| GlidingDutchman |
After a disgusted failure with my attempted construction of a high quality phono stage from scratch I turned my attention, to much horror of the thing, to my Pro-Ject Phonobox II.
The Phonobox II is powered by 16v AC from a wall-wart tranny. Some audiophiles are appalled by this configuration so I thought I should for once address the "problem".
Opened up the unit and scanned around the PCB... found the two little chips (full of smoke). 79L15 & 78L15 IC regulators, which attempts to filter and smooth the half-wave AC from the single feed AC supply.
I carefully removed the two (yes only two!) diodes that divides the single phase AC current into two out-of-phase half-wave feeds. Also removed the AC input jack.
A nice cable was prepared and carefully soldered in place to feed the two regulators with < [+] [GRND] [-] > from the two 12v (-12v 0v +12v) batteries.
Wow! Am I surprised by the increase in sound quality! Look, the Phonobox II is actually a bloomin good RIAA pre-amp compared to pre-amps costing tenfold. (These days every pre-amp designer uses Op-Amps anyway... there is only a few left that has the guts to design a pre-amp using discreet components).
The sound-stage projected by the speakers suddenly has air and is almost tangible. My blasted hum is virtually gone and overall sound is inviting!
I am very pleased I took the plunge at converting the Phonobox. I wanted to do so for a long time but was scared. The tinkering with pre-amp building taught me one thing for sure - how a regulator looks and works! So there you go!
D |
|
|
| despotic931 |
Nice! Have you considered building your own diy power supply for it, or will you just leave it running off of the batteries?
-Justin |
|
|
| GlidingDutchman |
| quote: | Originally posted by despotic931
Nice! Have you considered building your own diy power supply for it, or will you just leave it running off of the batteries?
-Justin |
Justin
Luckily I have a lot of these "alarm" 12v batteries and will continue to use them. That was the idea from the start.
I will look into building a simple mains PSU for the phonostage but for now I am happy!
Sound is alive and airy! I love it!
D |
|
|
| analog_sa |
| quote: | Originally posted by despotic931
Nice! Have you considered building your own diy power supply for it, or will you just leave it running off of the batteries?
-Justin |
Why?
The only reason that miserable thing sounds good are the batteries. Nearly impossible to get any PS/regulator to sound the same.
The "battery" sound is very impressive in immediacy, air and detal. There are some shortcomings though. |
|
|
| GlidingDutchman |
| quote: | Originally posted by analog_sa
The "battery" sound is very impressive in immediacy, air and detal. There are some shortcomings though. |
Hello Analog SA! Have we met before?
Yes... like I said before - the sound is airy and focussed! :cool:
What shortcomings are there? :hot:
D |
|
|
| shallbehealed |
| quote: | Originally posted by GlidingDutchman
What shortcomings are there? :hot:
|
For one, you have to replace them. ie. buy new.
For two, you have to recycle them. ie. pay someone to take the old away.
If you don't do two, then please start. |
|
|
| tubenut |
Battery drawback?
Other then "green issues", dynamics for one imo/experience.
Different batteries also sound different btw...
In comparison to what reference are you calling this thing a "Super Audiophile Phono-Stage "?
It is not bad for the money in comparison to commercial options, better once some modifications are done to poor quality filter components and quite listenable but audiopile? Depends on what that means to the individual I guess.
Compares well to tenfold the price? What have you tried? For one the Clearaudio Smartphono craps all over it for say 3* the price. At ten times the price it is another ballgame all together and it is left far behind.
|
|
|
| despotic931 |
| quote: | Originally posted by GlidingDutchman
Justin
Luckily I have a lot of these "alarm" 12v batteries and will continue to use them. That was the idea from the start.
I will look into building a simple mains PSU for the phonostage but for now I am happy!
Sound is alive and airy! I love it!
D |
Ahh, the reason I ask is that I was considering purchasing a phonobox and then building a new power supply for it, But didn't want to take the battery powered route.
| quote: | Originally posted by analog_sa
Why?
The only reason that miserable thing sounds good are the batteries. Nearly impossible to get any PS/regulator to sound the same.
The "battery" sound is very impressive in immediacy, air and detal. There are some shortcomings though. |
Batteries are a continual cost, something that will be a continual drain of my funds. These are funds that are short already, and I know these batteries are quite costly. I don't doubt that it doesn't sound way better than the stock psu, but I also believe that you could build a custom psu that would be much better as well.
