i must have an earlier version of the instructions.
''Be careful not to get the transistors mixed up or soldered in the wrong orientation. Q1, 4 and 5 are npn (BD135), Q2, 3 and 6 are pnp (BD136). on the diagram above Q2, 3 and 5 face printed side up. Q1, 4 and 6 face printed side down.''
its my (comprehension) dyslexia that read that to mean the backs were to the front and it's my fault for not understanding properly.
i'm not complaining as the Sapphire is one hell of a bargain and it sounds bloooody fantastic, there is a slight grain to the midrange but i'm putting that down to everything bedding in.
i'm at the moment running the Sapphire with 2 x 120va toroidal transformers and 4 GBPC3504W bridge rectifiers. volume is Analogue Metric 23 step Ladder-type Attenuator. all internal wiring is figure of 8 audio cable running into a daughter board.
source is cd's going threw Dell optiplex760 with Soundblaster x-fi xtreme Audio sound card and listening threw a pair of £5 mikomi cheep rubbish headphones, i have plugged the DT-770 Pro's in and it sounds well ******** awesome apart from that mid range grain. i will be plugging it into my OPPO BDP93 very very soon.
my teeth grind if music sounds bad and my jaw starts to tense up but so far not one bit of teeth grinding or jaw tensing. a massive thank you to Richard for making the Sapphire available to us all.
''Be careful not to get the transistors mixed up or soldered in the wrong orientation. Q1, 4 and 5 are npn (BD135), Q2, 3 and 6 are pnp (BD136). on the diagram above Q2, 3 and 5 face printed side up. Q1, 4 and 6 face printed side down.''
its my (comprehension) dyslexia that read that to mean the backs were to the front and it's my fault for not understanding properly.
i'm not complaining as the Sapphire is one hell of a bargain and it sounds bloooody fantastic, there is a slight grain to the midrange but i'm putting that down to everything bedding in.
i'm at the moment running the Sapphire with 2 x 120va toroidal transformers and 4 GBPC3504W bridge rectifiers. volume is Analogue Metric 23 step Ladder-type Attenuator. all internal wiring is figure of 8 audio cable running into a daughter board.
source is cd's going threw Dell optiplex760 with Soundblaster x-fi xtreme Audio sound card and listening threw a pair of £5 mikomi cheep rubbish headphones, i have plugged the DT-770 Pro's in and it sounds well ******** awesome apart from that mid range grain. i will be plugging it into my OPPO BDP93 very very soon.
my teeth grind if music sounds bad and my jaw starts to tense up but so far not one bit of teeth grinding or jaw tensing. a massive thank you to Richard for making the Sapphire available to us all.
just hooked the Sapphire up to my OPPO BDP93 
it's still bedding in but i think this thing has more to give so i'm going to order some Mundorf Mcap ZN or some Rike Audio S-Caps as they both seem to get good feedback for price. looking around for caps surprised me just how much you can spend on these things, who pays £1k for a single cap...
it's still bedding in but i think this thing has more to give so i'm going to order some Mundorf Mcap ZN or some Rike Audio S-Caps as they both seem to get good feedback for price. looking around for caps surprised me just how much you can spend on these things, who pays £1k for a single cap...
Very few people do, I imagine.
In addition to playing around with coupling caps - which will certainly allow you to tune the sound - there's also the op amp which can be substituted, and you might also experiment with changing resistor R14 (rev 14s board) from 1 ohm to about 47 ohms or so.
thanks Richard.
i looked at your gain calculator for the Sapphire which leads me to be a little confused as it states to change the value of R4, should that not read R14 or is the calculator for the new boards?
BTW, there must be some hocus pocus going on as the Sapphire is even making MP3's sound very very open and musical (using my oppo). i cant get over just how good this thing sounds and i admit i have NEVER heard any headphone amplifier sound like it, its fantastic. i let my boys hear it yesterday when i got it plugged in for the first time and they were well impressed then again this evening and the older one said its sounding better as its not got as much of that 'raspy-gritty' sound.
i cant wait to get the Phonoclone up and running as if it sounds as good as the Sapphire i'll be in audio heaven. both my boys will be getting the same system once i have ironed out all the bits i need to.
i looked at your gain calculator for the Sapphire which leads me to be a little confused as it states to change the value of R4, should that not read R14 or is the calculator for the new boards?
