Goldentone rhythm light circuit

[jhanly]

Hi All,

Thinking of exploring the goldentone rhythm light circuit in my goldentone bassmaster 20. The circuit is described in the attached (from the dalmura resources) and I've included a schematic of my amp.

Any thoughts or experiences with this kind of filament bulb based protection circuit?

I really don't have a good idea of what ballpark rating and material I should be looking at for the bulb - so any suggestions there would also be much appreciated.

Some quick background. The original output tx in this amp was effectively DOA. The amp actually sounded great but for a very loud and dominating low frequency hum which the tech I sent it to told me was the OT on it's way out. He dropped in a brand new OT which was a like-for-like replacement for the original 20w OT. The amp subsequently sounded cold and inspiring.

So some time later I sourced a NOS triad s-42a (50w) and dropped that in myself. The amp's golden tone has returned but as expected its transient response is now a little on the honest side, due to the over-rated OT. I wouldn't call it spiky but it's definitely high headroom. Despite this, it still sounds noticeably warmer and richer tonally with the nos triad OT than it did with the brand new replacement OT.

It's not one of my more precious amps so I'm happy to trial mods that might help soften the transient response - just a touch. I realise the rhythm light would make only a subtle difference but that's all I'm after. IOWs I'm not contemplating this mod to protect the OT. I'm hoping it'll impart some subtle rounding of the transients to make it less hi-fi.

Any thoughts?

TIA