Picked up a pair of RT35i...

adam2434

Pick up a minty pair of 35i a couple days ago on CL. Always had a “thing” for this RT series for some reason…the trilam tweeters, blue drivers, nice build quality, and great sound for the money. Helped a couple friends set up their first 5.1 systems in the early 2000’s with 2 pair of 25i and the CS245i. These were my go-to reco for the money at that time.

I use a CS400i with LS90’s in the 5.1 system in the finished portion of the basement.

Always wanted a pair of 55i and 800i, and still keep an eye out for them on CL.

Anyway, I’ll be playing with the 35i in a budget 2.1 system in the unfinished gym/workshop area of our basement. This is my “test” system that I have used to play with a couple dozen bookshelf models over the years.

I currently use NHT SB2 in this system, and swapped in the 35i, followed by a quick SPL calibration. BTW, the 35i are about 5 dB more sensitive than the SB2, based on the SLP calibration, and are identical to the S20 that I previously played with.

My initial impression of the 35i are that they are pretty balanced, but a bit mellow in the high frequencies – not bright at all and lacking a little shimmer and bite in the highs. The work “polite” comes to mind, not a bad thing per se, as I think they will be pretty forgiving and easy to listen to.

Wow, I had the RTi8 for a while. Super bright to the point of being unlistenable, IMO. This makes me curious about the sound of the current RTi A series vs. the older RTXXXi series (trilam and blue drivers).

Anyway, just a little love for this older RTXXXi series…

dromunds

Have you tried the RT-35i's on some of your other power? Just curious as to what effect on the highs you mentioned that would make?

adam2434

dromunds wrote: »

Have you tried the RT-35i's on some of your other power? Just curious as to what effect on the highs you mentioned that would make?

Hi, yes, my initial listening was with the Rotel RB-1582 MKII and Emotiva DC-1, with the 35i running full range in the same room. I have speaker wire running from the basement media room into the unfinished part of the basement so that I can power speakers from the media room or the 2.1 system in the unfinished part of the basement.

My impression of a bit mellow highs is with both systems. Not a bad thing...just my impression of the flavor relative to some of the numerous speakers I've had in this room. However, for reference, the original Elac B6 were much more mellow, to the point of sounding dull, IMO. And the NHT SB2 that I've been using just prior have a bit more detail and liveliness in the top end, but do not sound overly bright to me.

adam2434

Anyone happen to have a diagram of the RT35i crossover?

Already checked the crossover sticky, and it is not listed.

Thinking they might be a good candidate for some basic upgrades - Dayton Precisions and Mills, as both of these really opened up my 7C's.

If I had to guess...probably second order on both the tweeter and woofer, so 2 caps there, plus maybe a mylar bypass cap on the tweeter (which I would plan to eliminate). I would probably stay with a new electrolytic in the woofer circuit due to space. Probably a resistor in the tweeter circuit for attenuation - would go with a Mills there.

dromunds

Can't help you there, but I gave a pair of RT35i's to a friend of mine a few years back to use in his basic HT set-up. They are not 7C's but I have always thought they sounded pretty decent for bookies .

adam2434

Yeah, I think they sound pretty good, albeit a tad mellow in the highs.

Pushing 20 years old, so thinking some crossover upgrades might improve them a bit, and have not had a crossover project in a while, so have the itch to break out the soldering iron.

I emailed Polk CS asking if they can provide the crossover diagram. Not sure if they do that type of thing, so we'll see...

I can always remove a crossover to determine the cap and resistor values, but always like to start with a diagram, if possible.

msg

Love that series. I've only heard the 25is so far, but I'd love to try the 35i and 55i, and have heard good things from @Jimbo18 re: the 600/800i. The RTxxi is one of my favorites, along with the vintage and LSiM.

If you like them now, I can only imagine how much better they'll be after the crossover upgrades. Now you've got me thinking about cracking open my 25is...

honestaquarian

I've had a pair of 35i's for twenty years now that I bought new. They are definitely not bright like some of the newer models became known for. I had a bit of a surprise once when I was powering them with a Carver The Receiver 900 about a decade ago. I was playing around with one of my Pierre Verany test CD's running bass test tones and was SHOCKED at how strong a 31.5hz bass tone I was getting out of these suckers in my tiny bedroom!
That power port is amazing!

verb

Nice! I have a couple sets of RT35i's! They are destined to be included in my HT setup in the basement, whenever I get to it!

adam2434

Yeah, I would have heavily considered this RT series for my first 5.1 system if I had not bought 4 NHT SuperOnes and the SuperCenter a year or two prior to this RT series coming out. Loved those NHT's too, with a Velodyne 1012 sub (or model # close to that). Ahh, the memories...seeking out concert DVDs to play in 5.1 on that system (still play those DVD's, BTW).

