Just pad down your pre-amp interconnects with an coaxial attenuator.
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.
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.
- ...
- 10 posts total
Just pad down your pre-amp interconnects with an coaxial attenuator.
~~~~~~~~~ I'll let Ricahrd know of this possibility, Just got word froma Vox dealer, says his audio showrooms does employ some PP amplification on the Vox derivers with no issues. Right now i am running a 94 db 8 wide band, and can hear how a 845 tube has less interference vs my 12 tube PP amplifer. The better PP Jadis amp for the job would have been a JA30 monos with only a pair of 88's on each block. Here is where the EL34 will come in nice. I am almost sure the 12 EL34's will work superior to these KT88's ina high sens speaker. + I can get 12 EL34's EH's for like under $300. = beats the $500 for the KT88 price. Ok for that Italian made 46 step attenuator, allowing more flexibility for vol gain control. I think this is the lab Richard Recommends Acoustic Dimension, made in Italy http://www.acoustic-dimension.com/ So adding the EL34's, possibly toning down the wattage output New 41 step attenuator = possibly giving the DPL linestage a better control on gain. Trying to work in the massive Defy's power to the high sens single driver. |
I would just use the amp as is, and just operate the volume control over the lower end of its range; the only possible problem is poor left-right channel balance tracking over the lower range of the attenuator. Otherwise, the idea given above, for using an in-line attenuator is also a simple fix (downside is adding another thing in the signal path). As to using lower output or lower gain tubes, I would only do this if I also liked the particular sound of the alternative tube. I happen to prefer the sound of some lower output tubes than the KT88, but, that is a personal preference. If your amp can accept alternative tubes, or your tech can modify the amp to accept such tubes, you could try the EL34's you mentioned or my preferred tubes which are KT66's or 6L6's. In my own system, I run a pushpull amp that has Western Electric 349 output tubes. My amp runs four 349's and outputs 5.5 watts. It is an amp that I actually prefer over my parallel SET amp (Audio Note Kageki) which outputs a little more power. Both are excellent amps for high efficiency speakers and I do not necessarily think one type is better than another. You might also consider output transformerless tube amps that can also deliver fantastic sound. |
- 10 posts total