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05-01-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 1
Post ID: 2362
Reply to: 2362
Two-stages, hybrid, small, powerful class “A”?

I wonder if anyone make, commercially or otherwise, any (good sounding?) a two-stages classe “A” hybrid running 100-200W into 8Ohm, with no feedback?  AcousticPlan looks like tried to do something but their amp is just 50W and it looks they have no good driver for the first stage. Lamm did M1.1, good class A hybrid, quite powerful but with 4533 unnecessary stages. Hawk Audio does a little 50 watter with SRPP driving MOSFETs… I wonder why there is not a lot two-stages class “A” powerful amps out there?

I have my interest to ask, as Dima and I are very slowly working on a concept of a Super Zarathustra - a powerful 200-250W, pure class A, super-small size (!), two-stages amp with no feedback. I would like to learn what practice out there exists regarding the packaging of those type amplifiers. I have seen a few solutions but I violently do not like any of them. I wonder of anyone else might propose something else inspiring….

Rgs,
Romy the caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-02-2006 Post does not mapped to Knowledge Tree
Antonio J.
Madrid, Spain
Posts 272
Joined on 08-16-2004

Post #: 2
Post ID: 2363
Reply to: 2362
Two brands come to mind, while disappeared... and a currently active one.
One was the Llano Design Group's Trinity, which had 300wpc. The first stage was tube and was in a separated enclosure providing voltage amplification, while the second stage used transistors for current amplification. I guess it was pure class A or at least AB with high bias providing most of its power in class A.

The other were the Counterpoint models. In the 80's they introduced several models SA-8, SA-12, SA-100, etc uinsg MOSFET output and later the Natural Progression series which used bipolar transistors (IGBT) output. You can check their line out here: http://www.altavistaaudio.com/Product_Guide.html
A friend of mine has one SA-100 (modified and upgraded to get the feedback loop off) and it's not specially interesting, powerful but smooth compared to other pure SS amps, that's all.

rgrds,

A.

PS: Looking at the Counterpoint's site, I've found that its designer Michael Elliott started a new brand named Aria. They are producing amplifiers following the same design principles, a tube stage for voltage amplification and transistor based output stage. There are two models, one rated at 100wpc (stereo) and other at 350 wpc (monoblocks). Quite pricey, can be seen here: http://www.ariaaudio.com/WTStereoMono.html I wouldn't be using that "packaging" it looks awful :-)
05-04-2006 Post does not mapped to Knowledge Tree
Chirag
New York
Posts 32
Joined on 06-13-2004

Post #: 3
Post ID: 2381
Reply to: 2362
A few more hybrid suggestions
Hey Cat,

Well..my first question would be regarding the application.  The big Melq tube is already doing the bass towers...is it not enough current?  And wouldn't a proper class A 100w amp with its low low efficiency require something like 1000w+ of cooling?  Should be nice in the winter no?

In addition to the Aria guy, the tubecad.com guy has several circuits up using his "aikido" circuit as a driver and several mosfet and transistor outputs.  It looks on the surface like a complicated SRPP setup, but I am not capable of commenting on the design.  Most of his suggested amp diagrams focus on lower outputs of 10-20w, but using more current capable tubes, you may be able to drive a bank of solid state outputs to get you what you need.  I generally like his approaches and I'm not basing this on any experience with this particular design.

The other option I would suggest are the non-hybrid feedback based Pass Labs aleph amp circuits.  They remind me of the artificial sweetener Splenda...they taste kind of like sugar, but the overly sweet and chemical attitude does come through in the higher frequencies.  The Aleph 30 I tried for a few months did not screw up the midbass with my little Tannoys any more than my PP tube amps.  I am wondering how well his newer 30w "J" version could work on my 15" pro tannoys.

I think the italian Pathos company has a products that might fit the bill.  From the smaller integrated amp I heard, it may not cut the musical muscle you require.  This amp has a lot of fluffly names around it, but they do claim tube driver and class A output.

Regarding the Lamms, is it possible to cut away some of the odder opamp type middle stages and use a higher current tube to push the outputs?  The output setup and case is already there. 

If you're as intense as I believe, can your little 6E5P tube in the Melq configuration drive a bank of mosfets or transistors?

Best,
Chirag
05-04-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 4
Post ID: 2382
Reply to: 2381
One way to learn is to try...

