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Thread: Auditioning and choosing speakers

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    Auditioning and choosing speakers

    I was reading a review of an amp today, and the reviewer emphasize what a good choice the particular Celestion speaker was for that amp.

    Some of us have the luxury of being able to compare speakers, perhaps by going through them like consumables. But most of us are somewhat obliged to rely on recommendations and reviews.

    So I was wondering: have you come across commercial outlets of any sort, where you've been able to use a single amp/head to drive a variety of identical cabs with different speakers, and switch back and forth between them to find out what you prefer?

    Admittedly, such an affair would be a bit pricey for the dealer, and also take up space, but even, say, a quartet of 1 x 12" cabs, driven by the same amp, would allow one to compare efficiency, bandwidth, resonances, etc., in a meaningful way. The consumer can then look at the listed specs of what's in the cab, and have a better idea of what means what when looking through specs of other speakers. Simply auditioning a speaker in a very different cab, driven by a different amp, whose volume pot might have a different taper, or use different tubes, is a suboptimal way to compare speakers.

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    That would be a great way to audition speakers, but I wonder what % of buyers would then order on line. Not such a great deal for the retailer.
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    Senior Member Enzo's Avatar
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    That warning could be applied to just about everything sold in a music store.
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    Quote Originally Posted by Enzo View Post
    That warning could be applied to just about everything sold in a music store.
    or any "brick n mortar" store. Kind of ironic that Sears is closing more stores since they pretty much invented home delivery of ordered items, pre-internet obviously.
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    Quote Originally Posted by Enzo View Post
    That warning could be applied to just about everything sold in a music store.
    I had a salesperson at a local mom & pop store actually thank me for not returning a piece of equipment after purchase (the store had a generous 2 week no-questions-asked policy). Apparently this store was a victim of 'return and buy online'; they closed some time after this encounter.
    Quote Originally Posted by Steve Conner View Post
    If it still won't get loud enough, it's probably broken.

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    I think the cab has so much impact that it would still be very difficult to get a proper idea.
    I seem to recall seeing such a scenario for car audio, but never for MI gear.
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    You're probably right about the impact of cab. But then almost every amp has a different cab anyway. It would be nice to be able to hold cab and amp constant, and the only varying element would be the speaker.

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    Better Tone thru Mathematics bob p's Avatar
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    there's nothing in the world that i hate more than speaker swapping in a tone quest. ok, maybe that's a bit of an exaggeration, but i really do hate it.

    i'm at the point where i know what speakers i like, and i keep a few cabs around that represent my favorite tonal options. then if the amp isn't friendly with those options, i mod the amp.
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    Quote Originally Posted by Mark Hammer View Post
    ...use a single amp/head...with different speakers...switch back and forth between them
    We had something like this in the audio electronics company I worked for many years ago, and I guess it wasn't uncommon in Hi-Fi shops, back when such things existed. That was with solid-state power amps driving the speakers.

    With (valve) guitar amps, there is some additional complexity to deal with. We all know bad things happen if you remove the load from a (valve) guitar amp while it's powered on and putting out a signal, so speaker switching will have to be done in some way that guarantees there will always be a reasonable load on the output of the amp.

    A starting point might be to just use make-before-break switches. But what happens if you have a four-way switch, and only three speaker cabs are actually hooked up? Switch to the (missing) fourth position, and your amp fries its output transformer.

    Off the top of my head, I can't think of a simple way to guarantee the continued good health of the guitar amp. It seems to me you'd need some fairly elaborate protective circuitry to pull this off; maybe something that monitors voltage and current in the speaker leads from the guitar amp, and keeps a dummy load switched in until it calculates that loading conditions are okay, and the dummy load can be switched out of circuit.

    -Gnobuddy

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    That's an entirely reasonable position. The challenge is that there are a lot of folks like myself who don't spend hours and hours with different amps, cabs, and such, gaining familiarity with current and past production models, and the reviews and spec sheets are generally not a sound (sic) basis for selecting and ordering something.

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    VERY realistic and practical considerations.

    In response to the comments of others who noted the dismaying tendency for folks to audition in a bricks-and-mortar store but spend their money in a virtual/on-line retailer.

    Is there enough audio capacity in the average end-users on-line system, that samples of the same guitar lines, played through the same amp with the same settings, and sampled at the same distance from different speakers in the same cab, could provide an opportunity to get a better idea of whether a given speaker is more in line with what you want or need?

