PSU deglitching

[Admiral-dk]

I'm surprised that 100 Ohm didn't do the trick - but as others mentioned - there are other factors too.
I've always used 1N4007 (or in rare cases 1N5408) for the High Voltage Tube supply - here the UF4007 and other faster Diodes that are better.
Short PCB Tracks - from Entry over Diodes and into Filter Capacitors - as those can be considered Antennae's for this noise.

The correct Grounding off Scope Probes are a complete chapter in itself ....

Per

 

[merlin]

I'm surprised that 100 Ohm didn't do the trick - but as others mentioned - there are other factors too.
I've always used 1N4007 (or in rare cases 1N5408) for the High Voltage Tube supply - here the UF4007 and other faster Diodes that are better.
Short PCB Tracks - from Entry over Diodes and into Filter Capacitors - as those can be considered Antennae's for this noise.

You seem to be talking about rectifier switching noise, whereas the OP has 30kHz interference which is clearly not from mains frequency rectification.

 

[Admiral-dk]

Sorry I missed the bit about them being ~30mS apart

Spikes themselves has a very high Harmonic content .... but you are right - they didn't cause this interval ....

Per

 

[Walter66]

With this PSU, there are two kind of noise occuring. There are random, low frequency spikes which should be limited to 2mV at least and there are high frequent glitches which are 4mV. This is with 100 Ohm in series after the bridge rectifier diodes. All random noise due to breadboarding?

 

[ccaudle]

But I don't think their existence just results from bad wiring or too long wires.

That greatly depends on what else is nearby, for example a desk lamp with a switching power supply, LED lights nearby, etc. I have had several experiences where what appeared to be circuit noise went away with very fastidious (meaning minimal unshielded wiring length, minimal loop area) connections to the 'scope.

 

[Cqwet Dbdfte]

At mV sensitivity the scope probe can pick up all kinds of environmental EMI, like switching power supplies like CCAUDLE pointed out, that's why checking the "zero" noise signal with the probe ground lead shorted to the probe tip, then probing ground on device under test to check background level that can be subtracted from measurement.
A "breadboard" may not pan out for low level noise testing, as shielding is important and may not have been included in your setup.
The proof is in the pudding, does your mV noise appear at the output of your amplifier?

 

[Wavelength]

I have a power transformer I use for the amp in my moniker. It has a 400CT @40ma (DC) and 6.3V at 1.2A (AC). I use a 6ZY5G tube rectifier with a 3.9uF film cap into a Hammond 30H/40ma choke into a Black Gate WKZ 150uF/350V for a super clean 200V.
Something else is happening with your circuit if your having those spikes from a SS supply with a cap multiplier or HV LM317 regulator. There is a boat load of audio and guitar amps using basically a bridge->large cap->resistor or choke->cap = B+ without issues.