Phone preamp question

Relatively speaking, of course...

If anyone is still interested, I just replaced the "Ruby" that came with the Bellari with an nos Amperex. Sounds really, really good. The quality sound coming out of this little pre is really something for the price. Also a testament to what a higher quality tube can mean for the sound in a given system.

What the set up is:

Dual 1264 turntable in pristine condition I picked up for $100.

Odyssey Audio Stratos designed by Symphonic Line amplifier in pristine condition for $250.

Bellari vp130 mk2 with custom power supply for $200.

Nos Amperex tube for $20.

B&W CDM1NT’s bookshelves and B&W ASW 650 subwoofer I already had that are really for home theater duty and various cables I already had.

So for a $570 layout, some mighty fine sound!

Passive Preamplifier In essence is merely a volume control designed to attenuate the signal going from the source (usually a CD player) to the amplifier. Since it is passive, it has no inherent gain because it has no active components (tubes or transistors) in the signal path

^That^ is all true, but an active preamp is almost always an attenuation device too.
The active does have a lower output impedance.

By using neither one, the OP saved needing another cable.

+1@ sleepwalker65

Passive Preamplifier In essence is merely a volume control designed to attenuate the signal going from the source (usually a CD player) to the amplifier. Since it is passive, it has no inherent gain because it has no active components (tubes or transistors) in the signal path.

You might disagree but you are still wrong. How can call something a preamplifier when does not amplify the signal?

It sits where a preamp sits, and switches inputs like a preamp.

Also most preamps attenuate, so the amplifier part is not amplifying, and not really doing impedance matching like a power amp does.

@yogiboy ,

Agreed. I've bought several on EBay myself with zero problems.

I guess my point was, which I didn't convey well is given the voluminous amount of sellers there, as always, check seller feedback and transaction numbers.

@thecarpathian

I’ve been buying vintage preamp tubes on Ebay for the past twenty years. There are many reputable sellers that test before selling and I have never received a bad tube. If by chance you did receive a bad tube a refund is never a problem!

@yogiboy ,

True, but can be quite the crapshoot on there regarding tubes as I'm sure you know.

@sleepwalker65 ,

You are indeed correct and I am wrong. The very definition of a preamp makes passive preamp an oxymoron.

@thecarpathian 

 

Ughhh! There is no such thing as a "passive preamp". The two words are mutually exclusive,

Sorry @sleepwalker65 , going to have to disagree with you on that one!

You might disagree but you are still wrong. How can call something a preamplifier when does not amplify the signal?

There are many of those tubes listed on Ebay for  less than 100 bucks!

Thanks, yogi!

Yes, I believe that’s about as close as it gets to the 7316...

That price is mighty steep for a single tube.

Here ya go!

Anybody know if Amperex makes a 12ax7(ecc83) version of their 12au7/7316?

@corelli ,

Thank you also for that tidbit about powering it up before the amp.

Ughhh! There is no such thing as a "passive preamp". The two words are mutually exclusive,

Sorry @sleepwalker65 , going to have to disagree with you on that one!

Welp, SMPS are generally capable of producing more objectionable (irritating) noise than the 120Hz-ish ripple from a rectified 60Hz mains supply, but the economics and physical scale are in the favour of SMPS. Having said that, the manufacturing quality and sourcing of most SMPS wall warts and many SMPS modules is sketchy at best. 

@sleepwalker65

I’m in agreement with the notion that a wall wart will almost always be inferior to a well-designed power supply.

I hear ya, but there are also those out there that make the argument that SMPS’ do a great job of isolating 60 Hz hum.

AUDIO MYTH - "SWITCHING POWER SUPPLIES ARE NOISY"

I don’t know if you’ve ever heard the Benchmark amp mentioned in the article, with your own ears, but I have, and to my ears, it is drop-dead amazing, with a distortion figure of 0.00016%. I think I saw a S/N ratio figure of -130 dB. Most audio manufacturers cannot even approach that. Some people prefer the harmonics of tubes. I love the sound of them too, but give me low distortion any day over tubes. If you ever get the chance to hear the Benchmark amp at CES, or a local audio show; definitely make it a priority.

@dpop 

High quality audio is always directly associated with high quality power supplies.

a very general statement. No offense intended, but I'm not sure a bare bones $250 Bellari phono preamp qualifies as high quality. In this case, switching out power supplies will probably not reveal much. ...

I'm in agreement with the notion that a wall wart will almost always be inferior to a well-designed power supply.

In my case I've been using the similarity priced NAD PP2 phono preamp. There is substantial ripple voltage on the included wall wart. I don't have the measurements  handy, but they were disturbingly high for the application. So, I went to my local electronics parts store and bought a nice (over-overkill) 100VA, 28v transformer, a 7824 regulator, 4,700uF 50v and 470uF 100v caps and assembled a dead-quiet 24VDC power supply for the NAD PP2. While at it, I upgraded the power connector to a 2 pin screw-lock type, and replaced the plebeian NE5532 IC op-amp with a Burson SV6 Classic discrete op-amp. The results were quite pleasing to the ears, with the faster slew rate Burson and oodles of clean power at its disposal. 
 

So, yes - a wall wart can be a limiting factor, depending on the application, and the quality (or lack thereof) of the wall wart output. 

Ughhh! There is no such thing as a "passive preamp". The two words are mutually exclusive, like "military intelligence" or "Geoff Kate". 

I am glad you posted this, I did not know Bellari was made in USA. 

Glad to hear about it, just sent info to a friend.

