Curious_George

Now there is a question... In terms of sound quality / differences, the 211 has more micro-details to my ears. The dynamics and headroom that the high voltage affords has a dramatic affect on the sound, especially when you use a high impedance output transformer >10k. My output transformers are 16k into 8 ohm, so the load line is more horizontal reducing distortion, but increasing drive requirements. I like both the 211 and 2A3, but they do give a different presentation.

I bought 4 NOS GE 211 / VT-4C's back in 2005 or so. They each have developed issues, quite surprisingly. I have not messed with them lately, but it could have been a dirty tube socket. However, my Chinese 211's keep going and going. current is stable and no noise or other issues. Granted, I don't use the amps as much as I probably should, but now that fall / winter is here, I think I'll use them more to add a little extra heat in the basement / mancave.

For the price, I like the Sovtek 2A3. I have 3 pair of them and they are very consistent (measurement wise) and sound very good to me. It is a single plate and according to some other people who have used them, they have a higher power dissipation than your standard 2A3, but I have not tested or run them that hot. In use, they measure and perform like a "standard" 2A3 as far as bias, plate voltage, etc. Even though the price has crept up on the Sovtek 2A3, it is still the best tube in its class in my opinion. Except for 211 and 845 tubes, I prefer to not use Chinese tubes. I have not had good luck with them.

I bought 4 JJ 5751's and am happy with them. A pair (other 2 are back-up) are in a parallel SE 2A3 amp and they sound great. Originally, the circuit had Chinese 6N2's. The 6N2's were noisy and the circuit had too much gain. I rewired the circuit for the 5751 and it was transformed! The 2A3 amp is now one of my favorites after more tweaks and mods.

I too have ordered from Tube Depot in the past because what I was looking for had a fair market price and I've never had an issue with a sale. Long ago (circa 1999) I bought a pair of 300B's from Tube Depot and the filaments on both tubes failed (or stopped working). I called Tube Depot and assured them that the 300B's were in a proper circuit and they sent me another pair. They said they never heard of premature (only a few months use) failure such as this. Things may have changed since then, but my last purchase was a few years ago. As a business they can sell items at what they deem as a market price.

I have a few 6SL7WGT's and they appear to be NOS, but in circuit, they have high distortion. My favorite 6SL7GT is the GE "silver looking" plate. They seem to be consistent (tube to tube) and have low distortion readings in my single-ended circuits. They are quiet too and not microphonic. The 6SL7WGT's are strictly for back-up.

I prefer simple circuit topologies or topologies that satisfy the requirement, but no more than that. I know that sounds odd, but a lot of times, circuits are more complicated than they need to be. For a PP 2A3 I would go with a simple circuit such as a 6SL7 input coupled to a low gain triode "long-tailed" phase splitter coupled to the 2A3's. After tweaks and fine tuning, you can add a CCS to the long-tailed pair if you want to balance the drive signal (if needed or desired).

Here is a good primer for those interested. Actually, it reminds me of the late Harvey "Gizmo" Rosenberg's writings. SE-v-PP-Part1.pdf

That's one way to look at it... 11" = well done. 7" = medium.

I have to disagree with Carl's comments. Apparently, Carl had flame-proof "knickers" on. I'm guessing he has a British background from the use of that word. The LaScala port modification is similar to Claude's Super Heresy port modification and just as audible. The final port length should be 7", not 11". 11" works, but 7" seems to be give the best overall bass. In addition, to get the "full effect" of the port modification, you should use a high pass filter with 6~ 8dB of boost @ 40Hz. Both the porting and high pass filter (EQ in other words) is what gives you the best bottom end out of the LaScala. As far as a subwoofer is concerned, this is subjective and depends on personal taste. Will a subwoofer help? Yes. They always do. However, depending on your room and how the LaScala's react in your listening environment, you may be happy without a subwoofer. Let's put it this way, the ported and EQed LaScala is easily listenable without a subwoofer.

