45 Type Push/Pull Amps

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Did it again, sorry. I'll type it in this time, not paste it.

http://www.tubesrit.com/audio/albums...s_DHT_PP45.pdf

Let me know if this opens correctly.

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[Harleyjon]

Yes it does. Thank you.
One could use three 2A3's I suppose if 45's are not available..

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JF Lessard's Seth (check on the Magnequest site) uses 2A3s with an
autoformer phase splitter. Choke loading on the outputs is the main
distinguishing factor between the two.

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[45]

Originally Posted by Harleyjon

Yes it does. Thank you.
One could use three 2A3's I suppose if 45's are not available..

It is not the same thing. I have a 45 PP and I had 2A3 PP and PSE before. The 45 PP is better sounding and also measures better. However the 2A3 PP is very good choice and I prefer it to 300B's......
I get 10W clean watts from my PP. For me PP is better and I think the 45 SE is a little bit of a waste because 2W are really not enough with normal speakers. I don't like horns and huge high efficiency speakers at all....even less things like Lowthers..bleaaa!!
The best speakers for me are always stand mount (2 or 3 ways) with efficiency between 85 and 92 dB!

You can still find NOS 45's but they are expensive if new. However some used 45's can still be very good with plenty of life left. I have 3 quads, 2 are new in original boxes (RCA and Raytheon) and 1 quad used (Sylvania). I am using the latter in my amp because still measures almost like new and performs admirably.
You can also find new production 45's but they are expensive, again! Best current production 45's are Emission Labs, I think. In general I don't like Emission Labs small power tubes because they use huge bottles. Fortunately they have made a globe version of the 45 which is smaller and nicer. Their 45 is rated 11W. They also make a mesh plate version however mesh valves do not like to be driven into positive grid so the max power you can get is limited in comparison to the solid plate. Chinese 45's are not true 45's in my knowledge.

[Harleyjon]

Thank you 45. I will look around and steer clear of the Ch versions if I decide to produce a few mono blocks. I was thinking of producing a batch of PP triode output stage amplifiers with cathode drivers. I shall submit a design when it is perfected.

[jcmusic]

I want to thanks all who responded I am just trying to determine if a PP amp using a 45 tube is where I want to go??? Right now I am using an SET amp with a 45 tube and 106db speakers... Sometime I just wish for 1-2 more wpc and thought the PP might be the answer, comments???

[wicked1]

I was so impressed w/ my first tube amp, which was single ended, that I avoided PP for years. None of my commercial PP amps sounded nearly as good. I figured it was the single ended "magic" I liked so much.
This winter I finally built a good PP amp, and it is every bit as good as the single ended.. If not better at times. (I suppose there are tradeoff's). Don't be afraid of PP

[Vinylsavor]

Hi!

Originally Posted by jcmusic

Right now I am using an SET amp with a 45 tube and 106db speakers... Sometime I just wish for 1-2 more wpc and thought the PP might be the answer, comments???

Assuming your 45 SET amp has 1.5-2W, 1 or 2 more Watts will achieve a mere 2-3dB in terms of sound level. That is not much. In order to make a noticeable difference you'd need at least 4 times the power.

What is the effect which you are hearing which makes you think you need more power? Sometimes the need for a better damping factor is confused with the need for more power.

If your output transformer can handle more current, your amp could probably be converted to 2A3 which would deliver double the power. I make all my 45 amps switchable between 45 and 2A3. But pretty much all the users of my 45/2A3 amps only use 45s, as I am doing myself

best regards

Thokas

[jcmusic]

Originally Posted by Vinylsavor

Hi!



Assuming your 45 SET amp has 1.5-2W, 1 or 2 more Watts will achieve a mere 2-3dB in terms of sound level. That is not much. In order to make a noticeable difference you'd need at least 4 times the power.

What is the effect which you are hearing which makes you think you need more power? Sometimes the need for a better damping factor is confused with the need for more power.

If your output transformer can handle more current, your amp could probably be converted to 2A3 which would deliver double the power. I make all my 45 amps switchable between 45 and 2A3. But pretty much all the users of my 45/2A3 amps only use 45s, as I am doing myself

best regards

Thokas

Ok brother thanks for the info and tips, I am not hearing anything that tells me I need more power. My backup amp is a PP using 6L6 tubes at 25 wpc and it just seems to have so much authority that I thought if my 45 just had a little more power, well you get it...

[Vincent77]

Originally Posted by Vinylsavor

...only use 45s, as I am doing myself

Hi Thomas,

Can you please tell me what kind of speakers you drive with your 45 SE amps? What would be the minimum sensitivity you recommend?

Thanks.