Monitor 5B refresh
Answers
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GOD GOD THAT SOLDERING!@F1nut @westmassguy
Any reason this is an issue (extending bypass cap lead) instead of putting the cap parallel to the resistor? I can swap the inductor and 5.6uf cap positions if needed, but then I’d be running the inductor lead across the top of the board. Either way, no problem.
It looks better than my earlier attempts though! You'll get the hang of it.
See dude, it's comments like this that will get you accidentally pushed down a flight of stairs, or off a subway platform with a train coming in, esp when you're no expert.
Do you find that a room clears when you walk in, or are you just good at getting punched in the face?
No and I honestly don't see the problem, I was joking, and I never claimed to be an expert. -
Like I said, I’m used to soldering thru-hole PCB’s, turrets, tube sockets, and eyelets. Those I know how to do and look ok. Never soldered to a copper plane where I can’t really make a good mechanical connection so I figured a little extra solder wasn’t going to hurt. I also used braid and removed as much of the old solder as I could do it looks a little messy when it’s really not. Crank up the Hakko and let’r rip.
Got all the wires and components off the next board and extra holes to be drilled marked today. Too many other projects to take care of to do any more. -
Like I said, I’m used to soldering thru-hole PCB’s, turrets, tube sockets, and eyelets. Those I know how to do and look ok. Never soldered to a copper plane where I can’t really make a good mechanical connection so I figured a little extra solder wasn’t going to hurt. I also used braid and removed as much of the old solder as I could do it looks a little messy when it’s really not. Crank up the Hakko and let’r rip.
Got all the wires and components off the next board and extra holes to be drilled marked today. Too many other projects to take care of to do any more.
Honestly I've never seen a solid copper plane like that before, I'd probably struggle with that too, it's a really odd design choice IMO probably to cut down costs.
Fitting ClarityCaps on my M5JR+ boards required me to get creative, I wish I just grabbed some perfboard and cut it to size, would have been way easier. -
Honestly I've never seen a solid copper plane like that before, I'd probably struggle with that too, it's a really odd design choice IMO probably to cut down costs.
Fitting ClarityCaps on my M5JR+ boards required me to get creative, I wish I just grabbed some perfboard and cut it to size, would have been way easier.
I seriously thought about making a new thru-hole pcb for it so I could just lay it out to fit my components exactly. If it ever gives me fits I’ll do just that. It doesn’t get any simpler than this for pcb design. -
I think Polk's idea was to make the traces larger for greater conductivity. Thickness matters too. Also, having the ability to bend the component leads over gives greater contact area between the lead and the trace.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Gardenstater wrote: »I think Polk's idea was to make the traces larger for greater conductivity. Thickness matters too. Also, having the ability to bend the component leads over gives greater contact area between the lead and the trace.
And save money. You can run some pretty good voltage/current through moderate size/thickness traces. These just look like big ground planes. -
Honestly I've never seen a solid copper plane like that before, I'd probably struggle with that too, it's a really odd design choice IMO probably to cut down costs.
Fitting ClarityCaps on my M5JR+ boards required me to get creative, I wish I just grabbed some perfboard and cut it to size, would have been way easier.
I seriously thought about making a new thru-hole pcb for it so I could just lay it out to fit my components exactly. If it ever gives me fits I’ll do just that. It doesn’t get any simpler than this for pcb design.
Did you do the TL mod, and did you jump the polyswitch with a 0.5 ohm resistor? I can send you a KiCad schematic I made of the 5B boards, perhaps it'd help with making a new PCB? I might do it for my M5JR (custom PCB) but I don't want to sink in too much money, and I mayyy be buying a pair of RTA 11T in mint condition (don't know yet). -
Gardenstater wrote: »I think Polk's idea was to make the traces larger for greater conductivity. Thickness matters too. Also, having the ability to bend the component leads over gives greater contact area between the lead and the trace.
And save money. You can run some pretty good voltage/current through moderate size/thickness traces. These just look like big ground planes.
But then you are requiring the solder to bridge between a component lead and a hole, in the form of a fillet. Theoretically (at least), if you bend the leads over and have good physical contact prior to soldering, the conductivity is greater. Solder, even silver bearing, has pretty p iss poor conductivity.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Gardenstater wrote: »Gardenstater wrote: »I think Polk's idea was to make the traces larger for greater conductivity. Thickness matters too. Also, having the ability to bend the component leads over gives greater contact area between the lead and the trace.
