Curious_George

The T0-3 devices are LT1085 regulators for the 300B filament circuit. Amp is very quiet. Yep.. Orange Drops. Last forever and sound great.

Very few people realize that the sounds they hear naturally are single-ended. Great info in your last post.

.

.

Those are the strangest looking Trachorn or Elliptrac I have seen….

Can you expand on the parts so we can determine the quality for ourselves?

A lot of times, nothing. However, in this case, these are not mass produced products. They are niche audio products, so you are paying for a persons time who designed and produced them. If volume went up, the price may come down, but not necessarily.

The first question that should have been asked is what is your goal? More bass? Less midrange? An overall more balanced sound? The “upgrades” you have are common and a step in the right direction, but not necessarily the correct direction. It all depends on what you are looking for. The tweeter driver is good. The DE120 is top notch. The horn is also good. The Atlas PD5VH is nearly identical to the OE Klipsch K55V, no issues there. The LaScala needs a subwoofer to round it out. It does not have much response below 100Hz. If you think the midrange is a bit hot, you can attenuate it by moving the midrange from tap #4 to tap #3 and changing the capacitor from 13uF to 6.5uF. Do some research on “T2A autoformer”.

Please expand on the "built-in EQ".

Technically, the K77 (AKA EVT35) can be crossed over as low as 3500Hz according to EV data. The question is how does it sound being crossed over that low. At low to moderate levels, it is probably OK, but at higher levels it probably sounds better crossed over higher. Your crossover looks interesting. Are you going to build it and see how it sounds?

Clone drivers are always a crap-shoot. I would buy one and measure it to see how it performs. If it is a good clone keep it. If not, return it. If you don't have the capacity to measure, maybe someone can do it for you.

A bit overkill for a 2A3, but no doubt a good choice. I don't think you'll ever need to replace that tube any time soon.

Beefy... you are so alpha.

So this would be kindred to a tantalum? I'd try them and see how they worked. As an experiment awhile back, I used tantalums where high value electrolytics (polarized) were used for signal coupling and they work great. There is not much chance of over or reverse voltage in the coupling circuit, so I surmised they would have a long life and never dry out. I know tantalums are not usually used for signal coupling, but it is/was an experiment and so far so good.

The ALK Universal will make a LaScala smoother, but the K401 has to go. That is the biggest issue regarding the midrange performance.

I have a sensitivity to mid-bass frequencies and found the side panel mod helps a lot. In addition, I converted the 6dB woofer crossover to 12dB to roll off the woofer a bit faster due to an anomaly around the 400Hz crossover frequency. This helped tighten up the bass too. To convert to 12dB, add an 80uF/100V bi-polar cap across the woofer terminals. The K400 midrange horn can be quite “vocal” (pun intended). Replacing it will really open up the sound and have a more natural presentation even if you keep the K55.

It (18 x 10 & PRV) is a "no brainer" regardless of price of components. I believe it is that good.

They are very similar to the Celestion H1SC, but a few dollars less and the Daytons have a threaded brass insert.

My vote is for the ZXPC 18 x 10, mainly because that is what I have and have tested. The sibling ZXPC 17 x 11 also appears to be a great choice as well. The 18 x 10 is a great horn from just about any perspective; price, performance & aesthetics. I do not have any experience with the Trachorn or Elliptrac, but I would say all 3 horns are "similar", but different enough to have their own personalities. I like the conventional look of the 18 x 10 too.

If you add just one more choice, I could comment. But you strictly said ONLY.

The swamping resistor has a benefit in the following situation; 1. You want to move away from the factory (AA / A / E, etc. The swamping resistor can be added to a lot of networks. This is not a full list) network which is only 6dB/octave high pass on the midrange and implement a steeper high pass slope say 12dB or higher. 2. The swamping resistor also sets a continuous load for the midrange crossover, so you can now use the T2A taps to attenuate the midrange without messing with crossover components. Just move taps and the crossover will stay the same. 3. One small downside to the swamping resistor is now you have to isolate the tweeter crossover and possibly use an L-pad for attenuation. A small price to pay for being able to quickly dial in the midrange level. edit 4. If using a single ended tube amp or an amp that needs a fairly constant impedance, the swamping resistor will smooth out the impedance curve. I like the autoformer as a level component, but have no problem using L-pads either. Both are just tools.

Dean - what is your listening impression of battery bias networks?

Using a higher order passive crossover is a designer or personal preference. For brevity, we’ll leave out electronic crossovers for this discussion. Using a higher order network could be to maximize power output. Another reason could be to limit driver interaction or both. Keeping the “out of band” energy from overlapping into the adjacent passsband is the main reason for a crossover. Some people prefer steeper slope networks than others. Obviously, there is cost to consider as well as the steeper networks quickly add up to a lot of parts. Phase and group delay also play a part in the final design, but that is another conversation.

A good suggestion. One may sound better than the other.

What was your listening impression?