Grey Bulldogs needs to be pushed?

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Grey Bulldogs needs to be pushed?

Postby Rasmus-Skov on Mon Feb 06, 2012 4:52 pm

Hey folks!

I own and play an old 64' non-tb AC30 with original grey bulldogs.

My issue with this amp is that it's loud. Too loud. It' seem that it's a bit dull and dark until the volume reaches 12' o'clock, then it start to sound good.

I tried with an attenuator, but it's not really working.

So I've narrowed it down the the speakers. I've tried the amp with another cabinet, and it really is another amp. It's more dynamic, and it sounds better at lower volumes.

Is the sensetivity low on the Bulldogs? It's seems the only sound good when they're pushed.

I'm thinking about changing them the speakers, maybe put them on ebay, because as a touring musician it's difficult to play gigs with that kind of volume.

Because if it's not turned up, it sounds bad.
And after my last tour where the Ac30 ended up being off-stage, in a room in the back, with a microphone, it seems a little stupid.

Any helping advice?

Btw: how much are such a pair of 64' grey bulldogs worth?
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Re: Grey Bulldogs needs to be pushed?

Postby Grog on Mon Feb 06, 2012 5:32 pm

The sensitivity on the T1088 polygrey Celestion AlNiCo is 100 so not low at all.

They are exactly the same speaker as the blue T530 which preceed them and only differ in the paint that they have on them. Just on a pedantic point the term bulldogs should only really be applied to the US Thomas Organ speakers used later in the 60's the T1656 and the like, the bulldog never appeared on Engloish made speakers. If yours is a 64 then they are Poly grey celestion T1088's with a 100 senstivity rating. They do need to be pushed to give of their best as well.
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Re: Grey Bulldogs needs to be pushed?

Postby Rasmus-Skov on Mon Feb 06, 2012 6:22 pm

Grog wrote:The sensitivity on the T1088 polygrey Celestion AlNiCo is 100 so not low at all.

They are exactly the same speaker as the blue T530 which preceed them and only differ in the paint that they have on them. Just on a pedantic point the term bulldogs should only really be applied to the US Thomas Organ speakers used later in the 60's the T1656 and the like, the bulldog never appeared on Engloish made speakers. If yours is a 64 then they are Poly grey celestion T1088's with a 100 senstivity rating. They do need to be pushed to give of their best as well.


Ah, thanks on the info. I'll be sure not to mix up the terms about the bulldogs. I just thought that the blue was known as the bulldog, and since mine is the same.

Well it's a shame they need to be pushed, because they're soo loud! :(
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Re: Grey Bulldogs needs to be pushed?

Postby frankc on Mon Feb 06, 2012 6:57 pm

Maybe you should be looking at getting an AC15, so you can push it without it getting too loud?

/Frank
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Re: Grey Bulldogs needs to be pushed?

Postby Grog on Mon Feb 06, 2012 7:05 pm

Rasmus-Skov wrote: Ah, thanks on the info. I'll be sure not to mix up the terms about the bulldogs. I just thought that the blue was known as the bulldog, and since mine is the same. Well it's a shame they need to be pushed, because they're soo loud! :(



It just helps to know which speaker you're talking about so people don't get confused. yes with a sensitivity of 100 they will appear loud. To double perceived loudness you need to add 3 db so a Greenback with a sensitivity of 97db will sound much quieter than a blue or silver @100db.
AC30 Super Twin(1963) S/N 9952N Rear Panel TB Head, Dynamic Bass (1968) #1153, AC30CCH, V212BN 1 x Alnico Blue 1 x Wharfdale, VBM1, AC4TV, Marshall JTM312, Gibson 347(1987), Les Paul Custom, US Fender Telecaster and Stratocaster, CIJ Jaguar HH.

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Re: Grey Bulldogs needs to be pushed?

Postby Rasmus-Skov on Mon Feb 06, 2012 7:14 pm

frankc wrote:Maybe you should be looking at getting an AC15, so you can push it without it getting too loud?

/Frank


Yeah, but I don't wanna sell this one, and I have a matchless HC-30 clone(matchless trannies), which can play and sound good at much lower volumes.