And save money. You can run some pretty good voltage/current through moderate size/thickness traces. These just look like big ground planes.
But then you are requiring the solder to bridge between a component lead and a hole, in the form of a fillet. Theoretically (at least), if you bend the leads over and have good physical contact prior to soldering, the conductivity is greater. Solder, even silver bearing, has pretty p iss poor conductivity.
When it comes to a perfboard, I've had people recommend to me some thin single-stranded non-insulated wire to jump the joints and then build a solder bridge around it. I have no idea if this works out well as I've never tried it, but it could be better than bending a lead (maybe?). -
It's fun watching the hair splitting.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
@ChrisD06 I did do the TL mod. I removed the polyswitch and resistor and I put in a 2.7R resistor.
Interestingly, all the original components except the polyswitch measured out pretty good. The film caps were 12.3uF, resistor was dead on 2.0 ohms, coils were 1.57mH and 0.18mH and NP caps were 34.2 uF. Poly switches were measuring 2+ ohms.
No need for the kicad schematic. I can draw one up and make a pcb in about 10 minutes for this if I want. -
Gardenstater wrote: »Gardenstater wrote: »I think Polk's idea was to make the traces larger for greater conductivity. Thickness matters too. Also, having the ability to bend the component leads over gives greater contact area between the lead and the trace.
And save money. You can run some pretty good voltage/current through moderate size/thickness traces. These just look like big ground planes.
But then you are requiring the solder to bridge between a component lead and a hole, in the form of a fillet. Theoretically (at least), if you bend the leads over and have good physical contact prior to soldering, the conductivity is greater. Solder, even silver bearing, has pretty p iss poor conductivity.
When it comes to a perfboard, I've had people recommend to me some thin single-stranded non-insulated wire to jump the joints and then build a solder bridge around it. I have no idea if this works out well as I've never tried it, but it could be better than bending a lead (maybe?).
Meh, I’ll bet almost all commercial crossovers are on a PCB now. Most tube amps (hifi and guitar are as well, although I like p2p and turrets better). Depending on how you design your pcb you can allow for bending the lead on the underside of the board just like with my crossover. It’ll work the same and be neater as well.
I just leave the leads long and bend them where I need to connect them on perf board and protoboard. Less jumpers the better. If I have to make jumpers I’ll use old component lead cutoffs and do what you described. Made some guitar pedals and headphone amps this way.
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@ChrisD06 I did do the TL mod. I removed the polyswitch and resistor and I put in a 2.7R resistor.
Interestingly, all the original components except the polyswitch measured out pretty good. The film caps were 12.3uF, resistor was dead on 2.0 ohms, coils were 1.57mH and 0.18mH and NP caps were 34.2 uF. Poly switches were measuring 2+ ohms.
No need for the kicad schematic. I can draw one up and make a pcb in about 10 minutes for this if I want.
I believe the 5B poly (RDE050A) was supposed to be 0.7ohm, if it was 2+ ohms then it was tripped. I assume you mean you jumped the poly and changed the 2 ohm resistor to a 2.7 ohm one to make up for the poly resistance? Honestly impressive that all of the original components tested good, but it's not unexpected. Resistors and film caps last quite a while, inductors don't age except corrosion. -
I think 0.5 Ohms is the untripped spec. and 1.17 Ohms is the max. post trip spec.. I believe that Polk pre-conditioned them by tripping them once or twice. It would be good to get some verification on this though.
https://www.digikey.com/en/products/detail/littelfuse-inc/RXEF050-1/1040803George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
@shaneybob throw away the solder braid. Get you a good solder sucker.
I've never had solder braid work worth a darn.
The copper solder pads I have never had issues with. Bend the lead, flow some solder boom done. I do find advantage in raising those type XO boards up off the work surface to allow the parts weight I'm soldering to pull against the bent lead a bit. For me it helps ymmv. -
@shaneybob throw away the solder braid. Get you a good solder sucker.
I've never had solder braid work worth a darn.
The copper solder pads I have never had issues with. Bend the lead, flow some solder boom done. I do find advantage in raising those type XO boards up off the work surface to allow the parts weight I'm soldering to pull against the bent lead a bit. For me it helps ymmv.
