henry4841

From what I am reading here I would just purchase a pair of 8 ohm L-pads at Parts Express. Impedance of a speaker can vary a lot when in use.

One has to start somewhere by first by using the efficiency of the tweeter minus the efficiency of the woofer as a starting point. Use this calculator for the value of resistors after estimating the db's you think you will need. https://www.diyaudioandvideo.com/Calculator/DriverAttenuationLPadCircuit/

The Altec is one of the few 1" driver horns available. I have one on another system for mids only and it sounds great with a big soundstage.

Class A is still class A, the most linear of all the choices. This is not to say other forms do not sound good but technically still class A is class A. In other words it is the standard to compare other forms of amplification. I have not followed the thread too much on the new ACA mini but unless I am mistaken it is a PP and the older ACA is SE. I did build an ACA a few years back and it did sound really good considering it's cost. Tube sound in a SS amplifier is the best way I know to call many of Nelson's designs.

There is a newer version called the ACA mini that should be ready for sale in the next few weeks that is much cheaper to build not needing an expensive case. https://www.diyaudio.com/community/threads/diy-aca-mini.379037/

Granddaughter that had 2 shots of vaccine and booster caught covid along with my son and another grandson who both had vaccines as well. [ [Mod Edit: SNIPPED,, what works, doesn't work, isn't what the post is about, the impact on family, emotional, mental health, works are, just like the previous sentence and the following sentence. Again, your post was before I came up with specific rules for this thread to try and keep it alive]. All are doing well though so that is the good thing. All relatively young and in good health. Something we are just going to have to live with from now on it seems.

Good Lord, 7 pages on capacitors and all the guy wants to do is fix a crossover where it works first. Start talking capacitors on this forum and members start reaching for their knives. He seems to have covered the simple steps first and replacing the caps may be the next step to solve problem. I would just throw some Dayton caps in the bad crossover first and see if that fixes the problem. Then proceed fine tuning the crossovers using other caps or kit from JEM.

No, excellent crossover caps. I would first take a soldering iron and go over all the solder connections on the bad one. Just heat the old connections up and add a touch more solder to each one.

Big Altec horn?

A finished restoration project, a Sherwood S-7100A. Replaced all the electrolytic caps minus 1, the main PS filter capacitor which tested in spec with low ESR so from my experience it has a lot more life left in it. I have a new replacement I ordered but saw no need in replacing it. Checked alignment, cleaned all controls and gave it a thorough cleaning. The case is plywood with walnut veneer that is in really good shape but looked dry so I stained it and it came out looking great for it's age. Sounds really good with measured power of 22 watts at clipping 1000hz. Nice addition to my collection.

I do not think any engineer would intentionally create a phase shift in a speaker system. Just the opposite is what I think they are trying to achieve. Keeping the speakers in phase with each other in a system is almost if not impossible in reality but I still believe it is the goal of most engineers. This is an entertainment hobby so if there is an advantage of intentionally causing a phase shift I guess it is possible an engineer has tried doing so. Ideally a single speaker creating the entire audio band would be best but in the real world not technically possible. Some full range speakers do sound really good these days though.

It is called accurate reproduction. Keeping the phase the same as source is what is wanted in the end.

My thoughts are you want all the drivers in phase with each other and let the music take care of the musical phase shifts inherent in music. In real world, other then single full range speakers, it does not happen. Each and every component will create a phase shift of the original signal by the interaction of the drivers and or speakers with each other. Align 2 speakers in an appropriate box and throw in a capacitor on one of them and you will have some phase shift between the two speakers. Crossover designers, to my way of thinking, try and keep the phase shifts between the drivers to a minimal.

What you describe is what most say with a really good class D amplifier. Reserve judgement on tubes though after a few months listening with your new amp then listen to you tubes again. You may like the difference tubes bring to the table. At least my experience. Your taste in music also contributes to the one you may favor.

I would not go to the trouble myself. I am sure the RMS power rating will be much lower then what you think you bought judging by the weight and the size of the OPT's. I believe Bob was deceptive on advertising power but manufacturers have been doing this for decades. He did not state how he rates his power figure so that probably releases him from any liability. From all accounts though it is a well made great sounding amplifier so I would just forget all of this and just enjoy it or pass it along at some loss on the used market. Your speakers are not going to be seeing more then a few watts anyway and the amplifier provides way more then needed. I do believe Bob should not be deceptive in his advertising but just depend on an honest RMS rating and his reputation of building quality products.