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brl0301 12th October 2020 03:11 AM

TSEII 300b to 45 swap
Hey Ive been enjoying my tseii for a past year or so and its been great. Ive read quite a bit about how good 45 tubes can sound and it has me thinking. My amp is currently setup for and running 300b tubes and 5k opt. I have two questions:

What would need to be swapped to allow me to run 45 tubes?
Would the switch to 45 be worth the effort?

Im currently running 100db/w speakers so i think the 45 would be plenty of power. Thanks for any replies!

brl0301 15th October 2020 12:54 AM

So i looked a little more and it looks like id need to swap out r14 and r25 for 30k 3w. My current power transformer looks like it has the correct filament supplies but b+ is way too high. Is there any reliable way to drop b+ down to where it would be suitable for 45 tubes?

Duke58 15th October 2020 01:12 AM

New power transformer and there's a jumper on the TSE-II board you would need to change around. How about output transformers? I bought my transformers from Electra-Print Transformers. It was a very pleasant transaction.

I've got a TSE-II running NOS 45 output tubes and a TSE-II running Chinese 300B output tubes.

The 45 powered amp is one of my favorites, but it doesn't get as loud as my 300B. That's really the only difference I can hear. I also have some balloon shaped 45 tubes that sound great, but it might just be my imagination because of their age and I got them out of an old radio.

brl0301 15th October 2020 01:48 AM

I was trying to figure out a way to get away with not buying another transformer but I think it would cause more issues than it would be worth. It looks like r2 would also need to be swapped. Luckily my transformers would be suitable for the 45 tubes as is.

Would you say that the 45 sounds considerably better than the 300b or is it a pretty minor improvement?

Duke58 15th October 2020 03:51 AM

It's more subjective for me to say what you might hear.

The 45 tube is a great sounding tube, but I'm not the type of audiophile who can really tell you the difference in sound between one brand of tube versus another. It's like me trying to tell you what type of beer to drink (if you drink beer). Honestly, my hearing worsens when I'm drinking and I like it louder. That seems to be about 8 to 10 Watts minimum.

In the small space where I have my 45 amp, it works just fine. I'm using some tried but true old Omega Grande 8R speakers most of the time. Sometimes play the Klipsch Cornwalls, but those big speakers hog up a lot of room.

Also, I like the 45 for classical music and female vocals. The 300B rocks and plays country and western sound nice and detailed and louder. I also use the 300B amp to drive the mid/high JBL compression drivers for some JBL speakers I have. Gotta use the active crossover and only when I want it loud in a big room.

The 45 is a nice sounding tube. I'm not the person to ask if it's considerably better than the 300B because I like the sound of both tubes for different music in different listening rooms.

brl0301 15th October 2020 09:35 PM

thanks for the great feedback.

I am def a beer guy, I usually have around 25 gallons of homebrew on tap at any time. I dont get to listen very loud too often, the boss gets mad. Pushing 8 watts through my cornscallas is louder than I like to listen anyways.

I think I may just keep an eye out for a suitable power transformer and if something comes along then i will pursue the idea further.

colnago55 16th October 2020 12:29 AM

The Edcor XPWR131 was built for the TSE and is designed for both 300B's and 45's. You might look at that. You would need to change the jumpers as well. I've built a 300b and a 45 TSE. I also recently built a TSE-II using the same power transformer.

Good luck, enjoy.

brl0301 16th October 2020 01:28 AM

awesome info, thx!

what do you make of the differences btw the 300b and 45 tubes?

colnago55 20th October 2020 02:13 PM

I like them both, the 45's are a little smoother, but I prefer the sound of the 300b's, they have a fuller sound. The 45's use less power and create less heat. I'm listening to new JJ 300b's and vintage RCA 45's which I think are from the 1930's.


Duke58 20th October 2020 03:15 PM

brl0301-- I used to home-brew. Made a clone of Sabco brewing system. At one point, I spent around $500 on the brewing system and the boss asked how much I was going to spend and told me if I wanted to spend more, I had to sell some of my other toys. I sold a Denon HT system and gave her half the money and she never mentioned it again.

My stereo gear is mostly out in half of the detached garage. My wife and my son don't like the volume or music selection. Eight watts through the Cornwalls is loud. I mostly keep the noise level low so I don't disturb the ER physician next door who sometimes works the night shift.

The 45 tube sound is what I would call more detailed. The 300B do have a fuller, lush sound.


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