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-   -   Isonoe LRPS (http://www.wavemusic.com/community/showthread.php?t=14105)

CJ Branda 01-05-2014 11:33 PM

Isonoe LRPS
Hi all - am seriously considering upgrading my Urei 1620LE to be powered by the Isonoe LRPS. Anyone here have any experience with this unit?

Richi 01-06-2014 06:50 PM

It's a regulated power supply and should do what is says and provide a stable DC source to whatever relevant circuit needs to be powered. You would see the same noise improvement by using pretty much any standard regulated power supply, modern IC regulators do a good job at providing clean DC.

What Justin has done is shown that the Bozak's discrete circuit design doesn't reject supply noise very well which is going to mask the music that can be heard.

The UREI improvement is not as great as the Bozak as the TL072 op-amp has superior power supply rejection than the discrete design of the Bozak.

You may want to ask Justin to supply what the noise benefits are going through a line in on the UREI instead of the Phono section especially if you’re a heavy digital user.

A good regulated supply is certainly a worthwhile improvement if you like hearing music instead of noise.

DSA.audio 01-06-2014 08:03 PM

... if it is audible in your system...

they do look yummy!

CJ Branda 01-07-2014 04:49 AM

I spin vinyl almost exclusively through the Urei so I'm expecting the sound to become more detailed as the noise floor drops by installing the LRPS. Presently in contact with Justin now regarding price and logistics... :)

Pern 01-07-2014 09:55 AM

Don't know the cost for this unit but an option could be some external high quality phono amps, think that would do more to improve vinyl sound quality.

The UREI PSU is a really basic one, so i'm sure the mixer would be better with this one. But you still have the original Phono amps and that design/components isn't the best.

Captainjr 01-07-2014 10:28 AM

This was discussed quite a while ago. I have seen one of Justin's LRPS in action on a Bozak mixer. Yes it considerably cleans up the signal and lowers the noise floor on an oscilloscope but was it actually audible is up for discussion. Some people say they hear a major difference and others say not so much or nothing. I have no idea what it might do on your UREI so getting lots of input from different sources that actually have and use one would be a good avenue to explore. I have been told by several reliable sources that Justin is a good person to work with but the end result should be what avenue you decide to go down that would work best for your application like mobile, studio, etc. Also as Pern stated a good quality phono preamp may be worth looking into for use with the UREI.

Pern 01-07-2014 10:42 AM

This PSU and a couple of Lehmann Audio Black Cube Phono amps would be interesting :-)

CJ Branda 01-08-2014 02:40 AM

OK I'm pretty excited as I'm going to jump in and go for the LRPS upgrade + Burr-Brown opamps, Panasonic caps, Precision RIAA 1% upgrade & Cinemag transformers upgrades ! I'm sure I'd be kicking myself in the future if I only went for the LRPS and not the rest of the options offered by Isonoe ;)


Gonna keep the balance pots though. And as a final touch - change out the gold pot caps to silver (as per VJ's thread a few years back!).

ArmenianSoul 01-09-2014 12:36 PM

how much is this exciting upgrade gonna cost you?

1620_nz 01-09-2014 01:34 PM

how about a third phono card?

Captainjr 01-09-2014 02:03 PM

Not to down play anything but I have heard from several people that they experienced problems with Panasonic brand capacitors when used in a mixer. I have no idea if a brand used could really effect the audio sound in the mixer and from what I read I am sure Justin knows what works with his modifications. It was discussed here once about some capacitor brands working better than others but I do not know if it is really and issue.

CJ Branda 01-09-2014 02:21 PM


Originally Posted by ArmenianSoul
how much is this exciting upgrade gonna cost you?

As there are no prices listed on the Isonoe website I guess I'll leave it you to contact Justin if your interested ;)

CJ Branda 01-09-2014 02:24 PM


Originally Posted by Captainjr
Not to down play anything but I have heard from several people that they experienced problems with Panasonic brand capacitors when used in a mixer. I have no idea if a brand used could really effect the audio sound in the mixer and from what I read I am sure Justin knows what works with his modifications. It was discussed here once about some capacitor brands working better than others but I do not know if it is really and issue.

Yes I've heard that recently too. Justin does guarantee his work for 2 years so if there are any issues they could be rectified within reason.

vinyl_junkie 01-09-2014 05:22 PM

I'm almost certain you won't be disappointed with what he'll do to your LE, the PSU alone should make a good bit of difference imo and the rest of the upgrades to the mixer will get rid of that harshness the LE has.

Captainjr 01-09-2014 07:45 PM

Justin offering a two year warranty shows confidence in his work. A lot of people now a days fix it, take their money, and then walk away. There are a lot of good designers and do it yourselfers here on WAVE that are willing to help an give sincere honest advice.

Richi 01-11-2014 12:31 AM

Capacitor brand should be of no concern unless a bad batch was made which doesn't happen much. I have been using Panasonic for years and never had one fail on me there are generally considered very reliable.

As to audible difference between brands, well, if all specs are equal it's generally going to be very small indeed.

Captainjr 01-11-2014 09:58 AM

Richi, I agree with you on capacitor brands and production but there were several post here over the years where many people feel they hear better sound quality with say Black Gates, or other more expensive brands. I would have to go back over old post but I think Justin may have once commented on the subject. I have heard of several reputable repair people that will no longer use certain brand names because of customers complaints of sound reproduction quality. Like you I can not see where any quality brand should cause a problem but some people whether they really do or do not claim they actually hear a difference.

Richi 01-11-2014 07:34 PM

It comes down to testing, one must build a circuit and test said capacitors to find out if there is any truth in statements made by others. There are many factors that are going to change the sound especially in places like filters where the value of the capacitor will alter the cut off point.

Capacitors change their value as they get older which is also going to affect the final sound and changing the original design goals. Replacing older capacitors with new of the same value is going to bring a design back to it's original specifications and the sound will be different to those older capacitors. So, if you have lived with say a phono amp for 5 years and you know the sound of it well and then re-cap it, you will more than likely have a different sounding phono stage, as all the RIAA filters will now be different due to the value of the caps being to spec again.

Now, lets say i have brand A capacitor of value of 1uf 63v that is forming some kind of filter and we then replace that with brand B 1uf 63v. If all specs are the same, then the filter cutoff should stay the same. However, if we didn't measure both of the capacitors prior then the values may vary and the cutoff would then be different resulting in a slightly different sound. If we don't match channels properly as well we then have more variation in design.

So everything must be measured accurately before we can determine if there is any real difference.

To properly A/B we need switchable circuits with matched gain, so we can quickly move from brand a,b,c,d and determine if there is any difference. It all comes down to experimentation.

It's all very interesting if there is any difference, yet it should be done with at least some basis to A/B at a minimum.

Captainjr 01-11-2014 08:07 PM

Richii...Does this mean that a capacitor could make a difference in sound quality and frequency reproduction? I really have no idea except for what I read and the opinions I get from several technicians. Some have told me know way could it matter and others say it could possibly cause a sound variance people may hear. Filtering in a timing circuit vs audio circuit I could not understand how if the same value is used that it matters. Also could types of capacitors used like axial, radial, tantalum, etc matter in sound circuits not timing circuits?

vinyl_junkie 01-11-2014 08:20 PM

Modern capacitors also have a lower ESR compared those older ones originally fitted in say a Bozak or Urei.


This will no doubt maybe contribute to a "change" in sound too.

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