 Chirag wrote:
Well..my first question would be regarding the application.  The big Melq tube is already doing the bass towers...is it not enough current? 

Chirag, I’m not planning to use this power amp in my system.  The Melq LF section does perfectly enough for my room. The Zarathustra prototype that I mentioned before:

http://www.goodsoundclub.com/TreeItem.aspx?postID=1029#1029

did something quite good but there were also the areas where it did not do good (driving high sensitivity for instance). I attribute it to the class AB operation. Also, we have some interest to see how it will perform if the very same amp will be biased class A and made with no cheating of any kind (unfortunately it means expansive). We really do not know how it will sound in comparing to the Melq LF section. I think the only one way to learn is to try. I assume that if everything will be done properly then it might be a very good full range amp, as I have seen how the class A amps (M1.1 for instance) do drive high sensitivity with good results. In the end I will hate if the amps will sound good, as I will have no use for it. Well, at least it will give me some self-confidence and reasons to call names the other guys who do SS amps.  :-)

 Chirag wrote:
In addition to the Aria guy, the tubecad.com guy has several circuits up using his "aikido" circuit as a driver and several mosfet and transistor outputs.  It looks on the surface like a complicated SRPP setup, but I am not capable of commenting on the design.  Most of his suggested amp diagrams focus on lower outputs of 10-20w, but using more current capable tubes, you may be able to drive a bank of solid state outputs to get you what you need.  I generally like his approaches and I'm not basing this on any experience with this particular design.

Thanks, I will look at his lately. Although we do not need any circuits, we have the one but rather some interesting packaging ideas, though I did not see any high-power-low-size class “A” design with bold objectives.  Well, over the last few days we have come up with a solution that do look attractive so far… will see…..

 Chirag wrote:
The other option I would suggest are the non-hybrid feedback based Pass Labs aleph amp circuits.  They remind me of the artificial sweetener Splenda...they taste kind of like sugar, but the overly sweet and chemical attitude does come through in the higher frequencies.  The Aleph 30 I tried for a few months did not screw up the midbass with my little Tannoys any more than my PP tube amps.  I am wondering how well his newer 30w "J" version could work on my 15" pro tannoys.

Thanks, Chirag, we all set with the topologies and circuit design. We are not in Kansas anymore and the whatever Mr. Pass does  Sonically is good only to be use as a ballast for ships…

 Chirag wrote:
I think the italian Pathos company has a products that might fit the bill.  From the smaller integrated amp I heard, it may not cut the musical muscle you require.  This amp has a lot of fluffly names around it, but they do claim tube driver and class A output.

Actually I did hear this amp in Belgium I believe. It was driving Danlavy V and it was very pleasant.  I do not think they were powerful though….

 Chirag wrote:
Regarding the Lamms, is it possible to cut away some of the odder opamp type middle stages and use a higher current tube to push the outputs?  The output setup and case is already there. 

Not really, I would like the Super Zarathustra be twice smaller then Lamm 1.1, twice or trice more powerful and be at least 10 time more advancely made and sound, not to mention way better engineered. If I remember correctly Lamm 1.1 had cheap consumer-type PSs, the first stage was around some kind of integral buffers, then it had SS stages, then tube-based SRPP, then another SS stage and then the MOSFED output. There is negative feedback around the stages and a lot of other things… The Zarathustra will be completely different amplifier with completely different design objectives, so even the box of the M1.1 will not be reusable.

 Chirag wrote:
If you're as intense as I believe, can your little 6E5P tube in the Melq configuration drive a bank of mosfets or transistors?

It will be very simple: no expansive and properly (sonically) made PS, super effective heat dissipation mechanism, Melquiades’ input stage in SRPP configuration driving the SS stage, no feedback, and the Dima’s own “kinky” output stage. I can hardly comment what is in the Dima’s output stage but Dima climes that it has some his own inventions that make it “different”. I prefer do not know what it is as I know absolutely nothing about SS.

Rgs,
The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-05-2006 Post does not mapped to Knowledge Tree
jamesrm618
Posts 5
Joined on 05-18-2005

Post #: 5
Post ID: 2385
Reply to: 2382
Re: Vincent Hybrid?
The Vincent SP-T100 looks close

"The SP-T100 is a hybrid mono block with tubes in the input stage where voltage is amplified. The power output Amplifier circuitry works without feedback."

