MC preamp straight into power amp?

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Charlie1
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MC preamp straight into power amp?

Post by Charlie1 » 2019-06-24 10:20

This might be a daft question (since I don't understand the science very well) but is it technically possible to remove part of the amplification process by building a single source phono amplifier? My understanding is that a phono stage performs RIAA plus a small amount of amplification to bring it up to line level, so just wondered if that 'small amout of amplification' could be skipped somehow - i.e. go RIAA equalisation > volume control > power amp. A single source Boazu with integrated phono stage that cut out part of the normal process could pack quite a punch.

I'm often surpised how many folks have multiple systems so a dedicated vinyl-only setup in one part of the house is not all that unusual, espeically if it doesn't cost a fortune and take up too much space.

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Re: Entry Level Lejonklou MC

Post by lejonklou » 2019-06-24 10:45

Charlie1 wrote:
2019-06-24 10:20
This might be a daft question (since I don't understand the science very well) but is it technically possible to remove part of the amplification process by building a single source phono/power amplifier? - i.e. go from RIAA equalisation straight to the power amp stage. I guess you'd have to skip any form of volume control though, or could a stepped attenuator be inserted? I just thought that the phono stage performs RIAA plus a small amount of amplification to bring it up to line level, so just wondered if that 'small amout of amplification' could be skipped somehow...
Far from daft, this is a long discussion which involves the whole system and every part of the amplification.

Which is your goal? To make the design simpler or to improve performance? Some might believe those two go hand in hand, but that's not the case. Too simple is worse, too complicated is also worse. Just right is the best.

Which part do you want to remove?
The phono stage performs RIAA and LOTS of amplification, not a small amount as you said. For an MC stage, usually at least a thousand times.
The preamp performs input switching and volume control, which means a span from lots of attenuation to about ten times of amplification - if it's analogue. For digital, it's only attenuation.
The power amp usually performs amplification of 10 to 30 times.
Passive attenuators are much worse than a preamp.

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Re: Entry Level Lejonklou MC

Post by Charlie1 » 2019-06-24 10:57

lejonklou wrote:
2019-06-24 10:45
Which is your goal? To make the design simpler or to improve performance? Some might believe those two go hand in hand, but that's not the case. Too simple is worse, too complicated is also worse. Just right is the best.

Which part do you want to remove?
The phono stage performs RIAA and LOTS of amplification, not a small amount as you said. For an MC stage, usually at least a thousand times.
The preamp performs input switching and volume control, which means a span from lots of attenuation to about ten times of amplification - if it's analogue. For digital, it's only attenuation.
The power amp usually performs amplification of 10 to 30 times.
Passive attenuators are much worse than a preamp.
I was assuming 'simpler' would automatically result in improved performance but I take your point.

I didn't realise the pre-amp performed any amplification for either analogue or digital so I've learned something already.

So, in theory, could an MC phono stage perform 10,000 times amplification (instead of 1,000 times) and then go straight into volume control, thereby skipping the 10 times amplification done by the pre-amp?

But it doesn't sound like you think any of this is very worthwhile...

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Re: Entry Level Lejonklou MC

Post by lejonklou » 2019-06-24 11:20

Oh yes, it's very worthwhile! In fact, I'd say it's essential. I think it's impossible to make a great sounding amplifier without having tried many, many variations of "how much amplification and where".

The pre-amp doesn't perform any amplification unless you play very loud. That's where the volume control comes into play. Usually, it just attenuates.

Yes, you could have the phono preamp do 10,000 times of amplification. SINGularity has 3,500. Then straight into volume control. I call that Single Source Input on Sagatun and Sagatun Mono. :)

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Re: MC preamp straight into power amp?

Post by lejonklou » 2019-06-24 11:31

Split this into a separate thread - I hope that's OK with you Charlie.

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Re: MC preamp straight into power amp?

Post by Charlie1 » 2019-06-24 11:35

No worries - thanks for your responses Fredrik!

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Re: MC preamp straight into power amp?

Post by lejonklou » 2019-06-24 11:55

What is also worth questioning - and this is something I remember discussing with Matthias long ago - is why the power amp should add gain when the preamp usually just attenuates signal. It must be bad for quality to attenuate and then amplify, in summary doing manipulations adding up to nothing. Right? More logical would be to move all the amplification to the preamp and then let the power amp only add the ability to deliver current (drive a loudspeaker).

The answer is that each power amp design sounds best and is most stable with a certain amount of gain. I set out to make a really low gain design, but ended up with 11 times of amplification. I tried changing a lot of things to make it lower, but 11 was always the best. Sometimes nature rules and we have to comply!

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Re: MC preamp straight into power amp?

Post by Charlie1 » 2019-06-24 12:17

Even though there's tons I don't understand I still find things like this facinating, especially when explained simply like this.