-Justin |
|
|
| GlidingDutchman |
| quote: | Originally posted by tubenut
Battery drawback?
Other then "green issues", dynamics for one imo/experience.
Different batteries also sound different btw...
In comparison to what reference are you calling this thing a "Super Audiophile Phono-Stage "?
|
Dynamics are now better than ever as opposed to the crude AC system...
The thread name? Just to draw attention - :devilr:
Yes, I am aware that there are designs that will whack it in the face but for now it sounds marvellous!
D |
|
|
| GlidingDutchman |
| quote: | Originally posted by shallbehealed
For one, you have to replace them. ie. buy new.
For two, you have to recycle them. ie. pay someone to take the old away.
If you don't do two, then please start. |
Replace them how often? Every few years? Not a big deal I think...
Recycle - whats that? I live in Africa! :clown:
(Dont worry... I wont dump the used batteries on the wasteland. We have a scrap metal recycle yard here in town that recycles lead products)
D |
|
|
| GlidingDutchman |
| quote: | Originally posted by despotic931
Ahh, the reason I ask is that I was considering purchasing a phonobox and then building a new power supply for it, But didn't want to take the battery powered route.
Batteries are a continual cost, something that will be a continual drain of my funds. These are funds that are short already, and I know these batteries are quite costly. I don't doubt that it doesn't sound way better than the stock psu, but I also believe that you could build a custom psu that would be much better as well.
-Justin |
Justin
I do suppose one can build a quite fancy PSU for these phonostages that will equal battery performance. Try it.
Like I said - I have the batteries at my disposal so that is why I used them.
D |
|
|
| analog_sa |
| quote: | Originally posted by tubenut
Battery drawback?
Other then "green issues", dynamics for one imo/experience.
Different batteries also sound different btw...
|
Greetings G
Green issues?! Getting ready to move back to Europe? The only mass recycling in SA afaik is the result of theft. :)
I spent about five years listening to batteries: tube MC step-up and a 3-stage split passive opamp RIAA, each stage powered by a separate set of batteries.
Indeed different batteries sound surpisingly (or not) different. I liked a particular NiCd brand of around 300mA/h. When it became obsolete i never managed to find a suitable replacement. Acid batteries sound completely different of course.
These days i use ALW superregs in almost anything i build. They sound very good but not quite as good as batteries.
If one wants to compare batteries and mains supplies there is no better place IMO than a MC step-up. |
|
|
| peranders |
| What about a super regulator fed from a battery? I'll belive that batteries creates some noise due to the chemistry. |
|
|
| Onvinyl |
| quote: | Originally posted by analog_sa
These days i use ALW superregs in almost anything i build. They sound very good but not quite as good as batteries.
|
Quite the opposite to my findings. To me, a supperegged PSU sounds (a lot) better then the acid batteries I had before and the NiMH I tried in my phonoclone.
regards,
Rüdiger |
|
|
| GlidingDutchman |
This is what I actually did...
Beachwood face with 3mm green LED.
Rubber grommet from a Neutrik XLR plug and some Nylon braid.
DC connected!
D |
|
|
| BC |
| quote: | Originally posted by GlidingDutchman
This is what I actually did...
Beachwood face with 3mm green LED.
Rubber grommet from a Neutrik XLR plug and some Nylon braid.
DC connected!
D |
Hello All,
I realize the main topic is battery power, however..
I might possibly suggest to also replace the JRC2068/NJM2068 OpAmp with TI, NatSemi very low noise/faster? dual OpAmps.
(If I am reading the part correctly in the bottom photo; U4)
Possibly replace some of the ceramic caps with Poly/Styrene/Silvered Mica?
:) |
|
|
| GlidingDutchman |
| quote: | Originally posted by BC
Hello All,
I realize the main topic is battery power, however..
I might possibly suggest to also replace the JRC2068/NJM2068 OpAmp with TI, NatSemi very low noise/faster? dual OpAmps.
(If I am reading the part correctly in the bottom photo)
Possibly replace some of the ceramic caps with Poly/Styrene/Silvered Mica?
:) |
BC
It can surely be done... I just have to find the time and funds...
