[nathanm]

I designed a prototype case for this project:



What you lose in expensive potentiometer shaft extensions you more than make up in the extra convenience offered by the faceplate.  Use it as a surface for soldering, drilling, hammering or general crafts.  The hardened steel surface resists mars from C-clamps and mallet blows.  In case of emergency it can be used as a weapon to fend off rival audiophiles.

[DVV]

You won't see those designs out of Dejan the tube hater  

Hey Dejan, what I would like to see is what we talked about years ago. A pre-amp that contained it's very own crossover(s). Variable slopes, variable crossover points, variable gain for each band and last but not least a remote control that allows gain control for each band (for us lazyphiles). You could make them in bi and tri amped versions. Something absolutely unique to the market.

For the money Marchl ...

I'm not a tube hater, I just don't use them. However, if there's one place a tube is sitting right at home, it's a preamp.

It's a thought, Scotty, it's a thought.

Sure you get the commission on the first mil I make. All I have to do now is make it - a cinch, right?

Josh, I get the message, but I'm not likely to be into transports and DACs very soon. Too many things to do before one gets to that point.

Cheers,
DVV

[bubba966]

I wouldn't mind seeing an amp kit for more than 2 channels (like say... 7 channels ) that doesn't cost a small fortune.

Would also be good if it wasn't a space heater for a small airpane hanger.

[DVV]

I wouldn't mind seeing an amp kit for more than 2 channels (like say... 7 channels ) that doesn't cost a small fortune.

Would also be good if it wasn't a space heater for a small airpane hanger.

Not likely in the near future. However, perhaps 7 monoblocks would do, Bubba?

Point is, a monoblock gives you flexibility. For example, you can go for a say 50W amp for the tweeter, but from a say 150W job for the bass. In addition to that, you can start with two, move on to three and go up in progression to any level you care to go for.

Last but far from least, a monoblock gives you the option of quality unavailable in a multichannel single rig. I refer to large power transfromers and filter capacitors; all these require space, but because each monoblock, or three dual channels and one monoblock, offer far more space, quality PSUs become a VERY viable option. The result will be extremely low crosstalk no multiple channel single rig can manage.

That's how I see it, anyway.

Cheers,
DVV

[bubba966]

The 7 channels I'd be looking for aren't for bi-amping. I run a 7 speaker setup, w/2 subs. Luckily the subs are powered. Finding 9 channel amps is a lot harder than finding 7 channel amps...

Sure, monoblocks can be good. But that'd not only take up a lot of room (a 7 mono stack would be rather tall), but it'd take up a whole lot of power cords & outlet space. And I'm sure that mono's would be ultimately better sounding if taken to the extreme over a big MC amp.

But sometimes a little bit of convenience wins out over ultimate sound quality (at least IMO). Useability & ergonomics does play a factor into my gear decisions. But quality is certainly not left out of the equation.

So, while a 5 or 7 channel amp wouldn't (or maybe couldn't) sound as good as 5 or 7 mono's, I personally wouldn't go with mono's.

[JoshK]

I still think you'd be better off going with external amps (mono's or whatever) for the front three and using your receiver to power the rear 4.  Then you could have it all.

[JoshK]

Dejan,

I understand not wanting to get to the transport or DAC, but my suggestion was simply to illustrate what I think the DIY community needs as opposed to wants.   I am sure an amp kit from you would kick ass.

[DVV]

The 7 channels I'd be looking for aren't for bi-amping. I run a 7 speaker setup, w/2 subs. Luckily the subs are powered. Finding 9 channel amps is a lot harder than finding 7 channel amps...

Sure, monoblocks can be good. But that'd not only take up a lot of room (a 7 mono stack would be rather tall), but it'd take up a whole lot of power cords & outlet space. And I'm sure that mono's would be ultimately better sounding if taken to the extreme over a big MC amp.

But sometimes a little bit of con ...

A lot more room is right, but perhaps not as much more as you might think.

Many, many years ago, a not altogether unknown company by the name of Studer/ReVox had a 2x45W/8 ohms power amp in its prestige 700 series. What was very striking about it was its very small size. Remember, this was like 1974 or 1975, when metal was dirt cheap, and even a cheap JVC or Akai integrated amp weighed in like 20 or 25 lbs.

What Willi Studer and his boys did was to install two modest heat sinks, but also a fan beneath them. As long as you were within reasonable levels, at typical room sound pressure levels, the fan was still. Then, when you felt like pelting it, it would begin to turn in some rapport with the heat you were asking the amp to produce. By the time the fan really started whirling, the SPL levels in the room were, shall we say, very generous?

The upshot was that the amp was of truly modest proportions. These days, in view of our current selection of heat sinks, you don't even need that fan for MUCH greater power levels, simply because we can buy very efficient heat sinks which were not available then.

