poweramp Amp suggestion low power.

[camross]

I am after amp suggestions to run my Troels Gravesen DTQWT mkQlll . http://www.troelsgravesen.dk/DTQWT-mkIII.htm. 
These are listed at 94db and 4ohm so power should not be an issue. I am thinking solid state with a budget somewhere around 5 - 8k. I am presently running chord cutest to PrimaLuna Prologue pre and Cawsey 15 class mono blocks. I have also had a PrimaLuna Prologue power amp in the setup. 

 

- General listing volume around 70db 

- Room size 6m x 10m 
 

Cameron 

 

 

 

 

 

[andyr]

1 hour ago, camross said:

I am after amp suggestions to run my Troels Gravesen DTQWT mkQlll . http://www.troelsgravesen.dk/DTQWT-mkIII.htm. 
These are listed at 94db and 4ohm so power should not be an issue. I am thinking solid state with a budget somewhere around 5 - 8k.

 

What power do you call "low power", Cameron?

 

The fact they are 4 ohm means the amp needs to have a serious power supply.

 

I would think Hugh Dean could provide a NAKSA 80 (modified to drive 4 ohms well) for around $2k.  This is nominally about 65w into 8 ohms ... rather than the 80w the stock NAKSA 80 delivers (into 8 ohms).

 

As you're in Melbourne, with the 5k radius lifted, you might be able to audition one from Hugh.  If Richmond is closer, I could lend you one of my NAKSA 80s that's quite happy driving my 2 ohm ribbons.

 

Quote

 

I am presently running chord cutest to PrimaLuna Prologue pre and Cawsey 15 class mono blocks.

 

 

Do you mean 15w & Class A?  If so ... why do you want to change?

 

Andy

 

Edited October 25, 2020 by andyr

[camross]

12 hours ago, andyr said:

Do you mean 15w & Class A?  If so ... why do you want to change?

Hi Andy.

 

Yes I am running Class A 15 watt. A using the two different amps for some time now I feel they both have strengths and weaknesses. I keen to try something that may be better. As far as low power I guess anything under 100 watts, I just didn't want recommendations for 400w Mono block beasts.

 

I was thinking something like the below or a First Watt.

 

 

[camross]

I am still learning about the different power requirements in relation to sensitivity and Ohms. But reading around it looks like the Pass Labs XA 25 would be a good fit.

 

https://www.passlabs.com/products/xa25/

[blakey72]

What is it about the sound that you want to change? What do your current amps sound like? What are you wanting from the new ones? Do you want the sound brighter/faster/warmer/more detailed etc. Do you really want mono blocks or is a stereo power unit ok?

[TDX]

The fact that’s it’s 4ohm I think you better have a big amp with enough current to drive it. 

[cafe67]

One of the line magnetic valve amps - the 805 or the 845 ?,

[Ooogh]

On 27/10/2020 at 2:43 PM, camross said:

I am still learning about the different power requirements in relation to sensitivity and Ohms. But reading around it looks like the Pass Labs XA 25 would be a good fit.

 

https://www.passlabs.com/products/xa25/

Having lived with an XA 30.5 all I can say is I think they are fantastic amplifiers. Word on the street seems to be the 25 is better again.

 

Rich and full, sweet but detailed, magnificent bass, nuanced , tonally complex, brilliant. I needed more power but I would be shocked if the 25 doesn’t have plenty on tap to drive your speakers. If a 30.5 shows up second hand I would jump on it. Never missed a beat, great build quality. You might get the idea I like ‘em.

 

Otherwise Audion Silver Night PSE, holographic, fast , wonderful. 18 Watts works where 8 fails.

[andyr]

17 minutes ago, Ooogh said:

 

Otherwise Audion Silver Night PSE, holographic, fast , wonderful. 18 Watts works where 8 fails.

 

 

18w, eh ... providing your spkrs are easy to drive.  

 

Andy

 

[Ooogh]

16 minutes ago, andyr said:

 

18w, eh ... providing your spkrs are easy to drive.  

