Altec A7/VOT Bass Enhancer?

[Grainger49]

I can not find any reference to this. Maybe it is because I can't remember what exactly it is called. There is a green metal box that goes between the amp and the Voice Of The Theater speakers. I'm told it is internally potted.

This should be the place to find out what is inside this box. Surely someone here has removed the potting on this thing.

Thanks, I'm trying to help out a friend with two pair of these.

[1audiohack]

"Black boxes" are fun aren't they? They are actually easy to "see" into with measurment equipment.

Guessing that if it is a "bass booster" filter it would have two wires in and two out. If it is a network / crossover it would have two in four out.

Post a picture so we can see what you have.

Barry.

[Lee in Montreal]

I can not find any reference to this. Maybe it is because I can't remember what exactly it is called. There is a green metal box that goes between the amp and the Voice Of The Theater speakers. I'm told it is internally potted.

This should be the place to find out what is inside this box. Surely someone here has removed the potting on this thing.

Thanks, I'm trying to help out a friend with two pair of these.

Could this be simply be the crossover filter like on the rear left corner of this A7 (from Fame Studio, Muscle Shoals)?

http://img.photobucket.com/albums/v668/Lee_Vuong/2015%20Mississippi/DSC03726_zpssu8daorw.jpg

[Don C]

I think we've discussed these before, but I'm not finding it today. Maybe this catalog page will help.

Edit: More information Here (http://www.roger-russell.com/equalizers/equalizers.htm#altec)

[Grainger49]

Ok, you guys have it. It is the bass energizer. The crossovers have been rebuilt with film caps and Alpha Core/Goetz air core inductors. But the sound is still muddy and sometimes edgy. I'm looking to find out what is inside and don't have a ZY bridge, that is what Barry is posting about. A friend might, I'll ask.

[hjames]

I can not find any reference to this. Maybe it is because I can't remember what exactly it is called. There is a green metal box that goes between the amp and the Voice Of The Theater speakers. I'm told it is internally potted.

This should be the place to find out what is inside this box. Surely someone here has removed the potting on this thing.

Thanks, I'm trying to help out a friend with two pair of these.

ALTEC Bass Energizer Module 100A

80931
80932

[Lee in Montreal]

Ah, ah, ah. "Extreme low bass" must be a euphemism when discussing Altec A7 speakers ;-)

[toddalin]

These devises don't increase the bass, but actually reduce everything above that. The user then turns up the volume to compensate for this loss and that increases the bass. I'm betting if you open one up, it is nothing more than a choke in parallel with a resistor.

[hjames]

The Altec Bass Energizer Modules I bought arrived today. Now, I am in the midst of heavily modifying a pair of Heath AS-101s, basically early Valencias.
I have started rebuildng the crossovers with a mix of polycarbonate caps and a huge russian surplus teflon cap, but I'm not done yet so they are not yet in place.
And I presume I will need to recap the Bass Energizer Modules - I can't find a time stamp on them but I did find a review of them in a 1965 Audio magazine.
Anyway, they are a low pass network with 6-10dB insertion loss - the mids and highs get pushed down so the bass is "enhanced".
So I put them in place - fed with my Jolida 502CRC tube amp (65w/ch est 85w/peaks). I did have to turn it up a little, but I played a couple songs.
(Cousin Dupress, Thanks to You [Boz, from Dig], and Treetop Flyer [from Stills Alone])
I already had improved the dynamics from all the other mods I've been doing - physical mods to the woofers, enhanced fill methods and sub-dividing the cabinet
so the woofer has its own area to play in, venting the cap on the compression driver- QPads to dampen the 811 horn ... Now, with the Bass Energizers, I can hear
there is a little dullness, (as I expected - I really need to finish the crossover rebuild and recap the energizers), but - dang, these Altecs Hit Hard now!

8100481006

[toddalin]

A 6 - 10 dB insertion loss equates to a 4 to 10 times the power requirement to produce the same volume. Because the low end, that really requires most of the amplifier's power, sees little loss, the overall power requirement for the same dB is substantially reduced from these values.

[hjames]

81010

Except from 1965 Audio magazine reviewing the 100A Bass Energizer Module

[hjames]

A 6 - 10 dB insertion loss equates to a 4 to 10 times the power requirement to produce the same volume. Because the low end, that really requires most of the amplifier's power, sees little loss, the overall power requirement for the same dB is substantially reduced from these values.

The point is, these Energizer modules actually do work.
Bass levels are increased with a minimal change to the volume level.

81020

[toddalin]

Another way to accomplish the goal without using all that power or putting resistance/inductance in the path that can have other detrimental effects on the sound is to use the bass adjustment found on most preamps/integrateds/receivers.