    I.E., is there a way to do what I'm suggesting that does NOT require a bricks-and-mortar retailer to carry out?

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    Better Tone thru Mathematics bob p's Avatar
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    I don't think so, Mark. I tried setting up a high fidelity system running my computer output into a stereo system, then a pro-sound system. While it was better than listening though cheap PC speakers, or even a decent set of small monitors, there was a nagging problem that nullified remote hifi auditioning a practical exercise, namely that there isn't any consistency in how people record, and even if they make a good recording, Youtube is going to crappify it. Unfortunately there's enough recording variability that it's nearly impossible to make meaningful comparisons. that's how it worked out for me, anyway. I have to do my comparisons in person.
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    I agree that live is probably best, and also agree that pitting gear against other gear on Youtube is a bit of a fool's errand.

    At the same time, if an honest comparison can be presented, that goes above and beyond what normally passes for shootouts on Youtube, there can be reasonable value. So, player wanks away, and the same sample is played through the same amp with the same settings through the same cab, mic'd the same way, but with different speakers. Turn the volume up, and record the sample through the various speakers all over again.

    The overall loudness will not be accurately represented, and in most instances, nor will the bass. And unless the demo is an hour long, the full range of tonal properties of a speaker, with different playing styles, and different EQ settings, will not likely be factored in. But, within limits, one ought to be able to get a sense of relative efficiency and resonances, which is often a helluva lot more than print representations provide.

    I don't know that anyone should rely on such hypothetical demos, but they would be a good supplement to allow for a fairer and more fulsome comparison.

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    Brick and mortar shops should apply a 20% restocking fee on stuff returned for NO reason, which about covers "online discount" price difference.

    As of demoing spakers, at least Eminence has a display panel orn shallow cabinet, say 4f by 6ft or so, with some 8 speakers mounted and a switching selector.

    Cabinet has importance on deepest/lowest octave but none at all on mids/high mids which is where most guitar frequency, and specially "voice" lies.

    Itīs very easy to notice a 3dB louder speaker, or a scooped one or ashrillicepick one vs a smooth smokey one.

    All those differences come from huge peaks and dips in the 500Hz to 3500Hz area, which leave speaker cone surface and are beamed forward without even noticing the cabinet.

    Then thereīs comparison videos: same guitar, player, amp, cabinet and settings.
    Youīll notice what I mentioned earlier: deal break or make are all in the midrange section.
    Differences are **amazing**



    I (internally) laugh when people spend weeks arguing capacitor colour, tube make or plate colour, when differences are at most small while speaker differences are bone crushing.
    And yet thereīs little or no discussion about that,or at most very slight compared to what you can clearly hear above.
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    Quote Originally Posted by Gnobuddy View Post
    We had something like this in the audio electronics company I worked for many years ago, and I guess it wasn't uncommon in Hi-Fi shops, back when such things existed. That was with solid-state power amps driving the speakers.

    With (valve) guitar amps, there is some additional complexity to deal with. We all know bad things happen if you remove the load from a (valve) guitar amp while it's powered on and putting out a signal, so speaker switching will have to be done in some way that guarantees there will always be a reasonable load on the output of the amp.

    A starting point might be to just use make-before-break switches. But what happens if you have a four-way switch, and only three speaker cabs are actually hooked up? Switch to the (missing) fourth position, and your amp fries its output transformer.

    Off the top of my head, I can't think of a simple way to guarantee the continued good health of the guitar amp. It seems to me you'd need some fairly elaborate protective circuitry to pull this off; maybe something that monitors voltage and current in the speaker leads from the guitar amp, and keeps a dummy load switched in until it calculates that loading conditions are okay, and the dummy load can be switched out of circuit.

    -Gnobuddy
    Just mute the amp while switching.
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    Better Tone thru Mathematics bob p's Avatar
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    You'd mute the amp. I'd mute the amp. Gnobuddy would mute the amp. But when a teenage kid and his buddies go into a brick and mortar store to jam on 20 different speakers, they're not going to mute the amp. They're going to short it's transformer windings.

    I think Gnobuddy was trying to think of a kid-proof solution.
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    Quote Originally Posted by bob p View Post
    You'd mute the amp. I'd mute the amp. Gnobuddy would mute the amp. But when a teenage kid and his buddies go into a brick and mortar store to jam on 20 different speakers, they're not going to mute the amp. They're going to short it's transformer windings.

