybe my ears are influenced by their spec sheet?  (What I read said the AMTs are only rated to 20kHz - which is the same as the T-1D tweeter.)

Maybe you need to have your ears washed out or maybe  you are influenced by numbers.

You must have forgot the REW graphs I posted .The T1D Tweeter panel take a dive at 12khz.

So your comments are bias to the Amt's.

 

50 minutes ago, andyr said:

Putting these values into lspCAD shows the ribbon LP is 2600Hz (-3dB point) if you take the ribbon resistance as 3 ohms (using the 15uF value) - and 5000Hz if you take the ribbon resistance as 2 ohms

Maybe Ispcad is wrong as those figures are way of .

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1 hour ago, ghost4man said:

Andy in answer to your statement re tweeter and XO point for 3.5 I can only go off the following

b4681750e90d95a29d17f2c7528fe7ae.jpg

 

Sure, Ozzie - I agree that seems to be factory details.  :thumb:

 

As Peter has suggested, I am influenced by numbers.  So I feed the XO circuit values into an XO simulation program (lspCAD) and take the numbers that it shows me.

 

(In just the same way that Peter takes the graphs that REW gives him.  :) )

 

58 minutes ago, gonefishing999 said:

Maybe you need to have your ears washed out or maybe  you are influenced by numbers.

You must have forgot the REW graphs I posted .The T1D Tweeter panel take a dive at 12khz.

So your comments are bias to the Amt's.

 

Sure, Peter, my comments are biased against the AMTs - because their spec sheet says 'X' to 20kHz.  Which is the same upper limit as the T-1D tweeters.

 

You have posted many REW graphs - so many that I don't know whether the ones you posted include the fact that one tweeter panel seems to have a blown 'coil' (because it measures 10 ohms) ... or not.  :)  (Which would reduce its output.)

 

58 minutes ago, gonefishing999 said:

Maybe IspCAD is wrong as those figures are way off.

 

lspCAD is a computer simulation package.  It is no more 'wrong' than REW.

 

Andy

 

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Andy, this is something that I have known for some time in terms of the ability of the true ribbon to go down that far,

although it did surprise me particularly given some of the suggestions from the planar guys.

I think we need to bring back the focus to the listening experience and not be swayed by the numbers.

I dont know if you heard Davids system in the last month or so but the point - from what I can see that Peter is making - is

that you would HAVE to hear a difference between the Maggie tweeter and the AMT because there is a huge drop off around 12k

with the maggie but not the case with the AMT. If it sounds the same to the listener then can they make the distinction between 

12k and 20k.

I have not heard recently so I cant comment. 

Another concern is the maggie tweeter. The fact that it measures 10 ohms can only mean that one of the runs is faulty.

Re the Neo experiment - I am not convinced that it is the way to go. I just dont think enough people have implemented it

to be sure it will work.

 

 

 

 

 

 

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1 minute ago, ghost4man said:

I dont know if you heard Davids system in the last month or so

I listened to it this afternoon, Ozzie.

1 minute ago, ghost4man said:

but the point - from what I can see that Peter is making - is that you would HAVE to hear a difference between the Maggie tweeter and the AMT because there is a huge drop off around 12k with the maggie but not the case with the AMT.  I have not heard recently so I cant comment.

Yes but was this drop off the result of the fact that one T-1D tweeter is defective?

1 minute ago, ghost4man said:

Another concern is the maggie tweeter. The fact that it measures 10 ohms can only mean that one of the runs is faulty.

Correct - which is a bad reflection on Bil McLean's tech. :angry2:

1 minute ago, ghost4man said:

Re. the Neo experiment - I am not convinced that it is the way to go. I just don't think enough people have implemented it to be sure it will work.

 

Satie on the Planar Asylum was the first one AFAIK to implement Neo 8s for mids - he did this because the mids on his T-IVs are only 1/2-height ... not the full length like the T-IVa mids are (which is what I have).  So their sound is a step down from the full-length T-IVa / 20.X mids.

 

I'm prepared to accept that his Neo 8s deliver a much better sound than the stock T-IV mid ... however (given its double-magnet assembly), I'm not convinced that Neo 8s would deliver better sound than @djb's T-1D tweeters-used-as-mids.