Love my solder sucker, I can vouch for it as well. Makes a massive difference -
@shaneybob throw away the solder braid. Get you a good solder sucker.
I've never had solder braid work worth a darn.
The copper solder pads I have never had issues with. Bend the lead, flow some solder boom done. I do find advantage in raising those type XO boards up off the work surface to allow the parts weight I'm soldering to pull against the bent lead a bit. For me it helps ymmv.
I have a good solder sucker. I find GOOD braid to work very well, like Chemtronics. Adding just a tiny bit more liquid flux and spreading the braid out a bit makes it work well. I’ve built tube amps, SS amps, headphone amps, preamps, dozens upon dozens of guitar pedals so I’m not a newbie to that stuff. I have never had to solder to a flat copper plane before though. When I compared my soldering against the other crossover mine looked no worse than the factory one. I slid the braid around a bit so it looks like I used 1/2 lb, but on the actual joint I tried not to use any more than needed. I did go back and remove some from my first attempt though. There no way to make a true mechanical joint with this design. Nothing to wrap the lead to, only hold it against, similar to an eyelet, only not even that good. I guess I could break out my 100W iron, heat the whole plane up in about 3 seconds, and give it a whack to knock all the solder off 😜
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Or if the solder sucker fails and the braid doesn't work a human hair sized drill bit in a dremel will get the job done. I'm pleading the 5th on how many times I've had to use that method.
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I’m going to try and finish the other speaker this afternoon. I’m curious to see what the pair sounds like together, although there is an obvious difference from the orginals, I’m not sure it was worth the cost of admission. My last set of DIY speakers cost less and blow the 5B’s away. Might have just been better to replace the tweeter with a RD0194 and called it a day.
That I’ve never done.motorstereo wrote: »Or if the solder sucker fails and the braid doesn't work a human hair sized drill bit in a dremel will get the job done. I'm pleading the 5th on how many times I've had to use that method.
Here’s the next crossover with factory connections and with solder and components removed.
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I’m going to try and finish the other speaker this afternoon. I’m curious to see what the pair sounds like together, although there is an obvious difference from the orginals, I’m not sure it was worth the cost of admission. My last set of DIY speakers cost less and blow the 5B’s away. Might have just been better to replace the tweeter with a RD0194 and called it a day.
That I’ve never done.motorstereo wrote: »Or if the solder sucker fails and the braid doesn't work a human hair sized drill bit in a dremel will get the job done. I'm pleading the 5th on how many times I've had to use that method.
Here’s the next crossover with factory connections and with solder and components removed.
But now you can use the RD0198 which is better than the 194
Finish the second speaker and listen to your favorite songs and see how you feel. I definitely was a little confused after I finished my rebuild but after listening to some songs I noticed the difference and found it was worth it. -
I sure hope (and think) you’ll feel differently after you’re done!
Brian
One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM -
Got the other one done. The latest one sounds shouty for lack of a better term. Not nearly as balanced as the first one. It’s definitely the speaker as I swapped them left to right and back. Uggg. Gonna let it play a while and see if it straightens up.
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Got the other one done. The latest one sounds shouty for lack of a better term. Not nearly as balanced as the first one. It’s definitely the speaker as I swapped them left to right and back. Uggg. Gonna let it play a while and see if it straightens up.
By shouty I assume you mean that the midrange sounds more pronounced? Check your connections and compare the crossover boards to each other, especially the woofer circuit. -
It would be quiet AF, if it was the woofer circuit that was out.
Brian
One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM -
Helps when you have the small inductor on the right pad. 🙄. I really should do this stuff when I’m tired. You’d think I’d have learned by now.
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It would be quiet AF, if it was the woofer circuit that was out.
I was thinking more that the low pass filter was messed up or bypassed due to a short, causing higher frequencies to make it through. If it was out entirely then yeah it'd be super quiet. -
Helps when you have the small inductor on the right pad. 🙄. I really should do this stuff when I’m tired. You’d think I’d have learned by now.
Did ya fix it? -
Yep. Much better! -
Awesome! What mods do you have left to do now? -
None really. I could use some more poly fill. Mine only ever came with some above the midwoofer. I’ve put hurricane nuts on everything, a set of semi-rings from xchop, dynamat on MW and PR, rebuilt xovers for TL mod and replaced all the wiring, new binding posts, and spikes on my stands.
