Altec A7 refurbish

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06-08-2012, 11:35 AM
sbjacob

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Altec A7 refurbish

I pick up a few A7 cabinets in good condition and have repainted them I took the small crossover cover off the back and went to Ace and they scanned it to match the paint worked very nice I also ordered new logos off Ebay for them very nice for $18. for 4 . I have a pair of 511B horns and 909-16 drivers just need woofers I had a pair of Eminence Kappa C so I put them in just for kicks and used a Ashly XR1001 active with a BGW 750C on the LF and a BGW 250D on the HF had to turn the HF gain way down as it was over powering the LF any suggestions on woofers is the 416 the way to go on these?Attachment 55951

I went to GPA website and noticed the 515 LF specs are close to the Kappa C 4 ohm Vas is 11.7 vs 16.6 the Qes .25 vs .26 Qts .25 vs .25 Qms 10.14 vs 11.6 FS 31Hz vs 27Hz
06-08-2012, 10:21 PM
Carl_Huff

1 Attachment(s)

Nice looking cab!

I have a pair that I am running new GPA 416-8Cs in the same 828 cabinet as yours. I really like the way they sound. I use them every day as the heart of my reference home theater system. Here is a plot of their frequency response before and after EQ. In this case the EQ happened to be Dirac Live running in a Datasat RS20i but similar results can be realized by using other systems as well.

Attachment 55958

The 515 from GPA is very similar to the 416. The 515 trades off a little on the bottom for a little more efficiency.
_____________
Best Regards,
Carl Huff
06-10-2012, 01:33 PM
louped garouv

For Altec choices, 416 will have a fuller low end...
But some contend the 515s midrange is a fair tradeoff......

Some folks even will run JBLs or TADs or whatever, sometimes with some gasket considerations/ modifications...

I liked the 515b with some reflex subs best... (I was using four sets of EAW SB48s for low end)
06-10-2012, 06:14 PM
sbjacob

Quote:

Originally Posted by louped garouv

For Altec choices, 416 will have a fuller low end...
But some contend the 515s midrange is a fair tradeoff......

Some folks even will run JBLs or TADs or whatever, sometimes with some gasket considerations/ modifications...

I liked the 515b with some reflex subs best... (I was using four sets of EAW SB48s for low end)

I talked to GPA the they did recommend the 515's in bass horn enclosures however I pretty happy with the Eminence Kappa C's but then again I have nothing to compare them with. The specs are similar to the 515's so I'm not sure I'm using a Ashly active XR1001 and added a JBL 2404 and built a 4th order passive for it.
06-14-2012, 02:43 PM
sbjacob

1 Attachment(s)

Attachment 56043

Quote:

Originally Posted by sbjacob

I talked to GPA the they did recommend the 515's in bass horn enclosures however I pretty happy with the Eminence Kappa C's but then again I have nothing to compare them with. The specs are similar to the 515's so I'm not sure I'm using a Ashly active XR1001 and added a JBL 2404 and built a 4th order passive for it.

I finished one today sounds very nice I may add the JBL 2404 tweeter later
06-14-2012, 02:54 PM
Lee in Montreal

Nice work.
06-14-2012, 07:48 PM
sbjacob

1 Attachment(s)

Quote:

Originally Posted by Lee in Montreal

Nice work.

Thanks always wanted a pair of these I just added the JBL 2404's and dialed it in with my RTA and I must say it's very nice.Attachment 56045
06-14-2012, 07:50 PM
sbjacob

1 Attachment(s)

Quote:

Originally Posted by sbjacob

Thanks always wanted a pair of these I just added the JBL 2404's and dialed it in with my RTA and I must say it's very nice.Attachment 56045

Here are the networks I built for the JBL's as I'm using a Ashly XR1001 active 4th order Linkwitz 6000Hz crossover point.Attachment 56046
06-17-2012, 07:24 PM
sbjacob

1 Attachment(s)

Quote:

Originally Posted by sbjacob

Here are the networks I built for the JBL's as I'm using a Ashly XR1001 active 4th order Linkwitz 6000Hz crossover point.Attachment 56046

Here they are between the big boys .Attachment 56059
06-18-2012, 09:06 AM
Carl_Huff

I like your Klipsch/ JBL stacks that you have. Is that a custom built 12 inch mid horn there in the middle?
____________
Best Regards,
Carl Huff
06-18-2012, 11:42 AM
sbjacob

Quote:

Originally Posted by Carl_Huff

I like your Klipsch/ JBL stacks that you have. Is that a custom built 12 inch mid horn there in the middle?
____________
Best Regards,
Carl Huff

Hi Carl it is a Peavey MB-2 a near perfect match for the Klipsch MWM bass bins running them from 350Hz-1100Hz then the JBL 2360A's with EV DH1-A driver from 1100Hz up. I'm using a Ashly Protea 3.6SP processor with two Crown Xti 1000's on the MF and HF and a Crown Xti 2000 on the LF I needed a 2 ohm stable amp for the four K-43 2 ohm woofers 2 per side considered QSC RMX 1850 but I had the two Crown Xti 1000's and figured I would get the Crown so everything would match. I would like to get the Klipsch KPT-XII-MB(MF section) and the KPT-K-402-MF(HF section) but don't have the cash to spare as the K-402's with the K-69 driver are $2000 alone.
06-18-2012, 12:07 PM
Carl_Huff

Quote:

Originally Posted by sbjacob

Hi Carl it is a Peavey MB-2 a near perfect match for the Klipsch MWM bass bins running them from 350Hz-1100Hz then the JBL 2360A's with EV DH1-A driver from 1100Hz up. I'm using a Ashly Protea 3.6SP processor with two Crown Xti 1000's on the MF and HF and a Crown Xti 2000 on the LF I needed a 2 ohm stable amp for the four K-43 2 ohm woofers 2 per side considered QSC RMX 1850 but I had the two Crown Xti 1000's and figured I would get the Crown so everything would match. I would like to get the Klipsch KPT-XII-MB(MF section) and the KPT-K-402-MF(HF section) but don't have the cash to spare as the K-402's with the K-69 driver are $2000 alone.

The Klipsch K-402 and K-69 combo does sound good. I listened to many in commercial theaters. However I've got to believe that what you have must sound very good as well!
____________
Best Regards,
Carl Huff
06-20-2012, 09:26 AM
teddy.edwards1

Quote:

Originally Posted by sbjacob

Attachment 56043

I finished one today sounds very nice I may add the JBL 2404 tweeter later

Hey, they are nice... I have some with 515's in and JBL2440/JBL2395 lens horns... the tweeter is essential in my opinion i have tried JBL2405 and JBL2402 - i prefer the former.

I run BGW 250 on the mids
BGW GTA on the 15's
CROWN D75 on the tweeters

and you're right, there's no way that bass is gonna keep up with the mids!

I have also tried altec 421-8LF in the A7 - that's nice too.
I did look at the 416 and it's not enough power handling for what i want - and it won't help keep up with the mids
I have some TAD 1601b's to go in the A7 they sound amazing and much more energy in the lower end, but i can't turn them up loud yet because of gasket considerations!

Also would you be using a sub with the A7's?

Tom
06-20-2012, 09:40 AM
teddy.edwards1

Quote:

Originally Posted by sbjacob

Here they are between the big boys .Attachment 56059

oh, i replied to an earlier post. i see you finished them. i bet they sound great. are you happy with the sound?
I never tried the tweeter you used - is it a 2404? maybe i should get hold of one...
Some people made a good argument for using a 3-way 18db per octave xover, which is what i went for instead of the 24db one you're using. i have never heard them set-up otherwise...

the 515 i use is the 8g-hp which is 200W and all the other 515s and 416 are 75W.
Do you have the problem still of the bass not keeping up with the mids?
i tried to get hold of the bgw750 but they are rarely available in the UK so i went with the GTA... it was just too much to ship the 750.

and of course sub will help. i use a lot of sub.

tom
06-20-2012, 09:50 AM
teddy.edwards1

Quote:

Originally Posted by louped garouv

For Altec choices, 416 will have a fuller low end...
But some contend the 515s midrange is a fair tradeoff......

Some folks even will run JBLs or TADs or whatever, sometimes with some gasket considerations/ modifications...