Not necessarily. I worked with Chinese factories for 20 plus years, not all of them are unscrupulous. A lot of times, they will buy a real component and try to reverse engineer it. Most times, if the factory is not familiar with the technology of the component it will look the same, but rarely perform they way it was intended. Reminds me of Trelane from Star Trek who’s food had no taste and his wine, no flavor although it looked perfect.

Interesting... feedback or no feedback? A mixture of vacuum & solid state components?

I was thinking "interstage" when I was typing looking right at the schematic with the center tapped choke. The brain to finger interface has a hiccup... There is only a handful of ways to make a 2A3 push pull as far as the basic topology. When you say more modern, what do you have in mind?

A Brook 12A clone might be nice with RC coupling instead of the interstage transformer. You could do 816's for the power supply and have some blue/purple ambience...

Prices for goods have definitely gone up... I own a business (not audio related) and I can tell you that consumer index pricing is tied to (US) politics, but also tied to a "global market" as we have been reminded all to frequent during this pandemic.

Perhaps when this thread finally wanes, the original poster will have learned enough about crossovers, that he can build his own. It's quite easy in today's world with all the resources of the Internet. Maybe I've gone out on a limb, but if you read enough and comprehend what you have read, it will eventually sink in if you push through the learning curves and get your hands dirty. If it doesn't kill you it only makes you stronger or smarter right?

I've never bought anything from Crites, but you could have solicited other people here to build you some crossovers. I'm certain the price would have been double easily.

I think the listed items are incorrectly marked... the 1.5mH can be a solid core since it is for the woofer. The 2.2mH should be the Litz even though it is a shunt, it may not be as audible as if it were series.

No, according to PE, they are solid wire. Litz does cost extra, but if my pricing is off and Crites buys in bulk (they must), the end price for Litz may be similar to what I have listed.

Did you get screwed? No, but perhaps as others said, communications were not clear on both sides. Below is a break down of prices. The price of these items may be less for the builder, since I assume they buy in quantity for most parts. However, let's assume the prices below are somewhat accurate. Price Break Down: (Parts Express Prices) Inductors Erse 1.5mH coils - $35.89 x 2 = $71.78 Generic 2.2mH coils - $20.00 x 2 = $40.00 Resistors $1.50 x 6 = $9.00 Caps Erse 47uF/100V: $1.49 x 2 = $2.98 Dayton 8.2uF - $3.59 x 2 = $7.18 Dayton 27uF - $9.29 x 2 = $18.58 Barrier strips - $3.00 x 2 = $6.00 Wood = $20 Total Parts - $175.52 Labor - $124.48, 6 hours / $20 hour If anything, you got a bargain to have someone build you crossovers at $20 / hour much less an established small business in the audio community. Whenever I build something for somebody (which is not too often because then my hobby becomes "work" and it is difficult to justify the cost of "my time") the hardest part is trying to determine a cost for my knowledge / labor.

The Crown advice is good. An AB International 400 might also be an alternative for you. For the money (go for about $200) they are solid and have plenty of power for the Heresy's.

Or like the original Superman movie / comics, they couldn't bring themselves to kill anyone one, but would condemn you to the Phantom Zone or real rehabilitation such as in Demolition Man.

In my opinion, life in prison is a sick joke. Putting aside wrongful conviction for a moment. Life in prison is not justice, it is a waste of time & resources. In addition, the angst that the men and women have to go through to work at these facilities and then try and go home to have a normal life each day. Yes, everyone has a choice of profession. Our justice system needs serious reform no doubt. I support all law enforcement for the record, but some agencies do need to have better training. When I was in Kuwait in 2003 with the US Army Reserve, a local man raped and killed a Filipino service worker. He was sentenced to death in a matter of days. He was to be placed at the top of a precipice with a hood over his head and pushed off. If he survived that, he was to be shot by a firing squad. I can sleep at night with that. I'm not religious (at all), but know many of you are. An "eye for an eye", is my belief. There is only one way to combat violence, with greater violence. People who are truly evil such as terrorist or serial killers welcome a US prison or places like GITMO. They are laughing at us.

What is your budget? Do you want analog or class D? Power output?