Monitor 10 Rebuild with "TL" Mod

NJPOLKER

westmassguy wrote: »

Thanks NJPOLKER. I'm 10 minutes from Six Flags New England

Where the hell is that?

Yeah I know I can/should look it up.

westmassguy

NJPOLKER wrote: »

Where the hell is that?

Yeah I know I can/should look it up.

Over the river and through the woods from Springfield

Face

Nice job!

westmassguy wrote: »

I've been veneering on and off since I was 15 or 16. It's not as difficult as you would think.

I agree, beveled edges may be difficult for a newb, otherwise it's not all that bad at all.

westmassguy

Face wrote: »

Nice job!

I agree, beveled edges may be difficult for a newb, otherwise it's not all that bad at all.

Thanks Face. Lon-guy-land? Used to live in Wantaugh

Face

That's funny, I used to live there too.

westmassguy

Face wrote: »

That's funny, I used to live there too.

Small world

Ibjammin

westmassguy wrote: »

This project was a lot of work, but a lot of fun as well. In addition to the Crossover rebuild and modification, the cabinet was re-worked as well. Clarity ESAs were chosen for the Hi-Pass, Mills Resistors, Dayton 5% for the Lo-Pass, and Jantzen Inductors for the "TL" modification. I like using the Daytons for the Lo-Pass shunts for several reasons. Their quality is consistant, and they're relatively small compared to the Clarity PX or SA caps some others may prefer, and in my opinion, their sound is neutral when used in the shunt position. Changes required for the "TL" Mod included changing the Resistor in series with the Tweeter, and changing the Inductor located in the shunt. The resistor wasn't a problem, however the Inductor was a bit problematic. Jantzen had the exact value I needed, 0.27mh, but the DCR was slightly less than required. To compensate, I raised the value of the 2.7 ohm Resistor in series with the Inductor, to 3.0 ohms. This kept the overal resistance value of the shunt in line with the revised schematic, and would maintain the desired voicing of the new Tweeter. In addition to the other modifications, the Polyswitch was removed, and replaced with a 0.5 ohm resistor. All Resistors were relocated to the underside of the circuit board, to allow more room. A new supplimental riser board was fabricated and installed for the Clarity ESAs. New Nylon Stand-Offs were installed, and New Cardas Binding posts were added to complete the Crossover upgrade.

Westmassguy,

Really nice work on the mod. I was contemplating tackling the same. I see that you used Clarity ESAs rated at 630V. I don't know if the 250V ESAs were available at the time you did your mod, but they are available now, and they are cheaper. I checked out the crossover in my monitor 10Bs, and the highest rated cap was the 250V 12 microF Mylar. So,

1. Do you believe that the 250V version would be adequate (I.e. not blow up)?
2. Would it sound similar to the 630V version?
3. What advantage would the 630V have over the 250V version (I don' usually listen to really loud music)?

Thanks for any forthcoming clues!

westmassguy

Ibjammin wrote: »

Westmassguy,

Really nice work on the mod. I was contemplating tackling the same. I see that you used Clarity ESAs rated at 630V. I don't know if the 250V ESAs were available at the time you did your mod, but they are available now, and they are cheaper. I checked out the crossover in my monitor 10Bs, and the highest rated cap was the 250V 12 microF Mylar. So,

1. Do you believe that the 250V version would be adequate (I.e. not blow up)?
2. Would it sound similar to the 630V version?
3. What advantage would the 630V have over the 250V version (I don' usually listen to really loud music)?

Thanks for any forthcoming clues!

Thanks. Madisound didn't have any ESA 250 v stock to speak of when that project was done. They are selling off the remainder of their 630 volt inventory now, as well as the entire Clarity SA line.
The 250 volt will be more than enough, and I'd venture a guess that most of the old caps in there now are 100 volt.
Sonically, I can't imagine any real difference between the two.
If you're doing the TL Mod, pay close attention to the Hi-Pass Shunt Inductor, The only available inductor was the Jantzen, which was one gauge thicker, so the resistor that follows was increased to 3.0 ohms to compensate.

