HELP with Kaneda line stage PSU

[KanedaK]

Hello,

last summer I bought a second-hand Kaneda preamp, or to be exact a dIY preamp built by the previous owner following the Kaneda schematics.

English is not my mother tongue so I will try to explain the problem using my limited technical vocabulary...

So, this preamp sounds great to my ears. No, I've never owned any truly high-end preamp, but still it sounds a million times better than any "mid-fi" preamp i've owned, including Marantz, Rotel, Musical Fidelity, NAD, vintage Technics... it's probably quite easy to sound better than those, but the difference isn't marginal, it's very big.

Anyways, there's a major drawback with this preamp: noise. How can a preamp be "noisy" and sound good, you ask me? well, my speakers are horns (104dB), and the noise is only discernable in the absence of modulation (I suspect if my taste in music would be more towards piano sonatas I'd be much more annoyed by this problem).
The noise I hear sounds more like white noise, or pink noise i don't know, and is somewhat intermittent / variable, so I think the problem is in the PSU.

Now, i've never tried to use a soldering iron for audio projects, and DIY something electronic hasn't occured to me yet (although i'd really much like to try), but I can understand an electronic drawing to some extent.

Well, if I compare what I see inside my preamp (transformateur, two HUGE caps, and the main circuit) to the Kaneda PSU drawings I can find online, mine seems to have a lot of elements missing... only I can't really firgure out what... I'm joining a picture of the inside of my preamp.

Something tells me if I would correct the problem, not only the noise would disappear, but the preamp would sound even better. Maybe i'm missing out a lot here.

If the PSU is indeed incomplete, I'd like to add what's missing, or replace the whole PSU section; but I was wondering if it is possible to find / have someone make a Kaneda PSU board for DIY dummies like me?

I can find quite a few ready-made PSU boards on the internet but nothing seems to be ok for the 35VDC Kaneda... as far as I can understand it...

If someone could give me some tips / source me some PSU it would be fantastic.

thanks in advance,

François

[Pano]

Hello François - interesting question.

I have not built a Kaneda - though I've heard a few - but I'm sure someone here has a lot of experience.

Your version appears have the passive power supply, but is missing the choke and the second stage of filtering. It's hard to tell from the photo what else may be missing. I don't think the missing choke would cause hiss, tho.

Also: You are certain that the hiss comes from the Kaneda, right? If you disconnect it from the power amp, you have no hiss? No other preamp had as much hiss? At what level do you normally run the volume control? If it is always very low, you may have too much gain going into your power amp.

I will leave it there for those with more Kaneda experience.

[KanedaK]

I definitely have too much gain. I never go past 11 o'clock on the volume pot, and that is very, very loud -but then, it's also very loud because mys speakers are 104dB. Let's say with the volume knob at 11', the power-amps vu-meters average 10 watts. And that is with the power-amp input level controls set about halfway. The power amp on his own is dead silent, tho. My average power consumption is around 0,01watt... but the amp sounds full and clean even at such a low power.

The whole combo sounds really good; I don't totally understand this gain-matching stuff. The Kaneda is a high gain line stage, but i've always seen it used in hornloaded systems. So I don't really get it... also, if the gain is too high what is there to do? I mean, other that change all my electronics, wich I really don't wanna do...

I mean, no other combination has brought me such musical satisfaction trough the year, and as I understand there's a theorical mismatch here (high gain line stage, high power amplifier, high sensitivity loudspeakers) the result sounds good so either i'm deaf (but i don't think so) either there's some qualities in my system counterbalancing the gain problem...

on the other hand, no other preamp i've used exhibited any noise problem (or then u'd have to stick ur ear in the horn to hear it). But they also sounded like crap.

I think i'd try to make the PSU better, and if it's still problematic I'd maybe go look for another preamp... but I'd be hard pressed to find something that sounds as good as this one for cheap (I paid around 300$ for this unit.)

I'm on a very very low budget and my biggest electronic expense so far is my vintage power amp.

[Bonsai]

Can someone put the circuit up for this amp so we can take a look?

[pioux]

I have a kaneda DIY and no noise back , and no shield wire in the mine

[pioux]

the original Kaneda is split in two preamp section : one is the RIAA and the other one is the preamp line section , i do not use this second section on my system , for cd only selector and pot to RCA (two set of out RCA one just after the pot and an other one after the line preamp ) enought gain on the direct for me .

[pioux]

j'ai pigé ,parles tu francais ?

tu n'as qu'un étage ligne et donc un gain XX db

il n'y a pas comme sur le montage d'origine la sortie juste derriere le potar de volume

sans gain .

[Pano]

Sorry Pioux, this forum is English. If you post in French, you must provide an English translation.

Originally Posted by pioux

I get it. You speak French?
you have nothing but a line stage and thus a gain of XXdB
there is not, as on the original version, the output just after the volume pot
without gain

[pioux]

sorry i will do that now

[Pano]

Here is the schematic that I have for the Kaneda. I don't know if it's the latest, greatest. I agree with pioux that you probably have the second half only, the output section seen on the right half of the schematic.

Too much gain. It's a common problem. Still, I don't think that you should have so much noise from this circuit. There is a problem somewhere.
Until we find out what the problem is, you should reduce the volume on your power amp to as low a level as practical. Your Kaneda should be at about 11 o'clock for comfortable listening.

Start with the power amp volume all the way down and the Kaneda at 11. Slowly raise the volume of the power amp until you get to where you need to be. Once set, use the Kaneda volume control. That is a temporary fix for some of the noise.