wood cabinet?

[mlucitt]

Also, if you correspond with the man; he'll tell you some people use step-down transformers or rheostats in-line to slow em down.

I used two 120V fans side-by-side and wired them in series. With 60V going to each fan, they ran at half speed and are very quiet. I think two fans running at half speed push more air than a single fan at normal speed due to the increase in volume through the center area of two fans vs just one (must be a formula for that somewhere). Anyway, buy ball bearing fans, they are slightly more expensive, but are quieter and last longer.

 

[Gepetto]

Think I figured it out. 400s and 700s basically have same "foot print", but 700s have appx twice the output. So 700s would run hotter and a fan would benefit them.
Been many a time I've wondered about pulling the silicone insulators and going with mica and good computer grade non conductive heat sink compound. Thought maybe the silicone insulators were not transferring the heat properly.

Sil pads perform better than mica and grease...

 

[George S.]

I used two 120V fans side-by-side and wired them in series. With 60V going to each fan, they ran at half speed and are very quiet. I think two fans running at half speed push more air than a single fan at normal speed due to the increase in volume through the center area of two fans vs just one (must be a formula for that somewhere). Anyway, buy ball bearing fans, they are slightly more expensive, but are quieter and last longer.

Yup, plenty of good fans and speed controllers out there, just check out what's avail for gaming computers.

Sil pads perform better than mica and grease...

Good to know. Thanks.

 

[wattsabundant]

A year ago or I put together a fan controller from a PC and put it in an external 5.25" drive box. I used a high temperature tape to secure the thermocouples to the outputs. It worked good and looked good and I found out that my ears gave out before the amp got to hot.

 

[mlucitt]

Speaking of thermal cutout switches used in Phase Linear 400 and 700 amplifiers... (we were, right?)
In several amplifiers I noticed the thermal cutout switches carried the brand name "Elmwood Sensors" on them but I could never find that company listed on the web. A while ago, Gepetto pointed out that Elmwood Sensors was bought out by Honeywell and that the Honeywell P/N 2450HR (space) 84450017 might be a substitute for the Elmwood Sensors P/N 74/N L189 87-90, and this does not mean they were made from 1987 thru 1990; it indicates that these "open on rise" switches open at 87-90 ºC or 189 ºF (189 is also part of the P/N). Maybe "74" is the year?

WOPL Sniffer found a replacement for the Elmwood PL700 thermal cutout switch from a company called "SENASYS" and the P/N for their 170 ºF switch is 430-301A285-540. I think the price for one switch is $13.00.

I recently saw a reference to the temperature rating for the thermal cutout switch for the PL400 to be 70 ºC or 158 ºF and the temperature rating for the PL700 to be 90 ºC or 194 ºF (this one is close to the exact Elmwood Sensors P/N). Did Phase Linear use a different spec for the early PL400? The PL400 II I have on the bench has Elmwood Sensors P/N R87-92 L220 78/J. To me that seems like another 87-92 ºC rated thermal cutout switch.

I just found another thermal cutout switch on ebay from a Japanese company called "Selco" and they are rated at 170 ºF, 200 ºF, and 210 ºF under P/N's OA-170, OA-200, and OA-210. I am pondering the use of the 200 ºF Selco thermal cutout switch. It is close to 194 ºF and with the newer MJ21195/96 output transistors having a higher SOA, the rating of 200 ºF might actually be a better specification for the WOPL amplifiers to prevent nuisance cutouts.

I test all the thermal cutouts in the amplifiers I service with a Stortz contact thermometer, and most of them are fine, but I have seen thermal cutout switches that never open or open at much higher temperatures than specified. I think this is a prudent test because I don't want one of these fine WOPL amplifiers to burn up because of a bad thermal cutout switch.

Thoughts?