Nominal output power Class-A 8 Ohm: 10 Watt
Nominal output power RMS 8 Ohm: 100 Watt
Nominal output power RMS 4 Ohm: 200 Watt

vincent-tac.de/en/design/dl3/spt100.php

regards
James
05-06-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 6
Post ID: 2388
Reply to: 2385
Michael Framer's amplifier?

 jamesrm618 wrote:
The Vincent SP-T100 looks close

"The SP-T100 is a hybrid mono block with tubes in the input stage where voltage is amplified. The power output Amplifier circuitry works without feedback."

Nominal output power Class-A 8 Ohm: 10 Watt
Nominal output power RMS 8 Ohm: 100 Watt
Nominal output power RMS 4 Ohm: 200 Watt

vincent-tac.de/en/design/dl3/spt100.php
Thanks, James. I never heard this amp. I looks this company does a lot of consumers mass-market audio. Also the amp looks very fishy for 100W in class A. I do not see any forced cooling and with this given dissipation surface it should boil at 100W of class A.
Oops, a quick search indicates that the amp is a marketing fantasy:

“A vacuum tube-based 'Class A' input stage configuration complements the solid state output stage, which operates in pure 'Class A' for the ultimate in rich detail and imaging for the first ten watts. Above ten watts, the Vincent automatically switches to 'Class AB' to deliver over 200 watts of power for effortless transients and drive capabilities.”

How damn smart! To be proud that the input stages ruin in Class A is defiantly a big compliment for an amplifier for TV sets!

Rgs,
Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-08-2006 Post does not mapped to Knowledge Tree
morricab
Posts 51
Joined on 07-13-2005

Post #: 7
Post ID: 2390
Reply to: 2388
Re: Michael Framer's amplifier?

Hi Romy,

I did the review on the AcousticPlan amp, called the "Santor".  It is indeed a two-stage amp using 4 6922 tubes in parallel to drive a high Bias Mosfet output stage (it is class A to approximately 15 watts and runs very hot).  It is rated at 50 watts 8 ohms and 100 watts 4 ohms.  The first stage is simply a grounded cathode arrangement, thus the need for multiple triode sections in parallel. 

Sonically, I found this amp to be of a very high caliber.  In many ways it was superior to my own 3 stage hybrid (Sphinx Project 14MkIII...also no feedback and Class A to about 20 watts).  I think for relatively sensitive speakers (90db or greater) the Acousticplan amp has more than ample power.  It drove both my Apogees (3 ohms) and Acoustats (3 ohms in the bass and high treble plus quite reactive) with no problems and it drove a friend's Apogee Divas with no problem. 

I am now in the process of reviewing the Acousticplan Sarod preamp that has only 1 dual triode for both channels in the linestage.  It is a simple grounded cathode that is transformer coupled to the output.  So that's it 1 triode stage per channel for the line stage.  Output impedance is 200 ohms.  The power supply is an all tube affair with shunt regulation.   The sound from the line stage is phenomenally good.   One of the best I have heard.   The phono stage is more complex and uses all transformer coupling between the two active stages and then transformer coupling between phono and line sections.  Also, excellent sound.  The phono section I feel is not the equal of the line section.  Another top preamp I have on hand that you should seriously consider is the latest creation from Allen Wright of Vacuumstate, the RTP-3D.  The phono is the best I have so far had the privelege of hearing.  The linestage is also at the top.

 

I know of one other amp on the market that is just as simple and it comes from Monarchy Audio.  This amp is using 1 tube per monoblock (in an SRPP configuration I believe) coupled to a Mosfet output.  It has no feedback, is rated Class A to 50 watts with power available up to either 160 watts or 250 watts (depending on the model).   It is also a very good sounding amp.   The best news about the Monarchy is that it only costs about $2500 for the PAIR.  www.monarchyaudio.com

05-16-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 8
Post ID: 2407
Reply to: 2362
A laundromat amplifier?

