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Graham slee schematic


Bidoux

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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:

grahamsleesolodessoussc.jpg

grahamsleesolodessus.jpg

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:

grahamsleesolooutputsta.png

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.

grahamsleesolooutputsta.png

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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):

grahamsleesolooutputsta.png

Everything colored pink is ground, it seems that the op-amp is powered with V- grounded.:eek:

grahamsleesolodessoussc.jpg

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.

grahamsleesolodessuspar.jpg

Tell me if I say total crap.:)

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I knew it would upset you, it brakes two of your rule high open loop gain and caps in the signal path. ;D

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 ?

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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 :D

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.

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Saw another thing today, the heedamp:

HeedCanAmpVolPotInteriorDetail.jpg

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 ?

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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.

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I'm still a relative noob at this sort of thing, but reckon I can have a crack at it...... :o

-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.

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  • 3 months later...

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. ;)

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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.

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  • 1 year later...

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.

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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?

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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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