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,

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?

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.

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

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.

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

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

Keith.

Hi Keith,

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

Thomas

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.

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

... 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...

Paul, I do not think that “before or after RIAA losses” requirement has any merit as no matter what kind type RIAA filter is being used it always will lose around 20dB. I do not think also that there is a “safest path” or “reasonably affordable”. In my view any topology of RIAA filters are in the same cost, even the LCR RIAA filters are in the same price scale.  The 5K or 10K LCR would be expansive but 600R is tolerable. What I mean by tolerable is that the cost of the 600R LCR deluded in the cost of total corrector of compatible sound. To make a properly sounding feedback or RC phonostage is hard and when you do it then the cost of 600R LCR filter is well consumed into the cost of the whole project.

How difficult is it to find 437As good enough for a phonostage? For commercial applications is it a dead tube. WE might produce it again when they stated to redo the tubes but the existence of the Russian 6C45P pretty much killed the idea. For none-commercial applications it is a fine tube and if somebody has some stash of them then why do not use them?  And hard to get them new, they are expensive and mostly those 437A that let go are the noisy one, why would anyone sell good 437A?

It would be interesting to learn how much the 437A is better then 6C45P. The 6C45P are OK if they drive a lot of current. If do not use the stupid pulse version that everyone look like use and find them from 60s than the 6C45P might work out. I afraid that to find the 6C45P from 50s would be as hard as to find the 437A.  I do not know anyone who used 437A in phono. I think in Stefano case the 437A in input stage and output stage would behave differently.  Give him a few months and I am sure he will experiment with 437A, 417A, 6C45P, 3A/167M in different configuration and will decide what to use. Output tube in Thomas Mayer phono might be pretty much anything.

BTW, the stand alone LCR phonostages are not the optimum configuration in my view. It would be fun to have a full preamp with one two inputs with LCR RIAA, then you can optimize the amount of stages and do not use the preamp output stage as phonostage’s output stage, effectively dropping one active stage.

Romy the Cat wrote:

How difficult is it to find 437As good enough for a phonostage? For commercial applications is it a dead tube. WE might produce it again when they stated to redo the tubes but the existence of the Russian 6C45P pretty much killed the idea. For none-commercial applications it is a fine tube and if somebody has some stash of them then why do not use them?  And hard to get them new, they are expensive and mostly those 437A that let go are the noisy one, why would anyone sell good 437A? It would be interesting to learn how much the 437A is better then 6C45P. The 6C45P are OK if they drive a lot of current. If do not use the stupid pulse version that everyone look like use and find them from 60s than the 6C45P might work out. I afraid that to find the 6C45P from 50s would be as hard as to find the 437A.  I do not know anyone who used 437A in phono. I think in Stefano case the 437A in input stage and output stage would behave differently.  Give him a few months and I am sure he will experiment with 437A, 417A, 6C45P, 3A/167M in different configuration and will decide what to use. Output tube in Thomas Mayer phono might be pretty much anything. The Cat

twogoodears wrote:

Yes Roman... I feel pretty like I entered a sort of "cul de sac", tube-wise... I contacted, few months ago, Western Electric USA and they told me that, at USD 750 ea. they have "plenty" of N.O.S. WE 437A... I've been able to find and purchase for a much lesser amount, 9 tubes of different batches but in matched Mu pairs... despite Thomas' testing and matching and myself at the wallet commands;-) the consistency in perceived balance between left and right channel proved to be quite tricky, worth careful settings and several tubes swappings and combinations.

Yes, I did the same. What in 2000 I got Lamm LP2 that used 417A I also did call to WE and asked them about the 417 tubes. They told that they have them and gave me some absolutely ridicules price, with a first price drop of a few dollars after 500 tubes. I do not remember exact price they gave me but it was way in the realm of fantasy. Then I went “to word” and sourced of 417A, learning the 95% of them not usable. BTW, the $8 Raytheon 5842 was a very good sounding alternative to 417A. It had less flashy name but I learned that 5842 were more stable in quality primary because you buy a party of new 5842 vs. you buy the 417A as new that somebody have tried and find them to noisy – so I felt that the whole pool of 417A was better and I would not necessarily say that WE417A sounded better then Raytheon 5842. Now the whole phonostage did not sound right, but it was a totally different story…. Anyhow, that gave me some trepidations when I think about the high Mu triodes… I have a friend in NY in whose system a perfectly operating 417A totally out of bleu when nuts and blew up tweeters in $90K speakers. The high Mu fast triodes are strange….

twogoodears wrote:

Thomas reports the Telefunken EC-8020 as much more selected at factory before reaching final users...

One of the advantage of passive EQ that you have in your phono that you can use any tubes you wish, them design is not very strict as it is my case. Let your Thomas to cook for you your phonostage with 7788 in the first stage. You Europeans know it as E810F. That tube has higher gain at lowers noise and it is stunningly stable. You can take any Telefunken E810F, replace it with another and your will be have insultingly exactly the same operational parameters. I have less success with Mulard and Philips E810F but German E810F are very-very good. It is 5W tube and it will be able to drive you 600R load.

twogoodears wrote:

The British 3A/167M still more sought after and expensive than EC-8020 and 437A and - truly - unavailable everywhere, is a much better tube than WE 437A: sure mechanically, with its metal ring socket, it is.

