1.2tl recap (resistor questions)

Gerres26

Hey guys, im thinking I'm going to start ordering some parts to recap my 1.2tl's in the near future. I've decided on claritycap esa for the caps since i found them at a very good price right now and i hear great things about them. I was thinking of going with Mundorf mox resistors but I'm having a little issue finding the exact values. Closest value i could find for the 7.5ohm is 8.2, then a 22 in place of the 22.5 and a 12 in place of the 11.5. Will this work or is this a bad idea when it comes to resistors? Any input is appreciated.

F1nut

Some will tell you they will work. I'm telling you they won't. I can easily hear the different of less than .5 ohms. Get the Mills.

gimpod

For the 11.5 & 22.5 you'll have to get the Vishay Mills as Vishay bought out Mills. (I still need to update my site)

Here for the rest parts 1.2tll

Gerres26

I just checked, i still couldnt find an 11.5 listed under mills or vishay. Do you guys feel the mills/vishay are superior to the mundorfs? I know they're probably twice the cost.

pitdogg2

They are both good with a little lean maybe to the mundorf, mills are usually the cheaper of the two. Both are far superior to originals.
Agreed get the right ohm value, you can go up in wattage if you like but stick to ohm value

F1nut

Gerres26 wrote: »

I just checked, i still couldnt find an 11.5 listed under mills or vishay. Do you guys feel the mills/vishay are superior to the mundorfs? I know they're probably twice the cost.

Use an 11 and .5 in series to equal 11.5. Make sure you use the 12 watt version.

FTGV

Gerres26 wrote: »

Will this work or is this a bad idea when it comes to resistors? Any input is appreciated.

I'll add a few points of interest. Dependent upon where the resistors are positioned circuit wise in the crossover a .5 ohm change will translate into something like a very small response difference of a fraction or a db so. Also drivers themselves are rarely perfectly matched. It is not uncommon for samples of the same driver model even from same production batch to exhibit sensitivity and frequency response differences of 1db or more over parts of their operating range. These differences are likely to swamp the small variation in resistance. Unless Polk went to the trouble of testing and sorting resistors the original sand cast resistors likely had a tolerance of +or- 5% (or more) so may actually be an ohm or more different than their stated value to start with. While precise matching parts is a good thing there are other variances at play.

Gerres26

Thanks for all the input fellas. One more question, gimpods site says use between .1 and .5 ohm to replace the polyswitches so what value should i go for ideally?

westmassguy

.5 ohm

Gerres26

pitdogg2 wrote: »

They are both good with a little lean maybe to the mundorf, mills are usually the cheaper of the two. Both are far superior to originals.
Agreed get the right ohm value, you can go up in wattage if you like but stick to ohm value

If it's the mundorf mox 10 watt resistors, they are $1.79 a piece as opposed to the mills that are just over $4. Just so i get this straight, i can wire resistors in series to reach a certain value by adding them. Kind of like running caps in parrallel by adding their values?....sounds confusing when i re-read it, but hopefully u get what im saying

pitdogg2

I wasn't aware the Mundorf's were that cheap. I wrongly assumed they would be a dollar or two more.

westmassguy

Gerres26 wrote: »

pitdogg2 wrote: »

They are both good with a little lean maybe to the mundorf, mills are usually the cheaper of the two. Both are far superior to originals.
Agreed get the right ohm value, you can go up in wattage if you like but stick to ohm value

If it's the mundorf mox 10 watt resistors, they are $1.79 a piece as opposed to the mills that are just over $4. Just so i get this straight, i can wire resistors in series to reach a certain value by adding them. Kind of like running caps in parrallel by adding their values?....sounds confusing when i re-read it, but hopefully u get what im saying

It's the inverse of adding capacitors together. If the resistors are equal value, the result will be half. You can create many different end values by combining different values. I use an online calculator like this one:
http://www.1728.org/resistrs.htm

F1nut

Gerres26 wrote: »

pitdogg2 wrote: »

They are both good with a little lean maybe to the mundorf, mills are usually the cheaper of the two. Both are far superior to originals.
Agreed get the right ohm value, you can go up in wattage if you like but stick to ohm value

If it's the mundorf mox 10 watt resistors, they are $1.79 a piece as opposed to the mills that are just over $4. Just so i get this straight, i can wire resistors in series to reach a certain value by adding them. Kind of like running caps in parrallel by adding their values?....sounds confusing when i re-read it, but hopefully u get what im saying

More or less. You also have to pay attention to the wattage values.

Get the Mills, better sounding.

DarqueKnight

Gerres26 wrote: »

Closest value i could find for the 7.5ohm is 8.2, then a 22 in place of the 22.5 and a 12 in place of the 11.5. Will this work or is this a bad idea when it comes to resistors? Any input is appreciated.

The things to be mindful of are the tolerance range of the original part and the tolerance range of the replacement part. Optimal performance will be achieved when the replacement part is the same as, or very close to the nominal design value.

The chart below shows the nominal and measured values of the original resistors taken from my SDA SRSs.



Mills didn't make a 22.5 ohm resistor. I used a 22 ohm instead. Mills' MRA-12 resistors have a 1% tolerance, therefore the 22 ohm resistor would fall well within the tolerance range of the original resistor.

When I did my 1.2TL mods, Mills didn't make an 11.5 ohm resistor. I used an 11 ohm instead. When I replaced the Mills resistors with Dueland resistors, Dueland provided all the nominal values.

Gerres26

Thank you for the in depth info. So im assuming the 11ohm mills worked fine for you?

Gerres26

I plan on doing the recap in the next couple days hopefully. The only question i have for now is about the silver micas. Do i just remove them or am i supposed to replace them with a jumper?

westmassguy

Just remove them. Do NOT jumper. They are wired in parallel with the bigger cap.

Gerres26

Ok, thanks. I thought that was the case but i wasnt confident enough that i remembered correctly.