Altec Fever!!
- Thread starter sanjib
- Start date
I purchased the model 17's cabinets 10 cubic ft speaker cabinets loaded them with Altec alnico 422 8z talk about bass Im also got them into a three way crossover with horn mid , horn treble. pre amp at zero for bass and high end. useing 40 watt 1961 6550 NOS tube amps bought last year had electronics engineer in analog equipment total replace anything not up to snuff resistors, caps all high quality. the amps are Stromberg Carlson AP-437 tube amps. very rare patent company General Dynamics Corp that took us to the moon and still designs some of our military equipment.
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It must be a while ago. It is not easy to find the original cabinet alone, and the price is sky-high. I am planning to make the 620 this summer.
I have a friend in syracuse NY who bought them empty he called me I went right then and there they were 25.00 for both. been 10 yrs if not more. no heavy diggs all corners great had to redo the face covering. but they weight 150 lbs each thank god i have a two hand cart. id post a photo yet im running linux and still cant send photos ive get some 14 tube amps I want to get on ebay... dame government
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I have a friend in syracuse NY who bought them empty he called me i went right then and there they were 25.00 for b
After a long listening period, here is my realisation:
604-8G: Sounds very good with GPA crossover, not much change in a good direction with external crossover, and my current combination of 2 tube amps. They are in a repurposed speaker cabinet of volume 4.2 cu ft, bought from Amazon.
605A: With electronic crossover, they sound amazing in every department. Handily beating 604-8G with GPA crossover as well as electronic crossover. They are much better than the 19 that have recapped original crossover.
I am making a pair of 8.5 cu ft cabinets to realize the true potential of 604-8G. I prefer to use GPA crossover in this new, large cabinet.
Next step would be comparing 605A with the electronic crossover to 604-8G in the big cabinet with GPA crossover, and to the 19 with the electronic crossovers.
604-8G: Sounds very good with GPA crossover, not much change in a good direction with external crossover, and my current combination of 2 tube amps. They are in a repurposed speaker cabinet of volume 4.2 cu ft, bought from Amazon.
605A: With electronic crossover, they sound amazing in every department. Handily beating 604-8G with GPA crossover as well as electronic crossover. They are much better than the 19 that have recapped original crossover.
I am making a pair of 8.5 cu ft cabinets to realize the true potential of 604-8G. I prefer to use GPA crossover in this new, large cabinet.
Next step would be comparing 605A with the electronic crossover to 604-8G in the big cabinet with GPA crossover, and to the 19 with the electronic crossovers.
I think the original Altec 620 cabinet was tuned to 40 Hz. Any advantages to going lower than that, given that the cabinet volume is slightly less than 620?
Here is the response curve for 35 Hz tuning
That looks better to me. The little bump from tuning higher makes a harder sounding low end. Just one mans opinion though! You will get some room gain that will help some with the roll-off. And If you ever wanted to apply some eq, the gentle roll off would be easier to make correct.
fredgarvin
Super Member
Those look great.
After experimenting for a few days, I found both 604-8G and 605A sounded best by biamping with an electronic crossover.
Now I am thinking about protecting the tweeter and woofer as they are directly connected to the amps. Do I need to use a capacitor in series with the tweeter to protect from DC? If yes, what value is better to use? For the woofer, the amp I am using is not AC-coupled, so what can be done to protect the woofer from a probable amp oscillation and unwanted DC, if there is any?
Now I am thinking about protecting the tweeter and woofer as they are directly connected to the amps. Do I need to use a capacitor in series with the tweeter to protect from DC? If yes, what value is better to use? For the woofer, the amp I am using is not AC-coupled, so what can be done to protect the woofer from a probable amp oscillation and unwanted DC, if there is any?
If you are using an active crossover, your drivers are protected - only seeing the signal that is sent to them by the crossover.
Thanks for the reply.
But, the output of the active crossover connected to the power amp (not to the speakers), and the power amp's outputs are connected directly to the woofer and tweeter. If amps suddenly go into oscillation or produce high DC, it will directly go to the woofer and tweeter.