robertkd
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Electronics Engineer from sunny Queensland
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Post by robertkd on Feb 24, 2010 13:43:15 GMT
Well not sure where this might go it all started with some bantering over another design, Frans and a few others chucked in some ideas and not sure where it or indeed if it will go anywhere,..
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Deleted
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Post by Deleted on Feb 24, 2010 18:13:50 GMT
What we need is THOUGHTS of RG members. What do YOU, yes YOOOO LADDY reading this post, think should be and or should :)NOT be in a high quality headphone amp that will be EASY and preferably CHEAP (and fun) to build. No expensive/exotic parts. perhaps you could even give specifications. Throw it all in this thread and in a combined effort we will design a nice amp. an RG amp... ;D Valves, FET's, Opamps, transistors yes even LM317's will be considered. A mix of all of the above might be possible. AC/DC power supplies, battery operated.. Housing/appearance you name it... NO idea is crazy or will be shot on sight and you will not be branded a fool if you suggest impossible things.. We will let you know if your 'demands' are feasible and if not it will be explained WHY. BUT we will NEED input. If there is enough 'demand' I might even design a nice PCB/kit for it. Frans
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toad
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I am the Super Toad, the Original Toad, the Whole Toad and nothing BUT the toad.... don't forget it!
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Post by toad on Feb 24, 2010 18:50:02 GMT
Eeek... Well I couldn't design an amp if my life depended on it but as I am a Laddy reading this post I do think if it has an opamp in it then make it an LM4562. This chip has turned my green solo into the most accurate detailed gorgeous sounding amp I've personally heard and it works miracles in my CMoy too. Mick prefers his Zigis CMoy to his Bravo amp and his Zigis hasn't even bedded in yet.
Also PSUs add a shed load of cash into the mix so why not contemplate using a battery pack like I use on my CMoy. It lasts weeks for a few hours a day on a set of 8 rechargables. There's nothing to stop us using a couple of maplins 8 or 10 AA battery holders to up the voltage. Cheap clean power... just a thought.
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Post by clausdk on Feb 24, 2010 19:45:10 GMT
I like doing woodstuff..
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Deleted
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Post by Deleted on Feb 24, 2010 20:29:35 GMT
At the risk of sounding like a broken record; no smd please.
Never owned a single ended class A, hmmmm, interested.
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Deleted
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Post by Deleted on Feb 24, 2010 20:42:44 GMT
I hope that everybody realises that Robert started this topic in this area, as the intention was to create a Class A SE VALVE amplifier,or a variation on that theme where a valve is used. Designs that do not at least include a valve should not be discussed in this area. Alex
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Deleted
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Post by Deleted on Feb 24, 2010 20:53:09 GMT
Ahhh... but this is NOT a valves only thread on my part.
Anything goes... Valves included.
Maybe even 2 or 3 final possible designs will roll out of the equation. Perhaps a universal design that will allow more than 1 topology depending on how a PCB is loaded with parts..
Who knows.
Maybe the whole thread will fall apart and no agreement can be made. In this case too bad... but at least we tried.
So far I have seen the LM4562 roll by and battery operated preference. Single ended class A...
Need more input...
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Deleted
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Post by Deleted on Feb 24, 2010 21:06:35 GMT
Ok,
can it be an OTL design?
The reason I say that is, the ONLY valve amp I have ever drooled over and heavily desired is the Graaf GM20.
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Deleted
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Post by Deleted on Feb 24, 2010 21:31:11 GMT
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Deleted
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Post by Deleted on Feb 24, 2010 21:40:13 GMT
I have to admit I had the impression that Wills thread was solid state and this was valve Which may be sensible, to keep the two trains of thought apart until one shows to be the more popular route. Just thinking aloud...
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Deleted
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Post by Deleted on Feb 24, 2010 21:42:06 GMT
Ahhh... I was not aware.
Will read it and see what comes out of it.
Everything has been designed already of coarse. I was thinking of a hybrid with the best of all flavors so to speak.
We'll see what happens in this thread.
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Deleted
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Post by Deleted on Feb 24, 2010 21:52:42 GMT
The "best of all flavours" , is NO flavour !
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Post by clausdk on Feb 24, 2010 22:09:20 GMT
The "best of all flavours" , is NO flavour ! Nope it is strawberries with vanillasoftice ;D
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Deleted
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Post by Deleted on Feb 24, 2010 22:23:57 GMT
Perhaps a 1T4 and 3V4 combo and a small O/P transformer powered by a couple of rechargeable "D"cells, and a step up inverter for 45V ?
