Tri-amp with two B1 Buffers. Looking for opinions on setup.

alp79

Member
2013-10-28 2:32 am
PA
I wanted to get some opinions on my planned setup. Maybe someone would see a problem that I may be overlooking.

My current setup is a B1 buffer with an F5 Turbo powering a set of Dallas IIs (BLH with fostex drivers), and a sub. I wanted to add a pair of fostex super tweeters to make up what's lacking with the the fullrangers. The tweeters will be powered by a 10W tube amp. They are extremely efficient but I don't want to use an Lpad or an attenuator to match the horns.

The plan is to use my current B1 for source selection and main volume control. It would provide three signals. The F5 turbo, subwoofer and a second B1 for level control of the tweeter amp. Would this work well in place of an Lpad, and if it would are there any potential component values that would need to be changed?

Thanks in advance if anyone has any suggestions or ideas.
 

alp79

Member
2013-10-28 2:32 am
PA
Here is a diagram to help explain.
 

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vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
After the first B1 is a signal splitter?

In this setup, the second B1 will be at the mercy of the first B1 in terms of max volume.
Be best if you made a switch box or bought one. (Think I saw a bunch for sale on partsconnexion.com by QED. Not expensive.) Place the switch box in front of both B1, this way you'll have 4 independent channels.

Anyway you do this, you'll lose use of some inputs.

http://www.partsconnexion.com/80954.html

http://www.partsconnexion.com/accessories_qed.html

Now, maybe the resident geniuses have something to say about input loading or other.
 
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vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
Ok, you'll need a wire splitter after the switchbox to the B1s.

So, multiple inputs to the switchbox> output to "Y" cable> feeds 1 input of both B1s> B1s to HIs and Mids. On the Mids out, you'll need another Y cable for the Sub.

Yuck. This is why active crossovers are better for this purpose.
 

alp79

Member
2013-10-28 2:32 am
PA
After the first B1 is a signal splitter?

In this setup, the second B1 will be at the mercy of the first B1 in terms of max volume.
Be best if you made a switch box or bought one. (Think I saw a bunch for sale on partsconnexion.com by QED. Not expensive.) Place the switch box in front of both B1, this way you'll have 4 independent channels.

Anyway you do this, you'll lose use of some inputs.

More Information Page

QED Accessories

Now, maybe the resident geniuses have something to say about input loading or other.

I plan on adding whatever is necessary to the first B1 to split the signal properly.

I was counting on the tweeters being much louder so I can decrease their volume with the second B1 to match the rest of the system.

My goal is to have one overall volume control with separate adjustment of the tweeters.
 

vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
I was counting on the tweeters being much louder so I can decrease their volume with the second B1 to match the rest of the system.

You might be right about this. You have to take into account the amp gain in db as well.

In my 3-way, my F5T v2 on the sub has more gain than my SIT 6w on the 96db tweeter. I have to crank up the tweeter and lower the sub. See what I'm getting at? It depends on the setup, but I don't see why it wouldn't work. Give it a shot.
 

alp79

Member
2013-10-28 2:32 am
PA
You might be right about this. You have to take into account the amp gain in db as well.

In my 3-way, my F5T v2 on the sub has more gain than my SIT 6w on the 96db tweeter. I have to crank up the tweeter and lower the sub. See what I'm getting at? It depends on the setup, but I don't see why it wouldn't work. Give it a shot.

I do.

What would be perfect is an overall volume control with the ability to adjust the level of three outputs separately. This is beyond my design capability though.

My sub is powered too.
 

vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
What would be perfect is an overall volume control with the ability to adjust the level of three outputs separately.

3 B1s with mono pots (or not) would get you there. Mono pots will get you some balance action.

Do you know how to solder?

You'll be buying or building another B1? Build two and put them in one chassis.

My subs are passive. Needs an amp. Using B4s for crossovers.
 

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vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
I get it. If you want help, just ask. I'm in PA too, but PA is a big place. I could show you have to wire one up. Just remember that a new B1 is around 10x more than the parts.
I'm just trying to draw you into the dark side. ;)

BTW- I have a B1 in my second system and built 2 and part of a DCB1.

Best,

Vince
 
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alp79

Member
2013-10-28 2:32 am
PA
3 B1s with mono pots (or not) would get you there. Mono pots will get you some balance action.

Do you know how to solder?

Yes, I've built most of the gear I have. That's my favorite part of this hobby. Building something that sounds amazing compared to the junk you find in stores(in my price range anyways).

What kind of modifications and component changes would be needed to put three B1s together?
 

vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
What kind of modifications and component changes would be needed to put three B1s together?

Not much. Get the boards with jfets from passdiy.com ($40 a set last time I looked.) Get a 19v laptop power supply and you're half way there. Laptop power supply has way more power than what 3 B1s would require.

10k or 25k pots. See article.
DPDT switches
Power switch (not absolutely needed)
Input and output RCAs
Case
A few caps and resistors
Hookup wire

That's about it.

I'm outside of Phila.