8 Channel, 3U NEVE 1073 completed

[Clakejr]

When soldering the 2N3055 NOS Output Transistor; Do I need to add some sort of heat sink paste between the Transistor and the metal heat sink before adding it to the EZ1290 board.

 

[bassmangizmo]

There should be a mica or silicon insulator between the 2N3055 and the heatsink and a very thin layer of thermal paste should be applied to both sides of the insulator. Also ensure that there are insulators on the retaining bolts to prevent transistor case making contact with the heatsink. I am not familiar with EZ1290 board but the method above is the usual way of mounting them. Hope this helps.

 

[Clakejr]

There should be a mica or silicon insulator between the 2N3055 and the heatsink and a very thin layer of thermal paste should be applied to both sides of the insulator. Also ensure that there are insulators on the retaining bolts to prevent transistor case making contact with the heatsink. I am not familiar with EZ1290 board but the method above is the usual way of mounting them. Hope this helps.

Where would I go to get some thermal paste? Is there a specific kind or brand people get for DIY projects. Does a big box hardware store carry insulators for the retaining bolts

 

[Brian Roth]

Where would I go to get some thermal paste? Is there a specific kind or brand people get for DIY projects. Does a big box hardware store carry insulators for the retaining bolts

Is this for USA purchase? If so, several options.

Bri

 

[Clakejr]

Is this for USA purchase? If so, several options.

Bri

Yes, I apologize I live in the USA

 

[Brian Roth]

Yes, I apologize I live in the USA

No prob <g>. I am not familiar with that particular build and have no idea if/how the heat sink is attached to the PCB. I started to learn more about the PCB and overall build... but don't have time to read 124 pages in this thread! lol

Generally speaking, in some devices the heatsink is attached to a grounded chassis. In this situation, I ASSume the heatsink is solely on the circuit board.

Next question I don't know the answer is that heatsink "floating" from circuit board "ground" (0 Volt)? If NOT floating, then you need a full insulation/isolation hardware kit for the two mounting screws.

There are several ways to skin this cat depending upon whether the heatsink is "floating" or not.

In any case, you will require heatsink grease OR a "silpad" between the bottom of the transistor and the heat sink to ensure efficient removal of heat onto the sink.

Unknown to me if insulating parts are required for the two mounting screws.

Heatsink grease is a tried/true solution, but messy! lol Here's what I've been using; it comes in a convenient dispenser:

https://www.mouser.com/ProductDetail/SparkFun/PRT-09599?qs=WyAARYrbSnajBpU3xiBuQQ==
Bri

 

[Clakejr]

No prob <g>. I am not familiar with that particular build and have no idea if/how the heat sink is attached to the PCB. I started to learn more about the PCB and overall build... but don't have time to read 124 pages in this thread! lol

Generally speaking, in some devices the heatsink is attached to a grounded chassis. In this situation, I ASSume the heatsink is solely on the circuit board.

Next question I don't know the answer is that heatsink "floating" from circuit board "ground" (0 Volt)? If NOT floating, then you need a full insulation/isolation hardware kit for the two mounting screws.

There are several ways to skin this cat depending upon whether the heatsink is "floating" or not.

In any case, you will require heatsink grease OR a "silpad" between the bottom of the transistor and the heat sink to ensure efficient removal of heat onto the sink.

Unknown to me if insulating parts are required for the two mounting screws.

Heatsink grease is a tried/true solution, but messy! lol Here's what I've been using; it comes in a convenient dispenser:

https://www.mouser.com/ProductDetail/SparkFun/PRT-09599?qs=WyAARYrbSnajBpU3xiBuQQ==
Bri

Thanks for the reply I'll give it a try

 

[Clakejr]

There should be a mica or silicon insulator between the 2N3055 and the heatsink and a very thin layer of thermal paste should be applied to both sides of the insulator. Also ensure that there are insulators on the retaining bolts to prevent transistor case making contact with the heatsink. I am not familiar with EZ1290 board but the method above is the usual way of mounting them. Hope this helps.

