Exposed Power Transistor Question

[TigerAmps]

Back in the 1970's certain amps had exposed power transistors with the +/- rail voltages on the case of the transistor.
By the late 1970's, Peavey put the black transistor covers in the early Mark III Bass amps before moving them
inside the amp and adding the large heat sink on the back of the amp. (see picture)

The particular amp is a Marshall 2098. It had the exposed power transistors. (see picture)
I was thinking of putting the nylon/plastic T03 covers over the two output transistors for safety.
The entire back of the amp is a heat sink (fairly large area).

Would this trap the heat and cause the transistors to fail?
Would you recommend adding the transistor covers to this amp?

Any thoughts (heat vs safety)?

Thanks

[Leo_Gnardo]

Would this trap the heat and cause the transistors to fail?
Would you recommend adding the transistor covers to this amp?

No the heat travels out the flange bolted to the heat sink. Plastic cover has very little effect on this.

Yes it's a good idea to have covers on. Where do you get 'em?

Amps of that era generally had hi voltage rails that weren't so high, about enough to get a good tingle, not a major shock. But it was easy enough to short transistor case to chassis, or to any connectors hanging nearby. Then poof goes your amp.

[TigerAmps]

Thank you for the reply ...

The covers are made by Keystone Electronics part number 4634 or 4632 available at Mouser (covers only - one is slightly larger than the other).
The color is ugly natural nylon, so I would paint them black.

On the Peavey Mark III, one of the two screws is too short, so you might have to get longer #6-20 screws (I think also available from keystone/mouser).
On the Marshall, I was nervous because the jacks are near the transistors one might touch them while reaching around the back of the amp..

I will add them to the Marshall for safety then ...

Thanks Again