 

Andy

 

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10 hours ago, ghost4man said:

Andy in answer to your statement re tweeter and XO point for 3.5 I can only go off the following b4681750e90d95a29d17f2c7528fe7ae.jpg

 

Thinking about those underlined words on this page, I have figured out the 'problem'.  :(

 

Mis-communication!

 

10 hours ago, gonefishing999 said:

Maybe Ispcad is wrong as those figures are way off.

 

lspCAD is right - but the user of lspCAD (ie. me) had a brain fade!  :(  Sorry 'bout that!  :(

 

The 3.5's mid LP curve does indeed "cross over" to the ribbon HP curve at ~1700Hz.

 

I was focussing on the roll-off point (ie. -3dB point) of the 12dB ribbon HP curve - which of course is at a higher frequency than the "cross over point" ... just as the -3dB point of the mid LP curve is lower than the "cross over point"!

 

Andy

 

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It’s concerning that parts of the discussion are beginning to make some sense to me.

This was never my intention

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Posted (edited)
19 hours ago, andyr said:

As Peter has suggested, I am influenced by numbers.  So I feed the XO circuit values into an XO simulation program (lspCAD) and take the numbers that it shows me.

 

(In just the same way that Peter takes the graphs that REW gives him.  :) )

Ispcad is a simulation program. This might give you a starting point but by no is it to be taken for granted that the numbers  are accurate nor should be

the final figures for building a xover.

 

REW software is meant for analyzing speaker with a microphone and gives a graph with the speaker frequency response.

The graph is REAL and not a simulation like you use.

 

Edited by gonefishing999

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Neo 8S is the item to look for      https://www.parts-express.com/bohlender-graebener-neo8s-planar-transducer--264-752            Two per side would be required and they can be configured in a D'Appolito  arrangement with the ESS AMT , or with the AMT situated  above .
Vanarn

This is simply not the case.

There has been quite a bit of discussion on the planar forum about the uses of the Neo 8s.

The ideal number is 6 per side as Satie and comoanh are doing.

Only incorporating 2 per side is self limiting to say the least.

You are also not limited to using the Neo 6s and the Neo 10s which have their strengths and weaknesses.

I do applaud your thinking outside the square by at least having some alternative knowledge.

There is also talk that the Monsoon drivers are even better but no one on the planar forum has done this.

You need the 6 because you want an array which will resemble the type of imaging from a bigger driver.

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Ghost4man, you need to read the product specification sheet provided by the Parts Express site and also the accompanying white paper although the latter concentrates on  the earlier NEO 8. That two NEO 8 S units  are sufficient to provide the wanted midrange function and combine with the ESS AMT tweeter and the Tympani bass panels should be beyond question. The object is to improve the imaging of the  Magneplanar  assembly by getting rid of the inefficient , unreliable and oversized planar treble panel; the obvious fly in the ointment.  Using a line source approach, (too many stacked NEO  units) despite the wide horizontal dispersion  will only result in  problems with comb filter interference in the sensitive high frequency region*. Remember that the Tympani 1D, or what is left of the original, is  being listened to in a small room and in such a case the integration of the component speakers is much more critical than listening in a  far field situation (> 5m).  The use of the ESS HEIL AMT,  allows a low HF xover  point (1.2 to 1.5kHz) to be used and the longer wavelengths assist in providing a smooth transition between the mids and highs. Just for the sake of an example, take the difference between  the QUAD  models EL57 and EL63 where the latter  has noticeably improved imaging as a result of the concentric  segment arrangement  and time delay correction .

 

                                                                                                                                                                                                                                                            * if your concerns are to do with power handling and  a low xover at 300 Hz, then consider that using two NEO 8 S provides an AES rating of 50 W and 100 W using a program based rating.  The LF boost provided by mutual coupling  assists here. Adequate baffling area , a rear enclosure to prevent modulation from the bass panels have to be considered  and the original tweeter panel wing would be amenable for this as well as a shelf to fix the AMT firmly in place. 

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VanArn,

Just because the stated values for the AMT are such that it can operate at 800Hz does not mean that it will give you the best sound sonically.

Recall that the person implementing this combination already has a pair of 2 way speakers utilising seas drivers and the AMT's. Peter found that 2200Hz suited best. 

You are making the same assumptions that other people are making and that is wanting to introduce the Neo's at a much lower XO point because perhaps you hold that it will deliver the best sound.

