You seemed to have dropped your pro- ME pre-amp position very quickly.
Great news, well done.
Hanze.
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...for the sake of accuracy, I don't recall any viable DIY 'alternatives' offered to me by ZB. Only to 'stop trying to get a valve preamp to work with the ME550 and get an ME preamp'...in a nutshell...and in one comment when I suggested he be helpful; that he would 'not waste his time helping me with my project' or something along those lines... I don't recall any helpful DIY suggestions being made at all to be honest, unless a fleeting post escaped me. My thoughts were he could have been helpful if he wanted to, but chose not to for whatever reason. I dont hold any grudges, but I don't know why this is still going on...I really just want to get on with this project...
...moving along...
Regarding sonic quality of <10ohms vs 68Kohms, when I asked P.Stein this question and if there would be any sonic degradation his response in summary was that 'sound quality has more to do with how the input of an amplifier gets its signal'...and that 'cable quality will be much more influential, and how the preamp (if more than a few hundred ohms output Z) reacts to both the cable and the environment' ... ie: interference, and that 'this is outside the influence of the amplifier input,...it just amplifies what it sees'.
...moving along...
Regarding sonic quality of <10ohms vs 68Kohms, when I asked P.Stein this question and if there would be any sonic degradation his response in summary was that 'sound quality has more to do with how the input of an amplifier gets its signal'...and that 'cable quality will be much more influential, and how the preamp (if more than a few hundred ohms output Z) reacts to both the cable and the environment' ... ie: interference, and that 'this is outside the influence of the amplifier input,...it just amplifies what it sees'.
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Ah.. a complaint, I see..
For the record, I never quoted - or even paraphrased you. I understand your position but for some reason cannot see your head.
Hanze.
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Drive impedance and the capacitance of the cable. Yep. And the real issue with that is...?? output impedance into a shunt capacitance, and at what frequency?.. and the difference between 10R or 1000R into some pF for audio frequencies is what?.. yep, nothing. But technically it is correct. Good marketing material.
It is not a matter of '<10 ohms vs 68k ohms', but a matter of whether, say, 200 ohms is suitable to drive the amplifier as configured with Zin 68k. The answer does not require a response from the designer, the answer is solid: it is better than OK.
I think it might be time to stop listening to others and start listening for yourself. PStein did not write 'any book' let alone one on audio electronics, however Howard Tremaine did. Its pretty common knowledge that 1:10 is about as close as you want to be wrt drive (output) impedance to input impedance. If 68k is your input impedance.. well, its all been said before in this thread.
Build Douglas' stage, it'd be good if you can find matched tubes and tame the high Gm tube (some say easy, some say not - as you have read), time to step on out and start.
Quite seriously, all who said that the JP schematic is 'junk' are absolutely correct. It would be hard to come up with a worse design for your application, and there is not much more left to be said about any of this. You have two designs presented to you, one of which even comes with tube and socket. Pick one, or both - you will not regret it.
Hanze.
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No schematics have been posted for any design as yet...
I already have the circuit board and parts (caps quite $$) for the JP200, so I would still build it and then compare - but with the modifications I listed ie: 12AT7 on cathode follower stage etc; however I am keen to build Douglas's as well, once a solid schematic appears....I am not aware of any other design offered in the form of a schematic..., apart from suggestions. Although I appreciate them, when people suggest things, I need a schematic to make sense of it, not having much experience with all this....
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2 x 1uF - 400v = 4.44 GBP
2 x 0.47 - 630v = 4.64 GBP
2 x 0.01uF - 630v = 4.64 GBP
2 x 2uF - 630v = 7.7 GBP
I also got alternatives for mods as suggested by 'Norbert'...ie:
2 x 0.047uF - 630v = 4.64 GBP
2 x 0.1uF - 630v = 4.64 GBP
2 x 0.25uF - 630v = 4.64 GBP
I purchased Ansar supersounds from the manufacturer in the UK. They are used in some oem UK equipment. They were easy to deal with until the last time.