I liked the 515b with some reflex subs best... (I was using four sets of EAW SB48s for low end)

hey, i was just wondering how you crossed over your subs and at what frequency?
do you have them as additional to the 515's low end, or is there a HPF on the 515's?
I made 4 LAB Subs and also 4 Tuba 30's (not my pics) which are a bit impractical actually, but go very low and smooth.

tom
06-20-2012, 10:55 AM
sbjacob

Quote:

Originally Posted by teddy.edwards1

hey, i was just wondering how you crossed over your subs and at what frequency?
do you have them as additional to the 515's low end, or is there a HPF on the 515's?
I made 4 LAB Subs and also 4 Tuba 30's (not my pics) which are a bit impractical actually, but go very low and smooth.

tom

Hi I'm pleased with the sound I haven't hooked up any subs yet I have 4 Bose 302 bandpass subs not real good but I use them on small gigs with 802-II's it's a nice portable system. I was looking at the Danley DTS-10 sub they sell kits for around $1200 and have talked to some that have them and they are very happy "True Thunder" was what was said to me by a fellow Forum member.I tlked to GPA and the recomended there 515-G8 woofer for the A7 but I'm using the Eminence Kappa C's very similar specs to the GPA 515-G8. The Kappa C specs on the Eminence website are the same as the 8 ohm Kappa A's not correct Parts Express has the correct specs not alot of difference . http://www.danleysoundlabs.com/produ...y-subs/dts-10/
06-20-2012, 09:16 PM
louped garouv

Quote:

Originally Posted by teddy.edwards1

hey, i was just wondering how you crossed over your subs and at what frequency?
do you have them as additional to the 515's low end, or is there a HPF on the 515's?
I made 4 LAB Subs and also 4 Tuba 30's (not my pics) which are a bit impractical actually, but go very low and smooth.

tom

Hi Tom,
At the time, I was using an RLA x2000 xover..

The 515s were 25hz to 800hz
Subs ran 20hz to 100hz
06-22-2012, 12:02 PM
sbjacob

Quote:

Originally Posted by louped garouv

Hi Tom,
At the time, I was using an RLA x2000 xover..

The 515s were 25hz to 800hz

Subs ran 20hz to 100hz

Any one add fuses to the 2404 tweeters if so how large I'm crossing my 2404's at 6000Hz 4th order Linkwitz passive? Thanks
06-22-2012, 12:36 PM
Baron030

Rather than fuses, what about using JBL SK3 Crossover Protection Bulbs instead.

Baron030:)
06-22-2012, 01:03 PM
sbjacob

Quote:

Originally Posted by Baron030

Rather than fuses, what about using JBL SK3 Crossover Protection Bulbs instead.

Baron030:)

Didn't know about these I ordered a few I assume networking instruction come with them but just in case they don't do you add them to the + input on the 2404's?
06-23-2012, 12:37 PM
Baron030

1 Attachment(s)

If you had already ordered a few of the SK3 bulbs, I don’t think they come with instructions on how to use them in your own special application. But, don’t fret about it too much because JBL is using them in a lot of different crossover networks. So, I suspect that one of the following will turn up a schematic that you can copy.

JBL MR Series, JBL MR800 Series, JBL MR900 Series, JBL SF Series, JBL Cab Series, JBL TR Series, JBL Sound Factor Series, JBL Control Series, JBL MP Series, JBL M-Pro Series, JBL Eon Non-Powered Series, JRX Series.

The SK3 bulb does more that than act as a just a fuse. Because the tungsten filament’s resistance varies so greatly with temperature, it can act more like a compressor preventing damage to the driver without blowing like a regular fuse. In the TR125 example below, the two SK3 bulbs and the 16 ohm resistor form a series attenuator for the HF driver. At low power levels the bulb resistance is low and there is no compressor effect. But at excessively high power levels the bulbs light up and their resistance increases, which will reduce the power going to the HF driver. And at catastrophic overload power levels the bulbs will burn out, leaving only the 16 ohm resistor to supply a very limited amount of power to the HF driver until the SK3 bulbs can be replaced. I suspect that in other networks, R1 value maybe different depending on the HF driver’s impedance and power handling characteristics.

Baron030:)
Attachment 56118
06-24-2012, 04:42 AM
teddy.edwards1

caps

Quote:

Originally Posted by sbjacob

Didn't know about these I ordered a few I assume networking instruction come with them but just in case they don't do you add them to the + input on the 2404's?

you can also use protection capacitors...
The JBL/UREI - 525 active crossover manual has some frequency/capacitance tables
UREI 525

thanks
tom
06-24-2012, 05:12 PM
sbjacob

Quote:

Originally Posted by teddy.edwards1

you can also use protection capacitors...
The JBL/UREI - 525 active crossover manual has some frequency/capacitance tables
UREI 525

thanks
tom

I'm using a Ashly XR1001 active and I built a 4th order Linkwitz for the JBL2404's so I don't believe these bulbs will work they are for JBL networks I have stated a few posts back I was using a active with the passive I built.:blink:
06-25-2012, 08:42 AM
Baron030