Ibjammin

westmassguy wrote: »

Thanks. Madisound didn't have any ESA 250 v stock to speak of when that project was done. They are selling off the remainder of their 630 volt inventory now, as well as the entire Clarity SA line.
The 250 volt will be more than enough, and I'd venture a guess that most of the old caps in there now are 100 volt.
Sonically, I can't imagine any real difference between the two.
If you're doing the TL Mod, pay close attention to the Hi-Pass Shunt Inductor, The only available inductor was the Jantzen, which was one gauge thicker, so the resistor that follows was increased to 3.0 ohms to compensate.

I did notice that and thanks for reminding me. I have another question (for now!):

In one of these threads, a guy had pulled his polyswitches and measured their resistances in the 1.3 to 1.7 ohm range. You and others have settled on replacing the PS with a 0.5 ohm resistor. Just wondering how that value was settled on?

westmassguy

Ibjammin wrote: »

I did notice that and thanks for reminding me. I have another question (for now!):

In one of these threads, a guy had pulled his polyswitches and measured their resistances in the 1.3 to 1.7 ohm range. You and others have settled on replacing the PS with a 0.5 ohm resistor. Just wondering how that value was settled on?

Experience and simple mathematics. If you go through the vintage schematics for the Monitors, RTAs, even some SDAs, you'll note whenever a previously fused Hi-Pass section was changed to the Polyswitch, the resistor directly downstream was reduced by .5 ohms most of the time, or .3 ohms in a very few instances.

Ibjammin

westmassguy wrote: »

Experience and simple mathematics. If you go through the vintage schematics for the Monitors, RTAs, even some SDAs, you'll note whenever a previously fused Hi-Pass section was changed to the Polyswitch, the resistor directly downstream was reduced by .5 ohms most of the time, or .3 ohms in a very few instances.

Darn good detective work.

I just checked madisound - looks like they now only have the 12 uF ESAs in 250V series now...

westmassguy

As I said, they're selling off whatever inventory they have left of the ESA 630s, and the SAs

Ibjammin

I saw your note about the RDO-198 inventory - bummer. Still getting my ducks in a row, tho. The M10-SL3000mod schematic has a 2.0 ohm resistor that is slashed out and handwritten in as 2.7 ohm. Can you confirm that this resistor value should be 2.7 ohm?

If it is 2.7, Parts Express has a Dayton that would work. Are Daytons good enough - most people seem to like Mills?

Thank you again.

westmassguy

Ibjammin wrote: »

I saw your note about the RDO-198 inventory - bummer. Still getting my ducks in a row, tho. The M10-SL3000mod schematic has a 2.0 ohm resistor that is slashed out and handwritten in as 2.7 ohm. Can you confirm that this resistor value should be 2.7 ohm?

If it is 2.7, Parts Express has a Dayton that would work. Are Daytons good enough - most people seem to like Mills?

Thank you again.

If you're going to do it, do it right, Mills or Mundorf Mox. The P.E. Sand Cast resistors are no better than the ones in there now.
You will need the following resistors: 0.5 ohm to replace the dodgy polyswitch, 2.7 ohm to replace the 2.0 ohm, and a 3.0 ohm to replace the 2.7 ohm in the shunt, which is required to maintain the overall resistance of the shunt after you replace the .4 mh inductor with the .27 mh inductor.

pitdogg2

Do not try and save a dollar here on that sandcast resistor. Mills are cheap and very good.

F1nut

Not sure how I missed this one....excellent job!

westmassguy

F1nut wrote: »

Not sure how I missed this one....excellent job!

Thanks F1

philr168

those look nice

westmassguy

philr168 wrote: »

those look nice

Thanks

On3s&Z3r0s

Face wrote: »

Nice job!

westmassguy wrote: »

I've been veneering on and off since I was 15 or 16. It's not as difficult as you would think.

I agree, beveled edges may be difficult for a newb, otherwise it's not all that bad at all.

I hope no one minds me resurrecting this thread for a veneer question...

