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  »  New  Where are our good phonostages?..  Omnigon Tubes...  Analog Playback Forum     61  433775  05-31-2004
  »  New  Another interesting corrector: Likhnitsky's RX correcto..  Again, the capacitors...  Analog Playback Forum     6  44657  02-10-2005
  »  New  Allnic Verito MC Phono Cartridge..  One more example...  Analog Playback Forum     3  31541  10-19-2009
  »  New  An interesting Russian pnonocorrector...  Uber-tweeky phono topologies deconstructed...  Analog Playback Forum     9  56019  03-01-2010
  »  New  Van den Hul 's Grail..  Van den Hul 's Grail...  Analog Playback Forum     0  13600  09-30-2010
  »  New  The tales of two phonostages: Allnic and 834PT...  The tales of two phonostages: Allnic and 834PT....  Analog Playback Forum     0  14384  12-21-2011
10-16-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 21
Post ID: 11978
Reply to: 11977
...comparing of different RIAA methods.
fiogf49gjkf0d

 perrew wrote:
Romy,one thing that interest me is you use an active RIAA and the Allnic is passive circuit if I understood things?

Perrew,

Among the none-commercial, home-made correctors here is my evolution of phonostages.

1)    EAR-384PT - dual mono rebuilt with Thorsten medications

2)    7788-7721 – with Thorsten-made LRC filter.

3)    EAR-384PT-AIR  – with air capacitors

4)    7788-7721-AIR  with air capacitors and EAR-like feedback

I need to say the all 4 of them sound very nice, but the EAR-384PT-AIR, bundle with SU-2 step-up transformer made my “End of the Life Phonostage”.

http://www.romythecat.com/EndOfLifePhonostage.aspx

I had no problem with 7788-7721, ether the LRC or with EAR-style feedback, but I feel that Expressive Technology SU-2 transformer works better with EAR input tube and sound more pliable all together.

I need to say that what Alnic at their site linked above made comparing of different RIAA methods: (from the Alnic's site)

"Active filters (Negative feedback type)

Different quantity of negative feedback applied.  Deeper feedback to high frequencies and shallower to low frequencies. Improved S/N Ratio, low cost and consistent operation. Looser bass reproduction and possible a pinched and compressed high frequency playback due to excess feedback ratios.

Passive filters (CR type)

The frequencies filtered to fit that of the RIAA by varying the amount of attenuation at different frequencies through a complex resistor-capacitor network.    No voltage overload, purer reproduction form no feedback, and more accurate RIAA compensation.  No gain, insertion loss and impedance matching problems.

Hybrid filters (CR and Nega type)

Use of two type filters to low and high frequencies separately (Active filter to low frequencies and passive to high frequencies). The advantages and disadvantages of two types shown up at the same time.

LCR filters of H-1500 II SE

Two pieces of linear reactor (a kind of choke coil) comprises main parts, assisted  by precise RC filters to lower impedances and insertion loss. In vacuum tube circuits, active and passive filters usually are operated on hundred some kilo ohms of impedance, LCR RIAA filter's impedance is 600 ohms constant! Lower the impedance, more dynamic and more detailed reproduction.  Furthemore, LCR RIAA filter's series resistance, less than 13 ohms (Tango's 31 ohms)  But LCR RIAA unit drawbacks are high cost, difficulty of impedance matching which has been the hindrance of commercialization of superb unit and its phono amplifiers.   GIS KOREA LTD. manufactures itself the LCR RIAA Unit of high quality and develops the 600 ohms impedance matching method even without coupling transformer, Non-negative feedback circuit secures pure sound reproduction without coloration. "

The advantage of the passive LCR filtration that Alnic mention are correct it is not all that counts and there is other side of the medal. Still, I always liked the LCR phonostages and I feel that is one of the best way to go, despite that I do not use it.

