Curious_George

I know some of the newer tubes may look better (compared to USA NOS), like the Psvane shoulder 6SN7, but the shoulder or look of the tube has nothing to do with the sonics. This particular tube on Amazon says the shoulder version is made for HiFi and is warm (and fuzzy, just kidding, but is does say warmer because of the shoulder design). The metallurgy and design of the USA NOS is (or was) better than the new Chinese tubes in my opinion.

I have not tried them, but the price is crazy. The best 6SN7/GT made in my opinion is a USA NOS (any brand). I have a few Chinese (generic) and Russian (Sovtek) 6SN7GT's and they are OK, nothing special. I have compared (listened & measured) NOS RCA 6SN7GT's that are used with many hours on them to the Chinese and Sovtek tube mentioned previously. The used RCA tubes have a lot of hours on them, probably close to 6k or 7k hours. The tubes have so many hours on them, there are chrome looking spots above the cathode filament "tubes" on the top glass. Compared to the Chinese and Sovtek's, the RCA's sounds just as good, maybe better.

The LaScala bass modification is not half-baked, although a lot of opinions on this forum are. Yes, this is my opinion as well. Most people here give good advice, but in some cases, designs or topologies are not their favorite and instead of giving an objective view, they give a biased view, which does not steer a person who has limited knowledge in the right direction if they are asking about such. To get the full benefit from the LaScala bass modification, Dennis indicated that the high pass filter EQ was needed (and it is). I suspect most people who do modify their LaScala's do not use the EQ and this is where the "disappointment" may come in. Almost every speaker could benefit from a subwoofer, even some "subwoofers", if that makes any sense... I like a full music spectrum, but not everyone wants or needs much below 30Hz.

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How does the Inspire sound and what speakers are you mainly using?

I built a 6V6 (in triode configuration) preamp and those can be microphonic too, but it sounds great. An isolated mount (rubber bushings, etc to isolate the socket mount) will eliminate most, if not all microphonics, but you have to be creative.

https://www.simplyspeakers.com/speaker-repair-adhesive-mi-1291.html After you get 50 different answers, this will still be THE answer.

Not that I am looking to buy, but perusing eBay frequently just to see what is for sale, I have not seen a pair of Heresy l's for less than $500 unless they are beat up and ragged, but even then, they want top dollar. I paid $250 for my pair in 2012 at an antique store in Central Florida, from the original owner.

When I reconed some JBL D130's, I used a kit from Simply Speakers and in the kit was a small bottle of polyvinyl acetate and it was used to seal (dope) the outer surround. Worked perfect and sealed the surround.

It is probably polyvinyl acetate or some cousin of it. You can buy it from Simply Speakers.

Nice seti. What output iron is used for the 1625 SET?

I have never heard of them before your post, but I know there were a few variants of the 6SN7 made for specialized purposes, such as the 2C22 for VHF. The two are similar in specs, but not identical, however for audio, no circuit changes should be needed. The few things I read about them just now included all the typical audiophool adjectives about tubes. If the 2C22 were $1, it might be worth stocking up on them since USA NOS 6J5's are getting more expensive, but the 2C22 seem to be the same price or more than a 6J5, plus it cost more to implement since you need 2 top caps. The 6F8G (6SN7) and 6CG8 (6SL7) are also close cousins and can be used as substitutes, but the price on these seems to have skyrocketed lately. I remember buying them for $4USD, now eBay has them for $40~$50USD. Good ol'e eBay... driving up prices and inflation (at least for audio gear) for over 25 years.

This is what I had in mind if I came across a 185 amp. I'd convert it to Ultralinear.

Some inexpensive Edcor single-ended transformers would bring it up a few notches. They are a great value for the money, but the lead time is about 8 - 10 weeks.

I ashamedly admit getting shocked from my fore finger to pinky finger (on the same hand) when I was building the power supply for my 211 amp... 1200VDC. It got my attention real quick. That never happened again or since. When I take the bottom cover off of the 211 amp, I make sure I am fully rested and wide awake. No tinkering with that beast if I'm not wide awake and alert.

Sounds like a nice little find. How about some pix?

Yes, I have seen Thomas' website. I figured his builds were expensive, nice stuff though. I used 866A's in the first iteration of my 211 build despite all the "experts" telling me not to. They were quiet and worked well. They looked cool too. I switched to 3B25's to see if there was a difference, but none that I can/could hear. The mercury vapor rectifiers definitely have more of an cool glow factor than the 3B25's. I say go ahead with your 300B/10Y/816 build.

That is the main reason I started to build my own tube equipment, price. My first tube amp that I built was a Williamson Ultra-Linear clone back in 1996. As the Internet grew and more and more audio pages were added, I started to read more about single-ended tube amps. I thought it was crazy, 2 or 3 watts single-ended. I couldn't stand it so I built a pair of mono block 2A3's. To my surprise they sounded wonderful. I was hooked. Shortly after I built those 2A3's, I had to hear what 211's sounded like, so I designed and built a pair of 211 amps. Too bad more people can't experience the 211 and 845, they are great sounding amps, but the high voltage and complicated circuitry definitely drive up the price.

Are the Aric 211's worth 10k? Give us your impression of sound and build quality.

The rule is fairly broad, but 1 or 2 twists per inch is sufficient. No more than 2 is needed.

Here is a 2A3 review I always liked. 2A3 Article By Joe Roberts.pdf

For a DHT tube, it is hard to beat the 2A3. It's circuit can be simple and the voltage and drive requirements are easy to implement. The 211 and 845's require much more effort and cost to build a good amp, which is why I suspect more DIYers don't try them not to mention the high voltage (over 1kV) needed to make them work where the plate curves are most linear. I've been tossing around the idea of a simple 211 or 845 amp for the beginner just so more people try the big transmitting tubes. If I do, it will be the 845 because you can use a much lower impedance output transformer than a 211.