Anybody who ever tried SS amp with compressions drivers or the drivers of high-sensitivity that can be driven by minimum current knows how it works. Nelson Pass created with his First Watt project a lot of publicity to the idea. A few watts, in pure class A and in single-ended mode - it might be interesting. I say it “might” because I just do not know – I never had one. I still would like to hear a few watt single-ended VFET SS amp – not one does them…

A few days ago Reinhard from Germany mention another attribute of the same idea: Jean Hiraga’s "Le Monstre".

http://www.tcaas.btinternet.co.uk/hiraga.htm

You can go for the home page of the sites and will see a few other des of low power SS amps.

http://www.tcaas.btinternet.co.uk/

I do not partially care about the PP amps to drive soft magnets drivers but it might work. Unfortunately I never ever heard the people who use low power SS amplification to talk about Sound. So, if you know about any commentaries about Sound from the folks who use SS single-ended amps that have no feedback and drive with them over 105dB sensitivity then please post the link. Please discard the cases when people drive “yellow” drivers or those moronic full-range drivers.

There is a German company VALVET High-End Amplification and they do a little 10 watter Single-Ended amp.

http://www.valvet.de/en/bricks/e1/

There are few similar to this.  What is not clear is if they use caps in path and if they use feedback. I think by playing with the transistor itself and the biasing ways it would be possible to change sound of this thing…. Again, no one talks about the Sound of those things – they claim it to be “clean” and “transparent”. It is very much might be so but in my definition of Sound “clean” and “transparent” are not indicative entries.  Distil water is “clean” and “transparent” but you would not use it what you are thirsty….

The reason I brought the VALVET company is because they make own speaker that looks like use a compression driver (I do not know what they use)

http://www.valvet.de/en/loudspeaker/pulseon/

So, the might not be so dead in assessment of what their Single-Ended amp would do with the first watt.

coops wrote:

Mainly because of my young daughter I have been listening to mostly solid state amps, I have enjoyed 'Digital DoMain's' B1-a VFET, and am now listening to a German 'Audioprojeckte' CA10, 10 watt class A design, ( I will post a link later as their site appears to be down ) , I have  also ordered a pass labs 'First Watt'  J2 which  should be here soon. It is refeshing to hear something new, I would recommend it.

Keith, again this BS?

I created this thread explicitly in horn section because I do not want to see taking about amplifiers, to see uploaded enumeration of links, 3 –word sentences  and certainly I would like do not read anybody’s “recommendations”. I was asking about the thoughts and commentaries about Sound of those amps with compression driver. Keith if you have no own thoughts about Sound or the ways to express those thoughts then can you stay fucking away from my site? Find for yourself another avenue to spread the anesthetized recommendation and numb posts.

I have just taken out of my system a First Watt F5 clone Tim Rawson amp, It was substituted by a Telefunken PP amp with 6AQ5 tubes.

Let me to explain.

My system consists of 6 way horn loaded speakers.  I have a round Tactrix upperbass horn with 8" cone driver going from around 180hz up to 800 hz, then a compression driver from 800hz to 6khz and horn tweeter and supertweeter.  My bass modules are sealed cabinets amplified separately by SS subamps (soon to be changed).

I mainly use a pair of Leak TL12.1 amps with passive preamp to drive de Horn module from 180hz and up.  This horn module has a speaker level Xover.

I am trying now to use multi amps in order to achieve more transparency and dynamics, one amp for each driver, for this I need to add an active preamp.  After adding the new active preamp my Leak amps had too much gain and the system started to shout a little.  So I changed the Leak amps for the First Watt F5 clone amp.  

The difference soundwise in this half range 180hz and up horn module between the Leak TL12.1 amps and the First watt F5 clone was big,  mainly the tonal balance is very different with the midrange sounding thin.  Highs were more extended but a bit unnatural, they sound less liquid and more in your face, The midrange is not rude or scratchy but it is not full and round, it also lacks the attack on piano notes the Leak amps have.

I guess the tonal balance can be readjusted at Xover level but this I will not do at the moment. 

I also have a Chipamp (Thorstens inverted design) I have used for the upperbass channel alone and I remember it sounded very good in that range, The amp is a bit more jumpy and thinner than the tube amps I tried and on the upperbass horn the sound did become more transparent and mixed better with the tube amps and compression drivers on top. This test I will try to run again this weekend.

The same Chipamp on the full horn module from 180hz and up sounded terrible with a scratchy midrange and dirty high range.

My plan is to use a pair of spudamps similar partially to the Melquiades amp for the compression driver 800hz to 6khz and for the tweeter and supertweeter, and try either the F5 amps or the chipamps for the upperbass horn.