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
10-16-2009 Post does not mapped to Knowledge Tree
perrew
Posts 30
Joined on 10-06-2009

Post #: 22
Post ID: 11980
Reply to: 11978
Allnic and Lamm
fiogf49gjkf0d
Romy,you seem to ascribe very much of your LP playbacks success to the Expressive Tech SU-2 superiority, maybe 50% from my own guess,so it must be a very nice step-up, you are one of the few that has any experience with it. There is one forum member that owns the Allnic H-1500s bigger brotherthe H-3000 and runs it together with a ET SU-1.Anyway I see some resemblance between the Allnic and your beloved Lamm LP2, at least they share the WE417 tubes (can at least be fitted with WE if not delivered with) but I guess the Lamm dont have the LCR. So would you say LCR is the key here?
10-16-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 23
Post ID: 11983
Reply to: 11980
The LCR correctors are fun
fiogf49gjkf0d

Perrew,

I do not know if you use sarcasm in there but Lamm LP2 is not my bellowed phonostage. In fact I am one of the very few people whop do not like it at all. How much in what I do not like in Lamm LP2’s MM section come from the WE417 tubes? It is hard to say. I am not inclined to blame the tube just because a unit with it turned out did not perform up to my level of demands. The type of problem I hear from Lamm LP2 might come from anything. So, I do not necessary associate my bad LP2 experience with WE417. I feel that LCR is the key element in Alnic phonostage. Also, Alnic has one extra stage around E282F, so electronically it might be whatever you can imagine. Alnic also looks like parallels the output stages with WE417. Lamm with a single WE417 has 3.5K output impedance – remarkably high. Alnic shall have twice lover. Alnic said that it has 430R but it is most likely BS and I would trust to Lamm specification – he always very accurate with specification. Alnic might use output stage as some kind of follower but I doubt and the need some gain after the LCR. I am not a big fun to parallel tubes but it is what they do.

I looked at the H-3000 phonostage specification. It might be fun to run it with ET magnetics. The H-3000 according to Alnic has two stages of amplification – it is how it shell be. However, it has just 66dB gain not enough for most cases. Alnic used my 7721 for both stages, most likely first as pentode and second as triode. I did the same with 7788 in the first stage. It was if I am not mistaken and still remember 55DB from the first stage and 33db from the second stage, the 20dB was eaten by RIAA and I end up with 68dB of total gain…

Anyhow, the LCR correctors with good quality of LCR filters are fun. That DaVinci LCR phonostage from Switzerland shall be interesting as well, at list the early versions 10 year back, when they made it one by one to order. I afraid that nowadays, when they have publicity, market share and distribution chains DaVinci might do the mass-market crap as anybody else…

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
10-18-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 24
Post ID: 11997
Reply to: 11968
The Allnic’s Mystery and class “F” operation
fiogf49gjkf0d

It is not a the thread about Allnic but LCR RIAA correctors, still there was something expressed in here about the Allnic LCR phonocorrector… and  I feel bad about it. It is not that I don’t think that Allnic LCR phonocorrector deserve positive mentioning.  Furthermore, I heard recently Allnic MC cartridge that I also liked. The problem that I have is that a remarkable amount of idiots visit my site, stupidly search for the brands that they want to buy and use this site (and many other sites) and a guidance for some kind of audio “recommendations”. I can’t stress how much I hate it and how I am bored I with those people. I invests effort do not any explicit reconditions at my site. Still, I got for the last few days emails from the site visiting Morons asking me if I fell that Allnic phonocorrector is better than two other phonocorrector and if I think that they need to buy it. What the idiots!

Anyhow, to offset my positive comments about Allnic phono I am harry to inform you that Minority is not alien to Allnic. I local guy own Allnic preamp that sounded like shit. Ok, I need to tell you that it did not sound like a bad sounding preamp – it sound worse. Regardless what you feel in the preams it out 10dB of dynamic range – I am not exaggerating – it converted the whole spectra of sound into one octave wide of 10dB range and it was it. I was mocking the preamp owner and proposed him to throw this preamp into the head of the idiot who was responsible for this sound.

The Allnic’s preamp is just one stage transformer-coupled buffer – how complex shall it be? We opened up the unit and the very first think that shocked me was that Allnic used my phonostage’s 7788 tube as driver for the preamp.  The 7788 tube that used for microphone preamp and MC cartridges, the tube that has 0.5V bias and no ability to drive anything, Allnic used to be fed from line-level input signal, that might saving as high as 2-3V. Can you pretend what would happen indirect heated signal time you drive with signal 6 times more then it’s bias? It is not class “B” operation anymore but the class “F”, as an abbreviation from the “Fucked operation”. Funny  that the Allnic web site say that preamp use 7721 tube, the one that I used in my phonocorrectors output:

http://www.allnicaudio.com/eng/products/view.htm?brandcode=0010030000000003&page=1

The 7721 is a driver tube with 1.7V on grid; it is still low but already something. Also the 7721 can driver some load. Replacing the stupid in this location 7788 to the 7721 did “fixed” the preamp.