    I think Gnobuddy was trying to think of a kid-proof solution.
    You misunderstood what I was getting at. The muting is integral to the design of the switch.

    PS: I thought it was obvious, but on reflection I could have been clearer. I guess that's why I was never a technical author.
    Last edited by nickb; 09-01-2017 at 10:10 PM.
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    Better Tone thru Mathematics bob p's Avatar
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    Quote Originally Posted by J M Fahey View Post
    As of demoing spakers, at least Eminence has a display panel orn shallow cabinet, say 4f by 6ft or so, with some 8 speakers mounted and a switching selector.
    I think emincence came out with that speaker demo unit when the introduced the RedCoat and Patriot line of speakers. They had to do something like that, because they had introduced a bewildering number of speakers all at once and nobody had a clue how to tell them apart using only the ad copy. The demo box was a good idea, but 8 speakers isn't enough when the number of speakers they sell is many times that number.

    I like Rivera's video -- he tried to be consistent by recording a guitar signal and re-amping the recorded signal so that the player doesn't have a feedback loop to guide his playing and thereby change the results.

    As good as that Rivera video may be, it doesn't tell me all that much. Sure, it gives me a rough idea of frequency response differences at a fixed signal level, but how big of a signal level is that? They didn't say. I'd suspect that they're driving the speaker cabinet with a relatively small level signal. At small signal levels you hear the frequency response differences. But at large signal levels, you can hear some speakers fail by introducing nasty distortion artifacts while others just keep on going. Try pushing a setd of Jensen 12" speakers to their rated limits and they're going to get nasty, while the EV and the JBL will take it in stride. Celestions also get pretty nasty when you feed them real power. One of the things that the Rivera video doesn't even address -- which is a real concern for me -- is large signal speaker distortion. Some speakers are a lot worse than others and the video demo method doesn't really give me a feel for that, because nobody gives adequate demos under all conditions. Like Mark said, Youtube is a bit of a fool's errand. The videos are entertaining but I don't put any faith in them. It's too easy to skew the results using playing style and recording methods to minimize differences or unrealistically accentuate them.

    As it turns out I own at least a dozen of the speakers demo'd in that video, in a dozen different cabs. I can honestly say that when you drive any of them with power, the differences between them are much more significant than the video would lead you to believe.

    It's funny that you mention how people fuss over things that don't really matter, while paying less attention to speakers. IMO speakers are the biggest effector of amp tone. So I just keep several cabs loaded with several flavors of speakers and pick whatever is right for the occasion. And if there's an amp + speaker combination that is close but doesn't sound quite right, most of the time I can get it into the zone by tweaking the amp. It's a real bear to tweak speaker cabinets. It's both time consuming and expensive, and speakers take up a lot of space. IMO there's a lot to be said for having a few open backed cabs, a 4x12 loaded with Greenbacks, a 2x12 loaded with V30, and a set of EVMs in their T-S ported boxes. Once those bases are covered there's really no need to ever consider speaker shopping... until it's time to update the bass cabinet collection...

    honestly speaking, i have enough gear to outfit a Pink Floyd tour. My gear is designed to cover the necessary bases as far as tones are concerned, and it doesn't really change over time. I haven't made any real changes in 15-20 years. I don't understand why people constantly trade in and out of amps and speakers while searching for that "Holy Grail" tone. I guess I'm one of those guys who thinks that Holy Grail tone doesn't really exist, and that it's kind of pointless trying to find it. On a more practical level, I think that there are several "classic" classes of tones, each of which is in sort of a different tonal ballpark, and each of which can be made to work in it's proper context. Need a Marshall 4x12 sound? Any Marshall 4x12 will get you close. But I get the impression that a lot of gear hounds are spending more time than they should in cork-sniffing different speakers for their 4x12, trying to recognize minute differences between them. Is it worth it? I'd say no -- for me I'd be better off spending that time rehearsing than worrying too much about gear. As they say, the real tone is in your fingers. My problem is that no matter what amp and cabinet combination I may try, when I dial it in to get a sound that I like, it always sounds like me.
    Last edited by bob p; 09-01-2017 at 10:25 PM.
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    when I get something new strange thinks happen as I heard some in the evening and completly different in next morning...
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    Quote Originally Posted by catalin gramada View Post
    when I get something new strange thinks happen as I heard some in the evening and completly different in next morning...
    Don't wory about it. I think that's normal for humans. It's the fundamental differece between ears and measuring devices.
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    Quote Originally Posted by nickb View Post
    Just mute the amp while switching.
    And what happens when someone mutes the amp, switches to the 4th position (which happens to have no speaker connected), unmutes the amp, and does his best imitation of Pete Townshend's arm-windmilling power chords? Barbecued output transformer and output valves?

