Ampeg B25 Chassis Mounts?

[misterc57]

I am reconditioning an old B25. The chassis mount blocks and rubber mounts need to be replaced. I will be cutting new wood blocks.

I am wondering if anyone has found a local hardware store solution to replace the rubber mounts. Mine are so bad I cannot even tell how tall they should be.



Thank you

[Leo_Gnardo]

I am reconditioning an old B25. The chassis mount blocks and rubber mounts need to be replaced. I will be cutting new wood blocks.

I am wondering if anyone has found a local hardware store solution to replace the rubber mounts. Mine are so bad I cannot even tell how tall they should be.

Doubt you'll find anything like them in any hardware. Last I looked Fliptops offers these rubber stud mounts.

They also have metal mounting blocks but I think they're special-order and are sized for V2 & v4 & may not be the right size for B25. Also not cheap.

[drewl]

I've had to do this before.
Made wooden blocks, used rubber grommets from work, hardware store might have them.

Like the chassis grommets on old amps before strain reliefs came about.

[Leo_Gnardo]

I've had to do this before.
Made wooden blocks, used rubber grommets from work, hardware store might have them.

Like the chassis grommets on old amps before strain reliefs came about.

The trick on those Ampeg mounts is, there's a slug of heavy duty rubber between the studs, to provide a fair amount of shock absorption while the amp is being shipped around. Not so easy to accomplish that with grommets.

I also have a B25 that's in the final stage of electrical repair, about to try a multitap OT so I'm not stuck with the original 16 ohm output. I'll have to tackle those mounting blocks too, because the original MDF is crumbling into wood dust.

[g1]

Are we talking about things like these, or something different? :
https://www.google.ca/search?q=rubbe...w=1093&bih=494

[Jazz P Bass]

If I am not mistaken, that is the mount.
10-32 thread.

[misterc57]

I am wondering why a rubber mount is even necessary. I have never seen this in other amps.

My alternate thought;

- make the blocks closer to the adjusted height and use washers or nuts and washers to adjust the final height of the chassis sitting in the cab.

[misterc57]

I also have a B25 that's in the final stage of electrical repair, about to try a multitap OT so I'm not stuck with the original 16 ohm output. I'll have to tackle those mounting blocks too, because the original MDF is crumbling into wood dust.

If I am not mistaken, mine has both a 16 ohm and 8 ohm speaker connection.

[Mark Black]

I think the rubber compound is more flexible than most 'off-the-shelf' products in the industrial world.

Leo's tip about fliptops.net looks like a good way to go:

https://www.fliptops.net/catalog/p-1...-series-b25-gv

[drewl]

One place I worked had something similar used for garage door openers and various gate openers.

Same thing, in different sizes depending on which product.

[Leo_Gnardo]

If I am not mistaken, mine has both a 16 ohm and 8 ohm speaker connection.

True that, but the owner of this one is likely to use it with 4 ohm as well as other cabs. One of those "touring pros." Gotta be ready for anything.

Mounts $7.90 apiece from Fliptops, yikes. Makes it worth a look thru a Grainger catalog, letsee what we find...

[g1]

I am wondering why a rubber mount is even necessary. I have never seen this in other amps.

In my experience, the rubber mounted chassis vastly improves microphonic issues and tube longevity.

[Leo_Gnardo]

In my experience, the rubber mounted chassis vastly improves microphonic issues and tube longevity.

Maybe it's one of the secret ingredients that keeps these 40+ year old Ampegs in fit condition. FWIW I have seen some where the rubber mounts failed, and repairmen simply bolted chassis to end blocks. Obviously the rubber mount is not a necessity. As you said, no other amp has 'em. Sure was a nice touch though, from the days when engineering meant "build it to last" not "build it cheap as you can."

Just checked the B25 I'm working on, the mounting studs are 8x32.

Grainger has these, part # 2NNZ6, a quarter the price of Fliptops. They're rated for 20 pounds, with only 3 pound shear (sideways), wonder what's the rating on Fliptops' mounts?

https://www.grainger.com/product/GRAINGER-APPROVED-Vibration-Isolator-2NNZ6?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/2NNZ9_AS01?$smthumb$

[drewl]

Secret ingrediant to getting your fingers pinched and mutilated until you learn to deal with them and a pain to set on the bench even with a good mounting device.

And I've seen nothing in the shock mounts that helped preserve integrity better than contemporaries like Fender or Marshall etc.

[Leo_Gnardo]

Secret ingrediant to getting your fingers pinched and mutilated until you learn to deal with them and a pain to set on the bench even with a good mounting device.

Geez I never got fingers pinched, and just park the transformers atop a couple of 2x4 blocks to work on the amp. Yeh I suppose they would get in the way of a fancy chassis support gadget - that's when I back up to the lowest of low tech solutions: couple chunks of scrap wood.