single ended vs. push/pull

[mrclassicman]

No shortage for personal choices

I would still be Single Ended Triode had it not been for hearing a great Push Pull amp made by one of our members. Since then I have built two P-Ps, both different and both wonderful. Now can you go wrong! No way ! Either will fulfill your musical needs. In some cases one may perform better for you than an other, but you will have to be out there refining you requirements and training your ears to make this choice. I strongly advocate maintaining an open mind. You will hear more.


Terry

 

[jcmjrt]

I have both and use both. 45SET has a magical airiness that sucks me in...but it won't kick like a good PP amp and I do like to rock occasionally. I've wondered if some of the great characteristics of an SET is due to it having fewer parts which most people choose to make high quality. A PP amp built with the same quality of parts as most SETs....that's what I'm going for next. Maintain the kick and gain some of that gorgeous presence..... part of the fun is in the discovery too...

Pak, it sounds like you are going with some ultimate iron! 400lbs!! Man, I'd love to see/hear that.

 

[Tact]

I have EL84 PP amp, but wired in triode mode. so I don't know how to call this?

 

[Redboy]

Pak, it sounds like you are going with some ultimate iron! 400lbs!! Man, I'd love to see/hear that.

Me too! Can you fire up some pictures of the beast so far? :scratch2:

 

[PakProtector]

Me too! Can you fire up some pictures of the beast so far? :scratch2:

Hey-Hey!!!,
I don't remember if I've posted the latest, most of the work I've been doing on it has been concentrated on the little stuff. Either way, I'll shoot some new ones and put them up.

Cheers,
Douglas

 

[PakProtector]

I have EL84 PP amp, but wired in triode mode. so I don't know how to call this?

Hey-Hey!!!,
The configuration of the power tubes just makes it a PP triode amp. It could be a PP pentode or PP U-L... If the tubes don't ever stop conducting during a cycle, it's a Class A. It depends on how long one gets cut off to fall into AB or B. There are good reasons to build Class A, especially if you can live with the lower power output compared to what *COULD* be had with AB.

As an aside, the commercial pentode and U-L amps that gave PP amps such a bad rep when SET started catching on were all high NFB, AB biased amps.
cheers,
Douglas

 

[MikE]

Single-ended Triode

I have both and use both. 45SET has a magical airiness that sucks me in...but it won't kick like a good PP amp and I do like to rock occasionally. I've wondered if some of the great characteristics of an SET is due to it having fewer parts which most people choose to make high quality. A PP amp built with the same quality of parts as most SETs....that's what I'm going for next. Maintain the kick and gain some of that gorgeous presence..... part of the fun is in the discovery too...

Pak, it sounds like you are going with some ultimate iron! 400lbs!! Man, I'd love to see/hear that.

I thought Billfort and myself were the only two running 45 amp's on AK. What amp do you have? Bill has a custom 45 amp he built and mine is a modified Moth s45.

MikE

 

[jcmjrt]

I don't guess that there are too many of us running that tube. Mine are Welborne DRD 45s that I built. The amps are excellent quality but I wouldn't recommend them to anyone because the business has some serious issues.
The only other 45 amp that I've heard was a friend's Japanese sourced integrated. That's the one that made we want a 45.

 

[PakProtector]

I've wondered if some of the great characteristics of an SET is due to it having fewer parts which most people choose to make high quality. A PP amp built with the same quality of parts as most SETs....that's what I'm going for next. Maintain the kick and gain some of that gorgeous presence..... part of the fun is in the discovery too...

Pak, it sounds like you are going with some ultimate iron! 400lbs!! Man, I'd love to see/hear that.

There are a few differences to look at.

First is output Z. A SE amp is going to vary its output Z as the plate swings up and down in voltage. At max voltage and minimum current the output Z will be highest. It will be at minimum when the grid swings to zero (wrt the cathode ) at maximum current. A PP amp operating Class A and no NFB has a near constant output Z across a signal's voltgae excursion.

The second would be the OPT core. AFIK all SE are gapped to deal with idle DC. This gap delivers an average permeability between the gap and the iron that is a whole lot better behaved than a stack of iron with a minimum intentioinal gap. A secondary effect would be the core is already DC biased and it never swings through zero flux density. PP iron can be gapped too, and for largely the same reasons( that is intentionally creating something other than a minimum possible gap ).

Mark mentioned the harmonic spectrum. A SE amp is going to have more even than odd HD. Ideally a PP amp cancells the even, and it is easier to hear( and dislike ) the remaining odd HD. Now a good amp isn't going to be making much of either as long as it is big enough to stay away from redline. Both PP ans SE can get very unpleasant when that point is reached.

An amp's design will determine a lot of the overload behaviour. Some overload is just intolerable and some can be well hidden. That is where a lot of the fun lies, figuring out how to build an amp that suits your own listening style and system. There are lots ov blanket statements grown out of the SE v. PP discussion and I've found most of them don't apply to well designed amps of either topology.
cheers,
Douglas

 

[Chrisssssssss]

I think my Philips AG9016 is a SET???

I am really not sure what my amp is, but the only thing I know is that it is my favorite. It has a pair of 12AX7's (ECC83's) on the input side and EL95's on the output.

There are a pair of output xformers, so I am not sure what this one classify's as, but I think it is a SET.

2W x 2W of pure bliss. Mullard's on the input and a pair of Westinghouse on the outputs (for now...)

 

[PakProtector]

I am really not sure what my amp is, but the only thing I know is that it is my favorite. It has a pair of 12AX7's (ECC83's) on the input side and EL95's on the output.

There are a pair of output xformers, so I am not sure what this one classify's as, but I think it is a SET.

2W x 2W of pure bliss. Mullard's on the input and a pair of Westinghouse on the outputs (for now...)

If it is 2W from an EL95, I suspect that the output is a pentode. Still going to share a lot of the characteristics with a triode output, and dodge a few of the triode disadvantages.
cheers,
Douglas

 

[dagg39]

AG-9016 is SET

I am really not sure what my amp is, but the only thing I know is that it is my favorite. It has a pair of 12AX7's (ECC83's) on the input side and EL95's on the output.

There are a pair of output xformers, so I am not sure what this one classify's as, but I think it is a SET.

2W x 2W of pure bliss. Mullard's on the input and a pair of Westinghouse on the outputs (for now...)

The EL-95 works in class A, Single End.
http://www.tube-classics.de/TC/GermanTubeHifi/Integamps/Philips 9016/AG9016.htm