 

[Gepetto]

Speaking of thermal cutout switches used in Phase Linear 400 and 700 amplifiers... (we were, right?)
In several amplifiers I noticed the thermal cutout switches carried the brand name "Elmwood Sensors" on them but I could never find that company listed on the web. A while ago, Gepetto pointed out that Elmwood Sensors was bought out by Honeywell and that the Honeywell P/N 2450HR (space) 84450017 might be a substitute for the Elmwood Sensors P/N 74/N L189 87-90, and this does not mean they were made from 1987 thru 1990; it indicates that these "open on rise" switches open at 87-90 ºC or 189 ºF (189 is also part of the P/N). Maybe "74" is the year?

WOPL Sniffer found a replacement for the Elmwood PL700 thermal cutout switch from a company called "SENASYS" and the P/N for their 170 ºF switch is 430-301A285-540. I think the price for one switch is $13.00.

I recently saw a reference to the temperature rating for the thermal cutout switch for the PL400 to be 70 ºC or 158 ºF and the temperature rating for the PL700 to be 90 ºC or 194 ºF (this one is close to the exact Elmwood Sensors P/N). Did Phase Linear use a different spec for the early PL400? The PL400 II I have on the bench has Elmwood Sensors P/N R87-92 L220 78/J. To me that seems like another 87-92 ºC rated thermal cutout switch.

I just found another thermal cutout switch on ebay from a Japanese company called "Selco" and they are rated at 170 ºF, 200 ºF, and 210 ºF under P/N's OA-170, OA-200, and OA-210. I am pondering the use of the 200 ºF Selco thermal cutout switch. It is close to 194 ºF and with the newer MJ21195/96 output transistors having a higher SOA, the rating of 200 ºF might actually be a better specification for the WOPL amplifiers to prevent nuisance cutouts.

I test all the thermal cutouts in the amplifiers I service with a Stortz contact thermometer, and most of them are fine, but I have seen thermal cutout switches that never open or open at much higher temperatures than specified. I think this is a prudent test because I don't want one of these fine WOPL amplifiers to burn up because of a bad thermal cutout switch.

Thoughts?

Yeah just buy the Sensata 682-1NT01L-7941 from Mouser. Easy Peasey.

 

[Phase Linear Phanatic]

Yup, plenty of good fans and speed controllers out there, just check out what's avail for gaming computers.

Good to know. Thanks.

Yep. Lots of choices out there. The fan boxes you guys are talking about would personally do me no good. My amps are in their Phase Linear cases and that's how they fit into my racks so nicely. That way the glass they sit on doesn't get all scratched up. So I don't want another box sitting on top of the amp. Besides I'm pretty sure Sniffs the one who said to NEVER set ANYTHING on top of your white oak PL700B. And he also hates the look of the wood cases. So I'm the complete opposite direction due to the nice wood racks I have the amps housed in. That's why I prefer the PL original Fan chassis design on the back of the fins aimed right at the transistors and heat sinks and it keeps the OEM look as much as possible.

In talking with that guy who makes the shrouds; he said he invested over 4 grand to get the shrouds into production with the machine shop he uses for fabrication, so clearly he's dedicated to it. To keep the 120VAC fan that can plug into the amp as originally designed; he picked the quietest fan out there available. Even at that, you still won't match the db from the original boxer fan. Without having to rig up a 12V solution; you can simply use (like we are talking about here), a fan speed controller. I ordered one specifically made for axial fans, like this maker is using. It's 14 bucks. And it works fantastically. Even though it says LOW, MED, HIGH it's not three clicks. It clicks 'ON' in the LOW setting and it's variable up from there to where-ever you set it on the spectrum to your tastes.

I have an original PL700B fan here and was able to match the same fan db's with it so I know what setting to put it on. I find 3/4 between Low and Medium is exact. And for those ruckus nights, blast away on high! The fans are easy access to the control knob with a 6-ft cord you could mount it anywhere within reach. The point is it works and it's out there for those PL Purists that don't really want a home-brew looking solution. I've been convincing him to join us here on the forum. He knows White Oak, and Ed and Dean. Not sure how he hasn't stumbled upon US yet?