[Mr. Widget]

81010

Except from 1965 Audio magazine reviewing the 100A Bass Energizer ModuleThanks for the link. I love the notion of large vs. “so called bookshelf” speakers and wifely influences. :applaud:


Widget

[hjames]

Another way to accomplish the goal without using all that power or putting resistance/inductance in the path that can have other detrimental effects on the sound is to use the bass adjustment found on most preamps/integrateds/receivers.

Really?? Are you really going to go THERE?? Crank the bass way up on your amp to get the same results?
Unbelievable!
A more Apt comparison would be to TURN DOWN the Mid and Highs -
Or roll off the sound above 150Hz on a 31 band EQ, leaving the Bass there
or even get something like the BX-63A for the woofer ... ;)

Biggest issue I have with these right now is chasing down a suitable polycarbonate Cap (that will fit in the case)
to replace the ancient electrolytics currently in there.

[toddalin]

Turning down the mids and highs doesn't accomplish the same thing because the intermittent frequencies are unaffected and you end up with a couple broad dips in the band (e.g., Bactrian camel hump). 31 bands of eq could probably do it.

Adding a BA-63 or dBx is essentially going to do the same thing as the bass control, maybe even moreso with respect to power requirements from the amp, unless it goes to a dedicated sub.

What value cap are you looking for?

[hjames]

Turning down the mids and highs doesn't accomplish the same thing because the intermittent frequencies are unaffected and you end up with a couple broad dips in the band (e.g., Bactrian camel hump). 31 bands of eq could probably do it.

Adding a BA-63 or dBx is essentially going to do the same thing as the bass control, maybe even moreso with respect to power requirements from the amp, unless it goes to a dedicated sub.

What value cap are you looking for?

I'll find my own caps, thank you very much.

You crack me, up you really do ...
You've never heard one, have no idea what it does other than wild guesses,
yet you're going to dis it anyway, despite your ignorance.

You gave me the same kind of know-it-all BS when I bought a 31 band EQ
for my 4341s way back then ...
"Don't turn up the bass that way, it will just raise the noise floor"

Your kind of closed mindedness is why the Lansing Forum continues to shrink.
Who would want to stick around for such abuse?

Sad, just sad.

[toddalin]

You gave me the same kind of know-it-all BS when I bought a 31 band EQ
for my 4341s way back then ...
"Don't turn up the bass that way, it will just raise the noise floor"

Sad, just sad.

Wasn't me or you are remembering it wrong. I went through the old posts and I don't see it.

You can do/think/say what you want. My mentioning the bass adjustment just lets other people reading the thread recognize that they can get to the same place without relying on 60 year old technology that is unavailable to them.

[Robh3606]

Hello Heather

Hey if you ever get the urge to biamp them the Urie/JBL 5235 Active crossover has an option to add some LF boost without messing with the mids and highs. It has an option for a 40 Hz Q2 filter unlike the BX-63 which is fixed at 26hz and too low for that system. It also gives you several options with diferent Q's to try. Enjoy your speakers they should be a blast to listen to.

Rob:)

[hjames]

Hello Heather

Hey if you ever get the urge to biamp them the Urie/JBL 5235 Active crossover has an option to add some LF boost without messing with the mids and highs. It has an option for a 40 Hz Q2 filter unlike the BX-63 which is fixed at 26hz and too low for that system. It also gives you several options with diferent Q's to try. Enjoy your speakers they should be a blast to listen to.
Rob:)

Hey Robh! Cool info thanks for sharing that!
I kept a (spare) Ashly Active Eq from my 4341 Biamp days until real recently -
(this year's winter cleaning meant thinning some old parts stock)
but I'll keep an eye out for a Urie/JBL 5235 crossover.



Wasn't me or you are remembering it wrong. I went through the old posts and I don't see it.
You can do/think/say what you want. My mentioning the bass adjustment just lets other people reading the thread
recognize that they can get to the same place without relying on 60 year old technology that is unavailable to them.

Well, I do remember, but I'm not hunting LHF for such an old thread now.
Besides, the 100As are dedicated low pass filters, and they DO work better than just cranking up the bass adjustment on an amp.
Believe what you want, but trust me on this - I actually have a pair (not for sale) and I can actually HEAR what its doing.

But I gotta say, the Bass Energizers are hardly unavailable -
took me less than a month to find a pair for a reasonable price.
And you know, Lansing Heritage is full of examples of folks enjoying 60 year technology ...