What I'd really like to do is to build a monoblock amp, which would be a bit taller than most modern power amps in the low and mid category (high end is not concerned with proportions), and perhaps a bit deeper, but very narrow. That way, you could line up 3, 4 maybe 5 monoblocks into the horizontal space of a typical 2 channel power amp of similar power rating. And not need the fan at all.

Fischer SK71 heat sinks are ideal for this. They are exactly 12 inches long, 1.6 inches deep and can be 2.8 or 3.9 inches tall, yet afford the cooling efficiency of 0.25 for the 2.8 inch version. Perfect! I'll deliver like 150W/8 ohms on that if pushed, 120W conservative. And as you can guess, I'd go for the 3.9 inch version, which is still more efficient. In addition to which I tend to use more power transistor pairs than the industry, because I want that bass to rock and kick ass when required; I plain hate it when my tympani sounds like a guy hitting a medium depth pot.

This would allow the amp to be about 18-19" deep, about 4.5" tall and I would guess about 4-5 inches wide. Most people have no problem with depth up to about 20", 4-5" inches high is usually not a problem, and at even 5" wide, you could still put together four of them into a 20-21" space.

That's a thought, eh?

Cheers,
DVV

[DVV]

Dejan,

I understand not wanting to get to the transport or DAC, but my suggestion was simply to illustrate what I think the DIY community needs as opposed to wants.   I am sure an amp kit from you would kick ass.

I got that, Josh. But my comment still stands - developing a DAC worth the time and trouble takes a long time, much work and a team. That's definitely NOT a one man job.

But if you are really keen to do it, I have a DAC project around somewhere, developed by Europe's larges electronics magazine, Elektor (published in English, French, German and Dutch). I could scan it, it has the PCB artwork and generally everything you need to make a copy. But I fear it's a bit out of date now, being 3-4 years old, these days there are much better and newer DACs to be bought.

Also, my feeling and experience is that if you buy a solid mid-market player, there are many benefits to be obtained by tweaking it in the regions of power supplies and analog outputs.

My own Yamaha CDX-993 (now dead as a model) is a glaring example. It sounds completely non-digital, i.e. as if it were an analog unit, but it plays its hand a bit too much. Warm and cuddly is nise, but it's not the truth, strictly speaking. Change its VI op amps from shoddy NJRs to AD826AN, and it comes back at you with more resolution, more detail, yet still sounding non-digital.

Move on to the power supply, change those four 6,800uF caps for some Nichicons or Fischer&Tauche, change those crappy diodes for some fast ones, and you get still more resolution, more air, more finesse, but still with a very much analog kind of sound.

In the end, you spend like $500 on that player (that's what I paid for it), another $200 or so for better parts, sit down two afternoons and you end up with a player which sounds like it cost $5-6 grand. It really grew on me, I don't see myself changing it anytime soon.

Cheers,
DVV

[JoshK]

Thanks Dejan.  I have yet to play around enough with digital (actually not at all really) to know what can be done via tweaking. You are probably right.  When I get around to tweaking my Sony XA777, I'll bounce my ideas off you if you don't mind.

[DVV]

Thanks Dejan.  I have yet to play around enough with digital (actually not at all really) to know what can be done via tweaking. You are probably right.  When I get around to tweaking my Sony XA777, I'll bounce my ideas off you if you don't mind.

By all means do, I'll help what I can.

But let me warn you, although you probably know this - to be able to tweak intelligently and to the max, you will need the service schematics for what you want to tweak. We need to know exactly how the circuit was done to see what could stand improvement, and what should best be left alone.

Cheers,
DVV

[DVV]

So what about tone controls? For and against?

I should mention that their ill fame is not inherent to them, but is still well deserved because of the specs race among manufacturers. At some point, they started doing really wild things with tone controls, giving them 20 dB and over boost and cut, and under constant pressure to lower prices, they started executing tone controls in a really quick and didrty way.

To me, a tone control should have no more than +/- 6 dB boost/cut, and should act on the true extremes only, leaving the mid range well enough alone. Obviously, to be fully functional, tone controls should be separate for each channel, and should by default be active, to compensate for those !@#$%^&* capacitors.

In a more expensive design, tone controls should use fixed resistors (rather than pots) calibrated in exact 1 or 1.5 dB steps, and thus be completely repeatable. This is old pro practice, and oddly enough, some manufacturers did offer such controls in the early 70-ies (e.g. Studer/ReVox, Pioneer).

What do you guys think?

Cheers,
DVV

[eico1]

It's incredulous to me people are willing to invest so much into cables and swapping components rather than a smooth eq as you describe. All the detail, soundstage, whatever else etc. desired  would be at their fingertips.

What isn't understood is that eq corrects the source, not crappy equipment or rooms as the audio mythologists would have us believe and fear.

Build up the kit, just don't forget the Quad Tilt control! It may just create a whole new movement, it will be just like the 60's:).

steve

[DVV]

It's incredulous to me people are willing to invest so much into cables and swapping components rather than a smooth eq as you describe. All the detail, soundstage, whatever else etc. desired  would be at their fingertips.