Anyway, these 35i's will go into the stockpile of gear that I will give my kids when they move out. It's been fun picking up older speakers on the cheap and re-capping them and redoing the foam surrounds on a couple models The kids will definitely have some vintage stuff someday...all the way back to a pair of AR 18s from around '83.

honestaquarian

One of the things that I really liked about the 35i's is their near holographic imaging. right now I'm using one of them as the back surround in the living room home theater. i found a pair of RT-55's and absolutely love the way they blend with the stereo pair of PSW-200's. The 35i's blended well with them, but the 55's just do it better. I also ran the 55's without the subs for a while and was amazed at their ability to shake the floor on organ pedal notes! They sounded even better after I swapped out the SL-6502 tweeters for the SL-6506's from the 35i's and 55i's.

skrol

I picked up a pair for cheap just because I wanted to play with them for a while. I agree with other's comments about the highs. Still a nice sounding speaker. Very solid and heavy. I can't imagine hanging them from the plate on back.

I'm not sure what I'll do with them. They might go to my dad or one of my kids.

honestaquarian

@skrol
It’s been hanging from the back plate for about a decade.

honestaquarian

verb wrote: »

Nice! I have a couple sets of RT35i's! They are destined to be included in my HT setup in the basement, whenever I get to it!

@verb just so you know I’ve always run my 35i’s full range with no crossover in my home theater. They can handle it!

K_M

Take some inside pics, if you happen to open them up!

mantis

I had the RT35i's as surround back speakers. They where fantastic at that time. I loved my RT and RTi system then. Great speakers.

adam2434

Took a look at a RT35i crossover last night. Polk CS sent me a schematic of RT35 crossover, and said it was also used in the RT35i. Based on the actual part values, this is not the case.

Here are the actual values:
C1 = 9 uF
C2 = 0.47J (uF, I assume)
C3 = 16.5 uF

The board does not have much extra space, and C1 and C3 are radial NPE’s, which complicates replacement options a bit.

For C3 (low pass shunt), I’m thinking I will just go with an axial 17 uF NPE from Dayton. I can’t find a radial of this value, but should be able to figure out a way to make the axial leads work. 17 uF is within 3% of the stock value, and a new NPE in the low pass shunt is “good enough” for these speakers, IMO. Plus, fitting a film cap of that value is probably not possible anyway.

C1 and C2 are in parallel in the high pass (totaling 9.47 uF). Not sure what I’m going to do here yet, and
open for suggestions. I need to do some measurement to determine what will fit. Here are some of the options that I am considering.

1) Dayton Precision 4.7 uF x 2 (9.4 uF total) . I might be able to fit one on the top side and one on the bottom side of the board. Need to do some measurements.

2) A Dayton 8 uF NPE axial and Dayton Precision 1.5 uF (9.5 uF total). If fitting 2 film caps are an issue, I could use an NPE and a film cap, like the stock crossover. The stock crossover uses a 0.47 uF mylar bypass cap. Any issues with using a larger value 1.5 uF film cap in parallel with an 8 uF NPE?

In the photos, C1 is the red circle and C2 is the yellow circle.

Another option is just going with a single 9 or 10 uF Dayton Precision, which would be within 5-6% of stock, but will probably be too big.

Any other ideas on C1 and C2 replacement, considering the space constraints?

I am leaving the stock resistors in place because one of the inductors would need to be removed to replace the resistors.

adam2434

The first pic above should not have been inserted within the text - not sure what happened there. The first pic is C3.

adam2434

I replaced the RT35i capacitors on Jan. 19. Used Dayton Precision 2.7 and 6.8 uF for C1 and C2 (totaling 9.5 uF to replace the stock 9 and 0.47 uF. I went with a Dayton 17 uF NPE for C3, replacing the stock 16.5 uF.

Had to get creative with the 2.7 and 6.8 uF placement. I mounted the 2.7 uF vertically at C1, and mounted the 6.8 uF at C2 horizontally on the bottom of the board. Then I used a fair amount of hot melt to reinforce the mounting - not pretty but gets the job done (see pics). I can't see anyone else doing future crossover work on these, as they will be given to one of our kids, or another family member or friend.

I also mounted the 17 uF at C3 vertically. The stock cap had radial leads, and the new 17 uF has axial leads, but you can generally make axial leads work vertically, if the leads are long enough.

The highs have more "life", energy, and detail with the new caps - a noticeable improvement.

verb

Nice! Good job!

adam2434

But there is some bad news with these RT35i's.

Both speakers (one is worse) have a fuzzy distortion or resonance with certain material. It sounds like it is coming from the midwoofers. I noticed it on the piano solo in "All there is of Me" from Delbert McClinton's Nothing Personal (this is one of my "desert island" albums, BTW).

The midwoofers do not have any voice coil scraping. Also, I removed a midwoofer from the cabinet (still connected) and can't hear the distortion/resonance issue playing this material. Makes me wonder if it is a resonance in the midwoofer or cabinet when the midwoofer is mounted.

It sounds very similar to what this guy described in his RT600i's.
https://forum.polkaudio.com/discussion/68489/rt600i-distortion

Not sure what's causing it, or if it can be fixed. One thing I wonder is whether the shielding can around the magnet can resonate.

verb

adam2434 wrote: »

But there is some bad news with these RT35i's.

Both speakers (one is worse) have a fuzzy distortion or resonance with certain material. It sounds like it is coming from the midwoofers. I noticed it on the piano solo in "All there is of Me" from Delbert McClinton's Nothing Personal (this is one of my "desert island" albums, BTW).