It's also impossible to get a vintage AC15 worth paying for. :)
Grog wrote:
Rasmus-Skov wrote: Ah, thanks on the info. I'll be sure not to mix up the terms about the bulldogs. I just thought that the blue was known as the bulldog, and since mine is the same. Well it's a shame they need to be pushed, because they're soo loud! :(



It just helps to know which speaker you're talking about so people don't get confused. yes with a sensitivity of 100 they will appear loud. To double perceived loudness you need to add 3 db so a Greenback with a sensitivity of 97db will sound much quieter than a blue or silver @100db.

How would it be to combine the two of them? I have both a spare vintage G12H30 and a G12M. Would it be weird just to swap one of the Grey with fx. the G12H30?
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Re: Grey Bulldogs needs to be pushed?

Postby Grog on Mon Feb 06, 2012 7:31 pm

Not at all, go for it. I have a 1 x Blue and 1 x Wharfdale in both my cabs and I like the combination of sounds it gives, the Wharf is very similar spec to a Greenback so bit darker than the blue. The silver with the G12H30 is supposed to be a good pairing. :thumbsup:

As long as they are all 8 ohms so you end up with a 16ohm load with the two in series you're good to go.
AC30 Super Twin(1963) S/N 9952N Rear Panel TB Head, Dynamic Bass (1968) #1153, AC30CCH, V212BN 1 x Alnico Blue 1 x Wharfdale, VBM1, AC4TV, Marshall JTM312, Gibson 347(1987), Les Paul Custom, US Fender Telecaster and Stratocaster, CIJ Jaguar HH.

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Re: Grey Bulldogs needs to be pushed?

Postby exgenerator on Mon Feb 06, 2012 7:59 pm

Many boutique amp companies, like 65 Amps, have a Blue and a G12H30 as their 212 combination. I would just make sure the G12H30 is well broken in before trying it out.
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Re: Grey Bulldogs needs to be pushed?

Postby Rasmus-Skov on Mon Feb 06, 2012 8:21 pm

Grog wrote:Not at all, go for it. I have a 1 x Blue and 1 x Wharfdale in both my cabs and I like the combination of sounds it gives, the Wharf is very similar spec to a Greenback so bit darker than the blue. The silver with the G12H30 is supposed to be a good pairing. :thumbsup:

As long as they are all 8 ohms so you end up with a 16ohm load with the two in series you're good to go.


It's a 8ohm 70'-73'ish G12H30 I have lying around. I have a G12M too but I don't know how it'll match the grey one.

But how about the sensetivity? Wouldn't the grey one play 3db louder than the greenback?
exgenerator wrote:Many boutique amp companies, like 65 Amps, have a Blue and a G12H30 as their 212 combination. I would just make sure the G12H30 is well broken in before trying it out.


I too have a 2x12" with the same combination, and that works nice!
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Re: Grey Bulldogs needs to be pushed?

Postby dlvoots on Mon Feb 06, 2012 9:51 pm

frankc wrote:Maybe you should be looking at getting an AC15, so you can push it without it getting too loud?


Frank has the genesis of an idea that you could try -- make your own AC15. If you can solder and replace resistors, there is a quick and dirty experiment that you could try. The cool part is that if you don't like it, the changes are is easily reversible.

Like you, I found that my AC30 was almost too loud for the kind of gigs I was playing. THEN I found out my Fender Twin Reverb brothers and sisters were having the same grief with their amps. What the Fender folks do is pull the outside two output tubes and run it at half power. An 80 watt Twin Reverb became a 40 watt Twin Reverb.

It isn't as simple as pulling the outside two tubes and running it off. AC30s are cathode biased, meaning there is a BFR under the power amp chassis that sets the bias on the four power tubes (Big Fat Resistor). It needs to be changed. Pull the outside two of the tubes, double the value of the cathode resistor, and you've effectively created an AC15 right there on the spot.

There is one more thing you have to do to make it work reliably . Pulling two of the tubes raises the output impedance of the amp. With 4 tubes, the power amp had a 4K ohm output impedance into the output transformer, with 2 tubes it now has an 8K output impedance the output transformer. Transformers don't have a native impedance -- they simply transform a source impedance to another impedance. In the case of an AC30, the transformer takes a 4K input impedance / 4 tubes and transforms it to an 8 or 16 ohm speaker load. If you remove two of the tubes, the transformer takes an 8K impedance / 2 tubes and transforms it into a 16 or 32 ohm speaker load.

