Bidoux Posted July 27, 2009 Report Posted July 27, 2009 Since I saw a pic of the board, I was wondering if it is worth it to "clone" as a DIY project the amp. I found two very useful pics of the inside. Based on it, I tried to fill in the parts: Is it a AC coupled amp ? The two closest cap from the potentiometer are input caps and i'm wondering if the two electrolytic caps close to the 1W resistors are output caps. Also, I don't know the name of the componant below the left 1W resistor. There are two of them. I think the output stage is push-pull, it probably looks like this: here is what I got so far. What do you think ? PS: I don't know if it is the right section and if it is allowed on this forum, mods fell free to move or delete this post.
Bidoux Posted July 27, 2009 Author Report Posted July 27, 2009 I don't know how to edit my previous message, sorry for the double post. The correct output stage was this (didn't draw the npn well): Everything colored pink is ground, it seems that the op-amp is powered with V- grounded. the LM78** (or another chip) regulates the +24VDC, it is protected with a diode. Shouldn't it be heatsinked ? Q1 separates the power from the output stage and the op-amp power. The two mysterious parts are circled in red. Tell me if I say total crap.
kevin gilmore Posted July 27, 2009 Report Posted July 27, 2009 OH no... Its a ray samuels HR2 built with a single ended power supply, cap input, cap output... Massive piece of shit. DC coupled version on headwize someplace ray's is built a bit better however. http://www.raysamuelsaudio.com/products/hr-2
Bidoux Posted July 27, 2009 Author Report Posted July 27, 2009 I knew it would upset you, it brakes two of your rule high open loop gain and caps in the signal path. Someone sold is GS-1 to keep this little guy, I thought it could be a good amp, definitly not worth building one ? Was looking at a picture of the HR-2, the heatsinked chip are BJT transistors ?
Beefy Posted July 27, 2009 Report Posted July 27, 2009 OH no... Its a ray samuels HR2 built with a single ended power supply, cap input, cap output... Massive piece of shit. HiFi magazines and people on Head-Fi love them I thought it could be a good amp, definitly not worth building one ? Considering the huge number of good DIY amps out there, with excellent documentation and community support, why would you bother building this? Something like a CKKIII would be a much better prospect.
Bidoux Posted July 27, 2009 Author Report Posted July 27, 2009 Saw another thing today, the heedamp: Once again lots of things hu... (the E is an op-amp). i think someone did a schematic for this one too. I have to ask a few things about it: -first why is there a capacitor in the feedback ? -What is the point of using a transistor as emitter follower after an op-amp ? it doesn't add gain, is it to biais it as a class A amp ? -Brings me to my other point, replacing the 100 ohm resistor with something more efficient like jfet would bring anything ?
spritzer Posted July 27, 2009 Report Posted July 27, 2009 HiFi magazines and people on Head-Fi love them Do you really need to say more?
cetoole Posted July 27, 2009 Report Posted July 27, 2009 I have to ask a few things about it: -first why is there a capacitor in the feedback ? -What is the point of using a transistor as emitter follower after an op-amp ? it doesn't add gain, is it to biais it as a class A amp ? -Brings me to my other point, replacing the 100 ohm resistor with something more efficient like jfet would bring anything ? 1. For reasons of DC offset. 2. Its the output device, runs in SE class A. 3. Yes, though not many JFETs would work well.
Beefy Posted July 27, 2009 Report Posted July 27, 2009 I'm still a relative noob at this sort of thing, but reckon I can have a crack at it...... -first why is there a capacitor in the feedback ? Do you mean C1? Looks like an input cap to block DC from 'bad' sources. -What is the point of using a transistor as emitter follower after an op-amp ? it doesn't add gain, is it to biais it as a class A amp ? It is there to buffer the output so that the OPAMP isn't driving the headphones directly. -Brings me to my other point, replacing the 100 ohm resistor with something more efficient like jfet would bring anything ? I wouldn't even bother. The design is so lacking, you should just start with a better design in the first place.
TzeYang Posted July 31, 2009 Report Posted July 31, 2009 the capacitors at the feedback loop to ground is there to give full feedback during 0Hz (DC signals. Pretty darn sure it's not needed in that sort of circuit.
Bidoux Posted August 3, 2009 Author Report Posted August 3, 2009 I thought it should give no feedback at 0Hz, the cap is a shortcut so there is no divider bridge anymore.
TzeYang Posted August 4, 2009 Report Posted August 4, 2009 0Hz is meant as DC Caps do not take DC so the inverting input sees the full output signal.
nelsonvandal Posted August 7, 2009 Report Posted August 7, 2009 This looks very unimpressive for such an expensive amp. I can't believe there's a Graham Slee cult.