…and I do not know if 3A/167M is better than anything else and I do not see why the metal socket is necessarily better then plastic – the socket is not the part of the tube. It is the same 7W tube with 1K on late and Gm of 42. The 3A/167M for sue is much more expensive and much more difficult to get. I did not use it and I did not hear it is anybody installations. When you say that it is “much better” then you need to understand that audio people love to create a cult-like BS, which makes the things to be “sought after”. I do not think that it would be a huge actual different for you to use 3A/167M or 437A beside to make good pictures for your blog and let the Audio-Morons to envy. However, what I would like to point out is the fact that when you read/hear the exuberant comments from some 3A/167M users about the 3A/167M superiority then… then NEVER talk about Sound. At my time what I collected information about 3A/167M I never was able to suck of the 3A/167M users any thinking about sound that I find not even attractive to myself but even rudimentary-sensible. Sure, it does not say anything negative about 3A/167M but rather about the community of all those stupid DIYers but still I did not develope any encouragement to peruse into the 3A/167M direction.
 

twogoodears wrote:

The 6C45P was a serious alternative to WE 437A, even less consistent in performance in a tube-to-tube comparison, but I'm much more confident the next German/Italian task will be, always using a Tango EQ600 LCR, the WE 416B and 416C. It's still available for cheap and in quantity and an italian tube scholar and builder, Daniele Ansaloni http://twogoodears.blogspot.com/2009/09/western-electric-416-b-and-c-golden.html (who built and listened to such a phono stage with full Tango (old) irons) says - in perfect italian: "Wunderbar!"

I never heard the WE416B/416C, not about them but from what I just have seen in their sheets and in the description of their design they might be very interesting tubes. The only thing that you need to watch with them is my Vacuum Cap Syndrome. The Vacuum Capacitors are the best caps to use in my phonostage but there is one ugly factor. The Vacuum Caps are high voltage and the contact surfaces are very large. When you have you .25mV signal coming from your cartridge across the 38ga cable then suddenly you expose a plate of Vacuum capacitor with a contact of 30mm diameter than the rapid change of the conductive volume is affect sound very negatively (read my comments about the superior  posts:  http://www.RomyTheCat.com/TreeItem.aspx?PostID=11807)

twogoodears wrote:

Last but not least, another viable tube for phono-stages - still elusive, BUT not hideously priced, yet - would be Western Electric 436... worth investigating.  The WE 437A are very nicely sounding in my system

And what is wrong with your Sound of 435 that might encourage you to look into 436?  :-)

http://www.romythecat.com/Forums/ShowPost.aspx?PostID=432

twogoodears wrote:

...yet as Roman pointed out, I hope the search be not over... as it's a BIG part of passion.

twogoodears wrote:

Maybe someone read this http://twogoodears.blogspot.com/2009/05/we-437-based-phono-stage-solid-rock-did.html, worth reconsidering its design - also (partially) using WE 437A - after the last posts discussion at Roman's... also worth remembering that this super-expensive phono-stage went roasted in a fire at a Munchen Audio Fair, last spring...

From the picture it looks like they have a phonostage stage as a part of a full-blown preamp – that is a right direction to go. However, I really hate the Audio Consulting and the way HOW they think and WHAT they do. I have no negative experiences with them or anything like this that makes people to hate but the whole whorish and completely empty philosophy of sound from Audio Consulting is so disgusting to me that I feel a need to voice it. It is no surprise that the “sound” that Audio Consulting trying to promote made the 6moons cretin so “overwhelmed” (even I did not read the 6moons article).

Paul S wrote:

I have never used the 417 or 437, but I have heard plenty of whining from folks who do.  They often pay a small fortune for "special" tubes and wind up with tubes they simply cannot use for low-level input.

Paul S wrote:

Lastly, gain and impedance in the input or output tubes absolutely affect the sound of a tube phono stage.  As Roger Modjesky pointed out, these factors actually wind up affecting the "RIAA Curve" itself in any LCR RIAA circuit, whether "split" or "continuous".

Thomas Mayer wrote:

I never had a lot of trouble with high transconductance tubes. I use the EC8020 a lot.

Stefano, you might look into this EC8020. I never seen it but just looked into the datasheet and it looks very interesting tube and it might be better candidate to your phonocorrector’s fist stage then the WE 437A. I generally, under other equal conditions, prefer Telefunken/Siemens tubes to any other tubes. My second choose would be the older British tube and only then I would look into all of those RAC/WE/Raytheon. Of cause it is a gross generalization but … I am comfortable with this generalization.

Thomas Mayer wrote:

This is true for RC RIAAs, not for LCR RIAAs. This is one of the big advantages of the LCR technique. The network has a constant 600 Ohms input impedance, if it's terminated by the proper 600 Ohm value. Variation in the driving tubes rp does only affect the loss in the network, but the loss is always the same over the frequency band. So the RIAA curve will not chabge when the tube detoriates or when tubes are changed.

That is not necessarily true. I think any passive RIAA would not be a subject of curve variation with tube aging. Moreover, I would take this argument even further. Even if we have a feedback RIAA, where the gain of the open loop is in the task of direct shaping the RIAA curve, than I feel that aging of the tube and minor change of their gain is not truly a practical issue. There are a lot of people out there who go totally crazy with writing the accuracy of the RIAA curve with .05dB precession. I feel that it is absolutely not necessary. If you want RIAA precession then have your corrector to run multiple curves as 50% of records out there are NOT RIAA pre-equalized. It is not to mention that there was a huge deviation in the RIAA equalizers during the cutting of the records. From what I see the .25dB-.5dB accuracy is plenty for normal record playing. The MC R loading, MM C loading, VTAs, the cartridges themselves give much higher discrepancies then .25dB. so, if you look how the small tubes change gain with time then in most cases it is not significant to affect RIAA too mach. Unless your LP is the only source you use and unless you run your phonostage a few hours each day I would not feel that the tubes aging might be a factor in RIAA running away.