My frugels w/ new phono pre amp

[chuyler1]

I've had my frugelhorns for over 6 months (built from beta flat-pack) and I am in love with them. Recently I started getting into vinyl. I bought a decent turntable and for a while was using the phono input of a 90's Kenwood receiver, but I bypassed the amp stage of the receiver in favor of a Sonic Impact T amp.

Today a new toy came in the mail, a Bellari VP530 tube phono pre-amp. It seemed like a perfect replacement for my kenwood receiver. It was the same size as my T amp, had positive reviews, and included a headphone out as well as USB for ripping my favorite albums.

So what's the deal? I'm not sure if it's the right match for full-range speakers. The highs seem to roll off steeply when played through my frugels. It produces amazingly enjoyable music when listening on headphones but I almost prefer the old kenwood when it comes to sending the signal to the frugels. On the low end, I swear the bass is louder, but more muddy...as if I need to tweak the CC on the frugels or add some stuffing.

I went back and read some reviews of the Bellari unit (most are of its sister model VP129 w/o USB)....
http://www.soundstage.com/vinyl/vinyl20080615.htm
I agree 100% with the reviews when it comes to listening via headphone...but its just when I listen on my frugels that something just doesn't line up. Could there be too much HF rolloff for listening with speakers that rolloff on their own? Do I just need to tweak the CC volume and stuffing to get around the bass issues I'm having?

[Scottmoose]

Welcome to the world of system matching. This is one of the reasons I ignore equipment reviews, because without the same context they were conducted in, the results are at best questionable, and then you can factor personal taste into the equation too.

Clearly, at the moment, your new preamp doesn't work too well with your T-amp & Frugels, as it's rolling off the HF -it was there before; now it isn't, and only one thing has changed, right? You're really going to have to address the source of this problem; there isn't a whole lot you could do to the speakers to change things, as they're not the culprits. If you want an honest opinion, I'd kick that preamp into touch & either get something else, or go back to your old Kenwood. If you can return the thing, well & good. If not, I'd sell it on, & put the money toward something else.

[dhenryp]

One thought before you can the preamp; why don't you try feeding the preamp into the amp section of your Kenwood. The aux input will do if you don't have preamp out-amp in jumpers.

I'm wondering if maybe there is something about the T-Amp input impedance that is causing a mismatch with your tube preamp. If the preamp work OK with your Kenwood, you could consider losing the T-Amp - which I assume is cheaper than the preamp.

Just a guess.

Denis

[planet10]

Originally posted by dhenryp
One thought before you can the preamp; why don't you try feeding the preamp into the amp section of your Kenwood. The aux input will do if you don't have preamp out-amp in jumpers.

I'm wondering if maybe there is something about the T-Amp input impedance that is causing a mismatch with your tube preamp. If the preamp work OK with your Kenwood, you could consider losing the T-Amp - which I assume is cheaper than the preamp.

Exactly what i was going to suggest.

Also note that some of those phono sections are quite decent... in those days phono wasn't an afterthot and competition was fierce.

dave

[chuyler1]

I'll give that a shot denis. Might as well try a few different things before returning it.

Also, could the preamp need some break-in period before it performs optimally? I've only got about 5-10 hours on it right now. Maybe I'll give it a week or so and then go back to my previous setup and see if it still sounds different.

[planet10]

Originally posted by chuyler1
Also, could the preamp need some break-in period before it performs optimall

Yes.

dave

[rcdaniel]

It can be difficult to gain an understanding of the type and degree of sonic changes from our descriptions - our language is rather limited in this respect... The degree of difference between the two arrangements is unclear from your descriptions. However, your description *may* imply something more pronounced than the 'usual' system synergy considerations that are based on mainly sonic factors.

However, impedance mismatches between components can sound as you have described. What is the output impedance of the phono amp and the input impedance of the digital amp? The 12ax7 is not exactly a low impedance device. I don't know how it has been used in the Bellari... though I'd not be surprised if the Bellari had a high-ish output impedance and the digital amp had a lowish-ish input impedance. I also wonder how (if?) the headphone output differs to the amp output.

Cheers
Raymond

[planet10]

Originally posted by rcdaniel
... The 12ax7 is not exactly a low impedance device. I don't know how it has been used in the Bellari... though I'd not be surprised if the Bellari had a high-ish output impedance and the digital amp had a lowish-ish input impedance.

According to the promo, Chris' phono is an updayed version of the VP129, so is likely broadly similar... map attached.

dave

[chuyler1]

Output Impedence of the VP530 is 8ohms for the headphone and 100 ohms for the RCA. Not sure what the imput impedence is for the T-amp. The user's manual doesn't say anything.

I moved the speakers around a little bit today, I was able to resolve most of the bass issues by pulling them farther away from the wall.

[rcdaniel]

From the linked review:

"The company boasts that the unit utilizes all-tube circuitry and the output stage features one dual-triode 12AX7."

Which, from the schematic, is untrue. Looks like the 12ax7 is at the input with what I think are opamps later stages (I am not a SS guy). Therefore, it is not surprising that the RCA output is 100 Ohms, which is pretty low and should be capable of driving most amps.

My recommendation would be to let it burn in for a while then consider trying a different 12ax7.

Cheers
Raymond