For some reason they could not get the final list right this time, made mistakes, did not send all the parts on the list - and got offended and not-so-nice when I pointed all this out.
Eventually they sent the parts missing, and replaced 2 faulty components out of spec. Prior to this they were quite on the ball. It was quite surprising to me.
My address on an invoice and name was very badly misspelt - I could not help but wonder if excessive alchohol may have been involved - it crossed my mind...
6 x 100uF/450V Nichicon KX from elsewhere...
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If you want to use a cathode follower, look at something like a paralleled 6080 per channel. The 6BX7 and 6BL7 are also decent choices, and actually the EL34 setup as a cathode follower will also have adequate drive.
The best option for what you want to do is a transformer coupled tube linestage. The 6C45PI is a fine choice for this, and a 5K output transformer will get you the low output impedance you need.
Or you could run about ten 12AT7s per channel as paralleled cathode followers.
If you want someone to barf out a schematic, you should let us know if you have the budget available for a proper pair of output transformers.
The best option for what you want to do is a transformer coupled tube linestage. The 6C45PI is a fine choice for this, and a 5K output transformer will get you the low output impedance you need.
Or you could run about ten 12AT7s per channel as paralleled cathode followers.
If you want someone to barf out a schematic, you should let us know if you have the budget available for a proper pair of output transformers.
Hi TS,
Okay, you weren't that badly burned for capacitors. I feel better about those parts. That was my main concern.
High end audio has its share of characters, so don't worry about that supplier. Maybe when they dry out they will return to the helpful, efficient supplier they can be.
-Chris
Okay, you weren't that badly burned for capacitors. I feel better about those parts. That was my main concern.
High end audio has its share of characters, so don't worry about that supplier. Maybe when they dry out they will return to the helpful, efficient supplier they can be.
-Chris
Hi AW,
I am quite interested in pursuing the 6C45 path, but have not heard from Douglas as yet with regards to a schematic etc. I have no idea of the cost of a pair of output transformers for this. He did specify some components but I have not looked up the cost. I need a list.
With regard to the 12AX7/12AT7's, I already have the circuit board and major components specific to the JP200 (see attached schematic), so I am committed to making this - however still wish to make the other design suggestion and also consider other suggestions.
In the meantime, with regards to the JP200 and the mods I intend to make as per previous post - any design improvement suggestions using that pre-made circuit board are encouraged in that regard. Its the best quality circuit board I have seen actually, looks about 2 - 2.5mm thick with thick gold plated tracks and well coated.
He supplies OEM manufacturers and Cricklewood audio supplies as well as others - I doubt he would particularly care about my or one private persons business.
It was quite surprising. What you would basically expect when making an order to be logically fulfilled in an acceptable manner.
It was one of those situations where no matter how cordial and explanatory you are and try and explain something which common sense would make evident to the most simple; things just get worse and taken out of context so that the right perspective is lost resulting in a total breakdown of further interaction - which is what occurred on his side - getting emotive and taking every anomaly not fulfilled in my order that I brought to his attention as some kind of personal offront.
I did not find the attitude exhibited considerate nor honorable in what one would expect professionally from others, however he did rectify things eventually after I sent him a series of emails after his 'last response' which would have left me high and dry otherwise. I still thanked him for fulfilling the order and rectifying the faulty components eventually - in a cordial and civil manner.
I found one earlier email response from him surprising, when I was asking him if he had 'electrolytic capacitors' and he mentioned urinating in a pot or something to make them. He was indicating how inferior he thought they were to using PP caps in a manner he found amusing.
Have you any comments or suggestions to make regarding the modifications I listed on page 35 regarding using 2 x 12AT7's in the cathode follower stage of the JP200 and other related changes to components??
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Hi TS,
Not off hand. Don't forget that I have my hands full of something I'm working on. Besides, this is page 8 for me.