Another interesting thing: why not a lot of people make the single ended hybrids? I understand that single ended output has very low efficiency but still: it is only about the heat dissipation. I have seen some single ended SS amp. There was a strange 20W Italian hybrid. The Czechoslovakian KR amp does some kind 20W-30W hybrid. Brazilian Eduardo de Lima (the guy that I like) does 30-40 single ended SS amp…. Still, if it is juts about heat dissipation… then come on. It is 21 century! I can see a nice 2 stages hybrid where first stage driver 150W-200W solid-state assembly.  I wonder what can I head something like this? A very high efficiency forced cooling, or even water-cooling… Nowadays it is really not an issue… Even if that amp would have 20% efficiency and for 200W it would burn 1kW then what would be a big deal!? We Yankees are gloater anyway. An efficient and smartly built forces cooler with 4”” flexible pipe running outside, similar what we use for laundry dryers, would be quite simple to implement.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-18-2006 Post does not mapped to Knowledge Tree
behhl
Kuala Lumpur, Malaysia
Posts 5
Joined on 03-30-2006

Post #: 9
Post ID: 2410
Reply to: 2407
Macondo, Melquiades ... Zarathustra?
Hi Romy, but I am simply curious that your Designed-&-Made-Yourself have always had the flavour of the names and places from A Hundred Years of Solitude ... Macondo the village, Melquiades the gypsy ... so why the departue now to Zarathustra? Perhaps you will reconsider to name it Segundo?  [tongue in left cheek] Perhaps even the title AHYoS may clue us as to the point of this DMY equipment? [tongue in right cheek]

best regards
The General In His Audio Labyrinth  ;-)
05-18-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 10
Post ID: 2411
Reply to: 2410
Naming the amplifiers….

 behhl wrote:
Hi Romy, but I am simply curious that your Designed-&-Made-Yourself have always had the flavour of the names and places from A Hundred Years of Solitude ... Macondo the village, Melquiades the gypsy ... so why the departue now to Zarathustra? Perhaps you will reconsider to name it Segundo?  [tongue in left cheek] Perhaps even the title AHYoS may clue us as to the point of this DMY equipment? [tongue in right cheek]
Yes, it is a luck of consistency. In really everything is very simple. The Melquiades I named because it was my amp, conceptually, ideologically and sonically. Dima and some others folks (primary Dima) greatly helped with Melquiades’s  creation but I was the main driving force, therefore I find that I had rights to name it. Zarathustra is very different story. Zarathustra is Dima’s amp, his design, his implementation, his conceptualization and so on… Zarathustra was the name that Dima came up with last year wan I proposed him to name the amp. Dima built a few Zarathustras as one is sitting in his home.  My contribution to the entire Zarathustra project was juts moving Zarathustra into pure Class “A” and helping to facilitate the amplifier’s mechanics. To all the rest I have no relation, including naming the amp.

Interesting that naming of an amp could be ridiculously important. Let leave the metaphors aside. The amps name is the way in which the amp might be referred.  Ironical some people convert those reference names into absurd. It is customary that I keep bitching about Lamm electronics but Lamm is a great example how naming of product could become ridicules. Many people, including me and including Lamm business associates, with whom I spoke over the phone about Lamm’s electronics were confused in the endless tang twisting:ML1, ML2, M1.1, ML1.2, ML2.1, M1.2, M2.1, ML1.1, M2.2 and so on and so on…  I do not know why Lamm did not provide more distinctive names. Perhaps he was saving money on front panel paint or was trying to make this customers and dealers be confused in the infinite colloquialisms of upgrades and models... Who knows….

Rgs,
Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-19-2006 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 258
Joined on 08-03-2004

Post #: 11
Post ID: 2412
Reply to: 2410
Re: Naming Products
If you are a manufacturer with a range of products you have to export and sell to distributors all over the world (many of whom don't speak english), it is far easier to give your products numbers rather than names. It is also far easier for those distributors to then order them if they are listed in this way. It simplifies communication.
If you are making one or two amplifiers at home (not for resale) then, of course, you can call them whatever you like!
05-19-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 12
Post ID: 2413
Reply to: 2412
Naming own sense of really.