High quality audio is always directly associated with high quality power supplies.

It's a very general statement. No offense intended, but I'm not sure a bare bones $250 Bellari phono preamp qualifies as high quality. In this case, switching out power supplies will probably not reveal much. Tube rolling in this scenario would probably make more sense when trying to upgrade audio performance. I've personally always loved Telefunken's myself. 

These units have been heavily modified by many but the biggest bang for your buck is a better tube, then the power supply.

Yes, that’s next. The 12ax7 that comes with it is a ’Ruby’, whomever the heck makes that, which I’m certain can be improved upon. Going to get an nos low microphonics Telefunken from a guy close to me here in Connecticut. Too bad it’s not a 12au7 in the Bellari as I’ve got many really nice nos ones already.

@holmz , good idea! I’ll switch them out one of these nights and see if I can hear a difference. Just keep in mind we’re not dealing with real high end stuff here. I'll also report back on the tube switch out.

Most definitely. High quality audio is always directly associated with high quality power supplies.

Although I really doubt ^that^ is a truism, @thecarpathian could certainly try it and report back, which could give us some insight worth respect to the Bellari, but doesn’t say much about other gear.

I have a Bellari VP129 that I use in a dedicated vinyl/headphone system and have always been shocked by how well it performs.  My only nit that I wish I had a fix for is when you power it up, it will send a "pop" to your amp so be careful to power it up before your amp.

These units have been heavily modified by many but the biggest bang for your buck is a better tube, then the power supply.

@thecarpathian

the Bellari came with a custom and extremely robust separate power supply to use in place of the original, anemic wall wart. (Included)

I wonder if this has something to do with its performance?

Most definitely. High quality audio is always directly associated with high quality power supplies.

😀 yeah…

But it is pretty cool that it worked out for you.

Many phono stages only have enough adjustment to load a cartridge, so it worked out well for you, and I suspect that it sounds just dandy.

Well done sir!

Additionally - it could potentially not sound not as good with a passive shoved in the middle, depending on how it is trying to drive the amp(s). The Bellari would have a better (lower) output impedance than a passive, so if it is working a champ, then maybe do not start second guessing it?

Just score it as a win.

I have never seen a powered passive.(??)

Yeah, that was kind of redundant....

Just got it all set up, and with the gain setting not a quarter of the way on the Bellari, it's already loud enough and sounding pretty darn good. Too late to crank it, but I'm pleasantly surprised by the volume level. Forgot to mention, the Bellari came with a custom and extremely robust separate power supply to use in place of the original, anemic wall wart. (Included)

I wonder if this has something to do with its performance?

No - almost certainly the wall wart itself would be fine. 

Didn't think a non powered passive would do anything.

I have never seen a powered passive.(??)

Most sources output 1V, and most preamp and passives need that cut that back 10-40dB depending on time of day, dirty looks, mood, etc.

Glad it's worked for you. 

Just got it all set up, and with the gain setting not a quarter of the way on the Bellari, it's already loud enough and sounding pretty darn good. Too late to crank it, but I'm pleasantly surprised by the volume level. Forgot to mention, the Bellari came with a custom and extremely robust separate power supply to use in place of the original, anemic wall wart. (Included)

I wonder if this has something to do with its performance?

Anyway, thank you all again for your input.

A phono preamp and a passive preamp does not have enough voltage to use with an amp directly. You need an active preamp!

^No!^

The phono amp usually needs 10-40 dB of attenuation.

Guys, can I take a phono preamp (Bellari vp130 mk2) which has a gain control and plug it directly into an amp (Odyssey Audio Stratos) using the gain control as a volume control…

@thecarpathian it should get way too loud, but it is easy enough to try it. It should work.

yogiboy

4,713 posts

10-16-2022 at 01:57pm 

A phono preamp and a passive preamp does not have enough voltage to use with an amp directly. You need an active preamp!

 

 

Bzzzzzt…..wrong. But thanks for playing.

I have been using phono stages with passive preamps for years. It’s more about how passive friendly your system is. As I type this I am listening to an SPL Phonos into a Hattor Audio passive preamp. No problem with driving the amp to full power.

@thecarpathian 

I agree 100% with @russ69. It also depends on how loud you like to play your system. The Odyssey Audio Stratos' spec sheet does not specify an input sensitivity rating (that I could find), so it's hard to tell if 39 dB of gain on the Bellari will be sufficient for your systems needs. My guess is it will be. Make sure the Bellari is powered up first before powering up the speaker amp (if and when using speakers). In this scenario, I would also not allow a pair of headphones to be plugged into the Bellari when listening to speakers, as this may change the output impedance and output voltage of the Bellari (just to be on the safe side, as the Bellari spec sheet does not specify if when headphones are plugged in, the RCA outputs are muted). Speakers or headphones when using the Bellari, but not both at the same time is my recommendation. Let us know how it performs for you.    

Thanks all!

Didn't think a non powered passive would do anything.

Since it won't hurt anything, when the phono pre comes in I'll hook it direct. Won't have high expectations.

Jerry, I'll check out that pre. 

This is for a simple interim turntable system, so no big spending.

Thanks again, guys!

A phono preamp and a passive preamp does not have enough voltage to use with an amp directly. You need an active preamp!

Here is an idea.

The Bellari might have enough voltage to drive an amp, try it and see. Turn the gain DOWN at first. A passive preamp will not help as it attenuates the gain and has no gain of its own. Not sure if the Bellari will be a good match to your amp but it's worth a try. 

And I of course wrote 'Phono'. A pox upon autocorrect!