So lets skip both those lame excuses right now!
Folks will try a pair if they want - I just brought them up here since there is a lack of knowledge on them ...
(Altec) Lansing Heritage Forum, doncha know!

[toddalin]

Well, I do remember, but I'm not hunting LHF for such an old thread now.




The discussion was specific to using the Yamaha 31-band eq that you had obtained and my suggestion was not to put it between the preamp and the amp because it is a noisy piece of equipment and in my system when I was using it in this position, the noise was readily notable.

You said you couldn't hear the noise.

The EQ got here Friday!
I mounted it in the rack right away, but didn't have cables yet. I could also use one more perforated panel between the Yam and the Adcom power sequencer to make everything symetrical, but its not like anything up top puts out any real heat to speak of ...

I was expecting delivery of a package of XLR-XLR cables from Monoprice but they didn't arrive Friday or yesterday, so this morning I took some old connectors, cleaned them up and wired up an extra pair of M-F cables so I could try it out ...

Doesn't sound hissy to me - perhaps I need better amps than the JBL/UREI gear to hear it,
but the noise level seems unchanged when the Yamaha is switched in or out ...

Haven't had time to do anything other than just dink it a bit and make sure its working ...
hear it do some cuts and boosts - Seems to do that well enough

Hopefully I can do some room calibration later ... I do have a test CD with various audio tones,
and I could put my RS SPM meter on a tripod and take level readings ...
I suspect thats a kind of crude approach, but without fancy tools it should work ...



I'm glad it's working for you. :applaud: Do you run it just before the crossover then attenuate at the crossover and/or at the power amp?

For kicks, try putting it directly between the preamp and power amp (if you can) on the upstairs L200+ system and listen to the noise.

[hjames]

The 4341s and the biamp system are long gone, friend - I've moved on ...
got 2 pair of UREI 809As downstairs fronts and sides in a 7.1 system
The L200+ system was sold a few years back as well - again, I moved on.
Upstairs is a pair of L212s, the Von Schweikert VR-4s, and the Heath AS-101s I'm modifying ...
driven by Jolida integrated tube amp ... no tone controls.

But its nice to see you believe me now - that it wasn't someone else I was speaking about.






The discussion was specific to using the Yamaha 31-band eq that you had obtained and my suggestion was not to put it between the preamp and the amp because it is a noisy piece of equipment and in my system when I was using it in this position, the noise was readily notable.

You said you couldn't hear the noise.

The EQ got here Friday!
I mounted it in the rack right away, but didn't have cables yet. I could also use one more perforated panel between the Yam and the Adcom power sequencer to make everything symetrical, but its not like anything up top puts out any real heat to speak of ...

I was expecting delivery of a package of XLR-XLR cables from Monoprice but they didn't arrive Friday or yesterday, so this morning I took some old connectors, cleaned them up and wired up an extra pair of M-F cables so I could try it out ...

Doesn't sound hissy to me - perhaps I need better amps than the JBL/UREI gear to hear it,
but the noise level seems unchanged when the Yamaha is switched in or out ...

Haven't had time to do anything other than just dink it a bit and make sure its working ...
hear it do some cuts and boosts - Seems to do that well enough

Hopefully I can do some room calibration later ... I do have a test CD with various audio tones,
and I could put my RS SPM meter on a tripod and take level readings ...
I suspect thats a kind of crude approach, but without fancy tools it should work ...



I'm glad it's working for you. :applaud: Do you run it just before the crossover then attenuate at the crossover and/or at the power amp?

For kicks, try putting it directly between the preamp and power amp (if you can) on the upstairs L200+ system and listen to the noise.

[toddalin]

The 4341s and the biamp system are long gone, friend - I've moved on ...
got 2 pair of UREI 809As downstairs fronts and sides in a 7.1 system
The L200+ system was sold a few years back as well - again, I moved on.
Upstairs is a pair of L212s, the Von Schweikert VR-4s, and the Heath AS-101s I'm modifying ...
driven by Jolida integrated tube amp ... no tone controls.

But its nice to see you believe me now - that it wasn't someone else I was speaking about.

As I said, you remembered it wrong and were misquoting me. I don't like to be misquoted.

I never said not to use bass or even eq or that this adds to the noise floor as you say I said..., only that the Yamaha 31-band eq that you got at the time, and I have, is noisy and it does add to the noise floor, especially when used between thd preamp and amp. I made 10 dB line attenuators for mine before I took them out of the system (two were being used). If you can't hear the hiss, good for you.

Did you ever check this out by putting it between the preamp and amp in the upstairs system as I suggested at the time?