What isn't understood is that eq corrects the source, not crappy equipment or rooms as the audio mythologists would have us believe and fear.

Not strictly true, although not wrong either. Tone controls can compensate for room acoustics by, for example, compensating treble absorbtion by large curtains, carpets, etc.

Which is why if done properly, they should be separate for each channel, since each loudspeaker will be working under similar, but not quite the same conditions.

Build up the kit, just don't forget the Quad Tilt control! It may just create a whole new movement, it will be just like the 60's:).

steve

Wow, thanks! I wasn't that ambitious. Also, while Quad's method is an interesting approach, I feel the user should have ALL of the choice to adjust to his own requirements, meaning totally separate bass and treble for each channel, rather than Quad's tilt control (which was, by the way, later emulated by others, such as say Luxman, and which is back today with Rotel, for example).

Of course, a bypass control ("tone defeat") is also mandatory.

Cheers,

DVV

[Marbles]

DVV, I had a chance to talk to a gentleman who sells DIY speakers.

He wants to get out of the market into the "already made" speaker market.

He complains that the DIY consumers are very cheap, they know the cost of every part down to the cost of a washer!  He doesn't feel he can make any money with those consumers.  Just thought I would pass that info on.

DIY amps could be a whole different thing though, and as mentioned, Aspen seems to do it well.

[JoshK]

I think DIY speaker building is different as you say, Rob.  I think the folley in selling kit speakers, could be that really what you are selling is a design and for that and that alone you should be compenstated.  This design shouldn't necessarily be charged as a percentage markup over the total cost of parts, only if the whole kit is sold as a 'one stop shop'.  I think most DIYers don't really want the one stop shop convenience, they really only want the plans and schematics.  I think that is what vendors should charge for, the plans that they sat down to figure out.  Then the savvy DIY'er can go buy the parts from whereever is cheapest.  For those who do not want to hunt down the cheapest parts, the vendor can sell the collection of parts for a service premium.  This makes a lot more sense to me anyway.

[Marbles]

The only difference is the complexity.  Amps are much more complex to build than a speaker.

[DVV]

Rob, Josh,

Thank you for your thoughts.

Rob, while I believe the man is right about the speakers, electronics are a bit different. But the point is well taken, as Josh elaborates. I have long believed that a say pre/amp kit should be offered approximately as follows:

1. Boards and plans only - cheapest
2. Sensitive components, hand selected;
3. Critical mechanical components;
4. Power supplies, transformers
5. Cases

So, everybody can buy under 1. and over, whatever someone chooses to go for. Practically, only under 1. is mandatory, the rest is optional, so if somebody wants to buy their own from their own sources, fine, go ahead.

My belief is that any self-respecting DIY man will want to experiment a bit, so it's up to the designer to supply, free of charge, additional comprehensive data about tweaking, offering some insights and a few specific suggestions.

However, this also means that the designer can guarantee for the sound quality of the kit only if it duplicates the original work; going your own way means you may end up with better or worse than the original. So long as this is understood, go get 'em, guys.

Obviously, this also means that the designer must make available, in optional form, the parts for making the exact duplicate. That's his risk, no two ways about it.

I have to say it, it's a challenge.

Cheers,
DVV

[JoshK]

Dejan,

To clarify, I was mostly responding to Rob's comments and I agree that amp/preamp kits can be different because of the complexity and higher learning curve.  Kits here can be different, but I really like your ideas on how to offer it.  It lets DIYers at different points in the learning curve attempt it at a level they feel comfortable while allowing experienced guys have more flexibility and minimal starting point.

[DVV]

Dejan,

To clarify, I was mostly responding to Rob's comments and I agree that amp/preamp kits can be different because of the complexity and higher learning curve.  Kits here can be different, but I really like your ideas on how to offer it.  It lets DIYers at different points in the learning curve attempt it at a level they feel comfortable while allowing experienced guys have more flexibility and minimal starting point.

Peace, man. You have to remember I was on those 1968 barricades, so I'm a throwback to the flower power, love and peace, and all that. So, my motto was, and still is - power to the people.

I never wore a kaftan, but I sure had a lot of Carnaby Street bellbottoms. I did fail my generation by saying "No!" to drugs, never once smoked pot, and never once got drunk. I know Rob will think less of me now , but I gotta tell it like it was. My only redeeming trait could be that I sure liked ladies a lot, and baby, I still do. Why do you think I went into hardware testing? Because of low level formatting, that's why. You gotta get into the groove man.

But seriously, I really think people should be given the maximum choice there is, or is reasonable to be there. In addition to what you said Josh, there's another factor - small packages, containing only PCBs, are easy to send by regular mail, thus cutting mailing costs drastically.

And if by chance I can get a few people interested in electronics, well then I really struck it rich, the mother lode. I'll have to bust my butt writing, but that's the way it's got to be. I've started on that already.

Ciao,
DVV