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Well-known member
Nov 18, 2015
The price of any kind of tag board is gone insane, there big clumsy things and they break easily , turret board and turrets , stupid money
Ive been looking for a cost effective way to hardwire tube gear ,especially mics , and I think I found it .
M2.2 solder tags , M2 truss or countersunk semi hollow rivet, hollow M2 rivet , M2.2 washer , suitable punch and die set and some practice .

Circular 3mm thick PTFE washers/spacers/gaskets are available in several standard sizes relating to pipe diameter , with what ever centre hole cut out you require for next to nothing
It makes a perfect board material for tube mics. you drill punch and place the mountings tags or vias as dictated by the pitch/ mounting style of the components you've chosen , its all do-able with hand tools .
I'll can add illustrations if anyone is lost in translation .

My question is about metalurgy
what can I mix
plain brass , nickel plated brass, zinc plated steel ,carbon steel,stainless etc , if I want a reliable electrical connection between my rivet/tag/ solder do I need the same metal/plating ?

I took a closer look at some of the B&K head amp circuitry , many of the larger components have a through hole in the pcb made with tiny punched rivet , other extra high impedence nodes have PTFE insulated standoffs , ultimately your not relying on a copper strip glued to FRP with a blob of solder to support the weight of the component under extreme vibration , its anchored ,well and truely rocket proof , service or swap out a component , even the ham fisted wont fry the board , thats the kind of engineering you want .
My question is about metalurgy
Solder does not adhere well to all metals.
Based on my experience (not a metallurgist):

plain brass , nickel plated brass
Can solder to plain brass, but is prone to corrosion. Sand or scour before soldering to remove corrosion and oxide.
I think nickel plate takes solder OK, but I may be confusing that with tin plate, since some connectors have nickel plated contact surfaces but tin plated solder tabs.

zinc plated steel ,carbon steel

Not sure about zinc, can solder to carbon steel, but not a great contact. Carbon steel is also prone to corrosion, rust isn't conductive and solder won't stick.


Solder definitely won't stick to stainless. I specifically use stainless steel tools to hold parts when soldering because solder won't stick to the tools.

Tin plated would be best if you can find that, that is what component leads are plated with.
Zinc can also be soldered. Overhere, zinc coated iron tubes are used to drain rainwater from roofs. The tubes are joined by soft soldering, but additional oxide cleaning with zinc solder flux is required. But I definitely don't recommend using it in electronics.
Rembrandt electronics in the Netherlands do a range of punches to set the very tiny rivets . 50 euros gets you a set of 6 sizes. They also have specific drill bits for each size . There a little pricey on the rivets themselves , but Im sure equivalents can be found much cheaper on ebay . Copper seems to be the most appropriate material but brass is also available .Solder tags tend to be tinned brass ready to solder . Smallest size of solder tag I could find was 2.1mm id 3.2 outside .
First a 3mm thick PTFE gasket ,very easily and cheaply available , you can find it in diameters suited to any microphone body
then the tiny copper rivets ,
solder tags .
what the finished rivet looks like
and the punch tool at the end .

These guys seem to do a very small solder tag , M1.5
I know there were people asking about mini solder tags for capsule wiring also ,
https://www.kempstoncontrols.co.uk/011523213/Entrelec/sku/380623£1.36 per bag of 50 ,
Of course component leads can be soldered to either side of the rivet or a tag can be added if prefered .
They say you want the rivet about 1mm proud of the surface with a good interference fit before punching . Copper is maleable so gives a better result than brass which is fairly brittle .

The rivet with the 1.4mm OD 4mm long should work perfectly with M1.5 solder tags ,
3mm board thickness plus around .5mm in the thickness of the tag leaves only .5mm to punch ,should still be ok though .


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Telfon is a great insulator in very high impedance applications like mics. Usually on the grid leak resistor and capsule connections.
First a 3mm thick PTFE gasket ,very easily and cheaply available , you can find it in diameters suited to any microphone body
then the tiny copper rivets ,
solder tags .
what the finished rivet looks like
and the punch tool at the end .
Thanks for the explanation and the photos. Now I can follow you better, definitely interesting.

I only knew the normal teflon insulated stand offs, not these super small insulated rivets.👍


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The idea is to put a tube socket on the teflon washer , it can be drilled , rivets/tags fitted and used to mount up other components/wires . I know those teflon insulated pins there not cheap thats for sure .
I probably use two of these teflon discs , the upper one to hold the tube socket pins facing upwards , then a lower disc to mount up the transformer . I also want to build in anti vibration mounts to isolate the tube from any resonances in the mic body on loud sound sources .
do it !

on the u57 iirc the pcb is attaced to the frame rails those solder lugs--the hole has the threaded rod frame rail passing through ahd the solder tab attaches the pcb--i believe disassembly is best done by desoldering once its all wired up

(those keystone 90º threaded angles are also pricy)
I plan to use the Tbone retrotube II body , initially at least I'll probably stick with the original capsule .
A thiersch capsule would be nice , but that costs more than the donor microphone itself .
Id like to try the UTM mic transformer but Mobys new offering also looks interesting .
Im a bit up in a heap at the moment due to having to relocate but hopefully soon all the loose ends are tidied up .