Soihoang Posted November 22, 2009 Report Posted November 22, 2009 Hi, I'm looking GS headamp to diy. So, who can help me. ( i can't but GS novo at DAK )
penger Posted November 22, 2009 Report Posted November 22, 2009 Probably barking up the wrong tree buddy.
mrarroyo Posted November 22, 2009 Report Posted November 22, 2009 I wonder how old that picture of the Solo is? I ask because I have access to the last three updates of the Solo (Green, SRG, and SRG-II) and they are not the same as the one posted. Funny thing is that the picture of the Heed looks exactly as one I posted in late 2006.
Bidoux Posted November 23, 2009 Author Report Posted November 23, 2009 I never ask before using pictures and I thought it was not big deal. If there is a problem with it, I apologize but I can't remove it. To Soihoang, search for Dynalo or A Pure Class A Dynamic Headphone Amplifier, you will find.
mrarroyo Posted November 23, 2009 Report Posted November 23, 2009 I never ask before using pictures and I thought it was not big deal. If there is a problem with it, I apologize but I can't remove it. To Soihoang, search for Dynalo or A Pure Class A Dynamic Headphone Amplifier, you will find. If you are asking me the answer is don't worry. If the Heed picture helps I am glad. Heck if you need any additional Heed pictures send me an email and I will gladly send them to you. Cheers.
fireball Posted November 11, 2011 Report Posted November 11, 2011 Dear specialists! I'm looking for a good (native) amp for my Sennheiser HD650. They say that Graham Slee Solo is the best, since Sennheiser used it at it's own demo with HD650. But as far as I see here, you are don't really like this amp. So, please tell me, what is the best amp for HD650's: - ever? - under $500 (or any reasonable price)? Also, i found that there's a plenty few revisions of the Slee Solo: http://translate.goo...2617%26page%3D1 So, if your advice would still be a Graham Slee Solo, what kind of revision should I look for: red (old) for vinyl-like sound, or green (new) for a new CD digital era? Taking into consideration that I'm using: CD-transport: Technics SL-PS770A --> Aura VA-100 (B&W vintage integrated amp, not MKII) --> B&W 805S or Sennheiser HD650 up to 192kHz/24bit PC (flac/ape vinyl, cd grabs) source --> T.C. Electronic Desktop Konnekt 6 (DAC) --> Aura VA-100 (B&W vintage integrated amp, not MKII) --> B&W 805S or Sennheiser HD650 I'm listening most: Rock, New Age, Acoustics, Electronic (chip). BTW, do I need an amp for my HD650, or there's no nessesary because of Aura VA-100's internal headphone amp? I can't find any info if Aura's headphone out can handle (by ohms) my HD650. But I know that I need a high gain amp for my 300 ohms HD650's.
grawk Posted November 11, 2011 Report Posted November 11, 2011 1) reread your welcome pm 2) do you like how the hd650 sounds out of your amp? 3) what do you like, or not like, about it? 4) why do you have such shitty taste in music?
fireball Posted November 11, 2011 Report Posted November 11, 2011 1) Done, it seems like the key phrase was: "friends"... 2) Nope, that's why I'm looking for a chance they play "my way". 3) As of me, they lacks of panoram or volume. Also they lacks of mid-bass and mid-treble. 4) What do you care about my music tastes? Are you sure you know how my tastes are looks like? Yeah, sure... I though they say: "Tastes differ". And if rephrase one of my favourite movie actors once said: "If I wanted to argue my music tastes, I'd watch you take a leak". This is my answer to your "4)" Hope, ppl here has a good taste of humor. Now, please, you tell me: Do you have something to say essentially of my prob?
johnwmclean Posted November 11, 2011 Report Posted November 11, 2011 Talking about great movie phases, here's a classic. Oh, don't tell me how to talk in my own fuckin' place! Now, here's my counter offer to your counter offer - go *fuck* yourself!
justin Posted November 11, 2011 Report Posted November 11, 2011 They say that Graham Slee Solo is the best, since Sennheiser used it at it's own demo with HD650. so the company has a business relationship with Sennheiser or someone at Sennheiser has a personal relationship with Graham Slee.
fireball Posted November 11, 2011 Report Posted November 11, 2011 so the company has a business relationship with Sennheiser or someone at Sennheiser has a personal relationship with Graham Slee. Yeah, I think so too. Cause, when I looked at schematics here, I realized that maybe this is not the best inside part of a good amp. I can be wrong, but HR2 looks at least much more complex or thoroughly. Anyway, what do you think about Creek OBH-21 SE or Musical Fidelity X-Can V3 (v8), and HeadRooms?
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