BTW, there must be some hocus pocus going on as the Sapphire is even making MP3's sound very very open and musical (using my oppo). i cant get over just how good this thing sounds and i admit i have NEVER heard any headphone amplifier sound like it, its fantastic. i let my boys hear it yesterday when i got it plugged in for the first time and they were well impressed then again this evening and the older one said its sounding better as its not got as much of that 'raspy-gritty' sound.
i cant wait to get the Phonoclone up and running as if it sounds as good as the Sapphire i'll be in audio heaven. both my boys will be getting the same system once i have ironed out all the bits i need to.
Wow. I was ... not expecting that! You actually went and re-built the layout from scratch on vero-board... That's really innovative of you. And is that really a blower fan?
I noticed you followed the schematic literally. That is, the position of the components on the schematic got translated onto the layout itself, right down to the banks of three filter capacitors all in a row off to one side.
It's important to know that the position of a component symbol on a schematic has nothing to do with the position of a component on a layout. I grouped the capacitors C3~C14 on the schematic like that for clarity, moving them away from the main amplifier block. On the layout, however, they are distributed carefully to be up close to the component they aim to decouple from the power supply. Please see the arrangement on the image of the board, below.
/R
I noticed you followed the schematic literally. That is, the position of the components on the schematic got translated onto the layout itself, right down to the banks of three filter capacitors all in a row off to one side.
It's important to know that the position of a component symbol on a schematic has nothing to do with the position of a component on a layout. I grouped the capacitors C3~C14 on the schematic like that for clarity, moving them away from the main amplifier block. On the layout, however, they are distributed carefully to be up close to the component they aim to decouple from the power supply. Please see the arrangement on the image of the board, below.
/R
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just tried the OPA27 in the Sapphire and i must say i think i prefer it. ok so they are not as clear but they have a nice analogue sound to them and to my ears not a brittle as the OPA134. the OPA27 are a nice match to DT770's as they have a nice loud mid range to them that is missing in the DT-770's. the OPA134 to me sound much much more open but brittle and for some strange reason they seemed to have a funny grain/distortion to snare drums.
anything that can keep up with Rush - 2112 - Breakthrough and still sound in control deserve to be applauded, yes the OPA27 got a bit shouty but it a splendid job of keeping the dynamics in control, everything is there its just a bit grey.
next up i think i'll splash out on some OPA627
anything that can keep up with Rush - 2112 - Breakthrough and still sound in control deserve to be applauded, yes the OPA27 got a bit shouty but it a splendid job of keeping the dynamics in control, everything is there its just a bit grey.
next up i think i'll splash out on some OPA627
well well. so this is how the Sapphire is supposed to sound... bloooody glorious, i'm truly amazed.
Richard was kind enough to send me out his old Sapphire boards so i duly put some power sockets on and wired it up, stuck it in my casework and what a difference. i now see why he uses the OPA134, this man knows what he is doing. i noticed that he has bridged 2 pins on the opamp sockets underneath with some caps which i failed to do.
how does it sound? ermm beyond my expectations. the weight to the bottom end is sumptuous warm but well controlled and very very quick, it's difficult to get hifi gear that follows the bass guitar notes properly without them sounding 'one note' but fear not they are there in and well defined. mids are just astounding with no hint of grain which i was experiencing with my build. the highs are airy and sparkly. overall sound is open and lush. i was happy with the ones i built but Richards has taken it to the next level. i'm only listening to crappy MP3's threw a creative zen vision m as source and cheap £5 headphones but i'll be hooking it up to the oppo and using the DT-770's in a wee while. Talk Talk - colour of spring oooohhhh yes indeed.
thanks Richard you have made me a happy man indeed.
bibs
Richard was kind enough to send me out his old Sapphire boards so i duly put some power sockets on and wired it up, stuck it in my casework and what a difference. i now see why he uses the OPA134, this man knows what he is doing. i noticed that he has bridged 2 pins on the opamp sockets underneath with some caps which i failed to do.
how does it sound? ermm beyond my expectations. the weight to the bottom end is sumptuous warm but well controlled and very very quick, it's difficult to get hifi gear that follows the bass guitar notes properly without them sounding 'one note' but fear not they are there in and well defined. mids are just astounding with no hint of grain which i was experiencing with my build. the highs are airy and sparkly. overall sound is open and lush. i was happy with the ones i built but Richards has taken it to the next level. i'm only listening to crappy MP3's threw a creative zen vision m as source and cheap £5 headphones but i'll be hooking it up to the oppo and using the DT-770's in a wee while. Talk Talk - colour of spring oooohhhh yes indeed.
thanks Richard you have made me a happy man indeed.
bibs
I'm glad it worked out.