    Also, four out of four Fender (valve) amps I've owned have had truly marginal RF stability. It's quite possible that one or more of them might burst into high-frequency oscillation if the output is unloaded - whether or not the input is muted. If that happens, once again, poof, amp fricassee.

    Muting a valve guitar amp doesn't guarantee it will escape damage if the output is open-circuited. Considering the very considerable cost of many amps, I don't think it's an acceptable risk. Something fool-proof (or, at least, as near to fool-proof as possible) needs to be cooked up.

    -Gnobuddy

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    Quote Originally Posted by catalin gramada View Post
    when I get something new strange thinks happen as I heard some in the evening and completly different in next morning...
    Exactly. As Nickb says, this is exactly why we shouldn't trust our ears too much. They are very easily fooled, just like all our other human senses.

    What you're describing happens to me often when I'm trying to tweak a guitar amp design to sound good. It sounds good today, but after a week, I hear things I don't like, and tweak it again. Two weeks (or two days) after that, it sounds wrong again. It can be an endless loop, unless I put a stop to it by comparing with a reference amp that I use as a baseline. Never tweak the reference amp!

    It's not just our hearing - do you know what happens when the cook keeps adding salt and tasting the soup to see if it's salty enough? His/her tongue loses its baseline reference, because of all the salt he/she has already tasted, and the soup ends up over-salted.

    -Gnobuddy
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    Quote Originally Posted by bob p View Post
    when I dial it in to get a sound that I like, it always sounds like me.
    I have a number of musician friends who are constantly buying new guitars that they really can't afford, hoping they will sound different and better. But if the musician continues to have the same limitations, his/her guitar will always sound the same...

    The most extreme case was a boastful twit who had, he claimed, enough Gibson acoustics to play a different one each week for a year. This guy seemed to know only about three or four chords - every song he played was in the key of G, and 99% were I-IV-V progressions, the remaining 1% being I-vi-IV-V. I almost asked him if he played the same four chords on all his fifty-plus Gibsons, but managed to hold my tongue.

    For any musician who already has halfway decent musical equipment, and wants to sound better, IMO the best place to spend money is on guitar lessons. Find a teacher who is much more skilled than you are, learn new stuff from him/her, and your same old guitar and same old amp will magically start to sound better.

    Sometimes, of course, we just want to sound different, not better, and then, a change in gear might be the solution. Switch from a Les Paul to a nylon-string classical guitar, and I guarantee you will not sound the same - the super-short sustain will force you to change the way you play, like it or not!

    -Gnobuddy

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    I constructed a two single 12 inch cabinets and two 10 inch cabinets over these last number of years, so having a similar cabinet really makes comparing speakers a breeze when auditioning, simply pull the 1/4 plug and plug into the next one, the characteristic of a speaker can be easily determined.

    In the all around category for good old school rock, the Celestion Vintage 30, holds the highest respect, sort of a familiarity good balanced tone, clean or driven hard. Lots of power handling, slam 80 watts, that's what we are talking about ...under $200

    Next: Jensen Jet, seen a posting a couple of years ago, sale. Compared to the Celestion, close sounding, a little more scooped sound, fire a Fender amp through, mimicks a Fane to some in a good way.

    I was fortunate to have a studio give me a pair of Fanes, 80's Im guessing. The first issue with recessed baffle front mounting, is they had flange ears on four bolt circle, needed to use a router to accommodate. Very big magnets on these beast, they can maybe push a few extra decibels, the upper end gets a little piercing

    I had two Eminence series ... Red White Blue and some hemp cone model. From my perspective, both had a similar sound, not as complex as a Celestion, kind of throaty mid, sounded good, but recorded so so

    All these speakers were capable of 50 - 70 watt ...so if you have a head with that power, you want to wail, these speakers will do. Even a 10 watt amp would benefit these speakers, but the cabinet still determines the sound

    Interesting, I had some old 12 60's small alco magnet speaker, low efficiency, but in terms of low volume sweetness, this speaker simply sounded balanced, it just one of those things that leads you to play your fingers off ... cool ... easy to destroy, really records well.