Now the interesting question: how the hell the 7788 made into the Allnic’s preamp?  The guy who owns the preamp bought it brand ne and never opened it up.  It is not to mention that he just a user who does not know or care what is the difference between volt and ampere – he is highly not technical and very far from the nuts and bolts of audio.  The Allnic designer would hardly made this mistake – you need to be a completely idiot to use 7788 as a driver – the Allnic designer doe not strike me as an idiot. The distributor who sold the unit would also hardly make the substitute: the 7788 is twice more expensive and those industry primps would kill themselves for extra saving, it is not to mention that they are in most cases are too audio-retarded to do anything with hands or brain.  So, how the 7788 made into the Allnic preamp?

I did a courtesy call to the Allnic distributor informing him that I have in my hands a horribly performing brand new unit and I see that it uses 7788 tube as a driver. Instead of expressing regrets and proposing overnight the right tubes to fix the unit the Moron begin to question my assessment of the sound with 7788 and proposed me to talk with the designer.   Why do I need to talk with the designer – to confirm that the distributor is a dupe who has no idea what he sells? Oh, such a classified information!!!

Anyhow, I think I am too hard on the poor Allnic people.  It is most likely not their fault and the customers with screwed sound is not their liability. It is most likely the UPS people sting in this brown track, opening the Allnic units and replace the tubes. Nevertheless, if you do like the Allnic phonostage then you need to open it up and to confirm that Allnic did not use the 845 tube in input gain stage – they can as my experience shows…

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
10-27-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 25
Post ID: 12072
Reply to: 11997
The Alnic’s Preamp Mystery #2
fiogf49gjkf0d

 Romy the Cat wrote:

It is not a the thread about Allnic but LCR RIAA correctors, still there was something expressed in here about the Allnic LCR phonocorrector… and  I feel bad about it. It is not that I don’t think that Allnic LCR phonocorrector deserve positive mentioning.  Furthermore, I heard recently Allnic MC cartridge that I also liked. The problem that I have is that a remarkable amount of idiots visit my site, stupidly search for the brands that they want to buy and use this site (and many other sites) and a guidance for some kind of audio “recommendations”. I can’t stress how much I hate it and how I am bored I with those people. I invests effort do not any explicit reconditions at my site. Still, I got for the last few days emails from the site visiting Morons asking me if I fell that Allnic phonocorrector is better than two other phonocorrector and if I think that they need to buy it. What the idiots!

Anyhow, to offset my positive comments about Allnic phono I am harry to inform you that Minority is not alien to Allnic. I local guy own Allnic preamp that sounded like shit. Ok, I need to tell you that it did not sound like a bad sounding preamp – it sound worse. Regardless what you feel in the preams it out 10dB of dynamic range – I am not exaggerating – it converted the whole spectra of sound into one octave wide of 10dB range and it was it. I was mocking the preamp owner and proposed him to throw this preamp into the head of the idiot who was responsible for this sound.

The Allnic’s preamp is just one stage transformer-coupled buffer – how complex shall it be? We opened up the unit and the very first think that shocked me was that Allnic used my phonostage’s 7788 tube as driver for the preamp.  The 7788 tube that used for microphone preamp and MC cartridges, the tube that has 0.5V bias and no ability to drive anything, Allnic used to be fed from line-level input signal, that might saving as high as 2-3V. Can you pretend what would happen indirect heated signal time you drive with signal 6 times more then it’s bias? It is not class “B” operation anymore but the class “F”, as an abbreviation from the “Fucked operation”. Funny  that the Allnic web site say that preamp use 7721 tube, the one that I used in my phonocorrectors output:

http://www.allnicaudio.com/eng/products/view.htm?brandcode=0010030000000003&page=1

The 7721 is a driver tube with 1.7V on grid; it is still low but already something. Also the 7721 can driver some load. Replacing the stupid in this location 7788 to the 7721 did “fixed” the preamp.