It's hard to imagine that the single ceramic cap made the difference. I listened to the boards before and after I soldered them in and the change seemed to me quite small.
The cap between pin 4 and 7 of the op amp is a trick Douglas Self suggested for, iirc, the NE5534. Google is being unhelpful - sorry I can't find the link.
It's hard to imagine that the single ceramic cap made the difference. I listened to the boards before and after I soldered them in and the change seemed to me quite small.
The cap between pin 4 and 7 of the op amp is a trick Douglas Self suggested for, iirc, the NE5534. Google is being unhelpful - sorry I can't find the link.
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The postman arrived today with my new cans, DT-880 600ohm which completely blow the DT-770 80ohm out the water so I have been giving the Sapphire a good old thorough listen and I have noticed a slight problem (also evident with the 770’s) with what sounds like an occasional static pop and some distortion around the 1k mark, also vocals seem to be on the bright side of neutral with a slight fizzyness/grain to them.
The distortion reminds me of driving large speakers with a small underpowered amp but only in the midband frequencies.
Is it possible that the distortion could be due to the casework not being grounded and my cablework due to using the daughter board (which will be removed on the final version).
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Fronts
Bridge Rectifier Boards
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The distortion reminds me of driving large speakers with a small underpowered amp but only in the midband frequencies.
Is it possible that the distortion could be due to the casework not being grounded and my cablework due to using the daughter board (which will be removed on the final version).
Sneak peek
Fronts
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Bridge Rectifier Boards
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Inside
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It's important to connect the case to the circuit common. (IN-, OUT-, or COM, any should work fine) if the connection is not already made at the headphone jack. Also your case is black anodized/paint like mine, you have to file down to bare metal in places where the pieces fit together to make sure the electrical connection is made throughout. It is also important to ground the body of the volume control if this isn't done already.
I'm not too hopeful that doing any of this will solve the distortion problem though it might help with those static pops.
If the distortion reproducible (happens at the same point in a track if you play it back twice) or random?
I'm not too hopeful that doing any of this will solve the distortion problem though it might help with those static pops.
If the distortion reproducible (happens at the same point in a track if you play it back twice) or random?
it happens on all tracks and all the time. it's very subtle but there and i can only describe it as 'crackling' on loud passages and mainly in the upper voice register. the rest of the spectrum is pretty damned good.
i have grounded the boards and the pops are now gone. i have not grounded the attenuator. apart from the main in/out circuit.
what size resistor would you recommend for R7 for 600ohm headphones?
i have grounded the boards and the pops are now gone. i have not grounded the attenuator. apart from the main in/out circuit.
what size resistor would you recommend for R7 for 600ohm headphones?
I have almost finished assembling my new black beauty boards.
The build went well so far. I have a few changes based on available parts I had to hand. I used BD137 and BD138, and I shoehorned in some bigger caps: I had a stash of 220uF that I used in place of the 100uF, and I used 1500uF instead of 1000uF elsewhere. Lastly, my zobel is 22n and 10R - I seem to be somewhat short on low value decent film caps! C1 is a russian K73-16 2.2uF which I also used on the rev14 boards to good effect.
On my current 14 rev boards, I'm using a pair of 15V EI transformers through standard 1n4007 diodes. On this one, I sprung for a pair of toroids and MUR120 for the diodes. First up though is just to add in the new rev20 boards and see how they go.
Fran
The build went well so far. I have a few changes based on available parts I had to hand. I used BD137 and BD138, and I shoehorned in some bigger caps: I had a stash of 220uF that I used in place of the 100uF, and I used 1500uF instead of 1000uF elsewhere. Lastly, my zobel is 22n and 10R - I seem to be somewhat short on low value decent film caps! C1 is a russian K73-16 2.2uF which I also used on the rev14 boards to good effect.
On my current 14 rev boards, I'm using a pair of 15V EI transformers through standard 1n4007 diodes. On this one, I sprung for a pair of toroids and MUR120 for the diodes. First up though is just to add in the new rev20 boards and see how they go.
Fran
Attachments
Ok, so I left it powered up for 4 hrs and then listened. Bearing in mind expectation bias etc, to my ears there is a clear improvement over the rev14 boards. Greater soundstage and easier to hear micro details.