Consider the following. Ask yourself why it is that Magnepan cut the bass panels off at 1100Hz. Why not cut them off earlier?

My feeling is that whilst the Neo's can do the job it doesnt necessarily mean that they will do a better job in that 300-1100Hz range which is what the bass panels are doing.

To this day the 1D bass panels are regarded as one of the best if not the best made by Magnepan.

They sound even better when rewired with QR instead of the wire which is what I have.

 

I am not that convinced that the 1D tweeter is as much of a problem as some would believe although it has been said by the planar guys that the Neo's work better in that range and bear in mind VanArn that they are combined with a maggie true ribbon as opposed to this configuration with the AMTs.

I believe that Satie runs his Neo's full range but there is a resonance issue at around 8k.

This is all about integration. The suggestion here of combining a pair of maggie bass panels, 2 Neo's per side and a pair of AMT's is to my mind a very interesting mix. Will there be some phase issues doing this? Is the potential for phase differences mitigated to a large extent by the size or rather "smallness" of the room.

 

Cheers.

Ozzie

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  800 Hz!!!.   What I have suggested  are crossovers at 300 Hz and 1.2 kHz (or up to 1.5),  for  an implementation combining the NEO 8 S  and the ESS AMT with the Tympani bass panels to suit DJB's front  room.  This operates the  proposed mid and high frequency  units in their most efficient range and takes into account the dispersion patterns at the crossover frequencies. Large area drivers and especially line source versions covering different parts of the audio spectrum can prove difficult to integrate seamlessly and this should be  understood by technical people and experienced audiophiles.  The  Tympani 1D,s are certainly improved using later technology to avoid the wire delaminating from the mylar film such as the ribbon wire and better adhesives. Using the old   planar tweeter in a two way configuration is the major weakness of the speaker in its original format and this fact is readily accepted by owners who seek improvement as well as greater reliability.

Certainly  the actual crossover slopes, phasing and time offsets have yet to be performed but   with the versatility of a Minidsp  system  at hand, this task is  made much easier than trying to use passive networks.

 If it is necessary to run the ESS AMT at 800 Hz in  say, a passive two way speaker system i.e. when employing a high quality 12 or  15'' bass unit;  then  a network needs to be added to overcome the rising response of the Heil as the frequency goes higher (it extends well beyond 22kHz). The crossover slope needs to be steep to avoid the pleated diaphragm buzzing in the 300 to 600 Hz range. The end  result is a sensitivity of approx. 92 dB SPL  for a 2 volt input,  measured at 1 m on axis.  Using  a higher crossover frequency  such as 1.2 kHz permits the use of a shallower xover slope and the sensitivity   increases to around 94 dB.  How do I know this? I often make contact with Garry Cawsey and he uses the ESS Heil in his workshop monitors and custom builds speakers for discerning clients using  selected and  modified  Heil diaphragms.

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On 17/04/2018 at 12:37 PM, VanArn said:

the Tympani 1D, or what is left of the original, is  being listened to in a small room

When considering the home for the #5 frankenmaggie it is a room 3.6m x 5.2m but with an open-plan design where two other rooms wrap around two sides of the room.  So with the doors and walls open (as they usually are) it is a 8.0m x 8.4m space (minimum).  Would I have to budget in four figures if I was considering Neos?

 

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On 17/04/2018 at 10:23 PM, VanArn said:

The  Tympani 1D,s are certainly improved using later technology to avoid the wire delaminating from the mylar film such as the ribbon wire and better adhesives.

Interestingly enough I was reading about this exact thing earlier tonight and I think I passed some sort of test, like going from yellow belt to brown belt or maybe karate belts don't go in the same sequence as snooker balls. Anyway the eyes did not glaze over at this:

 

[snip]

Hint 2 not on the web is to thin the 30nf maybe w/10% to 15% water as it's a bit too thick right out of the can. I kept the top unscrewed but still sitting on the can and would raise the top up ( there is a long useless brush attached to the can top unless they have changed this in your kit) and dab a blunt toothpick or q-tip shaft ( no cotton ) to get a small drop of glue to touch onto the wire. I usually ran the q-tip shaft along the raised brush shaft from the can top to get my dabs. If you just leave the can open w/o the top/brush assy on it might start drying out the glue a bit in the bottle. I just decided to take the time to do it this way after doing the first panel. I used the glue full strength to do the tacking on the first panel and then decided to thin the glue for fear of running low and I felt the tacking spots were a bit too thick. I did 3 total coats of the thinned glue ( magnepan recommends 2 coats of full strength glue) using the recommended 3" foam brush. Brush along the wire only never across. The coating looked perfect to me but I could see all the places where I tacked the wire as brighter white spots. The remaining 3 panels done w/the slightly thinned glue had the tack spot virtually invisible w/the 3 thin coats of the glue.

