| Audiofanatic |
I'm looking for the best phono amp (to my ears) to build and I realize that my taste/choice is not the same as you guys or perhaps it is? But to tell you the truth, I'v tryed these and still didn't find the one that makes me happy.
-ONO
-Pearl
-Spectral DMC 12
-Krell KRC and KPE
-Audio&Techniek Tube DIY MM stage with the SUN AUDIO SAT-1000 Transformer.
The one I'm using now is the PLINIUS M14 (from a friend) and to be honest I like the softness of the Pearl the most. But it does not reach the deep bass of the Plinius M14.
Frank, or an other forum member, can you help me?
I want to try the Tube MC Headamp Frank sheared with us, with the Plinius on MM. What do you think of this combination?
I have the Delphi MK III with the IKEDA tonearm and the Shelter 901 MC.
I hope It's not confusing to you guys.
Thank you very much.
Best regards,
Audiofanatic ;) |
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| Notorious |
| I have Audio Research SP-11 and I'll never part with it.. But while my SP-11 was on service, I could borrow SP-10 which is full valve amp, and I thought when, and if my SP-11 ever gives up on me, I'll buy SP-10. It's an old amp, but a true beauty.. Really great thing.. :) |
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| analog_sa |
| quote: | | I want to try the Tube MC Headamp Frank sheared with us, with the Plinius on MM. What do you think of this combination |
An interesting question is whether the MC input in the Plinius is an add-on (like in Ono) or the gain of the entire phono is switchable. In the former case it will, indeed make sense to use a separate tube pre-pre.
The best types of phono preamps to my ears are variations of the Arthur Loesch circuit - 3 stages with split passive RIAA with separate PS for each stage. A very high quality transformer (amorphous or nickel) may be even better than an active MC input stage.
I am curious about the Allen Wright circuits - a different and interesting approach.
Does your assessment infer that the Pearl is superior to the Ono? |
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| Audiofanatic |
Hi,
I'm Just saying that I like the sound to be tubeee!
The Ono sounds (again, to my ears,) to analitical
The Pearl sounds smoother more natural and yet not so tight in the lower region. Am I asking to much?
I want a combination of both world. Is this posible?
Best regards,
Audiofanatic ;)
P.S. the PLINIUS has no ad on stage, but can be done by soldering the tube input on the boards MM input. |
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| analog_sa |
| quote: | | PLINIUS has no ad on stage |
In this case you may or may not experience an improvement using an additional tube stage as you are effectively complicating the signal path. As i am deeply suspicious of the concept of smoothness ( it seems to imply less resolution) i don't have further suggestions. Ime tubes bring 'smoothness' only when improperly applied.
regards |
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| Upupa Epops |
| topology is three independet ams topology with split RIAA correction - I very agree with analog_sa :) . This topology : first amp - tau 1 + tau 2 - second amp - tau 3 - output amp is realy the best in listening test and very good with noise. As first amp you may to use AD 745 or any goog opamp with differential input maded with 2SK170 or 2SK147, certainly in this case for MM. For MC you must use "pre - pre " with AD 797 or to use good step up transformer - again I agree with analog_sa :smash: . |
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| fdegrove |
Hi,
| quote: | | Ime tubes bring 'smoothness' only when improperly applied. |
And I'd second that one hundred percent.
In case Audiofanatic wants to go valves all the way, I'm most willing to help out....
Cheers,;) |
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| Panelhead |
If you like the sound of the Pearl, why not add a gain stage to the input. Several others have done it with good results. The input stage of the Pearl is a great circuit to start with.
Mine is a pair of matched 2SK170BL, each sitting on a 22 ohm resistor. The pair is cascoded with a ZTX450.
Power comes off the Q5 second regulator of the Pearl. Through a 10 mH choke, 1000 ufd cap, then 700 ohm resitor to the ZTX450. The output is cap coupled with a 1 ufd stacked film and foil cap into the 47K input of the Pearl. The board fits right in the back of the case.
The sound is much better than it was running a pair of AN UK step up transformers. I think the MC stepups work better with tube phono than with solid state. I think it has to do with drive current. When you step up the voltage, the current gets stepped down. The resulting current cannot drive the combined gate capacitance of the 4 2SK170BL in the Pearl.
George |
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| Audiofanatic |
| quote: | Originally posted by fdegrove
Hi,
And I'd second that one hundred percent.
In case Audiofanatic wants to go valves all the way, I'm most willing to help out....
Cheers,;) |
Hi Frank,
I may go for a tube, but only in the Head amp. Not the full amp.
If you think you can convince me to go full tube, send me a private mail to convince me.