Thanks for the reply

 

[Brian Roth]

Thanks for the reply I'll give it a try

The grease does NOT electrically insulate the case of the 3055 from the heatsink. That may or may not be a problem, depending on what (if any) electrical connection the sink has to the circuitry.

Bri

/EDIT if the heatsink is NOT isolated, you need a kit like this (as well as the grease):

https://www.mouser.com/ProductDetai...=sGAEpiMZZMsqIr59i2oRctJ6/au/CRO2ilGROPFfv8g=

 

[bassmangizmo]

I had a look at the EZ1290 kit and it appears that the insulation kit with thermal paste is not required. The transistor case (the collector) is bolted securely to the heatsink and the bolts with metal spacers (which are essential) connect the collector of the transistor to the PCB board. Thermal paste, while not essential, would improve the thermal conductivity to the heatsink. If you don't have suitable spacers you could use a nut and/or washers to achieve the correct height from the PC board (about 3/16"). Good luck with your project.

 

[Whoops]

The manual for this project explains how to mount the 2N3055

 

[Brian Roth]

@Whoops Yeah, I actually found the assembly manual and BOM: Free Audio Schematics & Resources | Analog Classics

I hadn't been following this HUGE thread at all. The discussion about mounting a 3055 to a heatsink just caught my eye.

As noted, no need for insulation/isolation hardware. I still suggest using A VERY THIN LAYER of heatsink grease for optimum heat transfer.

Since it appears that one/two 3055 mounting screws provide collector connection to the PCB, I suggest using "star" type lockwashers under the screw head and between the foil traces and nuts.

Unsure why the use of the spacers. Are there circuit traces running beneath the heatsink location?

Bri

 

[Whoops]

Unsure why the use of the spacers. Are there circuit traces running beneath the heatsink location?

yes, there's some stuff beneath the heatsink,
also it gets warm so it wouldn't make much sense to have it sitting straight on the PCB

 

[Brian Roth]

yes, there's some stuff beneath the heatsink,
also it gets warm so it wouldn't make much sense to have it sitting straight on the PCB

Thinking back through my Muddled Memory <g>....I don't remember seeing the heatsink/3055 combo being elevated above the PCB in a "real" Neve or similar clone. Was I just not paying attention all these decades? <G!>

Bri

 

[Whoops]

I don't remember seeing the heatsink/3055 combo being elevated above the PCB in a "real" Neve or similar clone.

But, it is elevated.

Was I just not paying attention all these decades?

Yes

 

[Brian Roth]

OK....as I hinted, it has been literally 15+ years since I last peered inside a genuine Neve module from that era. <g> The Neves I've been around in "recent" times were the "newer" opamp chip models. Thanks for refreshing my memory!

Bri

 

[MidnightArrakis]

Yes, I apologize I live in the USA

[I live in the USA] -- It would be useful if you included that information within your "User Profile" so it can be displayed within your on-screen avatar. You can see that Mr. Roth is from Kansas and I am in Maryland, here on Earth.

This small piece of trivial information becomes highly useful to other members who may wish to reach out to you like pointing out where to purchase something. Many of our European and "ROW" (Rest Of World) brethren often request "where to buy" questions that many of us here in the USA wouldn't have a clue with how to properly answer. Similar to Mr. Roth, I could easily provide you with a dozen or more sources here in the USA to purchase heatsink-related items, but I would have absolutely no idea where to point someone who lives in Greece or the Congo with where to buy anything!!!

So.....something as minor and trivial as your location can have a major impact and influence on someone's reply.

/

 

[MidnightArrakis]

caught my eye.

[caught my eye] -- Did it also "drag it 15-feet"???

In order for my response to make any sense, listen to the below starting at the 2:40 time-mark:



I hope you had a good laugh at this!!!

/

 

[Whoops]

Where would I go to get some thermal paste?

Any computer store will have it, also most electronic component stores. ( like RadioShack and others)


For DIY projects any Thermal paste you buy, any brand, will be good, don’t worry about it

 

[PermO]

Apply little, really very little, it's just there to fill miniscule uneven surface to get 100% contact surface, it's not plaster.

I use a small piece of cardboard to scrape all the exec, and don't get it on your skin, it's nasty chemicals.