 

Andy

 

Hi Andy,

 

94 dB 4 Ohm load.  It depends on how reactive the speakers are, if it is a fairly consistent load I can see no reason why they wouldn’t work via the 4 Ohm tap. I have heard them drive a plethora of speakers, they deal with NS100’s easily.

 

Cheers,

Hugh

[xlr8or]

Sharing my 2 cents worth as well. Get yourself a low-powered valve amp that has an 8 ohm tap and also get yourself a pair of speltz autoformers. With the autoformers set your speakers to the 2x setting so the load on the OPTs see nominal 8 ohm rather than 4 ohm. You will be hard pressed to find low-powered Class A SET valve amps with 4 ohm taps.

Edited October 28, 2020 by xlr8or

[camross]

On 27/10/2020 at 4:16 PM, blakey72 said:

What is it about the sound that you want to change? What do your current amps sound like? What are you wanting from the new ones? Do you want the sound brighter/faster/warmer/more detailed etc. Do you really want mono blocks or is a stereo power unit ok?

 

I just found that both Amplifiers had different strengths and that I may be able to get the best of both in a different amplifier. My heart says warmer and my head says more detailed.

 

I am not fussed on if they are mono blocks of a Stereo amplifier.

[camross]

On 28/10/2020 at 8:37 PM, Ooogh said:

Having lived with an XA 30.5 all I can say is I think they are fantastic amplifiers. Word on the street seems to be the 25 is better again.

 

Rich and full, sweet but detailed, magnificent bass, nuanced , tonally complex, brilliant. I needed more power but I would be shocked if the 25 doesn’t have plenty on tap to drive your speakers. If a 30.5 shows up second hand I would jump on it. Never missed a beat, great build quality. You might get the idea I like ‘em.

 

Otherwise Audion Silver Night PSE, holographic, fast , wonderful. 18 Watts works where 8 fails.

 

Sounds like the XA 25 is a little better than the 30.5. Depends on what you read , some seem to suggest it is a little cold and over detailed. I am going to try and get out and listen to one this week. Unlikely one will turn up second hand though.

[camross]

On 28/10/2020 at 11:54 PM, xlr8or said:

Sharing my 2 cents worth as well. Get yourself a low-powered valve amp that has an 8 ohm tap and also get yourself a pair of speltz autoformers. With the autoformers set your speakers to the 2x setting so the load on the OPTs see nominal 8 ohm rather than 4 ohm. You will be hard pressed to find low-powered Class A SET valve amps with 4 ohm taps.

Edited Thursday at 12:04 AM by xlr8or

 At this stage I am trying to stay away from a Valve amp but this may change down the track.

[camross]

New there are quite a few options around but not sure any of them will be better than what I have. I would rather buy second hand.

 

Jeff Rowland 525

Moon Neo 330a

Plinius P10

Plinius SA-103

Pass Labs XA 25

Sudgen FPA-4

 

[Smp]

RrFirst Watt F7 and First Watt SIT - 3, also made by Pass Labs. Both will drive your speakers without breaking a sweat. Hardest choice will be between them and the XA 25.

 

With 70 dB listening levels you could probably include the First Watt J2 as well.

Edited November 29, 2020 by Smp

[Eggmeister]

Would Garry Cawsey be able to "tweak" what you have  ?

[MattyW]

My choice would be between one of High Dean (Aspen Amplifiers) or a Pass Labs amp. 

[camross]

1 hour ago, Eggmeister said:

Would Garry Cawsey be able to "tweak" what you have  ?

Yes I am looking at one of his newer amps as well. I recently swapped out RCA cables to one of Garry’s better cables. This made a huge difference far more detail and the sound stage increased greatly.  

[camross]

1 hour ago, MattyW said:

My choice would be between one of High Dean (Aspen Amplifiers) or a Pass Labs amp. 

I will look into Aspen amps I definitely like the idea of First watt or Pass labs. 