    I just built two 10 inch cabinets, 80% the dimension of the 12 inch cabinets, similar materials
    One fitted with a Eminence 10 Ram Rod, like the 12 Eminence, very throaty mid. When pummeled with 80 watts, this bad boy can be felt.

    Next, a 10 speaker removed from a Fender Champ XP ... a nice complex sound speaker, no where as loud as the Ram Rod, but low volume simply sounds balanced and pleasing.

    Because I serviced guitar amps, I can attest in certain combo amps, the baffle can simply make a good speaker sound flat. Essentially, the baffle and cabinet material will play an important role in voicing your guitar tone.

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    "Thermionic Apocalypse" -JT nickb's Avatar
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    Quote Originally Posted by Gnobuddy View Post
    And what happens when someone mutes the amp, switches to the 4th position (which happens to have no speaker connected), unmutes the amp, and does his best imitation of Pete Townshend's arm-windmilling power chords? Barbecued output transformer and output valves?

    Also, four out of four Fender (valve) amps I've owned have had truly marginal RF stability. It's quite possible that one or more of them might burst into high-frequency oscillation if the output is unloaded - whether or not the input is muted. If that happens, once again, poof, amp fricassee.

    Muting a valve guitar amp doesn't guarantee it will escape damage if the output is open-circuited. Considering the very considerable cost of many amps, I don't think it's an acceptable risk. Something fool-proof (or, at least, as near to fool-proof as possible) needs to be cooked up.

    -Gnobuddy
    It sounds you put an imaginary dumb switch in place and then levelled criticism at it. Or course you'll get problems if you put it front of a rampant herd of monkeys on amphetamines.

    Like any system, you list the requirements and design the system to meet them. An electronically controlled switch can be designed that meets criteria of open and/or short protection and any else you might reasonably want it to. You just have to put in the time (and money ).
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    THis needn't be complicated. Put a 100 ohm resistor across the amp feed. That will be enough to protect the amp, but high enough to not materially affect the speaker.
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    Quote Originally Posted by nickb View Post
    It sounds you put an imaginary dumb switch in place and then levelled criticism at it.
    Nope, in my original post I pointed out that an electronically controlled switch that senses load impedance is what is needed. It was you who suggested that a dumb (mute) switch at the input would be all that was required!

    -Gnobuddy

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    Quote Originally Posted by Enzo View Post
    THis needn't be complicated. Put a 100 ohm resistor across the amp feed. That will be enough to protect the amp, but high enough to not materially affect the speaker.
    you beat me to it. i bought a lifetime supply of 5W 270R wire wounds when they were being cleared out at newark a few years ago. wire one across the amp's OT and stop worrying. they'll keep the amp alive long enough to figure out you've made a mistake.

    Fender also used shorting jacks on the output in an attempt to prevent monkey on amphetamine type disasters. sure, the OT won't like working into a shorted load, but it hates that less than the open circuit alternative.
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    Quote Originally Posted by Gnobuddy View Post
    Exactly. As Nickb says, this is exactly why we shouldn't trust our ears too much. They are very easily fooled, just like all our other human senses.

    What you're describing happens to me often when I'm trying to tweak a guitar amp design to sound good. It sounds good today, but after a week, I hear things I don't like, and tweak it again. Two weeks (or two days) after that, it sounds wrong again. It can be an endless loop, unless I put a stop to it by comparing with a reference amp that I use as a baseline. Never tweak the reference amp!

    It's not just our hearing - do you know what happens when the cook keeps adding salt and tasting the soup to see if it's salty enough? His/her tongue loses its baseline reference, because of all the salt he/she has already tasted, and the soup ends up over-salted.

    -Gnobuddy
    Thats remembered sound checks made with a friend of mine saying an A-B test worth nothing, do A-B-A instead... The problem when you get some is how to not lose the others. Is like a debate between micro and macro events analysis or details vs ensemble if you wish...
    Last edited by catalin gramada; 09-02-2017 at 05:05 PM.
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    Quote Originally Posted by Enzo View Post
    THis needn't be complicated. Put a 100 ohm resistor across the amp feed. That will be enough to protect the amp, but high enough to not materially affect the speaker.
    I have to defer to your experience here. I've read stories of the 32-ohm load in the "ultimate attenuator" causing damage to high-powered output stages, so I'm personally not keen on the idea of a 100-ohm resistor being sufficient protection. But I simply don't have enough experience with improperly loaded valve guitar amps to know for sure.

