My Cab Build - 2X15 monster

[83_Silberpfeil]

Made some progress on my build ---- 2X15.

Started with a great condition Ampeg SVT 1540 skin and bones (no "internal organs") that I acquired via CL.

Will be adding 2 X Gauss 4580 drivers at 8 ohm each. Each driver will be hooked up to discrete jack.

Here's some pics of my progress. Rear mount using 1/4" T-nut and 1/4" X 2" bolts (8 per driver"

cab build 1

• 83_Silberpfeil
• Jun 28, 2015

Gauss 4580 15" 8 ohm driver --- rear mounted w 8: 1/4" X 2" bolts

cab build 2

• 83_Silberpfeil
• Jun 28, 2015

Called it a night --- this is actually the top driver. Storing it on bottom to avoid tip over...

cab build 3

• 83_Silberpfeil
• Jun 28, 2015

used the T-Nut system (1/4" size). Very pleased at how secure these things are --- especially...

cab build 4

• 83_Silberpfeil
• Jun 28, 2015

face view ---photo as shot at an angle --- cone is actually well centered w cut-out

Gauss 4580 - Back of perimiter mounting lip3

• 83_Silberpfeil
• Jun 25, 2015

Hooky Cabs

• 83_Silberpfeil
• Jun 26, 2015

 

[83_Silberpfeil]

A note of appreciation to all the TB members here with their knowledge, experience, and sense of humor to help me get to this point. Much appreciated y'all!

 

[Philonius]

You'll be ready for the Janky Rig's 'O Doom thread soon!

 

[ThisBass]

Do you know the number for Qts of this loudspeakers?
IIRC Qts is 0.2-0.3 and therefore the loudspeaker would be inappropriate for sealed cabs.
Lean low end and overdamped loudspeakers.

Wasn't these loudspeakers made for horn or vented application at least?

 

[Omega Monkey]

What speakers were originally in that cab? It looks big enough to have 2 more 15s in it.

Also, why use separate jacks? Unless you're trying to do some kind of "stereo" thing (which would just be up and down), or you want to carry that entire monster around but then only plug into 1 speaker, there's really no benefit to that.

 

[BillyB_from_LZ]

What speakers were originally in that cab? It looks big enough to have 2 more 15s in it.

Also, why use separate jacks? Unless you're trying to do some kind of "stereo" thing (which would just be up and down), or you want to carry that entire monster around but then only plug into 1 speaker, there's really no benefit to that.

An Ampeg 1540 cabinet originally had 4 - 10s and a tweeter in the top (think SVT-410HE) and a 15 in the bottom with ports. They also made an SVT-215 during the same era https://web.archive.org/web/20050517231915/http://ampeg.com/images/products/SVT-215E.jpg

 

[Oren Hudson]

An Ampeg 1540 cabinet originally had 4 - 10s and a tweeter in the top (think SVT-410HE) and a 15 in the bottom with ports. They also made an SVT-215 during the same era https://web.archive.org/web/20050517231915/http://ampeg.com/images/products/SVT-215E.jpg

I have a 1540 that I toured with for about 8 years. That was after it was toured with for about 10 years with the original owner. Still going strong. Only had to replace the on/off switch and the fan on the 350 watt head.

 

[83_Silberpfeil]

The Gauss spec sheet I was able to find on the www indicates Qts of 0.23. What does that really mean --- in laymen terms?
All I know is that these sounded great in Peter Hook's cab and my band mate also build a similar one sealed cab --- sounding awesome. Peter Hook's signature basslines are usually on the high side of the neck.

Do you know the number for Qts of this loudspeakers?
IIRC Qts is 0.2-0.3 and therefore the loudspeaker would be inappropriate for sealed cabs.
Lean low end and overdamped loudspeakers.

Wasn't these loudspeakers made for horn or vented application at least?

 

[83_Silberpfeil]

LOL! This is an Ampeg SVT 1540 --- on top was originally 4X10 and on bottom was 1X15. Separate jacks because:

1) speakers are 8 ohms each
2) Power amp is vintage Crown DC300a --- runs in stereo @ 8 ohms
3) Wiring 2 speakers yielding 4 ohms would overwork the Crown --- according to wise men here on TB.