[camross]

OK so I finally picked up The Pass Labs XA 25 I am absolutely loving it. Sound getting better as it burns in I have around 25 hours on it at the moment. Amazing detail and tone the bass seems to be getting better after every listening session, tighter deeper and less flabby. I am noticing low bass rhythms  that I have never heard before. It may be the lack of any distortion but I seem to be playing louder to get the fullness in the mid range. It is so open and airy  that I am getting no complaints from my partner that I would usually get playing at these levels.

 

Waiting far a few more weeks then I will start playing with the different chords I have to see what improvements I cam make.

[Colonel Sanders]

On 27/10/2020 at 12:13 PM, camross said:

I am still learning about the different power requirements in relation to sensitivity and Ohms. But reading around it looks like the Pass Labs XA 25 would be a good fit.

 

https://www.passlabs.com/products/xa25/

 

I have the Pass Labs INT-25 and it’s an amazing amp. I used 300B or 2A3PP monoblocks and this amp have replaced these without myself missing the tube sound.

 

The INT-25 is actually a XA-25 with a minimalist preamp section. 

 

I haven’t been impressed this much by an amp since the Tenor Audio 15W OTL in the early 2000.

Edited June 18, 2021 by Colonel Sanders

[stereo coffee]

On 27/10/2020 at 5:13 PM, camross said:

I am still learning about the different power requirements in relation to sensitivity and Ohms. But reading around it looks like the Pass Labs XA 25 would be a good fit.

 

https://www.passlabs.com/products/xa25/

A very wise move, learning about sensitivity and ohms. I have provided some insight into it in the thread attached . In a nutshell  consumer line level which CD manufacturers and streaming services abide by see's 0.316V RMS as the upper limit of output at such sources. Peak level can be up to 0.894V

https://en.wikipedia.org/wiki/Line_level

 

This does not stop some manufacturers of some naughty  DAC's providing ability to select more gain, but for general CD players playing commercial CD's and streaming services,  they all abide by consumer line level.  

 

Since most good power amp manufacturers quote sensitivity also in v RMS and if you wisely choose not to add reactance from gain devices, and use passive resistance attenuation,  All you  need to do is to match the same consumer line level sensitivity to be also close to the power amp sensitivity. 

The Quad 306 being a great example as sensitivity of 0.375mv

 

As for ohms of loudspeakers as loads with power amps , a 4 ohm rated speaker uses more current than a 8 ohm, a good solid state amplifier will nearly double its available output power when driving 4 ohms vs 8 ohms.  Valve amps are the opposite, and are better suited with power delivery to high impedance speakers.  http://education.lenardaudio.com/en/14_valve_amps_7.html

 

The depressing side of this is that power amp manufacturers rarely test their amplifiers with actual loudspeakers, rather use a resistor dummy load rated for wattage higher than the amplifiers power.  A guide is to review the specifications of each resistance load. A loudspeaker though is quite different as it has reactance and back EMF that can upset some amplifiers stability. A circuit called a zobel placed at the amplifier output  helps the amplifier drive the cable, but not the speaker itself, but  another Zobel can assist at the speaker end.  https://www.ka-electronics.com/images/pdf/Cyril_Bateman/Bateman_Speaker_Amp_Interaction.pdf

 

Hope that helps you.      

 

 

[Ihearmusic]

On 28/10/2020 at 8:54 PM, xlr8or said:

Sharing my 2 cents worth as well. Get yourself a low-powered valve amp that has an 8 ohm tap and also get yourself a pair of speltz autoformers. With the autoformers set your speakers to the 2x setting so the load on the OPTs see nominal 8 ohm rather than 4 ohm. You will be hard pressed to find low-powered Class A SET valve amps with 4 ohm taps.

This one can be had with a 4 Ohm tap

http://undergroundsoundaudio.com/300B-SET-TT/

[Gryffles]

@camross I also play louder with my clone Firstwatt amps for some reason. I bet that's a cracker of an amp it's unfortunate they are so bloody expensive!