Jcm800 Downscale

[Chuck H]

That's why I design and make my own speakers
Not to mention that the amps also get designed and made considering the available speakers.

For the design I worked on (for a real player in the biz), speaker compatiblility ended up as a major design criteria! I had to test and tweak the amp with several popular speakers to ensure that each had it's own "useful" voice. It wouldn't have been acceptible to have an amp that was offered in a head type design that sounded bad with anything but one specific speaker. This, of course, quickly reaches the dilema of "mediocrity with everything" or "great with one thing but crappy with anything else." I actually feel pretty good about where I landed in the middle. "Great with several but only acceptible with many". That's about as good as it gets. But definitely an unexpected hurdle in the design process for me (noob).

[jazbo8]

That's why I design and make my own speakers
Not to mention that the amps also get designed and made considering the available speakers.

You da man!

Jaz

[Alan0354]

Well, the OP isn't asking us to do his homework, he simply placed here a legitimate doubt and asked for suggestions.
That's what this forum is for, and what most of us do.
Hope he keeps on, unless he has changed his project idea.
He *has* to submit a working one anyway, this one or any other, it's required by his University.
And it's difficult, but at least technically possible.
Let's say it's just on the cliff's edge.

As of the many bright caps, they are basically there to increase note definition and cut low frequency "mud", even with heavy distortion.
Edge rounding is provided by guitar speakers cutting frequency at 24 dB/oct (or more) starting between 3000 and 4500 Hz, OT transformer adding bandpass filtering, power amp clipping smoothing unbearable waveform peaks, 4x12" resonance peak providing thump and venue acoustics (and audience) providing further filtering.
That's why many *killer* (live) amps and pedals are dissapointing or buzzy at home.
Have you ever tried one of Jimi Hendrix's "weapons" , the Fuzz Face, straight into a Mixer or PC input interface?
UGH!!! is the understatement of the year.
Customers many times ask me "what is the secret of XXXX's sound?" or "which pedal gives me that sound?" or 100 other variations of the same.
The answer is **no single element**; results come from an interaction or careful tweaking of a 1000 factors, many of which are ignored by the very Musician who unconsciously uses them to his advantage.

Don't forget the person playing the guitar. It's the touch!!! Most sort after guitar sound played by famous guitarist were just simple setup, using mostly neck pickup of either a Les Paul or Strat or the like.

[Alan0354]

That's why I design and make my own speakers
Not to mention that the amps also get designed and made considering the available speakers.

I don't have the interest or the know how to design or build speakers. I was just writing email to some China distributors to find a cheap known brand speaker. Then I'll try to work around it. It is unthinkable to me to pay over $100 for a speaker particular the alnico ones. They are supposed to be the cheapest of the cheap speaker in the older days, now Jensen and Celection selling them for over $100!!! People are stupid enough to buy into that.

I can't find any 10" or 12" guitar speakers for like $30 or so, if anyone have any suggestion, I am all ears.

[printer2]

I do not see it as doing the OP's homework as even with the proper tube selection there is a great deal of work to be done after that. I used to herd students through their thesis's and was a resource for them no different than what the OP asked. Given that there is not much information on low voltage operation of tubes and even more so their distortion characteristics a little bit of help can't hurt. Not like he can just go to a cabinet and start testing a range of tubes (although I was a little disappointed when he said he needed the gain characteristics as he was not allowed to measure them. If it were me I would measure them myself and say I got them somewhere). If we were doing his homework for him he would still be here asking us to fill in the blanks. Since we have not heard much of him lately I would think he went on to more productive endeavors, such as Gretchen.

So why are we bothering? We are problem solvers, if we were not we would not have entered this field. There is a lot of 'what if' sprinkled in each of us, some people do crossword puzzles, I find them boring, but figuring how to make something that works well gets my brain going. Learning from others and a sense of discovery does not hurt either.

[Chuck H]

You won't get far for $30. But a bit more will get you into a Weber "Signature" speaker. Well respected name and good reputation. The Signature speakers are outsourced but made to Webers specs. I haven't tried them.

The Eminence Legend speakers are a good value. Very competitive quality and tone at a price lower than the competition. Including their own Patriot and Red Coat line. IMHO the Legend speakers sound just as good at half the price. I HAVE tried these.

I personally always seem to end up with Celestion speakers. I like their lively, brash tone. They're expensive. Especially when you consider that non guitar amp big speaker companies seem to sell what would be speakers of similar construction (but not voiced for guitar) for about one third the price!!! So we agree on that. It does take big money to market in the instrument biz. And specializing means a lot of R and D. But three times as expensive? $140. for a Chinese made Vintage 30 is actually insulting. So it sucks to be us because no one else makes them!