 guy sergeant wrote:
If you are a manufacturer with a range of products you have to export and sell to distributors all over the world (many of whom don't speak english), it is far easier to give your products numbers rather than names. It is also far easier for those distributors to then order them if they are listed in this way. It simplifies communication.
If you are making one or two amplifiers at home (not for resale) then, of course, you can call them whatever you like!
Sure, if you manufacturers a range of products that you sell to distributors all over the world then you probably should be preoccupied not with own conceptual fixations of neurological disorders but rather with comfort and benefits of your prospective customers, shouldn’t you. Any single person, customers or dealers, with whom I spoke about Lamms, mentioning not one single product but a number of the models, were dissatisfied with Lamm naming conversion calling it ridicules. If it is not an indicator that “something wrong” then I do not know what other indictors might be indicative enough.  I think in your ultimate desire to protect folks who make living on audio you are loosing the grip of realism. If you make home one or two amplifiers (not for resale) then you perfectly fine to call it as ridicules as you wish (as I did) and to grant to a unit the name “My 3.1415926535897932384626433832795028841971693993751” would be perfectly OK. In case you do the things not for yourself but for others then to use others rules  “might” be needed.  If your lived with those ML1, ML2, M1.1, ML1.2, ML2.1, M1.2, M2.1, ML1.1, M2.2  then thiser "names" would be not juts a worthless theoretical  debate on internet but  the actual symantic pain.... Talk to any person who sale Lamms and you would hear what I said. In the end: there is no need to reinvent anything and the guys who sell cars around the world deal with it for years….  Do not drive “Acura Legend”, drive PPTX, that was a modification of PXTP, or a model between the TTXP and TPXT….

I do not think that all of it has anything to do with “Two-stages, hybrid, small, powerful class “A” but who do not like early morning bitching”

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-19-2006 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 258
Joined on 08-03-2004

Post #: 13
Post ID: 2414
Reply to: 2413
Re: Lamm's naming strategy & Mravinsky
I would agree with you that Lamm's system of naming his products wouldn't appear to be helpful to anyone. They are all too alike.  When I was involved in that side of the business, I would always have preferred to use names rather than numbers, but it didn't work particularly with customers in the far east. They just became confused.

I found the DG Privilege (70's reissue) gatefold double LP of the 1961 Mravinsky 4-5 & 6 yesterday. How many LP's were in the box set you mentioned? Presumably these symphonies were also available individually?

Anyway, as you suggested, the performances are astonishing making every other version I have sound feeble. The sound quality (even squashed onto two LPs) is pretty fine aswell.
05-19-2006 Post does not mapped to Knowledge Tree
Bud
upper left crust united snakes
Posts 87
Joined on 07-07-2005

Post #: 14
Post ID: 2415
Reply to: 2414
Back to the beginning
Romy

Perhaps this link and the information trumpeted within will help on this project. Certainly the leader of this pack has solid credentials in HF switching power supplies, though this particular link is actually about roasting transistors in an Audio Amp... http://ridleyaudio.com/Technology.htm

Bud
05-19-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 15
Post ID: 2416
Reply to: 2414
Off the subject: Mravinsky 1961

 guy sergeant wrote:
I found the DG Privilege (70's reissue) gatefold double LP of the 1961 Mravinsky 4-5 & 6 yesterday. How many LP's were in the box set you mentioned? Presumably these symphonies were also available individually?

Anyway, as you suggested, the performances are astonishing making every other version I have sound feeble. The sound quality (even squashed onto two LPs) is pretty fine aswell.

The Mravinsky set you got is very bad, trash it, you should get off CD better sound.  DG Privilege was DG’s budget line, unfortunately produced. All Privilege LPs were horribly pressed, severally compressed, have no LF and actually the entire sound of the “Privilege” is not recognizable.  I literally threw the Privilege LP away is I accidentally get them. The best Mravinsky 1961 was available as 3LP box set, pressed in Italy. It is a very common set and it cost nothing: ~7$ everywhere. There were huge among of then pressed, they all sound very slightly deterrent but still they all better then their competitors. There are also the original DG pressing with the ring of Tulips. They are savable as the individual Records, one per symphony. Unfortunately the Tulipsed sonically are not as interesting as the Italians. The Mravinsky 1961 Tulipsed have problems with side imaging; have larger surface noise and a lot of other issues.  They also much less available and much more expansive, Only God knows why the morons pay extra for inferior pressing of the Mravinsky 1961. Perhaps the audiophiles stupid label adoration takes over their sense of Reality… Anyhow, in the future try to stay on the subject of the thread, as there is a dedicated thread bout the Mravinsky 1961 in the music section of the site.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-19-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 16
Post ID: 2417
Reply to: 2415
Ridley Audio's Ridley Effect™

