Dennis Had Inspire Amps

[Comzee]

->FloridaBoy - Comzee, if you are going to keep your amp consider a pre from Dennis. It will make a difference.

Maybe.. I've been around the block, I used to own a $10k stax 009 system (countless various other gear), been to plenty of meets in my time.
Thing is, I love passive preamps, never had an active give me more detail, always less.

I've tried a few actives in my current fire-bottle / Omega system as well.

Idk, one of those ymmv things

[FloridaBoy]

Originally Posted by Comzee

->FloridaBoy - Comzee, if you are going to keep your amp consider a pre from Dennis. It will make a difference.

Maybe.. I've been around the block, I used to own a $10k stax 009 system (countless various other gear), been to plenty of meets in my time.
Thing is, I love passive preamps, never had an active give me more detail, always less.

I've tried a few actives in my current fire-bottle / Omega system as well.

Idk, one of those ymmv things

I hear ya. I've been around the block too and 5 years ago decided to simplify my gear. I sent Dennis an e-mail and requested an amp. He replied with 'you gotta get the amp I'm finishing up now'. I said fine. Got the amp. Then about a week later an e-mail from Dennis about the LP27a. What an enabler. I bought one and am no longer thinking about tube gear.
I was using another pre but the LP27A was much better.

I tried passives in the past but I prefer actives. Yup, YMMV as always.

[Bombadil]

I like passive preamps too, have used them for many years in many systems. Great detail.

That said, my passive does not work well with either of my Inspire amps. Not enough gain, the Inspires are less sensitive than any amp I've ever owned. Even my active tube preamps require me to turn the volume knob up to higher settings than I've ever done before. Like all the way up to 1 o'clock and beyond. Still makes me nervous to do that.

[Comzee]

Originally Posted by Bombadil

That said, my passive does not work well with either of my Inspire amps. Not enough gain, the Inspires are less sensitive than any amp I've ever owned.

Interesting. Dennis gave me the option of 1.0 or 1.5 volt input sensitivity.
I picked 1.5v because my Schiit Yggdrasil DAC output 2.0v from SE.

In theory that means I have 0.5v headroom?

[Musica Amantem]

Originally Posted by Comzee

Interesting. Dennis gave me the option of 1.0 or 1.5 volt input sensitivity.
I picked 1.5v because my Schiit Yggdrasil DAC output 2.0v from SE.

In theory that means I have 0.5v headroom?

I believe (I have the Yggdrasil also) you need 1.5 volts from your DAC to set the amp at max power (assuming no Pre in the line path). This only means the volume dial in the amp or the Pre's (depending on which one is in use) won't make any difference in the amp after reaching the 1.5 volt setting (about 3/4 of the amp's volume dial turn, assuming the distribution is linear). There are no headroom implications, only a more flexible (more intermediate volume options) control by the amp's volume dial or the Pre's.

With a 1 Volt sensitivity on the amp, the amp's volume dial would only be able to work in the first half of its range, as the amp would be already at max power at that point (assuming a linear distribution again), allowing less intermediate settings. If the amp's sensitivity were 2 Volts, you could use the entire volume dial range before reaching max power in the amp, and so on ...

I have a DACT passive volume step attenuator installed in the Inspire so I can operate the amp directly connected to the DAC (Yggdrasil). I also bypass this control by setting it at max when using the Preamp.

Another option I use is the ZBit, between the Yggy and the Inspire amp, using the balanced output from the DAC and controlling the volume with the DACT on the amp with the ZBit's dial at max or close to it (all 4 Volts of the balanced Yggy's output)).

BTW, the Yggy is the best thing I've ever heard in DACs ... It still amazes me!

[FloridaBoy]

Originally Posted by Bombadil

I like passive preamps too, have used them for many years in many systems. Great detail.

That said, my passive does not work well with either of my Inspire amps. Not enough gain, the Inspires are less sensitive than any amp I've ever owned. Even my active tube preamps require me to turn the volume knob up to higher settings than I've ever done before. Like all the way up to 1 o'clock and beyond. Still makes me nervous to do that.

My volume setting are pretty normal 9-9:30 is decent and 12:00 is too much.

Amp & pre matching can be a bear.

[Musica Amantem]

Originally Posted by FloridaBoy

My volume setting are pretty normal 9-9:30 is decent and 12:00 is too much.

Amp & pre matching can be a bear.

According to Dennis, the amp should be maxed out while the volume can be controlled by the Pre's volume dial.

[FloridaBoy]

Originally Posted by Musica Amantem

According to Dennis, the amp should be maxed out while the volume can be controlled by the Pre's volume dial.

I don't have a volume control on my amp. The matching issue is from gain in the units. High gain amp with high gain pre equal hair trigger volume control. Been there done that. In Comzee's case it appears that he does not have enough gain. Low gain amp with low gain passive.

[FloridaBoy]

I believe (I have the Yggdrasil also) you need 1.5 volts from your DAC to set the amp at max power (assuming no Pre in the line path). This only means the volume dial in the amp or the Pre's (depending on which one is in use) won't make any difference in the amp after reaching the 1.5 volt setting (about 3/4 of the amp's volume dial turn, assuming the distribution is linear). There are no headroom implications, only a more flexible (more intermediate volume options) control by the amp's volume dial or the Pre's.

With a 1 Volt sensitivity on the amp, the amp's volume dial would only be able to work in the first half of its range, as the amp would be already at max power at that point (assuming a linear distribution again), allowing less intermediate settings. If the amp's sensitivity were 2 Volts, you could use the entire volume dial range before reaching max power in the amp, and so on ...

Can the sensitivity of the amp be changed easily?

[Musica Amantem]

Originally Posted by FloridaBoy

I don't have a volume control on my amp. The matching issue is from gain in the units. High gain amp with high gain pre equal hair trigger volume control. Been there done that. In Comzee's case it appears that he does not have enough gain. Low gain amp with low gain passive.

No volume dial in the amp equals Maxed Out volume in the amp. I was addressing the op's wrong impression of having 0.5 volts of headroom with an amp input sensitivity of 1.5 volts while using a DAC with SE output voltage set at 2.0 volts.