1 Attachment(s)

Hi SBJACOB
I am not suggesting that you replace your existing passive crossover networks. Just modify them to include SK3 bulbs if you are so concerned about protecting your drivers. Now if I understand your system correctly. You have a XR1001 electronic network between the woofers and the midrange horns. The BGW750C amp feeds the woofers and the BGW250D feeds both the midrange and the 2404s. And the 6000Hz passive network slits the signal between the midrange and 2404s. In the schematic below, what I don’t know is, what are the correct R1 and R2 values for your application. But, this is something that can be derived from studying other JBL networks that have SK3 bulbs. Now, if the 2404H driver has the same power handing as a 2412H driver, then the appropriate R1 value would be a 16 ohm 10 watt resistor. Otherwise, then a different value would be needed. Actually, for a home audio system I don’t see the need to fuses or SK3 protection bulbs. But, in a pro sound reinforcement system where microphone feedback could route several hundred watts into a HF driver the SK3 bulbs seem like a really good idea.
Baron030:)
Attachment 56122
06-26-2012, 11:54 AM
sbjacob

Quote:

Originally Posted by Baron030

Hi SBJACOB
I am not suggesting that you replace your existing passive crossover networks. Just modify them to include SK3 bulbs if you are so concerned about protecting your drivers. Now if I understand your system correctly. You have a XR1001 electronic network between the woofers and the midrange horns. The BGW750C amp feeds the woofers and the BGW250D feeds both the midrange and the 2404s. And the 6000Hz passive network slits the signal between the midrange and 2404s. In the schematic below, what I don’t know is, what are the correct R1 and R2 values for your application. But, this is something that can be derived from studying other JBL networks that have SK3 bulbs. Now, if the 2404H driver has the same power handing as a 2412H driver, then the appropriate R1 value would be a 16 ohm 10 watt resistor. Otherwise, then a different value would be needed. Actually, for a home audio system I don’t see the need to fuses or SK3 protection bulbs. But, in a pro sound reinforcement system where microphone feedback could route several hundred watts into a HF driver the SK3 bulbs seem like a really good idea.
Baron030:)
Attachment 56122

I didn't take it that way wasn't sure if you had seen the previous posts on the setup and yes that is the way I have it set up sounds fantastic I added a BBE sonic max. and it really helps the low-mid slam the Eminence Kappa C's are keepers can't imagine the GPA 515's would sound better the woofer parameters are almost the same between the two of them. I think I'll be ok without any protection the BGW 250D is about 100 watts and has protective circuitry so I'll leave it be for the time being as they add a very nice up HF to the sound.:D
07-11-2012, 11:48 PM
vernb

Quote:

Originally Posted by sbjacob

I pick up a few A7 cabinets in good condition and have repainted them I took the small crossover cover off the back and went to Ace and they scanned it to match the paint worked very nice I also ordered new logos off Ebay for them very nice for $18. for 4 . I have a pair of 511B horns and 909-16 drivers just need woofers I had a pair of Eminence Kappa C so I put them in just for kicks and used a Ashly XR1001 active with a BGW 750C on the LF and a BGW 250D on the HF had to turn the HF gain way down as it was over powering the LF any suggestions on woofers is the 416 the way to go on these
I went to GPA website and noticed the 515 LF specs are close to the Kappa C 4 ohm Vas is 11.7 vs 16.6 the Qes .25 vs .26 Qts .25 vs .25 Qms 10.14 vs 11.6 FS 31Hz vs 27Hz

Very nice job. I just got myselt a pair yesterday, but they need a paintjob aswell. Which is the right Altec grey for VOTT?
Best regards
Vern
07-17-2012, 12:11 PM
sbjacob

1 Attachment(s)

Quote:

Originally Posted by vernb

Very nice job. I just got myselt a pair yesterday, but they need a paintjob aswell. Which is the right Altec grey for VOTT?Best regardsVern

Hi I went to Ace and they scanned the crossover panel cover to match the paint and mixed up some for me a perfect match. Anyway I have just finished putting internal bracing in the cabinets and I'm pleased to say the bass is much tighter. I tied the two bottom sides together with a 2"x4" and added acoustic foam on the top horns space also added another 3/4" board to the back of the ports to stiffen them up honestly these cabinets stock are lacking.I also took the old grey cloth out and replaced it with new black Duracrest cloth.Attachment 56341

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