Nice work tube amp

shock-mounted preamp tubes? Is that's really needed? If so, the effectiveness of little rubber grommets under pressure seems highly ineffective, especially over time (as the rubber hardens).

I think I've seen old industrial portable gear that had spring-mounted tube sockets.. but maybe it was just a dream...

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** Yep - most 12AX7s suffer microphony right out of the box and the rest develop it in time.

The way tubes are made using mica supports is far from rugged and vibrations damage them so they turn into little microphones. This applies to power tubes as well.

** It's better than hard mounted. ** No dream. 9 pin sockets that include spring suspension were made.

The greatest idiocy with tube guitar amps is that combo amps even exist and most players insist to sitting the head on TOP of the speaker box.

.... Phil

Rich S wrote in news: snipped-for-privacy@googlegroups.com:

It is a guitar amp. They get tossed around. Less is less, period. Just like more is more. Same reason hard drives get mounted in rubber baby buggy bumpers.

No, but perhaps remedial grammar and composition is? I know it was a typo. You meant to write "if" and "that's what's" Another reason why contractions, and especially these variety are bad ways to write.

Modern grommet polymers are a lot better than those that were used in these originally. Not a very smart nit pick.

Whatever. The peg board aspect is what I thought was pretty well done frome a design/servicablitity aspect. They were all built the same.

Phil Allison wrote in news: snipped-for-privacy@googlegroups.com:

Maybe they had industrial disease.

Tell a guitarist that it's a bad idea to put the head on top of the speaker box and next time you see him playing the amp the speaker box will be sitting on top of the head

DSP emulation of the pre-amp stage into a tube power stage works well, virtual 12AX7s don't get microphonic.

st develop it in time.

tions damage them so they turn into little microphones. This applies to pow er tubes as well.

s highly ineffective,

tube sockets.. but maybe it was just a dream...

and most players insist to sitting the head on TOP of the speaker box.

maybe it helps their "tone", many guitarist seem to have some really weird ideas

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** Compared to you - not so much.

The reasons are having a traditional look plus convenience.

Since it is possible for amp heads to fall off speaker boxes, some makers provided a locking system ( ie Fender). Total madness.

The simple fact is guitarists have never worked out that vibration from speakers destroys their tubes. Tube supplier are not about to tell them and amp makers ignore the topic completely.

Microphonic tubes are the owner's problem, not theirs.

.... Phil

I read up about vintage analog guitar effects units, the Ibanez Tube Screamer TS808 in particular. It's an analog solid-state circuit that tries to emulate overdriven tubes. It seems to have a cult following and there are numerous clones on the market.

What's weird is that owners of such clones strive to get the 'original' sound by replacing the components with obsolete parts like a 4558 opamp from the '70s, carbon resistors and the like, and are willing to pay a small fortune for them.

While potentially a problem, not that big of a deal. Especially for heavy heads using big fat rubber feat, pretty much never a problem with those amps - the head is the head, obviously it goes on top. Even for combos it's not a huge problem if the amp is designed right (low-as-possible impedance before high gain stages to "short out" the grid microphone), use a sharpie to detect the ringers and keep them out of the first couple stages. Plus it sells preamp tubes!

One amp where it was a problem is those old Mk1 boogies with preamp tubes almost touching the speaker - they had rubber chassis mounts but that did little good, acoustic energy alone was enough to keep the tubes rattled up pretty good.

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** FFS it an go anywhere, on a road case, a chair or even the floor. ** Complete bullshit.

Microphony means the element of a tube are vibrating cos they are loose. This of course modulates plate current, with the first pre-amp stage being the most susceptible. Grounding the grid has zero effect.

** ????????

** Many combo amps are the same, but it is not the main problem.

Vibration is coupled to a tube via it own pins, damaging the mica parts. Then its becomes microphonic and sensitive to strong sound at high frequencies.

FYI, constant heavy vibration also destroys OUTPUT tubes, the elements become loose, the tube microphonic ( makes rattling noise through the speaker when tapped) and and you can even get low frequency feedback via them alone.

You know nothing.

..... Phil

Seems like a form of mental illness like obsessive-compulsive disorder and cargo-cults, or a form of conspicuous consumption like 90% of the car-modding community.

You can find a lot of ways to make a car perform worse than stock for big money and I'm pretty sure the BMW and Honda enthusiasts have found most of them.