The guys in his 60's and is in the middle of some back surgeries etc. so he's got a lot going on right now. But from what he told me; he has the milling for the transistor covers, and the plans for reproducing the wood cases EXACTLY as was offered from PL. I don't think there's a wood-maker out there dedicated to this yet so that'd be REAL neat. Anyway; below is the link to what I used. And it works fantastic. I haven't "installed it" yet where I want the controls to be. I just tested it today. But pretty much it's got a six foot cord so you could put the fan control anywhere within reach.

AC Infinity, Speed Controller for AC Axial Muffin Fans rated 100 to 125V AC | eBay

 

[laatsch55]

Coolness.....literally..

 

[Bradrock]

I like the wood & will be building some cases true to oem look & size for my amps . But I sure as hell won't be using particle board & cheap veneer. Even the front moulded edge on the PL cases is some sort of re-constituted wood product. The originals look great to me, but I live at the Black Walnut capitol of the world.

 

[mlucitt]

This is my setup and it does fit in the PL700B wood case. Totally quiet because they are ball bearing fans running at half speed.

 

[Phase Linear Phanatic]

I like the wood & will be building some cases true to oem look & size for my amps . But I sure as hell won't be using particle board & cheap veneer. Even the front moulded edge on the PL cases is some sort of re-constituted wood product. The originals look great to me, but I live at the Black Walnut capitol of the world.

That's EXACTLY what the guy I talked to said too. No cheap crap. It would def be nice to have a source that supplied these in general. I am really surprised there isn't one to date, considering everyone and their brother can do woodworking. Over the last ten years I have received wood cases through OOPS (I mean UPS) or another shipper, I've probably lost half a dozen to being split apart in pieces or cracked. I mean these are 40+ year old original cases and nobody is just 'Out There' making these things these days. So you break one, it done broke! I steer clear of the particle board versions for certain. The veneer was the best one you could get at the time. This guy said he would use real walnut and stain. Same miters, and same indentation around the front edge just as it was originally. Quite an exciting prospect for many out there. I hear they were an expensive option even back in the day, so most didn't opt for one.

 

[Phase Linear Phanatic]

This is my setup and it does fit in the PL700B wood case. Totally quiet because they are ball bearing fans running at half speed.
View attachment 48798

Very nice! I like it. And yep. running at half speed is the key word. I see those are INFINITY's. Same MFG of the speed controllers I posted. They make fans of all kinds for audio rack equipment and stereo furniture that has the fans on the ends, blowing air into the cabinets the audio gear is confined in. I checked out a lot of what they sell. Really nice stuff.

 

[laatsch55]

This is my setup and it does fit in the PL700B wood case. Totally quiet because they are ball bearing fans running at half speed.
View attachment 48798

I recognize those!!

 

[K-5BLAZER]

This is my setup and it does fit in the PL700B wood case. Totally quiet because they are ball bearing fans running at half speed.
View attachment 48798

got a link and how do you mount them?

 

[mlucitt]

got a link and how do you mount them?

I use a piece of aluminum angle sourced from Lowe's and just cut it with a hacksaw. Then I use the fans to mark the hole placement and drill the four holes. The key is to use a strip of industrial double stick tape on the underside of the aluminum piece and stick it on the top edge of the heat sinks.
The drawing is attached. Here is the link for the fans (best price I found):
https://www.ebay.com/itm/330929586893

 

[K-5BLAZER]

I use a piece of aluminum angle sourced from Lowe's and just cut it with a hacksaw. Then I use the fans to mark the hole placement and drill the four holes. The key is to use a strip of industrial double stick tape on the underside of the aluminum piece and stick it on the top edge of the heat sinks.
The drawing is attached. Here is the link for the fans (best price I found):
https://www.ebay.com/itm/330929586893

thanks