 Bud wrote:
Perhaps this link and the information trumpeted within will help on this project. Certainly the leader of this pack has solid credentials in HF switching power supplies, though this particular link is actually about roasting transistors in an Audio Amp... http://ridleyaudio.com/Technology.htm

Very interesting, Bud! I neither heard about this company nor hear their products. They do not say a lot what the Ridley Effect™ is all about. I have no expertise to assess how real it might be but I know that generally there is some sonic “kink” at high temperatures. Perhaps it is what makes tubes to sound sometimes interesting – the fact that we BBQ the electrons…. The “overheated electricity” usually sounds more “civilized” and less mechanical…

With Zarathustra everything is not known yet. I mildly fight with Dima regarding how much we should heat the Zarathustra output stage. He accustomed to the “SS that operates warm” as he mostly design AB-operating amplifiers. I keep arguing that 70-75 Celsius is perfectly normal oration temperature, particularly for the type of the heat dissipation that we use. Anyhow, he knows what he is doing and I am sure that in the end he will put the Zarathustra in the optimum operation temperature with respect to the sonic yield for the transistors we use. Still, the question is wide open how different the amp will sound at different temperature and what would be the sonic difference if would be change the stabilized operation temperature for 10 Celsius up or down. It will be very interesting to hear, I personally do not know who has this knowledge, as particularly regarding the different SS devises… I spoke with few people I know but I do not know if their experience would benefit Zarathustra as Dima uses his own ”different” ways to control temperature and bias.

BTW, do you know where is possible to hear the Ridley Audio power amp?

Rgs,
Romy


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-19-2006 Post does not mapped to Knowledge Tree
Bud
upper left crust united snakes
Posts 87
Joined on 07-07-2005

Post #: 17
Post ID: 2418
Reply to: 2417
possible patent search
Romy,

I have no direct knowledge about these products. I only have a brochure, given to me by an evil person... well maybe not evil, but he does try to get male children, who are friends of his male child, to play in "Garage Rock an Roll Bands" rather than doing the more acceptable drugs and sex part of the hallowed "Drugs, Sex and Rock an Roll" !

In the brochure Ridley does claim to hold patents on the "intentional heating" of transitors and the methods for doing so. They also claim that they can run transistors to 150 deg. C for 10,000 hours without concern...... Perhaps another denizen of this particular jungle can search for the relevent patents? I can hardly find my ass with both hands, so I am not at all good with search engine rules and regulations.

Call them @ 770-640-9024 and ask for a demo amp...what can you lose? Maybe they will even loan you one, so you can give it your unbiased opinion and a suitable review.....? Certainly if they were to visit this site they would learn something, and it would even be good for them too.

Bud
05-19-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 18
Post ID: 2419
Reply to: 2418
I have problems with “Sound professionals”

Bud,

thanks, perhaps I will get in touch with him but I do not know what I might doe with his AB amp…

Still, I generally have difficulty to talk with audio people and to extend any credibility to what they said if I did not experience personally the reference points that people have in their minds. You see, the technical people do deal most of the time with actual Sonic results but rather with development of the own algorithms to control events and to manage own egos. A person might be perfectly reasonable and intelligent in his/her realm of expertise but his research might have explicitly theoretical application only with the restricted context of “none applied theory”. Being applied the “research” might become a different way of doing….  Absolutely nothing. I’m sure that this guy is able to run transistor at 150 degree but the question is not how he does it but what result he is getting. I would need to hear “what I need to hear” and then a person might have a credit to claim how that Sound was done. Without the actual familiarity with Sound that those people are talking about all of them consider themselves geniuses and great inventors. I certainly do not mean the Ridley Audio guy but I dealt a lot with pro audio folk and with high-end specialists who consider themselves  “fancy” but after familiarizing with their Sound, or with Sound that they consider “acceptable” I realized that I wasted my time extending to them any trustworthiness.

Rgs,
Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-19-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 19
Post ID: 2420
Reply to: 2419
Transistors and operating temperature.

I would like to extend my last previous post a little. First off all, I would like to remind that I am very much not an expert in usage of transistor and second - I would like do not convert this thread into those DIY desecration: as you all know I hate DIY people.

Still, the Ridley Audio guy smudges that he found a way to runs his transistors at 150 degree C.  With raise of temperature the current carrying capabilities decrease significantly.