Best regards,
Audiofanatic ;)
Welterusten, late again! |
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| Saurav |
| quote: | | I think the MC stepups work better with tube phono than with solid state. I think it has to do with drive current. When you step up the voltage, the current gets stepped down. The resulting current cannot drive the combined gate capacitance of the 4 2SK170BL in the Pearl. |
OK, this has been bugging me all weekend long :) So how does one go about determining this? I have a Pearl, and I added input transformers to the chassis. I think mine are set up for 1:10 voltage gain (or current step-down). I tried finding datasheets for the 2SK170 transistors, and it looks like they have 30pF input capacitance? Could someone confirm that? The Pearl uses 4 of these in parallel, so that's 120pF. Which is pretty darn high, I think.
So how does one determine whether a specific cartridge, when its current has been stepped down a specific amount, is good enough to drive this capacitance? It boils down to a tradeoff between the reduced current drive with the transformer vs. the increased noise with an active head amp stage, right. Though if you can keep your noise below the surface noise of the vinyl then it doesn't matter...
120pF, 20KHz, 2.5mV, I can calculate the required slew rate from that. How do I find out how much current my cartridge is delivering? |
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| fdegrove |
Hi,
| quote: | | Could someone confirm that? |
Ciss for the 2SK170 is indeed 30pF.
Crss is 6pF.
This actually to be expected with high devices.
For a tube like a E88CC/6922 the input capacitance is 3.3pF grid to cathode and 1.4pF grid to anode.
Cheers,;) |
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| Saurav |
And the Miller C is Cgk + (A+1)Cga, right? I'm not sure which one goes where for the FETs, but if it's the 30pF value that gets multiplied by the gain, then it gets even worse.
Sounds like a compelling argument to take out my transformers and try an active gain stage. Any suggestions? I'd prefer solid state, because I don't want to build a new power supply. Mayber I could try what Panelhead did.
And here I was, convinced that transformers were better for step-up duty than active stages. Damn you, Frank, blowing a hole through another one of my beliefs :) |
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| fdegrove |
Hi,
| quote: | | And the Miller C is Cgk + (A+1)Cga, right? |
Correct.
| quote: | | And here I was, convinced that transformers were better for step-up duty than active stages. Damn you, Frank, blowing a hole through another one of my beliefs |
I fail to see the point but I think xformers have much improved over the passed 15 years...
I've known the Cotter as being pretty good, it's not perfect though.
Naturally at this early stage in the amplification stage, whatever sonic fingerprint is there, is going to be amplified throughout.
Come to think of it Audionote does the I/V conversion for their DACs in the exact same way we use for MC cartridges...
I use my MC Hammer design and that runs from a raw 30 something volts.
Cheers, ;) |
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| Saurav |
| quote: | | I fail to see the point |
OK, the point I was trying to make was that transformers may not always be the best solution for every step-up situation (as I once believed).
| quote: | | Naturally at this early stage in the amplification stage, whatever sonic fingerprint is there, is going to be amplified throughout. |
And I thought that was all that mattered, and that was reason enough to make transformers better than active stages, period. I hadn't considered the fact that the stepped-down current at the transformer's output might not be able to drive the input capacitance of the following stage.
| quote: | | I use my MC Hammer design and that runs from a raw 30 something volts. |
Is that available anywhere? Or is it copyrighted?
Thanks for the help.
Saurav |
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| fdegrove |
Hi,
| quote: | | Is that available anywhere? Or is it copyrighted? |
Nah...I offered it to the community awhile ago:
MC HAMMER.
It should be in there somewhere.
If you need advise on component choice etc., just ask.
| quote: | | Thanks for the help. |
You're welcome.
Cheers,;) |
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| fdegrove |
Hi,
Something I neglected to mention is that when you know what effect the Miller capacitance is having you can take that into account into the calculations of your RIAA correction.
This eases design quite a bit but you have to know what you're doing with your devices, be that tubes, FETs or xformers.
The latter don't suffer from Miller capacitance but can have a roll off in the highs.
If you see the big picture you'll understand why xformers are the component of choice for so many designers...
I still have to hear one that's totally transparent but I'll be the first to admit that I just can't afford to listen to all offerings.
These dilemmas are exactly why I claim that a very good preamp is way harder to design than an amplifier.
If you know how hard it can be to design an excellent SE amp, think of a MC capable phono preamp as a series of cascaded SE amps having to deal with milivolts at the grid...
Not to mention noise, RIAA correction etc, etc...
And no, having an MC head amp or phono passing a few herz is NOT a good idea if you value your woofers.:att'n:
Cheers,;) |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Audiofanatic
I'm looking for the best phono amp (to my ears) to build and I realize that my taste/choice is not the same as you guys or perhaps it is? But to tell you the truth, I'v tryed these and still didn't find the one that makes me happy.
|
Maybe you should try something like the Phonostage in my system now. You can check it out here:
http://www.arduman.com/aa/Sayfalar/...en/thorsten.htm
Scroll down towards the end....
