2. amps-preamps
  3. 166357-136265

PP amp + High sensivity speakers dilemma

So here's the situation.
Recent experience with high sens (91 and 94) single driver speaker has  won me over from the low (87db) speaker design. 
Seems the SET is  the ideal match for high sensitivity ~~FR~~ driver.

I recently made upgrades to the Defy7 and am not willing to part with the amp and take a loss. At least not yet, until i recover from my $1800 loss upgrading the 87db speakers which are sitting in a  corner right now.
Was thinking just now, 
what if we swap out the 12 KT88's for a  dozen EL34's, 
The 34's come in at a  much lower watt output 25, vs the 88's 40 watts.
This  might allow a  bit more flexibility on using more gain on the linestage vol knob. 
Also what if we bias the EL34's a  bit lower than specs. This might also lower watt output thus giving a  tad more ability to use more gain on the linestage volume knob.
Right now i only use 9oclock vol on the DLP linestage, both with the Seas Thors 87 db and also with the 91 6.5 FR which I am using now, 
Tonight i will pick upa  pair of Sony cabinets off CL and install the 94db FR 8 inch.

Its definetly more sens vs the 91db, speaker, so maybe even at the low 9 oclock gain it may come a  bit too forward for my preference.
I listen to low/mid volume, as I use music more as a backdrop while reading. 
In some years after i recover from all the mods/tweaks i;'ve made in my system past year, i will purchase a  LM 845 amplifer.
I have intentions adding a  new high sens driver which will  be  rated 98db. 
Now here is where there may be issues with the 100 watt PP amplifier. 
Perhaps Richard Gray may install a  Italian 47 step attenuator which will provide more volume control on the Jadis DPL linestage. = Can use a  high vol gain.
My 88's have about 1500 hrs, so its getting close to buy new power tubes.
Bottom Q is
EL34/biased a  bit low + 97 db sens speaker,, maybe i can just squeeze by  with this lopsided matching,  for some years, til i can get cash for a  845 SET. 
Doable?
All ideas welcomed. 


mozartfan
georgehifi's avatar
georgehifi
10,312 posts
 
mozartfan OP

Great amp, this is what Stereophile said about the DF7, you don’t need any preamp that has even more gain with it.

The high input sensitivity is ideal for passive preamp control, while the input impedance is >100k ohms. Input sensitivity: only 950mV in for maximum output.


Was thinking just now,
what if we swap out the 12 KT88’s for a dozen EL34’s,
The 34’s come in at a much lower watt output 25, vs the 88’s 40 watts.

And no gain will remain the same


Cheers George
mozartfan OP
2,143 posts
 
davidLouis 4 incher just arrived. 
Screwed it into my 12x12x12 DIY cabinet and  the verdict is in, running it no cap, open to the massive 100 watt Defy
Verdict is
~~WINNER~~
Dos thumbs up.
Bass check
mids check
highs, not bad, some roll off.

But for under $200, its a  winner.
FOUR inches.
Tempting to go with the DL 8 FR, but alas, I have my wife financing the Voxativ AC1A's. \
all I got to do is a bunch of house chors  rest of the year, clean toliets and such. 
The things we will do  for  a  stereo system 
;--))
mozartfan OP
2,143 posts
 
Well now, Just added the Magnovox 1963 tweeter horn witha 2.2uf Mundorf Silver OIl Supreme cap,
Super nice. far superior to the upper range comming out the davidlouis 4 incher.
I havea Jensen midrange horn 1960’s comming next week, rare horn, I know it will completely annihilate the DL 4 inch FR mids.
For $200 I’d say the DL 4 inch FR is a good deal. Most likely beats mids comming out of most xover box speakers including the one that sells for $360,000
But can’t beat the old american engineering from the 1960’s in horns.
My Frankenstein is comming out nice
Seas W18 + DL 4 inch FR + Magnovox tweeter horn(2.2 Mundorf Silver Supreme oil cap). = not bad, , far superior to the Millennium tweet.
atmasphere's avatar
atmasphere
11,909 posts
 
Just added the Magnovox 1963 tweeter horn witha 2.2uf Mundorf Silver OIl Supreme cap,
Super nice. far superior to the upper range comming out the davidlouis 4 incher.
I havea Jensen midrange horn 1960’s comming next week, rare horn, I know it will completely annihilate the DL 4 inch FR mids.
Tip of the iceberg! Horns have improved a lot since the 1960s.
gochurchgo
923 posts
 
@russ69  is right. I'm running 110wpc into 99db with a tubed preamp and its gained to hell and back. I tried the 12db (harrison) and it eliminated ALL hiss and what not. I just got some 6db I will swap in. Easy and doesn't detract from the sound (to my ears anyway)
More to discover