So, driving Zarathustra in pure Class A, with no tricks or biasing abracadabras, I wonder how mach “save current” (power) we would be loosing is we go over 100 C. It looks like the Ridley Audio guy uses custom made MOSFETs and suggest that they do better at high temperature. He might be very correct but would it affect only HIS MOSFETs? Zarathustra does not use MOSFET, does not operate in AB and meant, quietly wise be good enough even to drive horns (!), which is very bold requirement that I do not know if we would be able to meet. The Ridley suggest the Kevlar-ribbon loudspeakers… If my definition of success were to make a playback to sound good for  jazz then it would be enough….

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-20-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 20
Post ID: 2423
Reply to: 2417
Liquid helium brain inertia in Class A?

I keep thinking about the temperature. Whatever the best I heard in Class A was running very very very hot. However, what is the association between sound, heat dissipation design and temperature.  It is obviously that any amplifier designers would like to get more power within smaller package size. More power = more bias current and more parallel transistors, which means more heat during idle operation. Let now to pretend that we have a super high efficiency heat dissipation mechanism that can absorb unlimited amount of heat and that make temperature not a factor. Now we can select a desirable power or output stage without regards to the heating problems. Or let me rephrase: now we can select the power we would like to have and then select the temperature we would like the output stage to operate. Now is the question: what would be with sound if we maintain the same idle current but change the effectiveness of the cooling, from up 30 degree C. to 50 degree C? How about 80 degree C? 100 degree C? How about the different transistors? We limit our views with size and dissipateable temperature but what is it is not a factor and if we have some kinds hypostatical cryogenic coolant cooling down the output stage? The transistors data shits give to us data what happen with transistor at different temperature but it said nothing about it’s sound.  I wonder if anyone had experience to assess this moment and at the same time be able to evaluate sound musically objectively. I obviously have no such experience and I do know anyone who does.

I personally still have a very strong inclination to higher temperature but I have no tangible rational for it. It would be fun to run Zarathustra at different temperature and to see what it will be doing sonically….

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-20-2006 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 258
Joined on 08-03-2004

Post #: 21
Post ID: 2424
Reply to: 2423
Re: Transistor operarting temperature
Romy,

Did you ever listen to a Class A amp made by Andy Rapapport which later became the Octave Research OR1?

I never opened one up to look but I remember someone telling me (possibly salesman BS, I can't remember) about how much attention was paid in that amplifier to maintaining an incredibly stable operating temperature. I remember using one for a while and it definitely took several days to settle down but once it had, it was better than any other SS amp I've listened to before or since.
05-21-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 22
Post ID: 2425
Reply to: 2424
Zarathustra’s operarting temperature

Nope I’m not familiar with Octave Research OR1. I heard about Andy Rapapport but I never heard or have seen his amps. My thinking about all of this has littler rational and even less experience. I would never think about SS but the phenomenal success with Placette buffer make me to extend some credit to SS. The Zarathustra’s prototype was interesting. I run it on Kharma 3,2 and Wilson Alexandria and it demonstrated some great potential.  From my perspectives it had some issues but none of them related to what usually attributed to SS amplifiers. In the new complete Zarathustra version will be done a LOT to take care about temperature it it will be very different amp, much more advanced. We in fact will be able to drive the output stage in the chosen my us temperature. We juts do not know which temperature to target and how it will affect sound. I feel it will be a lot of listing, testing and interpretations before Zarathustra will be complete…

Rgs,
Romy


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-19-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 23
Post ID: 12983
Reply to: 2362
The Greek Hybrid amplifiers.
fiogf49gjkf0d

I do not know this company but they might do interesting hybrids…

http://www.ypsilonelectronics.com

http://www.ypsilonelectronics.com/technology.htm

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
03-25-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 24
Post ID: 15844
Reply to: 2362
The Robert Koda’s Takumi K-70 hybrid
fiogf49gjkf0d
Here is another interesting hybrid. The gain stage is made around 5842 tube, most likely with feedback and the current stage is SS reportedly single-ended and in class A.  They claim 150W, if it is in Class A and without PP then frankly I do not see a lot of surface to dissipate the heat.

http://www.robert-koda.com/product.html

However, God knows what they did in there. It reported that it has 32 transistors by channel, sure they did try to built a lot of current, how long it will stay in class A is not know. Did anybody hear the thing?

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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