Sayonara |
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| Audiofanatic |
Hi Frank,
I may try your designe eventualy. But first, your head amp and the Hiraga head amp! I'll let you know which one I like the most!
Thanks Frank and all other forum members, you'll hear from me within a few weeks.
I need to test the Tent XO2 first, probably by the end of next week.
Best regards,
Audiofanatic ;) |
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| fdegrove |
Hi,
| quote: | | I'll let you know which one I like the most! |
Ha,...Le PrePre...
I know that one inside out...
If you want good sound out of it, use a battery suply, well decoupled.
It's still not going to sound very dynamic but it isn't bad at all.
| quote: | | I need to test the Tent XO2 first, probably by the end of next week. |
Haga como quieres, hombre...;) |
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| Audiofanatic |
Hi frank,
Can I use BC transistors for this one? and will 9 volts batery be to high for it?
Is this one more dynamic? See att. pic
Gracias paco.
AF ;) |
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| Tube_Dude |
| quote: | | Can I use BC transistors for this one? |
Yes you can...specially the low noise types...| quote: | | and will 9 volts batery be to high for it? |
No ...it will be fine!!
If you want the some operating points change the 2k2 resistor to a 3k3 resistor!And the 6,2k to 9k3(10k will be fine)
Regards |
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| fdegrove |
Hi,
| quote: | | Is this one more dynamic? See att. pic |
Nope...
| quote: | | The pic you provide don't has voltage gain... only current gain! |
Yep...
A Texan answer I'm afraid....
Not my cup of tea...
Cheers,;) |
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| Audiofanatic |
Hi guys,
If this on is better I'll use it in the head amp.
If you say no! I'll use the BC550C.
Thanks ones again!
Audiofanatic ;) |
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| Tube_Dude |
Actualy...it does have voltage gain.
At first i though that the input was at le left of the schematic...but after some bourning eyes it look like that the input is at the botom..
In this case we have a paralel comum base transistor stage...and we have voltage gain and no current gain...;) |
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| fdegrove |
Hi,
| quote: | | In this case we have a paralel comum base transistor stage...and we have voltage gain and no current gain... |
Guess I suffer fron the same eye strain...Yes, you're right.
Still don't like it too much though:D
Anyway, the art is in the execution I suppose....;) |
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| Tube_Dude |
| quote: | Originally posted by Audiofanatic
I'll use the BC550C.
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Yes is a fine transistor...low noise and in the C version high current gain...
One of my favorits ;) |
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| jewilson |
Audiofanatic
You would be better off with the parallel FET's and an a gain stage vs. the bipolar transistors due to leakage currents. Also, that input cap should be a Teflon or polystyrene.
Tubes or ok but their noise is just to much for me. The transformers I have heard had no balls.
A comman gate fet have a natural low impedance. John Dunlevy used this in an older design and worked well. The parts are much better now.
"This is my Texan answer" |
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| Upupa Epops |
| Standard BC transistors are not good for this circuit. For low noise you must use transistors with low rbb. Look at pages of Erno Borbelly or on AD pages. |
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| fdegrove |
Hi,
| quote: | | Tube or ok but the noise is just to much for me. |
Johnson noise from the tubes in my circuit is the same as a 70 Ohm resistor...
With a CCS on the anode the PSU noise is out of the picture, no cathode resistors either...
It does I/V perfectly well but it relies on the tubes you use and the noise of the JFETs used as CCSs.
| quote: | | "This is my Texan answer" |
Hope you see the humour....:D
Cheers,;) |
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| Audiofanatic |
| quote: | Originally posted by jewilson
Audiofanatic
You would be better off with the parallel FET's and an a gain stage vs. the bipolar transistors due to leakage currents. Also, that input cap should be a Teflon or polystyrene.
Tubes or ok but their noise is just to much for me. The transformers I have heard had no balls.
A comman gate fet have a natural low impedance. John Dunlevy used this in an older design and worked well. The parts are much better now.
"This is my Texan answer" |
Jewilson,
Do you have a schematic?
Thanks.
Audiofanatic ;) |
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| Tube_Dude |
| quote: | Originally posted by jewilson
A common gate fet have a natural low impedance. |
The inpedance looking in the source of a fet is 1/Gm...in a typical fet we have 10mA /volts...
So we have 100 Ohms of input inpedance with the fet stage...
With the bipolar the impedance looking at the emiter is 25/Ic...so as the current in the schematic is 1,1mA we end up with 22 Ohms...
Five times better! ;)| quote: | | "This is my Texan answer" |
"This is my Portuguese answer!" ;)
Cheers |
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| fdegrove |
Hi,
Shall I put you through the thinking?
The ECC88/6DJ8 has some qualities few other tubes posess: it's low noise, has very good transconductance and is linear at Vg=0.