JM, are your speakers voiced similar to other guitar speakers or specific to your amps? I might like to try one if you'll sell it to me.

[Alan0354]

The software of this forum is really bad, it's been down many time already. Then when you post, it's so easy to double post.

[Alan0354]

You won't get far for $30. But a bit more will get you into a Weber "Signature" speaker. Well respected name and good reputation. The Signature speakers are outsourced but made to Webers specs. I haven't tried them.

The Eminence Legend speakers are a good value. Very competitive quality and tone at a price lower than the competition. Including their own Patriot and Red Coat line. IMHO the Legend speakers sound just as good at half the price. I HAVE tried these.

I personally always seem to end up with Celestion speakers. I like their lively, brash tone. They're expensive. Especially when you consider that non guitar amp big speaker companies seem to sell what would be speakers of similar construction (but not voiced for guitar) for about one third the price!!! So we agree on that. It does take big money to market in the instrument biz. And specializing means a lot of R and D. But three times as expensive? $140. for a Chinese made Vintage 30 is actually insulting. So it sucks to be us because no one else makes them!

JM, are your speakers voiced similar to other guitar speakers or specific to your amps? I might like to try one if you'll sell it to me.

Thanks

You try the Weber speaker? They are under $40, it's cheap enough for me. Eminence are in $80 range, that's too much.

I found Jensen MOD 12-50 12" 50W for $49, that's is barely in my range. You have any experience with Jensen?

[J M Fahey]

Hi chuck h .
They are voiced for *guitar* obviously.
That's what forced me to make them in the first place.
I make them in a few flavors.
To have an idea of the sound, in the menu there are "equivalents" to
Jensen C8R / C10R / C10Q / C12Q / C12N / C15N (as you see, I *love* Jensens)
Celestion G1025 / G10L / G12L / Tube 10 / G1265 / a somewhat lighter version of Greenback
Meaning: I can make most "Jensens", they are "easier/simpler/cheaper", (fine with me) ; some of the lighter "Celestions".
I am limited by my (so far two) magnetizers.
Can easily do up to 130 mm diameter magnets, *just* reaching 140/145mm ones.
Also can make a scaled down "Mini EVM12L" , with same technology edgewound aluminum ribbon on kapton base voice coil, curvilinear cone, but 2" VC instead of 2 1/2" and 147mm magnet instead of 190mm.
Same type of sound, but 1/2 the power handling and perhaps 1 db less efficiency.
Enough to crush a G12T75 anyway.
I'm (slowly) building a third magnetizer which will allow me make equivalents to V30 / G12H30 which use 156mm magnets and, maybe, with an even larger yoke, EVM12/15L (190 mm magnets).
But that lies in the future.
No plans to clone JBLs (I mean the *real* ones, not the wimpy stuff sold abusing that sticker) because I don't like them for guitar (nails on a blackboard) and their 220 mm magnets and complex magnetic structures put them way out of reach.
Big problem is that absorbed line power grows exponentially with diameter and the Utility Company simply can't supply it.
I mean, I must rely on what regular neighbourhood power lines can supply.
*Big* problem with speakers (that's why so few make them, outside the established makers) is that I need the *exact same* magnetizer as, say, Celestion or Eminence.
They can easily afford it when making 10000 to 50000 big speakers a month, compared to my meager 30 a month market.
Oh well.

EDIT: @alan: The Jensen Mods work well and sound good, good cost/benefit.
Are similar to the ones I make: reasonable cost, good sound, equalization halfway between "American/British" allowing one to get both sounds with a little amp tweaking.

[Alan0354]

Thanks JM.

[loudthud]

JM, do you make your own cones and voice coils?

I remember an ad from a long time ago by JBL talking about their edge wound voice coils. They make it look like they used a rectangular wire. Weber talks about edge wound voice coils and makes it look like it's just a round wire slightly squished down into an oval. What's the real story?

[soundguruman]

JM, do you make your own cones and voice coils?

I remember an ad from a long time ago by JBL talking about their edge wound voice coils. They make it look like they used a rectangular wire. Weber talks about edge wound voice coils and makes it look like it's just a round wire slightly squished down into an oval. What's the real story?

The edge wound coil reduces inductance and increases power handling.
The wire is oval, come to think of it...
the JBL coil is marked backwards, opposite of all other speaker manufacturers.
connect a battery to the + and - terminals, the speaker moves in, not out.
I was told through the grape vine...
that this is a mistake made by the factory long ago.
And, rather than admit that the terminals were labeled backwards...
JBL simply continued to manufacture speakers with backwards labeled terminals.
The JBL speaker itself, is actually (for some time now) Japanese.
But the crossovers installed in the cabinets are made in China...
(and they fall apart when shipped)...because the hot glue used, fails.