I wouldn't want to comment on mods because that means I have to study what the original circuits are, and then figure out what the suggestions are all about. Often, changes to specific brands and models that aren't industry standards are pointless opinions. I haven't time for that as I am engaged in my own work right now. I have given my viewpoint on components already. #1, they have to fit properly. Parts that are much larger than the average are typically bad choices. I'm not about to hunt down spec sheets to compare them only to find out the recommended parts are just puffed up audio jewelry.
-Chris
Not off hand. Don't forget that I have my hands full of something I'm working on. Besides, this is page 8 for me.
I wouldn't want to comment on mods because that means I have to study what the original circuits are, and then figure out what the suggestions are all about. Often, changes to specific brands and models that aren't industry standards are pointless opinions. I haven't time for that as I am engaged in my own work right now. I have given my viewpoint on components already. #1, they have to fit properly. Parts that are much larger than the average are typically bad choices. I'm not about to hunt down spec sheets to compare them only to find out the recommended parts are just puffed up audio jewelry.
-Chris
Hi Chris,
The 'ansar supersounds' were my own choice of capacitor, as I only got the circuit board from 'analogmetric' - not the entire kit, which uses "...Solen / WIMA MPK10 capacitors, Nichicon FW capacitors, BHC Averox / Philip BC capacitors, and Dale resistors."
Regardless of issues with the manufacturer, Ansar supersounds are a very good buy ... I have found.
I like the crisp detailed sound silver gives. I have used them in upgrading the crossovers in my ProAC and ARCAM II speakers and the difference is startling in terms of detail and life-like soundstage. I have also used solid-silver wiring internally which I annealed, and Mundorf lead-free silver solder. The comparison is like night and day...It does make a big difference and is worth doing IMO.
A possibly better more-$$ alternative might be Jantzen Silver Z-cap.
A value for money with good reports appears to be: Mundorf Evo oil, but it does not appear to have silver content. The Mundorf 'silver-gold' version indicates there is some silver content.
( Humble Homemade Hifi - Cap Test )
...silver is the best conductor for electricity out of easily available metals...that is why sound signals travelling through it sound crisper, more detailed and life-like...
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Hi TS,
I hate to say this, but most of what you just posted about silver has zero effect for audio. The PCB is made of copper, very thin copper in fact. The components often have copper coated steel leads. The fractional decrease in resistance is swamped out completely. In fact, connection resistance will also swamp any possible improvements the addition would bring. So save yourself the money and go for high quality copper interconnects. For components like capacitors, just buy the normal industrial components, they are often superior to the audiophile approved parts.
Now, what about the differences you think you heard ... expectation bias. Once you believe a certain thing it is very difficult to change your understanding even with cold hard measurements and facts.
-Chris
I hate to say this, but most of what you just posted about silver has zero effect for audio. The PCB is made of copper, very thin copper in fact. The components often have copper coated steel leads. The fractional decrease in resistance is swamped out completely. In fact, connection resistance will also swamp any possible improvements the addition would bring. So save yourself the money and go for high quality copper interconnects. For components like capacitors, just buy the normal industrial components, they are often superior to the audiophile approved parts.
Now, what about the differences you think you heard ... expectation bias. Once you believe a certain thing it is very difficult to change your understanding even with cold hard measurements and facts.
-Chris
At the within reason prices quoted they well seem worth trying, I agree.
Lead is the very first thing to get rid of in an audio system.....every last bit of it, all the way to and including the driver flex lead connections.
After that you have an even chance to discern and optimise all the other components/materials in your system, go for it.
Silver sounds different to other materials, the reason I suspect is not so much to do with low resistance, and with the property of increased conductance a byproduct.
Chris, I don't completely buy the 'expectation bias' argument......myself and many, many others have done enough experimentation to not fall for this.
Knowing by experience, and 'understanding' according to teachings are two very different conditions....think it through and consider your own assertions.
Just sayin'.
Dan.
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