SE amp question

[gjo]

Could any of you tube gurus out there enlighten me on the pros and cons of an EL -34/KT 66/6L6 based amp(possibly http://home.att.net/~chimeraone/aceschem.html) vs a 300B amp ( one th the JE Labs designs)? I have an EL 34 based pp amp and am looking at various options, all giving about 8 watts Class A output.

I use two sets of speakers for music, one is 95dB MTM and another a two way 87dB. I use a 12 inch powered sub for LF sound. My listening room is about 14 X 14 ft, and I listen at low to moderate levels, mostly folk, jazz and female vocals.

Does one go the pp way or the SE way?

Thanks for any input.

George

 

[Brett]

Could any of you tube gurus out there enlighten me on the pros and cons of an EL -34/KT 66/6L6 based amp(possibly http://home.att.net/~chimeraone/aceschem.html) vs a 300B amp ( one th the JE Labs designs)? I have an EL 34 based pp amp and am looking at various options, all giving about 8 watts Class A output.

I use two sets of speakers for music, one is 95dB MTM and another a two way 87dB. I use a 12 inch powered sub for LF sound. My listening room is about 14 X 14 ft, and I listen at low to moderate levels, mostly folk, jazz and female vocals.

Does one go the pp way or the SE way?

Thanks for any input.

George

It depends on what you're looking for in terms of presentation. All amps and amp/speaker interfaces are a compromise, so the best listening happiness comes from picking the sonic compromise that suits your favourite music, other gear, room, SPL's etc etc.

For me, PP done right is much clearer and truer to the source. However, from my recent experiments with SE (mainly parafeed, so I can use my PP OPTs) I understand more clearly why people like them. I'm also not that anal about 'absolute dogged determination to get the truest rendition of the source'; life's too short. Is it fun to listen to?

Personally, I would build a PP1C (PSU) as it's simple, cheap and very good sounding, unless you want to mess with things like a PP 2A3 which can take a bit more effort.

 

[EC8010]

As Brett says, it's all about personal preferences. I prefer PP to SE but I rather suspect that SE might be better for you. The strengths of SE are in the midrange, and your musical preferences suggest that SE could cater for them nicely. One weakness of SE is bass, but if you use a powered sub, you have that covered. Beware that SE relies far more on good construction technique than PP and is ultimately likely to be more expensive and heavier per audio Watt.

 

[SHiFTY]

I would also add that a good SET amp requires very good output transformers. Because a SET amp generally has no negative feedback, the open loop response of the output trannys must be very good otherwise it will roll off the ends of the audio frequency spectrum.

You would probably get more benefits from improving your EL34 PP.

 

[gjo]

Thanks for the input.

At this time my Welborne Labs V.35 pp ( which I bought as a kit from them a few years ago) uses Magnequest output trannies. I upgraded some Caddock resistors and Multicaps according to the mfrs recommendation last year. The tubes are EL 34 Svetlana Winged C, and the overall performance is quite pleasing. I dont know of any other upgrade at this time for this amp.

The preamp is the Grounded Grid from Transcendent Sound, and I'm very happy with it. Re the iron, I would have gone for either Magnequest or Lundhal for the output trannies,and a locally source mains trafo, for 220V 50 Hz power.

Not having heard either SE or OTL sound so far, my question was more from the view point of"What do I do next"?, I guess... I am not too keen on anything that requires a heck of a lot of effort and investment, at this part of my life!

 

[Brett]

Not having heard either SE or OTL sound so far, my question was more from the view point of"What do I do next"?, I guess... I am not too keen on anything that requires a heck of a lot of effort and investment, at this part of my life!

I'd suggest experimenting with what you have. Your OPT's are good (I have a set of Magnequest B21's) and your PS iron should be in the right range for a lot of topologies. Can you remove the transformers from your current amp relatively easily? If so, then get a piece of scrap plywood, mount the iron and some sockets, and try some other circuits. Costs you a few dollars for passives and a bit of hardware. If you like the result, build a new amp chassis; if you don't, then restore the original amp and be richer for the experince and the (hopefully) fun.

You could also try parafeed SE if you can get some chokes, or alternatively use a CCS (PS permitting).

Whilst experimenting, use a cheap SS amp, so at least you still have some sound, and you're not as pressured to get it finished.