I should have known you had already delved into the depths of this one but glad I asked anyway :)

The creative and explorative stages of your work must be very rewarding.

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Re: MC preamp straight into power amp?

Post by lejonklou » 2019-06-24 13:47

There's always new angles to explore! Even the basic premises need be discussed and constantly reevaluated for things to move forward.

That's part of what's so fascinating with this field where art meets science.

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Re: MC preamp straight into power amp?

Post by ThomasOK » 2019-06-25 18:01

I thought this might help to clarify things a little bit. Lejonklou preamps and most more recent Linn analog preamps have unity gain at a setting of 80 out of 100 (first versions of the KK were at 70). Unity gain means there is no amplification and no attenuation - the level that comes in is the level that goes out. So volume levels above 80 are using a small amount of additional gain and levels below 80 are using attenuation. Therefore the maximum gain on those preamps is 20dB, which is rarely used. But it gives the flexibility to get proper levels with amps with lower gain or inefficient speakers, or both (within the limits of what the amp can do).

SINGularity has an input stage with 62dB of gain! This is almost as much as most MC preamps have in total. The RIAA stage is then followed by another 9dB of gain for a total of 71dB, because this is what Fredrik found sounds most musical. This may be why Charlie1 thought there was an RIAA stage and a small amount of gain. But the big gain happens right off the bat which helps to capture as much of the music as possible and makes the signal more robust before it is equalized.

Of course, a phono stage can be put into a preamp or integrated amp, as has often been done. But this is generally just a complete phono circuit connected into a complete preamplifier, not some kind of hybrid setup. It obviously reduces cost to do so, as separate power supplies and cases are not needed, but there are compromises as well. Not least of which is trying to keep as much musical information as possible in an inherently noisier environment.
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Re: MC preamp straight into power amp?

Post by Charlie1 » 2019-06-25 20:12

Thanks Thomas! - that helps clarify things further.

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Re: MC preamp straight into power amp?

Post by nmakowsk » 2019-07-05 05:55

ThomasOK wrote:
2019-06-25 18:01
I thought this might help to clarify things a little bit. Lejonklou preamps and most more recent Linn analog preamps have unity gain at a setting of 80 out of 100 (first versions of the KK were at 70). Unity gain means there is no amplification and no attenuation - the level that comes in is the level that goes out. So volume levels above 80 are using a small amount of additional gain and levels below 80 are using attenuation. Therefore the maximum gain on those preamps is 20dB, which is rarely used. But it gives the flexibility to get proper levels with amps with lower gain or inefficient speakers, or both (within the limits of what the amp can do).


Hi, I think Thomas has answered a question I have had about my kikkin now that my slipsik7 is a full 4 months burned in and sounding rather excellent. I use some so called inefficient Linn speakers in my system which can cause clipping pretty easily in the upper ranges of the kikkin pre-amplifier color codes. In fact I have blown two tweeters now which I have to blame myself for not being more careful and maybe having a touch too much fun with the remote... Anyways, in the Kikkin manual I notice that the start of the orange color spectrum is set as 0DB and this is also in the exact spot where I think the system usually sounds the best. Maximum is +20DB solid red range like Thomas said but those levels will clip too harshly for me to ever get near. Now this orange (0-10 DB) is rather loud to a lot of company I have had over but when I am by myself I find it usually in that 0DB spot. It just sounds right about 90% of the time and its plenty loud enough in the room... My question is thus: Is the Kikkin producing any amplification then on anything over the 0DB first orange level? Anything above +6 DB is in danger of clipping it seems depending on the loudness levels engineered into the cutting. Thomas' post about Linn and Fredrik using an 80 out of 100 unity gain made me think. It probably sounds good to me since there is no attenuation being used by the volume control (at 0DB) so now I wonder where its amplification potential comes into play. -Nick
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Re: MC preamp straight into power amp?

Post by lejonklou » 2019-07-06 11:59

nmakowsk wrote:
2019-07-05 05:55
Hi, I think Thomas has answered a question I have had about my kikkin now that my slipsik7 is a full 4 months burned in and sounding rather excellent. I use some so called inefficient Linn speakers in my system which can cause clipping pretty easily in the upper ranges of the kikkin pre-amplifier color codes. In fact I have blown two tweeters now which I have to blame myself for not being more careful and maybe having a touch too much fun with the remote... Anyways, in the Kikkin manual I notice that the start of the orange color spectrum is set as 0DB and this is also in the exact spot where I think the system usually sounds the best. Maximum is +20DB solid red range like Thomas said but those levels will clip too harshly for me to ever get near. Now this orange (0-10 DB) is rather loud to a lot of company I have had over but when I am by myself I find it usually in that 0DB spot. It just sounds right about 90% of the time and its plenty loud enough in the room... My question is thus: Is the Kikkin producing any amplification then on anything over the 0DB first orange level? Anything above +6 DB is in danger of clipping it seems depending on the loudness levels engineered into the cutting. Thomas' post about Linn and Fredrik using an 80 out of 100 unity gain made me think. It probably sounds good to me since there is no attenuation being used by the volume control (at 0DB) so now I wonder where its amplification potential comes into play. -Nick
Hi nmakowsk!