Now the interesting question: how the hell the 7788 made into the Allnic’s preamp?  The guy who owns the preamp bought it brand ne and never opened it up.  It is not to mention that he just a user who does not know or care what is the difference between volt and ampere – he is highly not technical and very far from the nuts and bolts of audio.  The Allnic designer would hardly made this mistake – you need to be a completely idiot to use 7788 as a driver – the Allnic designer doe not strike me as an idiot. The distributor who sold the unit would also hardly make the substitute: the 7788 is twice more expensive and those industry primps would kill themselves for extra saving, it is not to mention that they are in most cases are too audio-retarded to do anything with hands or brain.  So, how the 7788 made into the Allnic preamp?

I did a courtesy call to the Allnic distributor informing him that I have in my hands a horribly performing brand new unit and I see that it uses 7788 tube as a driver. Instead of expressing regrets and proposing overnight the right tubes to fix the unit the Moron begin to question my assessment of the sound with 7788 and proposed me to talk with the designer.   Why do I need to talk with the designer – to confirm that the distributor is a dupe who has no idea what he sells? Oh, such a classified information!!!

Anyhow, I think I am too hard on the poor Allnic people.  It is most likely not their fault and the customers with screwed sound is not their liability. It is most likely the UPS people sting in this brown track, opening the Allnic units and replace the tubes. Nevertheless, if you do like the Allnic phonostage then you need to open it up and to confirm that Allnic did not use the 845 tube in input gain stage – they can as my experience shows…

Again it has nothing to do with LCR RIAA correctors but since I brought the subject of the Alnic preamp in this thread I feel I need to follow it up. I have a story with Alnic preamp that still can’t interpret.  Not that I care too much but I think for sake of truthfulness I need to tell the whole story and all that I think about it.

In the post above where I was blaming Alnic for use 7788 with .5V on grid was not absolutely accurate. I spoke with the Alnic designer who informed me that 7788 use as a triode with 3.5V on grid. I do not remember that in my case 7788 has 3.5V but I think it was 1.7V but I would not insist that I am right. If you wish to see how 7788 behave as a Triode then look here - there is plenty of data.

http://www.diyaudio.com/forums/tubes-valves/102393-7788-triode-curves.html

According to Alnic designer the 7788 were not made in his preamp accidently but was substituted because according to Alnic it “sounds better”. I very much disagree with Mr. Park – he feels that 7788 is a wonderful driver. I do not like the 7788 as a driver it has no current - who need such a driver. It is difficult to dispute anything with Mr. Park as he overly polite .  Also, I did not particularly cared about Mr. Park’s “theory” as I has right in my home his Preamp with 7788 and 7721 and what I heard was beyond any need to debate. Mr. Park was trying to present the differences as “personal preferences” but it was very far from it. Playing the preamp with 7788 has dynamic range of 15dB and it no needs to talk furthers a about any preferences. The 7721 did wipe out the problem, making the Alnic’s Preamp to sound acceptable.

I need to make very clear that I very much do NOT supports the Alnic’s idea about the transformer coupling. The advantages that Alnic’s enumerated at this site:

http://www.allnicaudio.com/eng/products/view.htm?brandcode=0010030000000003&page=1

I would call very controversial and in many case I would not agree with them. I would not debate it here just will mention that the transformer coupled preamps are very sensitive to the load impedance and it changes very dramatically harmonics of the output tube. I loaded Alnic’s Preamp to EVS attenuator and each click of it made the Alnic to sound differently. So, everything was clean – the 7788 was the Alnic’s mistake, the 7721 was fine. I can question that 7788 has more gain and the OPT ration for the 7721 and 7788 has to be different but… it is not might preamp to care too much.

The Mystery came next. The Alnic’s owner invited me in a few days as he bought more tubes and to do some other thing and he did listen the Alnic’s Preamp with different lording amps and different tubes again. THIS TIME the 7788 did not behave as bad as before and we fed the 7788 and 7721 with the same input voltage as before. There was still a difference between 7788 and 7721 and the 7721 was better but this time it was not day and high result and there was no compression to barbaric 15dB. I was sitting in there, listening, flipping the tubes like an idiot and was not able to understand why the difference that use to be so huge suddenly went to much less scale. I still have no explanation and I was not alone who witnessed it.

Anyhow, here is what I think I would do if I use the Alnic’s Preamp. Get rich the 7721 and 7788 and to put in there my 6E6P-DR in triode mode. The tube has very same pins and a full equivalent.  Increase the plate voltage to 200V. The 6E6P-DR is 8W driver it is a very powerful driver with 33 times gain. I would driver it with 22mV that would make it ~ 5W. I n this mode the 6E6P would have 1K on pals and the ratio of the transformer need to be adjusted accordingly – it looks like Alnic doe good transformers as it will not be hard for them….

