Big Reds!

[Earl K]

Todd,

Sorry my wording was ambiguous, but no, I don't own any Super Big Reds ( though I had weeky access to a pair back in the 80's ).

Yes, 1500hz is a reasonable crossover point.

I see the seller also has a TDM 244 ? unit for sale.
- That's a reasonable electronic crossover for this duty ( it's a variable 2-way with 24db LR slopes x 4 > if it's the same type I used to own ).
- It would be worth snagging if the price is right ( as would any number of those QSC or Crest > even the Altec amp ).

[toddalin]

Todd,

Sorry my wording was ambiguous, but no, I don't own any Super Big Reds ( though I had weeky access to a pair back in the 80's ).

Yes, 1500hz is a reasonable crossover point.

I see the seller also has a TDM 244 ? unit for sale.
- That's a reasonable electronic crossover for this duty ( it's a variable 2-way with 24db LR slopes x 4 > if it's the same type I used to own ).
- It would be worth snagging if the price is right ( as would any number of those QSC or Crest > even the Altec amp ).

Thanks Earl.

I informed the seller that the two units that he gave me (actually #51 and #52) are not crossovers, but HF contour units. He lists #37 and I emailed him and told him that I thought that it was for use with these speakers. He leaves town on Tuesday and said I could come pick it up on Monday.

37: COAXIAL loudspeaker crossover

51: high frequency equalizer network 16 ohms

52: High frequency equalizer network 16 ohms

My email:

What is #37, the coaxial loudspeaker crossover? What are #51 and #52, the 16 ohm HF eq networks?

His response:

I’m afraid I already sold number 51 and 52… And number 37 is basically an in-line equalizer I think… It has the options of switching the HZ as well.

[toddalin]

Todd,

Sorry my wording was ambiguous, but no, I don't own any Super Big Reds ( though I had weeky access to a pair back in the 80's ).

Yes, 1500hz is a reasonable crossover point.

I see the seller also has a TDM 244 ? unit for sale.
- That's a reasonable electronic crossover for this duty ( it's a variable 2-way with 24db LR slopes x 4 > if it's the same type I used to own ).
- It would be worth snagging if the price is right ( as would any number of those QSC or Crest > even the Altec amp ).

I know that he wants $425 for the Altec amp, but could probably get it a bit cheaper if he still has it.

[toddalin]

Todd,

Sorry my wording was ambiguous, but no, I don't own any Super Big Reds ( though I had weeky access to a pair back in the 80's ).

What would you think that they would have crossed the Jensen over at? I know that the Mastering Labs crossovers note a special provision for the auxiliary speaker on their crossover descriptions raising its cost by $35.

[Earl K]

Hi Todd,

That price seems pretty high for such an old amp ( though maybe there's some latent collectors appeal ?? ).

It's been decades since I heard one in action / so I don't have anything really to say about them ( apart from something that age usually needs a top-to-bottom refresh ).

[Earl K]

What would you think that they would have crossed the Jensen over at? I know that the Mastering Labs crossovers note a special provision for the auxiliary speaker on their crossover descriptions raising its cost slightly.

I imagine somewhere around 90hz.

One large a$$ coil will do it.

Is that woofer 4 or 8ohms ?

[toddalin]

I imagine somewhere around 90hz.

One large a$$ coil will do it.

Is that woofer 4 or 8ohms ?

I've no idea.

I think that this, or one of its variations, is what they used, though its hard to believe that they would charge $130 for one of these when they list the 604s at just $225. Of course they call it an Audiotechiques woofer.

When I get the wrap off, I can measure the dc resistance. I wonder it it serves as a passive radiator as much as a woofer.

https://www.ebay.com/itm/Vintage-Jen...6Ug:rk:30:pf:0

[rusty jefferson]

I have this link someone previously posted about the Altec/UREI chronology. About half way down the page is your speakers. Looks like designed as 16 ohm system impedance to work with the ML crossovers, and concern that sometimes drivers are accidentally reconed/diaphragmed 8 ohm.
https://www.technicalaudio.com/pdf/D...04/DUPLEX.html

I believe the UREIs crossed in (not over) the helper woofers much higher, like around 400-500hz. Don't know if these would be similar?

[toddalin]

I have this link someone previously posted about the Altec/UREI chronology. About half way down the page is your speakers. Looks like designed as 16 ohm system impedance to work with the ML crossovers, and concern that sometimes drivers are accidentally reconed/diaphragmed 8 ohm.
https://www.technicalaudio.com/pdf/D...04/DUPLEX.html

I believe the UREIs crossed in (not over) the helper woofers much higher, like around 400-500hz. Don't know if these would be similar?

Do you mean low passed (i.e., used up to 400-500 Hz) or high passed (i.e., used above 400-500 Hz)?

Thanks

[rusty jefferson]

Do you mean low passed (i.e., used up to 400-500 Hz) or high passed (i.e., used above 400-500 Hz)?

Thanks

Low passed, used up to maybe 400hz, but no high pass on the coax woofer. So, both working together below say 400hz in the same enclosure volume. That's my understanding of the UREI implementation, though I have never measured mine, and they are currently disassembled.

[Earl K]

Low passed, used up to maybe 400hz, but no high pass on the coax woofer. So, both working together below say 400hz in the same enclosure volume. That's my understanding of the UREI implementation, though I have never measured mine, and they are currently disassembled.

I'd say that 400hz figure is about right Rusty ( based on looking at the 813c schematic ).

[toddalin]

I picked this up today. All makes sense now! I would bet that there were very few of these ever made. Note the wording on the "lables."

[toddalin]

Todd,

Most likely the system is designed to be biamped with the HF amp feeding what's seen in the pic ( for tonal shaping ).

FWIW, I do the exact same thing.

Who would have made them and who would have made the electronic crossover..., Audiotechniques? Certainly these aren't Altec pieces and there are no manufacture names on any of them.

[speakerdave]

Who would have made them and who would have made the electronic crossover..., Audiotechniques? Certainly these aren't Altec pieces and there are no manufacture names on any of them.

They are most likely custom one-offs; no manufacturer's tag with all the legal stuff.

[Ian Mackenzie]

http://www.audioheritage.org/vbullet...1&d=1280933585