Add to that that it's perfectly happy transforming I/V just like a J-FET, stick a CCS on it's anode and you have what a MC needs...
The I/V is done by the load resistor serving as the gridleak and hey, the tube is forced into current mode operation, elegant and simple.
I use a very low output MC and I can't hear any noise...
Not in my system anyway, at a 92dB/WM I'd expect to hear it yet I don't. No noise and dynamic range to die for.
Cheers,;) |
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| Tube_Dude |
Hi
The ECC 88 with the transconductance of 12,5 ma /volt as a cathode impedance of 80 Ohms...as good or beter than a fet...
cheers ;) |
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| Audiofanatic |
Hi Frank,
I'll go for the tube version, eventualy!
But first I would want to know if you can supply the 4 tubes and, what would be the price?
I'm gona use the Raven R2 Tweeter 96db/W/M, instead of the Martin Logans, so, what about het noise of this head amp vs. the Hiraga/Threshold?
Audiofanatic ;) |
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| fdegrove |
Hi,
| quote: | | The ECC 88 with the transconductance of 12,5 ma /volt as a cathode impedance of 80 Ohms...as good or beter than a fet... |
We need to look at the tube's transfer curves in the circuit proper, than look at what it's going to see next and how it will look than etc.
I designed it in such a way that the system as a hole is holistic, the preamp can be used for MM cartridges, the MC Hammer + MM preamp work together well too...
Respecting all standards along the way.
In fact I can't think of a single cartridge it can't cater for...
The preamp's output can drive both lowish impedance and long capacitive cable without changing it's frequency response within the audio band and often way beyond.
This set of qualities is why I'd like Audiofanatic to understand that matching commercial product can and often does result in a mismatch...
Not to mention the fact that most commercial designs need to be even more stringent designing their product...
Designing for your own needs is alot easier, believe me.
Cheers,;) |
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| fdegrove |
Hi,
| quote: | | But first I would want to know if you can supply the 4 tubes and, what would be the price? |
Quit the tube business some years ago but I fully trust Ger Fust who was a customer of mine:
| quote: | | http://www.fust-electronica.nl/ |
Send him my sincerest regards and ask him to match the tubes to Reference Audio standards...
He'll understand and have a little laugh...
Cheers, ;) |
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| Audiofanatic |
Gracias Paco!
I will.
Bye bye.
Audiofanatic ;) |
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| fdegrove |
Hi,
Con mucho gusto...No me falta nada, no te preoccupes. :cool:
Buenas noches,;) |
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| jewilson |
Audiofanatic
I might still have it, however I had this amp back in the late 70's |
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| planet10 |
| quote: | Originally posted by analog_sa
I am curious about the Allen Wright circuits - a different and interesting approach. |
Parts are gathering for mine... give me a couple years :) to get it finished and i'll comment on how it sounds. The full-diff version lets you run out from the TT in fully balanced mode with absolute phase switching.
dave |
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| fdegrove |
Hi,
| quote: | | The full-diff version lets you run out from the TT in fully balanced mode with absolute phase switching. |
Absolute polarity switching is nice to have but Allen Wright's circuits are hybrid ones...
Using a 2SK170, I think...as an input device.
Nice circuitry but I don't want to hold my breath for two years to find out, Dave..........Neither do I want to go into in too much detail on who thought of it first.
Choking,;) |
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| planet10 |
| quote: | Originally posted by fdegrove
Absolute polarity switching is nice to have but Allen Wright's circuits are hybrid ones...
Using a 2SK170, I think...as an input device. |
There is a version with a tube section on the bottom (usually not quite as quiet), and he is now recommending a different device on the bottom... he suggested i start with the 2SK170 version thou.
dave |
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| fdegrove |
Hi,
Thanks, Dave.
| quote: | | There is a version with a tube section on the bottom (usually not quite as quiet), |
Ah,ah...didn't even know that.
Is there any extra info on that somewhere?
Having a low noise floor is a must but there's a point of diminishing returns...
I mean, there's little point in going below the noise floor of your source, is there?
Vinyl isn't particularly excelling in that department but somehow it seems to make music....;)
Cheers,;) |
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| planet10 |
| quote: | Originally posted by fdegrove
Ah,ah...didn't even know that.
Is there any extra info on that somewhere? |
In his book... uses a 6922 section instead of the FET.
| quote: | | Vinyl isn't particularly excelling in that department but somehow it seems to make music....;) |
That bears repeating :^)
dave |
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| fdegrove |
Hi,
| quote: | | In his book... uses a 6922 section instead of the FET. |
I guessed as much...
The 6922 and cousins really sound great once CCS'ed...
| quote: | | That bears repeating :^) |
Hear, hear...Couldn't agree more.
Cheers,;) |
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