Like any paint job thinner coats are always smoother and just build more coats if necessary. I saw some pretty ugly owner refurbed panel glue jobs on the web. Ensure you have good Glue "fillets" meaning 100% full glue diaphragm/wire contact for the whole panel length wiring.

When laying the center "doubled" wire runs remember to lay the first wire so it's edge is in the center of the field so that when you come back to run it's 'brother" you can lay it right up against the first run so that the pair will be centered in the magnet field. Using the thinned glue to tack also helps to lay the brother wire right up against the first wire. The glue dabs will wick around and under the wire so it spreads onto the diaphragm if done right. I also run the dabs along the wire a bit instead of just putting a blob in one spot.

 

[end snip]

 

https://www.audioasylum.com/cgi/vt.mpl?f=mug&m=189364

 

 

 

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9 minutes ago, ThirdDrawerDown said:

When considering the home for the #5 frankenmaggie it is a room 3.6m x 5.2m but with an open-plan design where two other rooms wrap around two sides of the room.  So with the doors and walls open (as they usually are) it is a 8.0m x 8.4m space (minimum).  Would I have to budget in four figures if I was considering Neos?

 

If you speak to the guys on the planar forum yes. You would need 6 per side.

If you were to follow @VanArn then 2 per side only. 

I would go for the  6 if only for the fact that someone has done it with 6 and not 2.

I wouldnt necessarily be rushing into the Neo's just yet though.

 

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7 hours ago, ThirdDrawerDown said:

Interestingly enough I was reading about this exact thing earlier tonight and I think I passed some sort of test, like going from yellow belt to brown belt or maybe karate belts don't go in the same sequence as snooker balls. Anyway the eyes did not glaze over at this:

 

[snip]

Hint 2 not on the web is to thin the 30nf maybe w/10% to 15% water as it's a bit too thick right out of the can. I kept the top unscrewed but still sitting on the can and would raise the top up ( there is a long useless brush attached to the can top unless they have changed this in your kit) and dab a blunt toothpick or q-tip shaft ( no cotton ) to get a small drop of glue to touch onto the wire. I usually ran the q-tip shaft along the raised brush shaft from the can top to get my dabs. If you just leave the can open w/o the top/brush assy on it might start drying out the glue a bit in the bottle. I just decided to take the time to do it this way after doing the first panel. I used the glue full strength to do the tacking on the first panel and then decided to thin the glue for fear of running low and I felt the tacking spots were a bit too thick. I did 3 total coats of the thinned glue ( magnepan recommends 2 coats of full strength glue) using the recommended 3" foam brush. Brush along the wire only never across. The coating looked perfect to me but I could see all the places where I tacked the wire as brighter white spots. The remaining 3 panels done w/the slightly thinned glue had the tack spot virtually invisible w/the 3 thin coats of the glue.

Like any paint job thinner coats are always smoother and just build more coats if necessary. I saw some pretty ugly owner refurbed panel glue jobs on the web. Ensure you have good Glue "fillets" meaning 100% full glue diaphragm/wire contact for the whole panel length wiring.

When laying the center "doubled" wire runs remember to lay the first wire so it's edge is in the center of the field so that when you come back to run it's 'brother" you can lay it right up against the first run so that the pair will be centered in the magnet field. Using the thinned glue to tack also helps to lay the brother wire right up against the first wire. The glue dabs will wick around and under the wire so it spreads onto the diaphragm if done right. I also run the dabs along the wire a bit instead of just putting a blob in one spot.

 

[end snip]

 

https://www.audioasylum.com/cgi/vt.mpl?f=mug&m=189364

 

 

What the guy may not have said in his article is to use a 6v SLA battery to run a current through the wires whilst the glue is drying, to pull the wires against the magnets which are behind the mylar.  This makes sure the wire is glued tight to the mylar.

 

Andy

 

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