The midwoofers do not have any voice coil scraping. Also, I removed a midwoofer from the cabinet (still connected) and can't hear the distortion/resonance issue playing this material. Makes me wonder if it is a resonance in the midwoofer or cabinet when the midwoofer is mounted.

It sounds very similar to what this guy described in his RT600i's.
https://forum.polkaudio.com/discussion/68489/rt600i-distortion

Not sure what's causing it, or if it can be fixed. One thing I wonder is whether the shielding can around the magnet can resonate.

Aw man! Did this issue appear before you made the tweaks to your XO?

adam2434

I did not play that track before the crossover work, so can't be sure. Also, I didn't listen to them much or critically before the crossover work.

I don't think it's related to the crossover though. The NPE I used in the woofer circuit (shunt) is within 3% of the stock value, so I don't think I changed the crossover function with the new cap.

It very much sounds like the same issue the guy had with his RT600i's in the link above.

I have only heard the issue on this one track with dominant piano. I'm going to listen to more piano to determine if it shows up more widely.

If the issue is not present in 95% of content, I'm not going to worry too much about it. I plan to gift them someday, and I don't think the recipient will notice or care.

honestaquarian

Hey
Is that specific distortion issue still present now that you’ve had more break in time with the crossover upgrades?

audioluvr

That orange thing looks like a thermistor which should be replaced with a 0.47 ohm resistor. Also those sandcast resistors should be replaced with mills resistors. Would need to see the schematic to be sure though.

adam2434

honestaquarian wrote: »

Hey
Is that specific distortion issue still present now that you’ve had more break in time with the crossover upgrades?

Hey, been a while since I visited this thread.

No, more time has not changed anything. Actually, I had them boxed up for a while and broke them out for a little listening this weekend.

The distortion, or maybe a resonance (not sure which) is there in piano and electric guitars on a couple tracks. It is not noticeable 95% of the time. It almost sounds like it is coming from inside the cabinet, like maybe an internal driver or cabinet resonance. However, the cabinets are pretty heavy and well-braced, so I really doubt it is a cabinet wall resonance.

adam2434

audioluvr wrote: »

That orange thing looks like a thermistor which should be replaced with a 0.47 ohm resistor. Also those sandcast resistors should be replaced with mills resistors. Would need to see the schematic to be sure though.

The orange part is the mylar bypass cap in the tweeter circuit. I eliminated it (pic above).

I could not replace the resistors without removing one of the inductors, so I just left them stock.

pitdogg2

audioluvr wrote: »

That orange thing looks like a thermistor which should be replaced with a 0.47 ohm resistor. Also those sandcast resistors should be replaced with mills resistors. Would need to see the schematic to be sure though.

Nope that .47uf is known as a gumdrop cap. It is not a polyswitch or thermistor.

Is the plastic bezel around the woofer and tweeter loose?

adam2434

pitdogg2 wrote: »

audioluvr wrote: »

That orange thing looks like a thermistor which should be replaced with a 0.47 ohm resistor. Also those sandcast resistors should be replaced with mills resistors. Would need to see the schematic to be sure though.

Nope that .47uf is known as a gumdrop cap. It is not a polyswitch or thermistor.

Is the plastic bezel around the woofer and tweeter loose?

No, I've got the plastic bezel very tight, checked it and tightened it a few times.

Sigfried

honestaquarian wrote: »

One of the things that I really liked about the 35i's is their near holographic imaging. right now I'm using one of them as the back surround in the living room home theater. i found a pair of RT-55's and absolutely love the way they blend with the stereo pair of PSW-200's. The 35i's blended well with them, but the 55's just do it better. I also ran the 55's without the subs for a while and was amazed at their ability to shake the floor on organ pedal notes! They sounded even better after I swapped out the SL-6502 tweeters for the SL-6506's from the 35i's and 55i's.

Howdy! I've been reading through some older posts and came upon yours here. When you swapped out the SL-6502 tweet for the SL-6506's do you remember what changes (if any) you had to do to the crossover to make them work properly in your 55's? Thanks!

pitdogg2

Sigfried wrote: »

honestaquarian wrote: »

One of the things that I really liked about the 35i's is their near holographic imaging. right now I'm using one of them as the back surround in the living room home theater. i found a pair of RT-55's and absolutely love the way they blend with the stereo pair of PSW-200's. The 35i's blended well with them, but the 55's just do it better. I also ran the 55's without the subs for a while and was amazed at their ability to shake the floor on organ pedal notes! They sounded even better after I swapped out the SL-6502 tweeters for the SL-6506's from the 35i's and 55i's.

Howdy! I've been reading through some older posts and came upon yours here. When you swapped out the SL-6502 tweet for the SL-6506's do you remember what changes (if any) you had to do to the crossover to make them work properly in your 55's? Thanks!

Well to be honest some of the tweeters were no longer available. I know for my RT55i the OEM tweeters were superseded by another set when I went to buy spares for my speakers. They were drop in replacements and had a different part number. This could be the case here as well.