Questions/Suggestions on refinishing 1.2TL's

RichCanDo

I am about to rework my crossovers with new resistors and capacitors, and install new grillcloth. As cabinets need to be disassambled to install side grillcloth, I am thinking of refinishing the walnut end caps and side panels due to a few small dings in veneer and a slight waterstain on top of an endcap.

Questions:
1) Can anyone recommend a good glue they have used to install grillcloth? (Ponte 100% polyester knit fabric)

2) Anyone know which Walnut stain Polk used on the cabinets? (mnfgr & stain color or #) Water based or oil stain? (I'd use Danish Oil stain which worked well in past, but not on speaker cabinets. It has a linseed oil base.)

3) Any reason to use 12 Watt Mills resistors rather than 5 Watt? (Originals are all 5 watt)

4) I obtained 8 new binding posts. After receiving them learned they will protrude about 3/8" past the rear cabinet face due to their length. Does anyone know where to obtain a new binding post plate that is deeper than the original, and will fit the origial hole size? (OK if hole has to be made larger.)

Thanks in advance for any suggestions.

george daniel

I have used Mills Mra 12 watt resistors, Vampire BP-Hex binding posts on SRS 2's 2.3's and 2.3 tl's , there are some excellent,,almost step by step threads on this subject,, use the search function in the upper right portion,,good luck and have fun. Capicators, most use solen Pb series or sonicap,, I have used both,,but never mixed the two brands

RichCanDo

I've read all the posts, none answer my questions.

F1nut

1. Any glue made for fabric will work.
2. Impossible to answer, but I guarantee the original was an oil based product. Use whatever color/brand you like, but I do not recommend Danish Oil products for this job. What clear coat finish are you planning in using?
3. Either will work. The 12 watt has a higher temp rating, the 5 watt has lower inductance.
4. There is nothing wrong if the posts aren't flush, don't worry about it.

ben62670

F1nut wrote:

4. There is nothing wrong if the posts aren't flush, don't worry about it.

I used washers on the posts. Thin plastic cups.

Ben

RichCanDo

Thanks for the input F1nut. Only want the binding posts to not protrude past rear face of cabinet as it makes them easier to lie on their backs to transport.

Was not planning to use any finish coat. If I did, would use a Satin Polyurethane. If endcaps were solid wood like my old SDA SRS's, I use Lemon Oil on them which provides some moisture to the wood to keep it from cracking. I've always liked the Danish Oil stain as it can be buffed to a high sheen and holds up well. (Though linseed oil smells bad.) Would like to keep to original materials if I can learn what they were.

Was looking at Fabric Glue today, never used it that I recall. Originally thought of using rubber cement as can easily be removed if cloth to be changed in the future. Contact cement is usually a bit messier, have to be real careful not to get it where it will show.

Just completed parts order to Parts Connexion as they have all the values I want for caps and resistors. Getting all Solen matched pair caps. Using 5 Watt resistors which saves about $20. Will most likely mount all resistors on the opposite side of the xover board, above the board with a ceramic spacer on the leads for some air circulation. This allows more room for the larger caps.

Looked the crossovers over pretty good, appears the traces will allow new holes to be drilled for leads so component leads do not have to run at odd angles.

Ricardo

Looks like you have everything well planned. I had the same concern with the binding posts, but it is not a big deal as long as YOU REMEMBER when/if they need to be transported. Wouldn't be nice to put them on their backs and hear something break

I used a couple of 2x4 pieces below each speaker when I sold mine. That did it.

F1nut

Like HT said, just support them properly and if you have the original cartons it's a non-issue.

Lemon oil is nothing but mineral oil with lemon scent added to it. It's crap. Danish Oil offers little protection unless you apply 5 or more coats and it slowly evaporates with time, not good.

You do not want to add moisture to wood, period. Wood should have no more more than 8% moisture content when used to construct furniture, that is considered dry, stable wood. Clear coat finishes are used, in part, to keep moisture out and are the best choice for protection and beauty. The original stain doesn't matter, just find a color that's close or that you like. The original finish was sprayed lacquer, always an excellent choice.

Any craft or fabric store will have fabric glue.

Mount the resistors vertically, saves space and provides circulation.

Drilling new holes is a bad idea and really isn't necessary. Review the countless crossover upgrades posted here for examples of how easy it is to bend the leads to fit the exsisting holes.

RichCanDo

Thanks again F1nut. Been reading all the upgrade posts for about a year. From xover board measurements I've taken I am hoping to come up with a better component layout than I have seen used by others. Don't know if it wiil work until I actually have the parts and try though. Mounting resistors vertically usually provides best air circulation. But, I think mounting them horizontally, spaced from the board on the opposite side will provide better circulation than vertically mounted close to and in between large capacitors. This also allows more room to mount the new caps.
Project may now be on hold for awhile as the house I am in has just been sold, so will be moving. Did not expect sale to be for at least 2 months but sold as soon as went on the market.

Deadof_knight

What characteristic do you hear with the two different caps Anonymouse ? Ht used solens Ibelive in my 1.2s ?( Im not looking to change them really just curious.)