I will use an Alembic F2B preamp into stereo Crown and use both speakers (driving same input signal)

What speakers were originally in that cab? It looks big enough to have 2 more 15s in it.

Also, why use separate jacks? Unless you're trying to do some kind of "stereo" thing (which would just be up and down), or you want to carry that entire monster around but then only plug into 1 speaker, there's really no benefit to that.

 

[83_Silberpfeil]

Bought my SVT 1540 via Craigslist from an events equipment services provider. All speakers except horn was removed --- that's what I was seeking, a 'shell'. According to seller, the cab once belonged to John McVie of Fleetwood Mac. Cannot verify, but makes no difference to me. It was a good deal

I have a 1540 that I toured with for about 8 years. That was after it was toured with for about 10 years with the original owner. Still going strong. Only had to replace the on/off switch and the fan on the 350 watt head.

 

[83_Silberpfeil]

A bit more progress tonight. Mounted the second (bottom) driver. Tested the capacitance --- looks good with both @ 7.0 ohm

 

[ThisBass]

The Gauss spec sheet I was able to find on the www indicates Qts of 0.23. What does that really mean --- in laymen terms?
All I know is that these sounded great in Peter Hook's cab and my band mate also build a similar one sealed cab --- sounding awesome. Peter Hook's signature basslines are usually on the high side of the neck.

f3 will be around 135Hz, f6 will be around 90Hz, thus marked lean low end response.
Total quality factor Qtc of the system will be around 0.26 thus the system is obvious strongly overdamped.

 

[Mr. Foxen]

I'd add some telescopic ports and figure tuning the cab.

 

[83_Silberpfeil]

Interesting --- got an image of what a telescoping port looks like?

I'd add some telescopic ports and figure tuning the cab.

 

[Mr. Foxen]

Interesting --- got an image of what a telescoping port looks like?

Just get a tube and another tube that fits inside it. Can do it just by rolling up some card to test, then cut the final one to right length.

 

[83_Silberpfeil]

This is going way over my head. Where do I want to be in terms of Qtc? I tried using WinSD and input the parameters of the cab and chose Gauss 4580 from the list. Got a Qtc of 0.71. How did you get 0.26?

f3 will be around 135Hz, f6 will be around 90Hz, thus marked lean low end response.
Total quality factor Qtc of the system will be around 0.26 thus the system is obvious strongly overdamped.

 

[83_Silberpfeil]

Question on the Gauss drivers and how to secure the speaker wire to the terminals. As you can see in my foto below, the driver has the types of terminal where you push the button to open up the hole and insert the speaker wire leads (e.g. banana plugs). The button has fairly strong spring action, so seems like very small chance the speaker wire can fall out.

Any reason to distrust this and do a soldering job here? Please advise.

bottom speaker @ 7.0 ohm

• 83_Silberpfeil
• Jul 2, 2015

 

[ThisBass]

May be you did an error for volume dimension or at decimal point?

A loudspeaker like Gauss 4580 with Qts around 0.25 can't generate a Qtc around 0.7 unless the net volume per speaker becomes impractical small 0.3-0.4 cu ft

 

[B-string]

Question on the Gauss drivers and how to secure the speaker wire to the terminals. As you can see in my foto below, the driver has the types of terminal where you push the button to open up the hole and insert the speaker wire leads (e.g. banana plugs). The button has fairly strong spring action, so seems like very small chance the speaker wire can fall out.

Any reason to distrust this and do a soldering job here? Please advise.

bottom speaker @ 7.0 ohm

• 83_Silberpfeil
• Jul 2, 2015

The spring connectors are fine and wire strands will start stretching and breaking before they will pull out.

 

[83_Silberpfeil]

f3 will be around 135Hz, f6 will be around 90Hz, thus marked lean low end response.
Total quality factor Qtc of the system will be around 0.26 thus the system is obvious strongly overdamped.

So, how to reduce the dampening --- and increase the Qtc? Porting?