[hjames]

Again, as I said at the time, there was no added noise in my system with our EQ.
Neither my wife or I heard any noise, and she has quite good ears.
At the time (and now, apparently) your mind was made up that we DID have noise,
it seemed pointless to argue with you. It still does.

And as I told you yesterday, I have moved on - you have a nice rest-of-the-week.


As I said, you remembered it wrong and were misquoting me. I don't like to be misquoted.

Did you ever check this out by putting it between the preamp and amp in the upstairs system as I suggested at the time?


Since we did not have noise from my Yamaha EQ in my system, why would I have tried in another system?
I didn't realize I misquoted you, I apologize for that. I had mostly put the whole conversation out of my mind
after you kept insisting we heard something that wasn't there. My memory was that it wasn't the same Yamaha model,
but lets just let the old argument die now, shall we? No one else cares.

Going BACK ON TOPIC - the original point this week was you said turning up the Bass control
was the same as using the Altec Bass Energizer, I said it wasn't so there we differ.
Its a neat piece of tech that others seem to find interesting.
I'm just happy I could share some new info on them.

The rest is simply old news that no one cares about today.
Time is precious - have a nice day.

[Ian Mackenzie]

Hi Heather,

Glad you are having fun with the bass energiser

With that capacitor do you know the value?

If it is electrolytic type that tells me it’s large only because of the frequency the energiser works at.

Due to size limitations you could replace it with a modern non polarised electrolytic capacitor (for audio)

There are suitable large values of non polarised electrolytic caps made for crossovers like the ones used in the Everest helper filter.

Try Parts Express
https://www.parts-express.com/cat/non-polarized-electrolytic-capacitors/1385

[hjames]

Had a bit of time on Saturday morning. Opened up the Bass Energizers and saw an iron core choke and bundle under black potting compound.
Felt waxy but its not like the beeswax in the old JBL crossover cans.

Put it in a shallow pot of water and set to boil ... it softened but never melted -
I gather its some kind of tarry compound and not wax.
But with an old fork I was able to pop the old network loose from the warmed compound.

The old NP caps (circa 1966) are 100mfd.
I had already ordered 4x 50mfd NP electrolytic caps from Madisound on Monday
(I was worried that size might be an issue for larger values in that can),
so I'll start reassembly with fresh caps shortly.

810438104481045

[Earl K]

Cool Stuff Heather,

Is there any chance that you could test the (uF ) value of that ancient NP cap that you just pulled out?

Thanks <> Earl

[hjames]

Cool Stuff Heather,

Is there any chance that you could test the (uF ) value of that ancient NP cap that you just pulled out?

Thanks <> Earl

Don't know about testing the value, no cap meter
- but they are marked. Does this help?

81046

[Earl K]

Oh,

I mistakenly thought you had a volt meter that could also measure capacitance.

My bad!

:)

[hjames]

Oh,

I mistakenly thought you had a volt meter that could also measure capacitance.

My bad!

:)

Lemme see, I know my ancient Fluke VOM doesn't,
but I bought a cheap inductance meter recently for tuning coils.
Honestly haven't looked to see if it does caps -

[Earl K]

Lemme see, I know my ancient Fluke doesn't,
but I bought a cheap inductance meter recently for tuning coils.
Honestly haven't looked to see if it does caps -

You think the values are different than the marked values?
(Of course it HAS been 52+ years)

My interest is purely academic.

I don't really know if they'll be far off ( in value ) or not.

Current group-think is these caps are NP electrolytic ( which by inference would suggest the values should have drifted by a large margin ).

OTOH, my research ( & single example dissection ) shows the caps might not be electrolytic ( which happens to jive with all the measurements that I've made of this type of cap where the values I measured where unexpectedly close to the stated values ).
- Still, my own experience doesn't translate into not replacing these sort of caps, since there are indeed better sounding caps for the job at hand.

As I said, it's a purely academic interest.

:)

[hjames]

And yes, apparently that new Meter DOES do caps! heh!

in 200ufd range,
One measures 116, the other measures 95.5
(Of course it HAS been 52+ years)


My interest is purely academic.

I don't really know if they'll be far off ( in value ) or not.

Current group-think is these caps are NP electrolytic ( which by inference would suggest the values should have drifted by a large margin ).

OTOH, my research ( & single example dissection ) shows the caps might not be electrolytic ( which happens to jive with all the measurements that I've made of this type of cap where the values I measured where unexpectedly close to the stated values ).
- Still, my own experience doesn't translate into not replacing these sort of caps, since there are indeed better sounding caps for the job at hand.

As I said, it's a purely academic interest.

:)

[Earl K]

Thanks Heather!

:)