So.......it sounds counter-intuitive, but assuming your speakers are wired for 16 ohms and you pulled two of the tubes and replaced the cathode resistor, move the wire to the 8 ohm tap (which magically became 16 ohms when you pulled two of the tubes).

I did it to my AC30 years ago, and it tamed the amp down to where it plays really nice with a drummer and bass player. And if you don't like what it does, then simply put the speaker wire back on the 16 ohm tap, plug the two output tubes back in place, re-solder the original cathode resistor back in place and it is back to normal.

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Re: Grey Bulldogs needs to be pushed?

Postby SkeleTone on Mon Feb 06, 2012 10:22 pm

It might be worth trying a set of JJ EL844's before you sell off original speakers, since that would affect the value of the amp. They worked well with my '61 AC30 and tamed the output a bit, maybe a couple of dB's, without dramatically altering the character of the amp. They're a slightly lower power version of the usual EL84 power tube and no modification of the amp is needed.

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Re: Grey Bulldogs needs to be pushed?

Postby Rasmus-Skov on Mon Feb 06, 2012 11:15 pm

Hey Steve.
I think the procedure you're describing is way over my skills with a soldering iron!
I don't really wanna go there.:-)

@Niklas, I just recently went from normal JJs to mullard ri, to get more clarity on the treble side.

And I think the issue is that the speakers sounds best with a lot of power going trough them. And when they move some air.
So making the amp break up earlier wouldn't really make a difference. Just my guess.:-/
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Re: Grey Bulldogs needs to be pushed?

Postby Roy Boltz on Tue Feb 07, 2012 2:09 am

Yeah, the silver alnico is a loud speaker when you pair them in an AC30.
I have an AC10 driving a single silver alnico & it sounds just right for my ears.
The AC30 with a pair is indeed a loud amplifier when sounding it's best IMHO.
I find the silver alnico to sound alot like a 25 watt greenback where it will break up sooner than a g12H30 watt but the 20 watt alnico being more efficient will yield more volume & more bottom end.
I find the alnico very hard to tell the diff to be honest, but there is a slight compression with the alnico that seems to soften the attack some when pushed.
I find the alnico no slouch in the bottom end & can sound extremely thick but you sometimes will have to cut some bass on the amplifier to get more definition.
The G12H is way more clear & defined until they are pushed & they are pretty loud before they even break a sweat.


:cheers: Cheers
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Re: Grey Bulldogs needs to be pushed?

Postby Cirrus on Thu Feb 09, 2012 1:25 pm

I've noticed the same thing - the speakers definitely sound better when pushed and if you get used to that sound it's a disappointment to have to turn them down at gigs. For that reason, while the tayden ace25's (basically celestion blue clones) in my aC30 combo are my favourite sounding speaker to record I've taken to using a 4x12 of vintage 30's with the amp for live playing because they sound better over a wider range of volumes.
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Re: Grey Bulldogs needs to be pushed?

Postby dlvoots on Fri Feb 10, 2012 3:23 pm

There's another option you might consider to drop the volume -- play with a single speaker instead of two.

I wouldn't recommend playing with a single silver, as it couldn't take the amp at full power without blowing. However, if you could score on a higher power alnico speaker like a celestion gold (50w), the gold could take the entire output of your AC30 and then some. There are a couple advantages to doing so;

1.) A single speaker automatically cuts the amount of air you can move in half. Instantly, the amp becomes less efficient, allowing you to "turn it up", and it may get you into the sweet spot all by itself.

2.) If you get a 16 ohm gold speaker and then run it off the 8 ohm tap on the output transformer, the impedance mismatch will make the amp even more inefficient, allowing you to turn it up even more.

Don't sweat the 8 ohm amp-16 ohm speaker mismatch -- if it is in decent electrical shape, the amp should easily handle it. Mismatching upwards from the amp to the speakers actually makes it easier on the electronics. The tubes are not stressed as hard and don't wear out as quickly, because they're asked to deliver half the amount of current as a perfect impedance match. It also adds a bit of compression to the sound. Gerald Weber (Kendrick Amps) wrote in one of his books about subjecting people to a "blind" impedance test to see what sounded best. He said many of the folks consistently chose the "upwards" mismatch as having better overall tone.

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