Anyhow, it looks like Alnic’s Preamp  is very versatile unit and you can put in there many tubes… Still, I would not use the 7788….

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
10-28-2009 Post does not mapped to Knowledge Tree
montepilot


Boston, MA.
Posts 42
Joined on 12-13-2007

Post #: 26
Post ID: 12074
Reply to: 12072
What is the sonic character of the 6E6P-DR tube?
fiogf49gjkf0d
 Romy the Cat wrote:
Anyhow, here is what I think I would do if I use the Alnic’s Preamp. Get rich the 7721 and 7788 and to put in there my 6E6P-DR in triode mode. The tube has very same pins and a full equivalent.  Increase the plate voltage to 200V. The 6E6P-DR is 8W driver it is a very powerful driver with 33 times gain. I would driver it with 22mV that would make it ~ 5W. I n this mode the 6E6P would have 1K on pals and the ratio of the transformer need to be adjusted accordingly – it looks like Alnic doe good transformers as it will not be hard for them….

Anyhow, it looks like Alnic’s Preamp  is very versatile unit and you can put in there many tubes… Still, I would not use the 7788….

The Cat

How would modifying preamp affect sonic character other than just providing more gain.  What's the advantage? Once such a modification is made are you restricted to using the 6E6P-DR tube only?  Will it change the sound of 7721 & 7728 tube?

Rgs,

montpilot


"It's like an act of murder; you play with the intent to commit something"--Duke Ellington
10-28-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 27
Post ID: 12077
Reply to: 12074
The Alnic output stage’s driver.
fiogf49gjkf0d

 montepilot wrote:
How would modifying preamp affect sonic character other than just providing more gain.  What's the advantage? Once such a modification is made are you restricted to using the 6E6P-DR tube only?  Will it change the sound of 7721 & 7728 tube?
I would not make the comments about “sonic character” in context of Alnic preamp. I do not know exactly what Alnic does in there. I know that 7788 must not be use as it is not a good driver tube. It was tested by myself multiple times and by deferent people to whom I pitched the 7721 as a substitution of 7788.  People loved to use 7788 as out driver in phonostages and DACs but 7721 so much beat it as driver.
The 7721 vs. the 6E6P is a very interesting subject. The 7721 is good 4.5W driver the 6E6P is 8.2W driver.  Here is the triode strapped 7721 according to Philips.  

7721_as_triode.gif

The 6E6P will have a bit less plate resistance and able to driver more current. Alnic uses out transformer and I think the loading of 6E6P or 7721 shall be managed accordingly by a transformer. The Alnic not is very sensitive to load – against 10K and 20K load it sound like different preamp.  If you driver with it a reactive load it become even more problems. So, even I do have an opinion about 7721 vs. the 6E6P but it would be upon many contingencies.

Therefore I would like Mr. Park of Alnic himself to investigate this subject and make the recommendation for his users - it is his game. For him it would be very easy to extend recommendations how to make the 6E6P to sit at 200V and 20mA with the default Alnic regulator. The 6E6P is also is 30 times less expensive then 7721, so Mr. Park shall be motivated.

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
11-03-2009 Post does not mapped to Knowledge Tree
perrew
Posts 30
Joined on 10-06-2009

Post #: 28
Post ID: 12128
Reply to: 11983
LCR Promotion
fiogf49gjkf0d
 Romy the Cat wrote:

Perrew,

I do not know if you use sarcasm in there but Lamm LP2 is not my bellowed phonostage. In fact I am one of the very few people whop do not like it at all. How much in what I do not like in Lamm LP2’s MM section come from the WE417 tubes? It is hard to say. I am not inclined to blame the tube just because a unit with it turned out did not perform up to my level of demands. The type of problem I hear from Lamm LP2 might come from anything. So, I do not necessary associate my bad LP2 experience with WE417. I feel that LCR is the key element in Alnic phonostage. Also, Alnic has one extra stage around E282F, so electronically it might be whatever you can imagine. Alnic also looks like parallels the output stages with WE417. Lamm with a single WE417 has 3.5K output impedance – remarkably high. Alnic shall have twice lover. Alnic said that it has 430R but it is most likely BS and I would trust to Lamm specification – he always very accurate with specification. Alnic might use output stage as some kind of follower but I doubt and the need some gain after the LCR. I am not a big fun to parallel tubes but it is what they do.