Having heard that, I decided to press on and I installed the new toroids and MUR120. Well, another improvement there! Sound is more "well rounded", and more detail and separation. So for example I can hear a saxophonist taking a breath before easiing out a note, or the decay around the reverberation of a note can be heard dying away in the mix.
Overall this is a substantial upgrade from the rev14 I think. Thanks Richard!
Fran
Having heard that, I decided to press on and I installed the new toroids and MUR120. Well, another improvement there! Sound is more "well rounded", and more detail and separation. So for example I can hear a saxophonist taking a breath before easiing out a note, or the decay around the reverberation of a note can be heard dying away in the mix.
Overall this is a substantial upgrade from the rev14 I think. Thanks Richard!
Fran
@bibio
Use 20k for the gain set resistor. Re. the distortion, you have me stumped at present. What is your measured values for V++ and V-- again? The only suggestion I can make right now is to move it to a couple of different environments, try it with some different sources just to make completely sure the problem is with the amp itself.
@fran
Good. Thanks for sharing your experiences.
Use 20k for the gain set resistor. Re. the distortion, you have me stumped at present. What is your measured values for V++ and V-- again? The only suggestion I can make right now is to move it to a couple of different environments, try it with some different sources just to make completely sure the problem is with the amp itself.
@fran
Good. Thanks for sharing your experiences.
hi Richard
voltages are L-board = 34.9 and R-board = 34.9 with my cheepy maplin voltmeter.
i have put a 10k in for R7 as i had them lying about and the gain is pretty good and decent levels between 1-3 o'clock depending on material.
C15 on my boards have 40+hrs on them and sounds much better then your old boards which the C15 only has 5+hrs on them so it could be letting things settle in longer is required.
in my stupidity i broke some legs off the vishay bridge recs and replaced with some others that were cheeper so that also might have something to do with it.
its nice having 2 sets of boards to play with, i removed the bypass caps on my boards and found that i like it without them. cymbals are a lot crisper with better decay, there is also more air around the instruments and everything sounds more 'real'. i then took out the bypass caps on your old boards but left the opamp caps on and again found the sound more to my liking apart from there was a strange detached sound or it could be a placebo effect.
i'll try and narrow down the distortion for you. i don't know if you have heard Tracy Chapman - Talking about a revolution but when she sings 'poor people gonna rise up' the 'o' is distorted and the 's' is very sibilant. on simple well recorded stuff like Cat Stevens album teaser and the firecat it sounds wonderful but get into more complex stuff like Rush - 2112 and things go a bit pear shaped now and again. still no where near as bad and is leagues ahead of my Yamaha receiver.
i have been reading this thread a bit more and decided that i'm going to increase C15 to .68uf in order to get more bass as at the moment using the DT-880's the bass sounds very thin.
now some good news, i took the Sapphire over to a friends house last night and he was blown away with the sound.
voltages are L-board = 34.9 and R-board = 34.9 with my cheepy maplin voltmeter.
i have put a 10k in for R7 as i had them lying about and the gain is pretty good and decent levels between 1-3 o'clock depending on material.
C15 on my boards have 40+hrs on them and sounds much better then your old boards which the C15 only has 5+hrs on them so it could be letting things settle in longer is required.
in my stupidity i broke some legs off the vishay bridge recs and replaced with some others that were cheeper so that also might have something to do with it.
its nice having 2 sets of boards to play with, i removed the bypass caps on my boards and found that i like it without them. cymbals are a lot crisper with better decay, there is also more air around the instruments and everything sounds more 'real'. i then took out the bypass caps on your old boards but left the opamp caps on and again found the sound more to my liking apart from there was a strange detached sound or it could be a placebo effect.
i'll try and narrow down the distortion for you. i don't know if you have heard Tracy Chapman - Talking about a revolution but when she sings 'poor people gonna rise up' the 'o' is distorted and the 's' is very sibilant. on simple well recorded stuff like Cat Stevens album teaser and the firecat it sounds wonderful but get into more complex stuff like Rush - 2112 and things go a bit pear shaped now and again. still no where near as bad and is leagues ahead of my Yamaha receiver.
i have been reading this thread a bit more and decided that i'm going to increase C15 to .68uf in order to get more bass as at the moment using the DT-880's the bass sounds very thin.
now some good news, i took the Sapphire over to a friends house last night and he was blown away with the sound.