    -Gnobuddy

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    Quote Originally Posted by Gnobuddy View Post
    I've read stories of the 32-ohm load in the "ultimate attenuator" causing damage to high-powered output stages, so I'm personally not keen on the idea of a 100-ohm resistor being sufficient protection.
    I think these are 2 quite different scenarios, mis-match that sounds correct vs. no-load, audible fault condition.
    Most (though not all) guys using attenuators are doing so to get power amp clipping. The amp in this case gets sustained high power use and as far as the user can hear, it is all working right. I don't think the mismatch makes it blow up right away, and probably not all that often or Ho would have re-designed by now or have a lot of angry customers.
    In the case of the 100ohm across the output for protection, even the most dim user should clue in pretty quick that there is a problem (no sound). Worst case a couple windmill power chords.
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    Senior Member Enzo's Avatar
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    I had a guy in my shop once demo-ing some problem, and I was in the rear of his Twin Reverb disconnecting one speaker at a time. We played through one speaker, then I told him to stop as I disconnected that speaker and hooked up the second. Unfortunately, as I was holding the hot lead of hte second about to put it on the speaker, he decided to do one of those windmill chords. Did you know you can get quite a poke holding an unterminated speaker wire when they do that?
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  33. #33
    Old Timer J M Fahey's Avatar
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    You bet.
    Even an SS amp can tickleyou big time, but Tubed ones are *much* worse because of the OT inductive kick.

    LOTS of tens of volts, wouldnīt be surprised by them reaching 100V peaks if fully unloaded.

    Of course that translates up to a couple KV at the plate side and thatīs what punchesn through insulation , arcs sockets o tube guts..
    Juan Manuel Fahey

  34. #34
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    Quote Originally Posted by g1 View Post
    In the case of the 100ohm across the output for protection, even the most dim user should clue in pretty quick that there is a problem (no sound).
    I mentioned this on another thread, but it may be worth repeating here: I have taken to using a switching output jack on my DIY valve guitar amp builds, and wiring an 8 ohm power resistor to it, so that if nothing is plugged in, the amp sees an 8 ohm load. Then I wire a pair of anti-parallel high brightness LEDs and a protective series resistor across the 8 ohm resistor. If I forget to plug in a speaker and play something through the amp, the LEDs flash brightly (in addition to lack of sound) to remind me that I've screwed up.

    I've toyed with the idea of wiring a diode bridge across the same 8 ohm power resistor, and feeding the rectified DC from the bridge to a loud piezo buzzer, but I've never actually bothered to try it. But this should get you loud beeps along with the flashing LEDs to let you know the speaker isn't plugged in. It might not work on a loud stage with the rest of the band already going, but short of that, should be noticeable.

    My interest is in low-powered amps, so it isn't hard to find an 8 ohm resistor that can cope with the full output power of the amp for a reasonable length of time, certainly long enough for me to realize there is a problem, and fix it. Might not be so easy with a 200 watt monster.

    Then again, a 200 watt amp is already heavy, bulky, and expensive, so it may be worth adding this sort of protection, with an appropriately large and heavy dummy load. Maybe four 12-volt, 50 watt, automotive headlamp bulbs in series or something similar.

    -Gnobuddy
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  35. #35
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    Quote Originally Posted by g1 View Post
    I don't think the mismatch makes it blow up right away, and probably not all that often
    I would guess the design around the screen grids is the big factor here. Using a bigger anode load lets the anode voltage drop lower on negative peaks, and screen grid current wants to shoot up as the anode becomes less effective at collecting electrons.

    But if there are conservatively large screen grid dropping resistors in place, and/or a conservative screen grid DC bias voltage, no harm should be done, because those measures will limit screen grid power dissipation to tolerable levels.

    The thing is, conservatively designed valve guitar amp output stages are not exactly universal. Just ask the 6V6 bottles in my Princeton Reverb reissue - the factory schematic shows around 440 volts on the anodes.

    -Gnobuddy

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