I am not quite sure what your question is. Yes, above the first orange level (80), Kikkin amplifies the signal with 1 dB per step. Otherwise it wouldn't become any louder when you increase in the orange range and up to the red.

Technically, however, it's not a "zero amplification in=out" when Kikkin is at level 80. In fact, the level is still attenuated slightly on the input, which is compensated for by a slight amplification on the output. It was designed that way because that made it perform best.

Also, the various volume levels on Kikkin (and Sagatun, and Sagatun Mono) perform very, very alike musically. Lots of work went into that aspect of performance. So I regard it as very unlikely that you experience the music to be best at volume 80 because of anything the preamp does.

I rather think the reason why you enjoy a volume of 80 is that Tundra doesn't mind playing near its clipping point. Most power amps - even the really powerful ones - sound gradually more compressed the louder you play. Tundra and Tundra Mono keep their dynamic, musical character the same, all the way up until they hit the ceiling with a distinct "plop". One customer described it as his Tundra had "infinite self confidence". I really like that description!

[Addition] I'm really sorry to hear you blowing tweeters! The usual cause for that is playing too loud (as you've probably understood) and it doesn't really matter how strong the amplifier is, it's rather a matter of the power it's forced to handle. An amplifier that clips sends a lot of spikes to the tweeter, which it can usually handle for a limited time, but eventually it overheats. Some tweeters handle this better than others, as it's all about dispersing the heat from the voice coil. Unfortunately some tweeters cook rather fast and that's no fun! I hope you had them replaced successfully![/]

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Re: MC preamp straight into power amp?

Post by Charlie1 » 2019-07-11 22:23

Hi Fredrik - have you ever compared with and without volume control, just to gauge the impact of the volume control? - i.e. a single fixed level of attenuation

Nait XS3 and SN3 now have MM phono. Are you tempted to include MM in the Boazu? The one-box solution does seem to appeal to some people, based on XS3/SN3 comments elsewhere.

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Re: MC preamp straight into power amp?

Post by lejonklou » 2019-07-12 22:38

Hi Charlie! Apologies for the late response - took care of 30 loose ends and closed the lab for vacation TODAY! Yesss - four weeks from today when I'll do my best not to think of the projects (although I really want to, experience has taught me that unexpected benefits can arise from completely ignoring them for a while).

Yes, I did compare fixed volumes with a variable one some years ago, but I found the difference to be very small if you just do the volume adjustment right. The analogue input switching, however, surprisingly does a lot more harm! This resulted in the Kikkin single input preamp, which I believe you've owned and compared to your Linn Klimax Kontrol a couple of times. Right?

The Sagatun preamp, when used on the Single Source input, was in practice a direct descendant of Kikkin, but now in dual Mono and with switch mode power supplies that performed better. Sagatun Mono was an unexpected improvement of the same concept, with left and right channels completely separated and their power supplies individually fine tuned. I really think you need to hear them both, as your recent clips don't convince me! I'm half joking but I'm serious too.

Regarding Boazu, the final prototype DID have an MM phono input. The MM was one of FOUR features that I removed in order to make it better. It was really good but somehow I wasn't convinced by it - I just wanted to play the same track on my Mono-Mono setup. When I had finally removed all features, including the MM stage, the music became so much more convincing and fun.

So, No, I'm not tempted to include MM as it makes Boazu perform worse. And a Gaio 2, which should be easy to hide behind the Boazu if necessary, performs better for those who are into vinyl. Those who aren't won't have to pay for the phono stage!

MC into an integrated can certainly be done, but the main things are that it's more expensive than MM (if done right) and also more sensitive. So it makes sense keeping it separate. I'm currently trying to squeeze my latest MC design into a Slipsik case. I hope that works, as my plan is to make a lot of them, to keep the price as low as possible. It's going to be the most fun MC stage you've ever heard.

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Re: MC preamp straight into power amp?

Post by Charlie1 » 2019-07-13 09:09

Thanks Fredrik.

Yes, Kikkin was great value.

Whilst Sagatun Monos would be lovely, I'm only spending up to about £500 on amplification for each system now so even a second hand Boazu would be a stretch at the moment.

Thanks for sharing your experiences with volume control and inputs.

Hope you have an enjoyable and relaxing break from work.

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Re: MC preamp straight into power amp?

Post by lejonklou » 2019-07-13 14:09

Thanks!

So £500 then? I'm taking a note of that. Let's see what I can come up with. :)

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