I will leave the Leak amps for the bass modules and see how they perform there.

PS.  Johan in South Africa uses Firstwatt F3 amps for upperbass horn and tweeters,  his upperbass horn is loaded by a JBL compression driver,  not a cone driver. 

Saturntube wrote:

The difference soundwise in this half range 180hz and up horn module between the Leak TL12.1 amps and the First watt F5 clone was big,  mainly the tonal balance is very different with the midrange sounding thin.  Highs were more extended but a bit unnatural, they sound less liquid and more in your face, The midrange is not rude or scratchy but it is not full and round, it also lacks the attack on piano notes the Leak amps have.

Saturntube,

In context of your post a few things is needed to be to reviewed:

1)    What magnet types of your MF drivers and tweeter? It is my long observation that PP amps are very bad for driver with Alnico driver, they usually eat all details. The ceramic drivers however, that are ordinary are horrible for HF, are very nicely work with PP amps…

2)      What do you think, if you cone to use the First watt F5 and if you would be interested to recuperate some of the “midrange sounding thin” then would be able to do it with driving your upperbass with a slightly more open upper bound?

3)      The First Watt F5 is not truly the amp for consideration as it is not a single-ended amp.  Mr. Pass was progressive with his first amps - single-ended not feedback and then with his late model he become acting like a Moron who just read a lecture about conversion to vegetarianism and then stuffing himself with pepperoni on his elevator ride down to garage…

Romy the Cat wrote:

It is my long observation that PP amps are very bad for driver with Alnico driver, they usually eat all details. The ceramic drivers however, that are ordinary are horrible for HF, are very nicely work with PP amps…

el`Ol wrote:

Hello Romy, have you searched for explainations for these observations? Are there others who made the same observations and tried to explain them? Does the damping factor play a role? From my limited experience I can say that a SS PP amp doesn´t eat details in combinations with this driver (obviously ceramic, but why two demodulation rings?) Apart from the details (comparable to vacuum tube / alnico) I find that there is more control/precision/stability, so is it the damping factor that plays a role?

Nope, I do not know anybody ever made such a claim and I have no explanation for it. Put in this way – I was not looking for an explanation. To me any “explanations” in audio are interested only as long they address my practical interests. Since I do not use for HF any drivers that are made with ceramic then I see no reasons to look deeper into the PP/ceramic compliance. I am a practitioner and I am very much not in the Moronic realm of the Lynn Olsons whom writes 34534 “War and Peace” books about a single fart that their VIRTUAL loudspeaker and VIRTUAL result.

Yes, in a way the “eating details” might not be a perfect description of the phenomena. The ceramic drivers at HF have not details deficiency but different type of the details. If we compare drivers with dog’s surface (fear, fire, fur, fair - I can’t spell this fucking word!) then Alnico sound like a dry, long-hear dog. The ceramic is the same dog with a wet skin – the shape is there but this [fear, fire, fur, fair] does not stick out.

I discovered this phenomenon in 2000-2002 when I was doing over a LOT of compression drivers, in fact I was buying all possible driver to try. In that time as was driving everything with Lamm ML2.0. Many ceramic drivers did not sound very exiting – in fact it was truly trashy sound.  One day I was drying it with Lamm M1.1 SS push-pull and I was very surprised how wonderful it was. I made a conclusion that it might be pattern in it. Sure in all my following experiments I got significantly and predictably better results driving ferrite and ceramic driver with SS push-pull.

Was it damping factor in play? Hm, I do not think so. The damping factor is a fact what you have a EMF (electro-moving force) returned from the driver. To have it the driver shall have excursion and powerful inductive coil. In case of compression driver there is no EMF returned back to amp, it is like a ribbon – an amp do not care about the drivers reactive existence.   It might be not the “damping factor” itself but the way how the high damping factor is accomplished in SS PP amps. That is a whole another subject and do not feel equipped to think about it. Do not forget that compression drivers are driver with ultra low currant. I use 100 mV for my 16R driver. So any conversations about problems with sound around the crossover distortions in PP amps might be negligible if you drive 15” roofer but what the amp outputs 1/8 watt and 1/10000 of the nominal gain then those “little things” become too critical…

Anyhow, with SS amp and compression driver I would never consider any PP amp and would experiment ONLY with single-ended SS amp, but it is me. What the purpose to use PP – to make the ferrite driver to sound better? Let do not use bad driver to begin with and it would not demand us to “fix” them with PP amplification….

Here is another amp from Germany

http://www.audioprojekte.de/html/ca10en.html

10W, class A, might be good to drive compression drivers. What is missing is that it not said if it is PP or single ended. It looks look like it has 2 power transistors:

 http://www.audioprojekte.de/CA10c.jpg