I have two sets of speakers I will be re-veneering. The first is a test run for me to make all my mistakes on. They are a pair of newer Monitor 4s, and the important pair is a set of Monitor 5jr+ I'd like to get right. The 5jr's had some bad enough dings in the cabinets that I pulled all the old vinyl veneer off, so I'm down to bare MDF and will bondo the spots that need it. The black "oak" vinyl on the 4's is in good shape so I'm debating whether to remove that before adding the PSA backed veneer.

Anyway, both sets have the same angled bevel as on these 10's so I was hoping someone would have tips on how to handle the bevel. Do you make a clean cut and just do the bevel in strips, or do you try to just score the veneer along the back to help it make the bend? If any of you veneer experts (the level of skill here and on the forum in general is dam* impressive) has any tips, they'd be much appreciated. Thanks!

On3s&Z3r0s

I think I just found a partial answer to my own question... just found another thread that references this one: http://forum.polkaudio.com/discussion/158653/refinishing-a-pair-of-5jrs

It mentions westmassguy using egde banding for the bevel, so I guess my only question would be how best to trim? Just a very sharp box cutter type razor blade?

Also, I got the Rockler African Mahogany veneer. The same thread mentions Wunderfil as a grain filler, but they don't have a Mahogany color. Should I go with something more neutral like a water based filler or just match the filler color to the stain color I end up using?

nspindel

I used this when I did my veneer job. It worked really well, but you must only cut with the grain, You'll make a royal mess if you try to use this to cut across the grain:

http://www.parts-express.com/band-it-edge-trimmer--260-058?utm_source=google&utm_medium=cpc&utm_campaign=pla

westmassguy

I use a utility knife with a hardwood block. Hold the block against the face of the veneer you're trimming. Hold the utility knife flat against other veneer, and make a continuous cut, moving the block as you go. Once you get the hang of it, you'll fly through these types of projects. Some still use veneer saws, but they tend to make a mess of things.

On3s&Z3r0s

Thanks for the tips. There's a FastCap trimmer with some demo videos that makes it look pretty effortless, but since these are smaller speakers I'll have about as much cross-grain trimming as with the grain, and the tear-out seems like a probable outcome given my newb-ness and lack of dexterity generally. I think I will give the block and utility knife method a try since I even found a video of someone doing exactly that on YouTube. It looked pretty simple too, although it was a thin edge band getting trimmed. Hopefully by taking my time and doing bottoms first I'll get my technique down.

The videos I've seen have guys trimming the edges within minutes of setting the PSA backed veneer, so I guess there's enough grab right after a hard smoothing that you don't need to worry about unsticking while trimming.

Speaking of YouTube videos, you should definitely have a channel, westmassguy. It'd be Norm Abrams meets Joseph D'Appolito. That'd be a nice break from cats playing pianos.

Thanks again to both of you for the input.

Nightfall

Good idea! Westmassguy, start doing some how to videos and putting them on YouTube. I'll subscribe to your new channel. Then when somebody asks how to do something you can show them instead of tell them as well as add a tidbit about your speaker services and how to contact you. A little advertising as well as helping people out.

westmassguy

I appreciate the thought guys, but I've got enough on my plate right now. Don't have time to start a YouTube Channel, make videos, and work to keep a roof over my head. Polkies can always PM me, or contact me through my website.

xschop

Very nice veneer job WMG. Thanks for redirecting here. These older threads are hard to find when doing searches.

westmassguy

xschop wrote: »

Very nice veneer job WMG. Thanks for redirecting here. These older threads are hard to find when doing searches.

My pleasure

Toolfan66

WOW!!! How the hell did I miss this old thread?? Fantastic Job, I have been on the search for some Monitor 7's to play around with, I so regret letting go of mine years ago..

westmassguy

Toolfan66 wrote: »

WOW!!! How the hell did I miss this old thread?? Fantastic Job, I have been on the search for some Monitor 7's to play around with, I so regret letting go of mine years ago..

Thanks. Monitor 7s are my favorite of the series.