I looked at the H-3000 phonostage specification. It might be fun to run it with ET magnetics. The H-3000 according to Alnic has two stages of amplification – it is how it shell be. However, it has just 66dB gain not enough for most cases. Alnic used my 7721 for both stages, most likely first as pentode and second as triode. I did the same with 7788 in the first stage. It was if I am not mistaken and still remember 55DB from the first stage and 33db from the second stage, the 20dB was eaten by RIAA and I end up with 68dB of total gain…

Anyhow, the LCR correctors with good quality of LCR filters are fun. That DaVinci LCR phonostage from Switzerland shall be interesting as well, at list the early versions 10 year back, when they made it one by one to order. I afraid that nowadays, when they have publicity, market share and distribution chains DaVinci might do the mass-market crap as anybody else…

The Cat


Romy, sarcasm from my side, I know you dont like LP2 and I very much believe you. Dont know if yu had Deluxe version but funny why someone put 15lbs of metal inside just to make people think it built like a tank. Anyway you made big effort to make the LP2 sound good but was this confined to replacing tubes or did you replace caps and resistors and RCA jacks as well? As for the LCR corrector I dont see why this network would be suprior to RC. Wont L cicuit complicate matters and eat to much of gain away?

Funny though to see you quoted as PR guy on Allnic http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1256413395&read&keyw&zzromy

/P
11-08-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 29
Post ID: 12190
Reply to: 12128
The twogoodears’ new LCR-437A phonostage.
fiogf49gjkf0d

Perrew,

I would take RL filtration ageist C filtration any time and under any circumstance. If you look at the circuit of 600R LCR classic Tango filter

 http://www.vinylsavor.de/lcreq.gif

…then you will see that the serial capacitance all the way out of signal path. BTW, twogoodears in his bog posted a picture of his new ???- LCR-437A phonostage that was built for him by German Thomas Mayer with looks like Dave Slagle's magnetics.

http://twogoodears.blogspot.com/2009/11/western-electric-437a.html (the images are clickable)

It shall be similar to my 7788-LCR-7721 phonostage. Interesting that it is not know how what Thomas Mayer use as input tube.  To have a phonostage with two stages only the stages have to be very high gain, low noise and the first stage shall be able to drive low impedance of the LCR network.  The 7788 shall be a good choice for Mayer’s phonostage but I do not know what he uses. Interesting that on the twogoodears’ pictures there are no plugged tubes in input stage. If Mayer uses 437A for input as well as the output (which is legitimate) then this phonostage will have just 35-40dB gain and will be good only for MM needles.

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
11-09-2009 Post does not mapped to Knowledge Tree
twogoodears


Italy
Posts 116
Joined on 03-26-2008

Post #: 30
Post ID: 12194
Reply to: 12190
Thomas Mayer's WE 437A + Tango EQ-600 LCR phono-stage
fiogf49gjkf0d
Yes, Roman: the two stages design is having the gain you correctly pointed-out.

Sure would have paid - and it was discussed, as well, during pre-building weeks - to go for an higher gain design, BUT I feel more confortable in going ahead to play with my collection of old MC-trannies which, talking about best designs, also if (maybe) loosing something in "detail/resolution/quickness", they sure add a very pleasant "oomp" and bloom to the overall result: a golden, yet unveiled, burnished-like character which let every note to shine brightly, "right" to my ears and taste.

It's like these MC-trannies gives to me more colours on my palette to play with...

Will try to involve Thomas Mayer himself in the interesting debate concerning the LCR's.

He sure is much more expert than myself in technical matters and will add - I trust - interesting details to the discussion.  


"Use your ears as your eyes" - Gertrude Stein

Stefano
11-09-2009 Post does not mapped to Knowledge Tree
Thomas Mayer
Posts 4
Joined on 11-09-2009

Post #: 31
Post ID: 12196
Reply to: 12194
WE437 phono stage gain
fiogf49gjkf0d

Hi!