[Alan0354]

I am even curious, do you design the frame, the dimension of the magnet and all the hardware, or do you buy existing parts? I have no knowledge how you even start making your own speaker. I thought you need a lot of overhead to make speakers.

JBL do use rectangular wires, they would on the short side so they wind only one layer with a lot of turn as it is very thin on the short side. The voice coil is very thick as the thickness is the long side of the rectangular wire.

JBL and Altec Lancing type of speakers don't sound good. They are too hifi, the cone response to very low frequency and you can see the cone jump. Not only this make them unreliable and easy to damage as it move so much, they sounded very thumpy. The original big OT of the Bassman 100 give me a little of the same characteristic of the JBL. Also because of the aluminum dome, it has more highs, which is actually a bad thing for guitar particular for distortion.

JBL are such a fragile speaker they burn all the time. I remember when I went to a repair shop, there were stacks of old cut voice coil from JBL, the guy even gave me one to play with. The coil is so big (4" diameter ) that it does not take much to deform and start sticking. As for personal experience, I had a K120, it start sticking for absolutely no reason and I had to recone it. I did not even play in high volume.

JBL are all but disappeared and deservingly so. Expensive, fragile, heavy and sound bad!!! I remember the good old Twin Reberb speaker can really take a beating. They sounded good and survive all the full power abuse. The kicker was I had one JBL parallel with the Twin speaker, both 8 ohm, the Twin never have an issue. The JBL never even take half the power of the Twin as I never had occasion to crank up those days.

[soundguruman]

I am even curious, do you design the frame, the dimension of the magnet and all the hardware, or do you buy existing parts? I have no knowledge how you even start making your own speaker. I thought you need a lot of overhead to make speakers.

JBL do use rectangular wires, they would on the short side so they wind only one layer with a lot of turn as it is very thin on the short side. The voice coil is very thick as the thickness is the long side of the rectangular wire.

JBL and Altec Lancing type of speakers don't sound good. They are too hifi, the cone response to very low frequency and you can see the cone jump. Not only this make them unreliable and easy to damage as it move so much, they sounded very thumpy. The original big OT of the Bassman 100 give me a little of the same characteristic of the JBL. Also because of the aluminum dome, it has more highs, which is actually a bad thing for guitar particular for distortion.

JBL are such a fragile speaker they burn all the time. I remember when I went to a repair shop, there were stacks of old cut voice coil from JBL, the guy even gave me one to play with. The coil is so big (4" diameter ) that it does not take much to deform and start sticking. As for personal experience, I had a K120, it start sticking for absolutely no reason and I had to recone it. I did not even play in high volume.

JBL are all but disappeared and deservingly so. Expensive, fragile, heavy and sound bad!!! I remember the good old Twin Reberb speaker can really take a beating. They sounded good and survive all the full power abuse. The kicker was I had one JBL parallel with the Twin speaker, both 8 ohm, the Twin never have an issue. The JBL never even take half the power of the Twin as I never had occasion to crank up those days.

I do know that JBL speaker burn out very easily.
And, they are essentially hi fi speakers that are made by Sansui, Japan.
And, I do know that when they burn out, the "warrantee" is fairly useless.
And I do know that the frequency the high frequency drivers are set to, is too low.
This low frequency causes the diaphragms to blow pretty frequently.
AND, this provides a never ending stream of replacement diaphragms, $$$.
JBL refuses to honor the warrantee, unless the speaker is returned to the original point of sale.
Which might be, 2000 miles away, or on the other side of the Earth.

The sound has a really crisp upper mid range, which may or may not be good for guitar.
It has a nice sound for PA, stereo, if you alter the crossover frequency.
Some players love these speakers...
but I will stick with EVM 12L, they are much harder to kill, and take all the abuse I can muster.

[Austin]

I think the speakers from the console stereos from the 50s 60s and 70s sound wonderful for guitar. I always stop and grab the speakers out of them when I see one on trash day and have lots of them now, I need more speaker cabs to put them in! I once met an old preacher guy that had a storage unit full of these old consoles, there must have been 30 or so.. They consoles imo were nothing special but the speakers can sound great, they have super thin and lightweight paper cones and only need a watt or two to be extremely loud. All those speakers he had if installed in 4x12 cabs could have made a pretty big wall of sound... What exactly do you call the speakers with no magnets in there like the fender blue dot kind? Field coil speakers? Some of them are like and that some have magnets.