D |
|
|
| analog_sa |
| quote: | Originally posted by Onvinyl
Quite the opposite to my findings. To me, a supperegged PSU sounds (a lot) better then the acid batteries I had before and the NiMH I tried in my phonoclone.
regards,
Rüdiger |
It's not quite the "opposite". The superregs are very nice indeed and batteries vary to a surprising extent - one of the reasons i gave up on using them. Acids sound a bit slow and lacking PRAT; NiMH i used quite recently (5 years ago - from Nokia 5110 batteries in a 2SK170 MC step-up) and they were really not bad. |
|
|
| Onvinyl |
Hi analog_sa,
I second your sonic classification of lead acid batteries. NiMH are a lot better. But a superreg psu has the additional 'kick' -- and a very tiny bit of uneasiness. Mabye the open loop shunt regs I'm now using combine the best of both worlds -- but they are subjectivly so good I was too lazy to acutally check against NiMH's and superregs for now...
but to an extent it's all a matter of taste...
Rüdiger |
|
|
| tubenut |
Glide, looking at the pics it seems you connected DC in the pads left by the diodes?
That means you are feeding 15V regulators 12V, this would not work properly and they would certainly be starved. It probably works though because for some bizarre reason project bypassed the regulator inputs to outputs with some resistors of a few hundred ohms though I know not why...
You may wish to remove the badly behaving starving regulators all together, or replace them with types that are at least 3V below your battery voltage, or up the battery voltage to at least 3V above the 15V regulators.
Or at least, remove the resistors and feed directly to the OP amp PSU pins through the pads left by the resistors. Leaving the regs out of circuit. This would loose the miserable small smoothing caps though.
Those teeny regulators starve the poor stage anyway, I replaced them with a little dexterity with TO220 versions and got rid of all the ceramics in the RIAA.
Rolling op amps can be fun and fustrating, like some cables and tubes.
@PK, no but since the advent of Croaky/ lill tubenutty I see a lot more batteries coming through my house before becoming landfill, there is guilt with that and our urban explosion just means that soon those dumps will be nearer some folks houses then ever, even in big old Africa! |
|
|
| GlidingDutchman |
| quote: | Originally posted by tubenut
Glide, looking at the pics it seems you connected DC in the pads left by the diodes?
That means you are feeding 15V regulators 12V, this would not work properly and they would certainly be starved. It probably works though because for some bizarre reason project bypassed the regulator inputs to outputs with some resistors of a few hundred ohms though I know not why...
You may wish to remove the badly behaving starving regulators all together, or replace them with types that are at least 3V below your battery voltage, or up the battery voltage to at least 3V above the 15V regulators.
Or at least, remove the resistors and feed directly to the OP amp PSU pins through the pads left by the resistors. Leaving the regs out of circuit. This would loose the miserable small smoothing caps though.
Those teeny regulators starve the poor stage anyway, I replaced them with a little dexterity with TO220 versions and got rid of all the ceramics in the RIAA.
Rolling op amps can be fun and fustrating, like some cables and tubes.
|
Croak... yes, the DC is connected to the diodes pads - this is very interesting, I now only realise it just after you mentioned it... mmm. Have to see about bypassing the regulator(tjies) or replacing them.
I will see about the ceramic caps. What value? :confused:
I dont find the mystery codes on caps very funny! :mad:
D |
|
|
| tubenut |
| quote: | Originally posted by GlidingDutchman
Croak... yes, |
Round here I am tubenut, though, at this time all my tubes are in cupboards and I use mostly chemical processes to amplify rather then swarms of warm electrons in a vacuum. This may change...
regulator(tjies) ------> spanning afvlakker(tjies) IIRC... |
|
|
| GlidingDutchman |
| quote: | Originally posted by tubenut
Round here I am tubenut, though, at this time all my tubes are in cupboards and I use mostly chemical processes to amplify rather then swarms of warm electrons in a vacuum. This may change...
regulator(tjies) ------> spanning afvlakker(tjies) IIRC... |
Ik denk niet de karakters hier de woord spanning afvlakker zullen begrijpen.
No tube in your system? :hot:
What do you use BTW at the moment?
D |
|
|
| earsandeyes |
| Als echte nederlander ik ook niet;) |
|
|
| tubenut |
Plenty Dutch fellas around here but I actually meant the Afrikaans word. Not sure what the dutch word is. (Tjies being afrikaans, tjes Dutch).
I Pod Shuffle + Sennie MX300 or HD40 :D |
|
|
| tubenut |
| quote: | Originally posted by GlidingDutchman
Ik denk niet de karakters hier de woord spanning afvlakker zullen begrijpen.
D |
Calling a person a character, in English, Dutch or Afrikaans is not very compimentary or polite....
Nuff Lingo, back to phonohoax/battery power...
though I have little more to say on the subject at this time.