Stefano just made me aware about this forum, so I registered. Interesting thread about LCR RIAAs, one of my favorite topics :-)

 

About the gain of the WE437 phono: Since Stefano wants to use external MC step ups, I designed the phonostage for MM sensitivity. Still it has quite a lot of gain to match up with his line sources. The phono stage has approximately 46-48 dB of gain (would need to measure it to get the exact figure). My own version of the very same preamp using the EC8020 has a built in MC-step up (Lundahl LL1933, 1:16). The phono stage has a low output impedance. If needed it could drive a step up inut transformer in the linestage. I left out the step up in Stefanos line stage since he has quite senistive power amps and usually listens at moderate levels. This way he has a sensible range on the volume control (Slagle TVC). If needed the line stage could be equipped with a 1:4 or 1:8 step up. In my own line stage I have one of the inputs with such a step up to be prepared for all gain needs.

Best regards

Thomas

11-09-2009 Post does not mapped to Knowledge Tree
coops
London, United Kingdom
Posts 115
Joined on 02-16-2007

Post #: 32
Post ID: 12197
Reply to: 12196
Welcome to the forum
fiogf49gjkf0d

Thomas Hi, welcome, wonderful work , how can one contact you directly?

Keith.

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perrew
Posts 30
Joined on 10-06-2009

Post #: 33
Post ID: 12199
Reply to: 12197
LCR active vs. RC passive
fiogf49gjkf0d
Romy,

what I meant was why choose LCR active over a RC RIAA passive EQ?
Is there a logical explanation for this or does it just sound better in your experience?

/P
11-09-2009 Post does not mapped to Knowledge Tree
Thomas Mayer
Posts 4
Joined on 11-09-2009

Post #: 34
Post ID: 12200
Reply to: 12197
Thanks!
fiogf49gjkf0d

Hi Keith,

thanks for the welcome. I can be reachund by email: thomas >at< vinylsavor >dot< de

Thomas

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Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 35
Post ID: 12203
Reply to: 12196
The random phono-thoughts…
fiogf49gjkf0d

Perrew,

LCR is not active at all; it is the very same passive EQ as your RC? I think you a bit confused with terminology. The main logical explanation (there are many of them) is that capacitive filtration is very bad one and need to be minimized or eliminated. Capacitance still might be conditionally used in the peripherals but when a dielectric deals get constantly recharges by AC in the middle of the band-pass then it is not a good idea and indictor behaves much better in those cases. If you look how the filters are made in the 6-chenal Melquiades the you will clearly see my vote – the RL filters sound way more superior then C-filters.

Stefano,

Yes, the MC-tyrannies certainly would add colors on palette. Be careful with trios miniature WE high gain triodes – they might be very “live”, much more live than you would like them to be. The WE high gain triodes were a bit not stable and you might get over a great number of them until you find a pair of the same gain and the same noise characteristics.  Considering the price of WE437A it might be a pain in ass. I did not play with WE437A but I spent along time to play with 417A. The 417A and WE437A are the very same triode but 437A is taken a bit farther – it has twice more power (7W vs. 3W) and higher transconductance (beginning of 40.000s vs. high 20.000s). The 417A were very unstable, I had 30 or 40 of the original WE and I was able to have 4-5 of them suitable for the first stage. Evan if they were properly handled and used the still were a bit too prone foe some strange noises. They also tend to be oscillative what they get older, again, even if all anti-oscillative precautions are taken care. BTW, Stefano running the WE437A you might find the use of the Alnic shock-absorbing socket savers. I mentioned them

http://www.romythecat.com/Forums/ShowPost.aspx?postID=3333

…and I think it might be beneficial for this type of tube.

Thomas,

So, you have 46-48 dB of gain by two stages juts because WE437 has higher transconductance. In my 2-stages I used the tube with transconductance of 55.000 and I have 68dB of gain. In my book it is a bit low and I like very high gain phonostages: 75-85dB – the higher is better. You claim that your phonostage has a low output impedance – how did you mange to do it? What is the impedance number you got? How do you couple the output? I also do not feel as an optional step-up at preamp level is a good idea architecturally. If you have capacitive output at your phonostage (that you mostly have) then it fine and it is OK to drive your preamp. Then you decided to have more gain and you switch to the preamp’s input that has step-up. You will have your gain but now you have a cap on the phonostage outs side and a transformer in the preamp input – 2 DC clocking devises that are not necessary together. One might argue that in this case you would use a transformer with no gap and an ability to care DC but I would argue that at line-level I would like to have only ether transformer or cap -we do not deal here with high currents and bit, killing-inductance gaps.

