Grid stopper on octal socket

[Sir Cuitous]

I'm pretty sure I have seen this before in a few amps. The 1.5k grid stopper is soldered across pin 1 to pin 5. Is there any drawback to this? It seems pretty convenient to use pin 1 for this purpose.

[mooreamps]

Is there any drawback to this?

one drawback. The socket could no longer be used for an EL-34, in that configuration.

-g

[Daver]

The other drawback is the resistor getting cooked by the tubes heat, especially in a "tubes hanging down" configuration like a Fender.
Dave

[Sir Cuitous]

Good points - thanks. I didn't think of either of those.

[tubeswell]

Its not so bad if its a solid (3-5W) resistor. In fact it is desirable to have grid stoppers right at the grid pin - otherwise they don't work as good. So I find Pin 1 as the anchor point quite handy, and I used Pin 1 as a resistor anchor for a screen resistor on my last year's 5E3 build. (You could also hang it on Pin 6 and wire it around the 'outside' of the socket perimeter to pin 5, which partially overcomes the heat problem)

[mooreamps]

The oldtimer makes a point which people should be paying some attention to. The grid stopper really is most effective if mounted directly on the tube socket. That is a trueisim.

-g

[Sir Cuitous]

I have some 2 watt resistors that I planned to use. I do want the grid stoppers right at the pin. I may just dress my grid wire with a resistor at the end and just solder them straight to pin 5.

[Daver]

I use a 2 or 3 lug terminal strip attached to one of the tube socket mounting screws. Solder your resistor between the terminal strip and the tube socket. You can have the resistor right up to the socket terminal and not have it laying across the socket. It works for me anyway!
Dave

[defaced]

From one of the guys who posts on the SLOClone forum:
http://www.c3amps.com/SLOEnlargementPages/RRisers.html
and
http://www.c3amps.com/SLOEnlargementPages/XPreout.html
Looked like a pretty slick solution to me.

[jrfrond]

The trick of using an outboard terminal strip is most popular, and you can usually hang it off of one of the tube socket mounting screws.

Having said that, any form of RF suppression is most effective right at the tube socket. In addition, a 2W resistor is WAY overkill. Half-watt is plenty.

[Enzo]

And thinking back over the last 40 some years of working with tube guitar amps, I can think of any number of times I had to replace the 470 ohm screen resistors. usually damaged by a failed tube rather than heat in the socket area. But I can't recall ever having to change out the control grid stopper where it seemed heat was involved in any way.

[jrfrond]

But I can't recall ever having to change out the control grid stopper where it seemed heat was involved in any way.

Same here. Maybe once or twice, but that's about it. It's safe to say that the vintage Fender designs were fairly bullet-proof.

Bakelite is a pretty good thermal insulator (remember old coffee pots?), and that area is not as hot as one would think.

[lowell]

From one of the guys who posts on the SLOClone forum:
Soldano SLO100 Photo Log
and
Soldano SLO100 Photo Log
Looked like a pretty slick solution to me.

that's a great solution right there, saves time and money vs the terminal stip approach.

[defaced]

He recommends getting round nose jewelry pilers to bend the leads and to get that loop. I picked up a pair for less than 5 bucks locally and I will never do component lead bending again without them. They're so incredibly handy it's not funny. I'll grab a picture when I get home.

[lowell]

cool please do.