RichCanDo

I am taking others word for it about Sonicaps for Highs. Wrote Sonicraft 2 days ago for price quote including .25 uF custom value caps as not a value they stock. No reply yet. Will use Solens for low freq.
Wrote Parts Express for Solens, they will not match cap pairs. I want two 6.8 uf paralleled to equal 13.5 uf +/- 1% as I prefer to use paralleled caps near the same value.
Today wrote Parts Connexion to see if they will match the caps, I assume they will. New grill cloth arrived today.

Ricardo

Deadof_knight wrote:

What characteristic do you hear with the two different caps Anonymouse ? Ht used solens Ibelive in my 1.2s ?( Im not looking to change them really just curious.)

I did use Solens on my (errr....your ) 1.2's; I used Sonicaps in my 3.1's. With the Sonicaps I noticed improvements all over the frequency range; with the Solens improvements were more noticable with bass. Neverteheless, I was very happy wit the results in the 1.2's and I wouldn't recommend you to make the change. Maybe from Solen to Sonicaps you don't hear an improvement worth the difference....maybe you do, but they sound pretty good as they are, right?

F1nut

Rich, friendly tip.....call, don't write.

Gino1550

I have a pair of Sda 1.2 speakers.
Where can I get replacement tweeters?
Where can you get the up grade fuse for the tweeters
Is it a very hard project

F1nut

Welcome to the forum.

The search function is your friend.

RichCanDo

Received upgrade suggestions from Sonic Craft today after sending them the high frequency only part of the 1.2TL crossover schematic.

One recommendation was to never connect resistors in series, but always connect in parallel to meet target value. I've worked as a technician and have been an electrician for 35 years. Only time I've ever connected resistors in parallel was when I did not have correct values for series, but had values that worked when paralleled. Appears crossovers are different than other circuits! (Yes, they said resistors should be in parallel. Even sent values for the 11.5 ohm, as this only unavailable value. - Has nothing to do with capacitors. Just mentioning this before someone asks if I mean capacitors in parallel.)

Another suggestion was to use Mills 12 watt resistors rather than 5 watt due to "sonic flavor" in this application. $11.90 above 5 watt cost.

Schematic calls for a 22.5 ohm resistor. Recommendation was 22 ohms is good enough as it is part of a Notch Filter.

Schematic calls for a 250 Volt .25uF cap across the inductor. Recommendation was to use a 200V, .22 uF Gen II. (Said they'll probably come up with a .23-.24uF value.) Though in main signal path, my assumption is 200V is good enough, as other caps are less voltage. (Had asked if I should parallel a 400V & 600V, or use two 600V caps, or have a custom .25uF value made.) $17.00 less than using paralleled .15 & .10uF 600v caps.

Any comments on these recommendations? Any electrical engineers have input?

Ricardo

You should be fine with all those recommendations; Jeff suggested similar things when I did the 3.1's. I did the parallel resistors also.
Did he recommend a Platinum 0.1uF in place of the by pass capacitors (Silver Mica)? Thought you should know some of us used that but decided to remove it later; a $60 adventure for me, since Jesse did suggest I should not use it. They make the highs a bit unnatural IMO.

engtaz

HTrookie,

Are you going to do a how to article on 3.1's. Not much is out there and I am just asking if you can post a 1, 2, 3 on 3.1's upgrading.

Thanks,engtaz

Ricardo

http://www.polkaudio.com/forums/showthread.php?t=47929&highlight=3.1%2A

RichCanDo

I have a pair of Sda 1.2 speakers.
Where can I get replacement tweeters?
Where can you get the up grade fuse for the tweeters
Is it a very hard project

Polk Customer Service. SEARCH WORKS!

Deadof_knight

I was just curious since You had done the modification already to the 1.2s that you sold to me. dont get me wrong I love them, just poking around seeing what the difference is or was in the caps, and how they sound

F1nut

never connect resistors in series

First time I've heard that one.

Agreed, forget the bypass caps.

RichCanDo

Did he recommend a Platinum 0.1uF in place of the by pass capacitors (Silver Mica)?

I had sent a list of caps & resistors required only for a price quote. The only recommendation I asked for, was a recommended replacement for the .25 uF cap as it is not a stocked value, and is in the main signal path.

I am not going to change the Silver Micas as these do not go bad like electrolytics. (They are never replaced in radio circuits when other caps are changed due to age.) There is a good post regarding changing these by DarqueKnight which includes values of other caps tried in different model speakers. I believe this post states Polk recommends not changing the micas. Also, as others have stated, appears to be no real difference with bypass caps in or out of circuit when good film caps are used, other than adding artifacts if other than silver micas are used.

Ricardo

I would try the sonicaps without the silver micas; you might be in for a good surprise; give them 100 hours to break in, and if you don't like it, put the silver micas back.

RichCanDo

I thought of trying the upgrade without the silver micas. If I remember correctly, DarqueKnight stated he heard no difference with the micas in or out of the circuit. (May have pertained to another model SDA) I thought of adding a temporary switch outside the cabinet to be able to switch the bypass caps in and out of the circuit for an A/B comparison. The length of wire required for a switch, may alone cause a difference in the true sound though.

F1nut

Also, as others have stated, appears to be no real difference with bypass caps in or out of circuit when good film caps are used, other than adding artifacts if other than silver micas are used.

The sliver mica's will add artifacts also. The only reason to use a bypass cap is to improve the sound quailty when using electrolytic caps.

Polk65

Is there a special tool to easily remove the flush grille staples?