Thomas, about your phonostage: as I understand it has remote power supply… so, why it is so big? It must be virtually empty inside. I feel that the phonostage with no PS must be very small to sit right to TT with very short cartridge cable. If you have 48dB gain then Stefano might run let say Ortofone Mono that has 3mV directly to your phonocorrector and do not run the output signal across the whole unit back to the output jacks. Also, in the chasses type you used if it was my phonostage then I would use input and output on the different sides of the chasses. I would reverse the layout making the front tubes as input and putting a set of RCA jacks right there, as far as possible from the power enters. I also find that tonearm cable that runs in front a phonostage is kind of cool idea.

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
11-09-2009 Post does not mapped to Knowledge Tree
Thomas Mayer
Posts 4
Joined on 11-09-2009

Post #: 36
Post ID: 12204
Reply to: 12203
Phonostage gain
fiogf49gjkf0d

Roman,

 

I can't follow most of your arguments. There are many ways to do things and to lay out the architecture of a system. This line/phono combo was designed to work together and to the given requirements. 75-85 db of gain ? Remember this was speced for MM sensitivity. That kind of gain would be way to much. Most preamps and systems have too much gain. Even for MC I consider 85dB gain a bad idea, with a typical MC cartridge with 0,5mV output that would give almost 9V output ! That's about 20dB more than a sensibly designed power amp needs to be driven to full power. With sensitive speakers you hardly drive your power amps to full power. I design systems with as much *headroom* as possible but with as little *gain* as needed. Otherwise all this precious gain needs to be destroyed in a volume control.

Best regards

Thomas

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twogoodears


Italy
Posts 116
Joined on 03-26-2008

Post #: 37
Post ID: 12205
Reply to: 12203
SOME PIXES
fiogf49gjkf0d
Thanks for the tube gel sockets/absorbers hinting, Roman... Thomas had to use such a vibes taming mandatorily, being both 801 AND 437A tubes rather microphonic prone...
Using his clever design... ZUT! Completely silent... also, unfortunately, he had to made it by himself, as the Noval socket used isn't so commonly used in commercial audio.

Nonetheless, ALLNIC's and Pearl's design are VERY nice, smart designs.

Also have a look to the inner belly of the LCR phono-stage... the load of Lundhal's and German made (can't remember the name of manufacturer...) irons used make the inner quite crowdy, yet a clean, elegant mount.


"Use your ears as your eyes" - Gertrude Stein

Stefano
11-09-2009 Post does not mapped to Knowledge Tree
twogoodears


Italy
Posts 116
Joined on 03-26-2008

Post #: 38
Post ID: 12206
Reply to: 12203
SOME PIXES (will follow...)
fiogf49gjkf0d

... ooops... troubles with multiple pictures posting... apologize.

Using a link with very same pixes... http://twogoodears.blogspot.com/2009/10/thomas-mayer-and-we-437alcr-phono.html

and

http://twogoodears.blogspot.com/2009/09/extraterrestrial-landed-near-bodensee.html

Sorry again for spamming...




"Use your ears as your eyes" - Gertrude Stein

Stefano
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Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 39
Post ID: 12208
Reply to: 12204
A phonostage that is “breathing” with signal
fiogf49gjkf0d
Come on, Thomas, no one talks about the 75-85db of gain at MM level. However, the higher gain does has some things that I find is very useful and I find it is much worth to burn extra 15dB in prams then to have a preamp wide open and run photo at low gain. I never experienced such a thing as too much gain. We are taking about gain not about volume. Too much gain it means higher current flows across all stages, cables and coupling devises – high current at line level softening sound. I do not mind to kill a lot of dB at my preamp. I like what the phonostage is “breathing” with signal.

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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Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 40
Post ID: 12214
Reply to: 12208
Tiny Dancer
fiogf49gjkf0d
Who has had success with active amplification of very low level signals (like LO MC output), apart from Boulder 2008 and super-expensive lab-type equipment?

It seems like the safest path (that's still reasonably affordable) for LO MC lift-off is a (passive) transformer step-up, and then start the active amp from there.

To make sense in this discussion, I think everyone needs to declare if by "gain" he means before or after RIAA losses.

Lots of the "modern" RIAA networks are sandwiched between the active stages. How does it work in this case?

How difficult is it to find 437As good enough for a phonostage?

Paul S
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