Curious_George

Yeah but right about now, she would look like a beauty queen…

Iron is going to be the bulk of the cost unless you have a clever design to use a low cost low voltage transformer in a voltage doubler circuit. I for one would splurge a little and spend a bit more for “more of whatever” the extra dollars would bring.

Yes, I changed the woofers for the port mod. I am using Celestion TF1225's. I believe I am using the T2A -6dB for the mid and an l-pad made from 2 resistors for the tweeter @ -3dB.

These are ported (of course) and have ALK Universal clone crossovers.

Here are my 1979 Heresy I's (87T619/620) converted to my new model called "Heretic". I bought these in 2012 at an antique shop in central Florida for $250 (from the original owner, a woman) out the door. A steal!!

Just because someone says something does not make it absolute. In this case, some speakers, in some rooms benefit from being raised off the floor. It is that simple. You have to experiment.

I will have to disagree. When I placed my LaScala's on moving dolly's such as from Harbor Freight, the bass improved noticably. These dolly's raised each speaker about 3.5" from the floor. Now each room is different, so your milage may vary, but I think rasing up the speakers helps various listening anomalies.

This amp will need a preamp of some sort unless the source can provide approximately 1VRMS of signal to drive it to full power. The source will also need a level control. Technically, you could drive it direct and get some power out of it. Probably enough with horn loaded speakers. Unless specifically stated, I always design amps with a 1 ~ 2VRMS sensitivity. I always use a preamp with all my amps because some degree of tone compensation is always necessary. I’ve tried to listen to music with just gain and it sounds flat and uninviting.

For all their supposed imperfections and limitations (like a SE amp), I love the sound of the K77's I have heard and own.

Feedback is great if used correctly, like anything. The modern world we currently know could not exist without feedback in all of its forms. Now AI (Artificial Intelligence)... forget it.

So, there is a budget in there somewhere... You can spend from $1000 to $5000 on a 300B amp or more. I would stick to the brands that have the better reviews, but audio is so subjective. One item to consider if your are intent on running your khorns on a single-ended amp is the khorn crossover. From the factory, the khorn impedance varies quite a bit over the audible range. This is usually not good from a single-ended amp point of view. It is not absolutely necessary, but I would consider modifying your factory crossover (to have more of a constant impedance) to compliment your tube amp slection. There is a lot of info here on crossovers for khorns, LaScala's. etc.

Wha is your budget?

What are your current main listening speakers?

So how does the Cornwall IV actually sound compared to other similar speakers?

True, but a day in court some people may not be able to afford.

To “voice” a SE amp, you should consider the load lines of each stage (if you have these resources) and how they could possibly cancel 2nd order distortion in order for the “total” final distortion to be as low as possible. The tube selection also needs to compliment the output transformer primary impedance. You would need test equipment for this to measure THD+N though. The lowest distortion may not be everyone’s metric, but I like to keep it as low as possible to start at 1 Watt. I recently found a great combination that yielded fantastic sonic results: Lundahl LL1627 transformers (wired for 3k), Sylvania 6SL7WGT and Sovtek 2A3. I can post the schematic if anyone is interested.

Eliminate the negatives, accentuate the positives...

Extrapolating data from the DH1A SPEC sheet, it looks like the impedance at 500Hz is @ 12 Ohms. However, the impedance may be different if you are using a horn that is not an HP9040. Assuming the impedance of your driver and horn is 12 Ohms the L-Pad chart I posted will not be valid. I’ll have to post another one for 12 Ohms.

What is your crossover point?

The amp is now in the annals of audio history… Carver Dismal 275. This is very sad that it bears Carver’s name.

I would use 10 to 15 watt resistors in the final circuit (depending on listenibg levels), but for experimenting, you can use 1 or 2 watt resistors.

I compiled these awhile back when I was thinking of developing a stepped attenuator. This particular stepped attenuator has a fine step increment which is not common. I never developed the attenuator, but I had various prototype parts around to make a few. One is in a tube preamp that I designed. For those who want to make a stepped attenuator with less steps, you can select your desired "step width" (dB steps) and use that combination of resistors to give you the desired attenuation. For example, 24 seems to be a common step width and you could use the following dB steps for a 10k attenuator: Step 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 18 21 24 27 34 37 44 50 58 Stepped Attenuator Worksheet_v1.0.0_011522.pdf