Do I need to upgrade my output transformers?

[mchrismag]

Hey, guys. Some advice/opinions needed here. I am currently running some edcor gxse 15-8-5 output transformers. All of the speakers I currently own are small monitor speakers. Right now I have small Fostex fe103en speakers running with my sse and for low volume and late night listening I really like them. After a few months break in I decided to crank 'em up a bit and see what they can do. I heard some distortion in the bass at higher levels and thought maybe it's the speakers. I had my amp wired in triode with no feedback. Didn't think I needed it with my speakers limited bass response. Well, I decided to try cathode feedback with them just to see what would happen. No more distortion in the bass. When I push the amp too hard it just starts to compress the sound but no fuzz type distortion in the bass. I noticed the same thing with my rca speakers which have more bass but still have small woofers (5") I plan on building some larger speakers, probably one of the pi speakers which have much larger woofers and deeper bass response. I could just wire my amp with cathode feedback but here's the problem...I think it sounds better without any feedback except for the fuzzy bass at higher volume. I can't quite describe what I am hearing but it just sounds better to me. I'd like to run it in triode with no feedback with the new speakers but I am thinking the bass will sound distorted this way. So after a long winded explanation (sorry) would I be better off getting some better transfomers before I build the speakers? Or maybe an output tube change would help? Or maybe the pi speakers would sound better with feedback no matter what transformers I have?

 

[mchrismag]

I should add, running jj el34s.

 

[chrisb]

Well, maybe specify how high you cranked them up - SPL meter or smart phone app should be close enough for this purpose. Depending on the speaker enclosure design, you can't except much in the way of LF extension from the FE103s at anything above 90dB and below, maybe 80HZ

I doubt upgrading the OPT or any component further upstream than the amp won't eliminate the driver's limitations.

 

[zman01]

What power transformer are you using in your SSE build and what is your mains line voltage?

 

[Sodacose]

I still have a pair of GXSE15's on my SSE with KT88s and it sees regular service with a pair of Super Pensils. No bass distortion that I've ever noticed (and I do occasionally crank it).

I have a pair of FE103s as well and I haven't noticed any distortion in the bass, but I also don't crank those much (they're in a small room). I think any distortion you hear is more likely related to the little Fostexs than your output transformers.

 

[sreten]

Hi have a look at this article :

Easy-to-build SE amplifier ⋆ Lundahl Transformers

The OPT configuration is novel, and feedback variable.

rgds, sreten.

 

[Evenharmonics]

Take care of 2 weak links before doing anything else to other electronics. Those 2 are speakers and room acoustics.

 

[mchrismag]

What power transformer are you using in your SSE build and what is your mains line voltage?

Allied 6K7VG. Last time I measured 122 volts.

 

[mchrismag]

Thanks guys. Most likely I was just pushing the speakers and or amp too hard. I didn't think a SET amp would hard clip. Probably the speakers distorting.

 

[Evenharmonics]

I use active tri-amp. TSE for upper frequency, solid state push-pull amp (very common) for mid-bass and subwoofer for below 80Hz.

My TSE powers high-efficiency drivers (for upper frequency) and work well. Perhaps you need more efficient speakers.

 

[colnago55]

Have you tried the amp in UL mode? As I understand it, it should give you more power.

 

[mchrismag]

Just a little update to this thread. I am going to leave my output transformers alone. I really like the midrange with the sse and the fe103en. I have 4 dynaudio 17w75s currently just sitting around. My Dad is going to give me his Bryston 3b. So I am going to try using the sse on the fostex for mids and treble and the 3b on the dynaudios for the bass. I'm going to buy an inexpensive active crossover to experiment with this combination and then maybe get a better one later if I really like it.

 

[Lee from Chitown]

I'm a noob. And I have been lurking reading the threads.
I just ordered my SSE board.
I am planning on using the same tubes, EL34s, and transformer choices as mchrismag- Allied pt and Edcor GXSE opts.
I have a new set of Klipsch r26f (97dB) speakers I will be using.
I just wanting to make sure I won't be short on power for good bass, or should I get the Edcor CXSEs?



(All other parts on build list are appropriate?)