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Deleted
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Post by Deleted on Feb 24, 2010 22:47:13 GMT
This thread started out as a variation of the indeed.
MAYBE we should honour the Bravo indeed design and cook up a technically better one and see if it will outperform the Bravo/indeed in specs and sound.
So no fancy things ... a variation of the Hybrid ? There are not too many of these designs out there..
Plenty of all tube and all SS not much to improve there I reckon.
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pjc68
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You dissin me?
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Post by pjc68 on Feb 24, 2010 23:41:33 GMT
No good at designing amps, but could it at least have a 6.3mm hf socket. ;D
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Deleted
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Post by Deleted on Feb 25, 2010 6:54:51 GMT
What do the 'LADDY's' think of this Bravo variation.
4 RCA's (2 in and 2 directly coupled through-outs 6.3 mm output (or 3 with different output Z's ?). Volume control. 2 heatsinks on the side. 1 tube as a voltage amp (Bravo topology but better CCS) so the typical Bravo 'sound' is there. an Opamp buffer with or without DC servo feedback. same class A output stage as Bravo BUT WITH feedback AND without an output capacitor.
Easy/cheap to build.
made so you can roll tubes and IC's easily
24 volt DC supply voltage
selectable OUTPUT impedance (10-56-120 Ohms)
a lesser gain as the original Bravo.
preferably lesser hiss when the vol pot is at zero.
Would anyone be interested ?
If not ... I'm not going to bother to spend time on it. If there is I will design something and everyone may shoot at it and come up with suggestions about parts used or change in topologies.
Also suggest housing appearance and specify board sizes even.
Frans
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Deleted
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Post by Deleted on Feb 25, 2010 7:59:26 GMT
It looks good Frans. I suppose it all comes down to the cost and how that relates to the Bravo. If it's a better version (or variation) then I'm sure people would love it because I really enjoy the full, fruity sound of the Bravo a great deal. Being able to alter the output impedance is a nice touch. Bravo doesn't hiss until you turn up to daft volumes so the gain is set too high. With lower gain, you would never be that aware of noise. It doesn't hiss at all at zero volume - it's more a case of at what level the hiss starts to appear. Mine is quiet until you just don't want it any louder. Being able to use most of the volume pot travel range is also useful so that tracking is better. I use the Bravo at a very low setting only and it would be nice to have a little more finesse there. I've just thought - you know how people rage about Chinese amps being clones? Is this a European clone now? In which case, I wonder if you could clone an Earmax? I could do with another one. And I'd be prepared to pay slightly more than a Bravo!!! Ian
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Deleted
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Post by Deleted on Feb 25, 2010 8:04:06 GMT
The costs would have to be low. Hard to compete with Chinese parts though. The labour for manufacturing is the most expensive part and will be FOC of you assemble it yourself (if in kit form)
As stated I will only spend shitloads of time and some money on it if there is 'enough' demand for such a thing.
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robertkd
Been here a while!
Electronics Engineer from sunny Queensland
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Post by robertkd on Feb 25, 2010 8:06:54 GMT
prototype Need to cut the heatsink up one part for each end,.. Ok that didn't take much with the cutoff saw
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Deleted
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Post by Deleted on Feb 25, 2010 8:07:41 GMT
Hard to compete with Chinese parts though. I think that's why people would be more forgiving of a Chinese amp. Considering the sound with the cost is quite amazing in this case. It's hard to match/compete with a pre made amp at that price/sound. Ian
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Deleted
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Post by Deleted on Feb 25, 2010 9:01:41 GMT
Here is a thought.. SHOOT !!
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Deleted
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Post by Deleted on Feb 25, 2010 9:14:23 GMT
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Deleted
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Post by Deleted on Feb 25, 2010 9:37:46 GMT
No, not SHOOT, SHIT ! In comparison with the other version with a decent CCS and a more reasonable HT voltage, that is. I can't help but feel that the opamp is going to alter the tonal characteristics a smidgin too. What is the BW of the 1st one Frans ? Alex
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Deleted
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Post by Deleted on Feb 25, 2010 9:44:00 GMT
prototype Need to cut the heatsink up one part for each end,.. Ok that didn't take much with the cutoff saw Geez, Robert. Why didn't I think of that ? What better way to illustrate the difference between valve amps and a good SS design, than have a 12AT7 in one channel, and a 12AU7 in the other channel !!! ;D Alex
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