This thread hasd more info http://www.diyaudio.com/forums/show...1833&highlight=
I see you found it already. |
|
|
| GlidingDutchman |
"Regulateur de tension" in French... so it must be "Spanning Regulator" in Dutch & Afrikaans
D |
|
|
| GlidingDutchman |
| quote: | Originally posted by tubenut
Calling a person a character, in English, Dutch or Afrikaans is not very compimentary or polite....
|
Politely speaking sir! :clown:
Yes, I have found the other thread but what difference are ther between the two phonobox designs...?
D |
|
|
| tubenut |
IMO the box and I think SE gets rid of the ceramics.
(Afvlakker is correct word in Afrikaans for sure, there may be that and spanningsregelaar in Dutch.
Afrikaans electronic lingo is a mix of Dutch and bastardised english words. The word for capacitor in Afrikaans and dutch is not the same for eg, the dutch word voeding is a kragbron in Afrikaans etc etc etc..) |
|
|
| GlidingDutchman |
So you recommend me changing these marked with the red arrows?
 |
|
|
| tubenut |
Absolutely!
Just spotted difference 2 for the MKII, the MC/MM switch. The MK1 uses internal jumpers (that may actually be preferable). |
|
|
| tubenut |
The signal path oppies are dual devices so you would need op275. It will work, it will be different, will it be better, probably? hmmmm expensive gamble.
Op amps can be very subjective, and which to use where is science and to some extent hard trial and error listening etc. Many would consider this knowledge/experience part of their marketable skill.
Nite nite. |
|
|
| shallbehealed |
| quote: | Originally posted by tubenut
Compares well to tenfold the price? What have you tried? For one the Clearaudio Smartphono craps all over it for say 3* the price. At ten times the price it is another ballgame all together and it is left far behind.
|
I spent about $50 more for a Pass Pearl. More thump, more goosebumps. I think that the the VSPS is an excellent "budget" option. A good friend of mine just built the cheap battery version of the Hagerman and it's not too bad either. His total cost: $65 |
|
|
| GlidingDutchman |
| quote: | Originally posted by tubenut
That means you are feeding 15V regulators 12V, this would not work properly and they would certainly be starved. It probably works though because for some bizarre reason project bypassed the regulator inputs to outputs with some resistors of a few hundred ohms though I know not why...
|
G jou doring!
I now am starting to think this is the reason my DIY phono amp doesnt want to work... It uses the same tiny regulators!! I fed it the same dual rail 12v instead of 24v... :dead:
Today no regulator will stand! :smash:
D |
|
|
| jacco vermeulen |
| quote: | Originally posted by GlidingDutchman
price is scary for what you get! |
Gliding-Cheese,
You'll pay less if you punch in AD797 on the RS link.
Life will be simpler if could decide whether you will use the phono-pre for MC or MM, if you are serious of rebuilding the phony-box. |
|
|
| GlidingDutchman |
| quote: | Originally posted by jacco vermeulen
Gliding-Cheese,
You'll pay less if you punch in AD797 on the RS link.
Life will be simpler if could decide whether you will use the phono-pre for MC or MM, if you are serious of rebuilding the phony-box. |
Jacco... okay where do I begin?
Mainly MC as I have 4 different MC cartridges at my disposal and only 1 MM...
At the moment I feel like trashing the whole Phon'y'-box cause it is driving me mad. Today, whilst changing ceramic caps I have busted & lifted two PCB track!! Makes me sizzle with anger! :mad:
I think I should rather just get a decent new phono stage or at least a pre-owned one.
D |
|
|
| GlidingDutchman |
This sucks!!
Now I have killed the thing - it is a piece of ****!! :smash:
D |
|
|
| tubenut |
| quote: | Originally posted by GlidingDutchman
This sucks!!
Now I have killed the thing - it is a piece of ****!! :smash:
D |
Should maybe have read: Now I have killed the thing - my non teperature contriolled solder station it is a piece of ****!!
The pads lift easy, I normally destroy the old component when modding, Ie have only one leg to deal with at a time. |
|
|
| GlidingDutchman |
| quote: | Originally posted by tubenut
Should maybe have read: Now I have killed the thing - my non teperature contriolled solder station it is a piece of ****!!
The pads lift easy, I normally destroy the old component when modding, Ie have only one leg to deal with at a time. |
You said it! :bawling:
I have a run-off-the-mill Weller soldering iron - temprature controller? Whats that?
Will have to invest in one...
D |
|
|
|
