TU-8500 phono stage upgrades

[Hmavv]

Hi Robert!

Sparkos have too high of a bias current.. that hum you hear is the current itself. They are not suited for phono sections, but they Sparkos are still great in other circuits like head phone amps.

The Muses01 are phenomenal in the TU-8500 and its what I'm currently using, I have a pretty big write up in this thread in a pervious page. I spent several days going through Japanese websites going back to the mid 2000s trying to dig up everything I could about them!

 

[Silvolde]

@Hmavv. I've ordered the Muses01 as well as the Sparkos discrete +12V and -12V voltage regulators.

Furthermore I'd like to add tape rec/pb connections for my Teac 3300SX/Tascam DBX combination. Due to the available size it will be difficult to modify the chassis. Has anyone here done this modification?

Rgds,

Robert

 

[batty]

I have a pair of Burson V5i that I am thinking of trying in mine, I have just swapped the valves for JJs.

Rest of the gear is a Townshend Rock mkII, RB250 with an Ortofon Quintet Bronze (also have a V15 III) power amp is a DiyAudio M2x speakers are LK1 DIY kits from Mike Lenehan.

 

[Silvolde]

Quite some time ago I read a modification on the Elekit TU-8500 preamp where the 0.1 uF caps (C5 and C6) have been replaced by Black Gate NP series equivalents. Can someone inform me about this modification as well as the effects of the replacement?

Thanks in advance.

Best regards,

Robert

 

[paczeltf]

Black Gates were electrolytic caps, which have been out of production for many years. There is no reason to replace a foil cap with these.

 

[Silvolde]

The Black Gate NP series are non-polar caps. I suggest you read the Black Gate article of Martin Colloms.

Rgds,

Robert

 

[paczeltf]

I know what Black Gates are. And non-polar electrolytics are still electrolytics, usually two of them connected serially in reverse polarity. Where does this article say otherwise?
And I am very sorry, but could not care less of what M.C. wrote in one if his" professional" reviews.

P.S. I am not sure if attaching possibly copyright-protected magazine content complies with forum rules.

 

[rodman1]

I purchased this a few years ago but just assembled it about a month ago. Using GE12AT7 tubes and Muses01 in phono stage and I have to say that I'm not impressed. I upgraded every part in the phono stage, resistors are low PPM military grade and signal caps are WIMA and Mundorf. I have about 40-50 hours on this and the phono to my ears is just ok. My 2nd gen Hagerman Bugle is actually quite better and my Salas Ultra Folded makes a joke of it, unfortunately... Not sure what I'm missing but having built and rolled many simple phono stages over the years this design seems to be on the lower spectrum of performance. Any thoughts or comments good/bad are welcome. The picture is the completed PCB with the soldered components.

Thanks

 

[grunf]

OS-CON in phono stage, strangely
they are better in digital as DAC or similar because they are good at high frequencies, for analog or audio range there is a much better choice

 

[rodman1]

These are what is supplied in the kit and according to the schematic are not part of the "signal path" per se and are used for supply filtration. Every iteration of phono stage that I can remember in detail uses electrolytic's in the same fashion.

 

[grunf]

These are what is supplied in the kit and according to the schematic are not part of the "signal path" per se and are used for supply filtration. Every iteration of phono stage that I can remember in detail uses electrolytic's in the same fashion.

And I was thinking about supply filtration or decoupling, although I wouldn't be surprised if we soon see OS-CON on the signal path as well

 

[KKumar]

Hello, after reading this thread, I would like to change the op amp in this pre-amp. However, it seems that the LM4562NA is not available and instead there is a LM4562MA. I chatted with someone at TI web page chat and was informed that they are not the same.

I would appreciate some advise.

Thank you.
Regards
KKG

 

[vkung]

op-amp 2777p

 

[KKumar]

Hi Victor thanks for your input I can't find this locally either and via mouser the freight is 2 x the value of 2 units.

Regards

 

[vkung]

i have this in stock..
where are you located?

 

[KKumar]

I am in Singapore, however, I'd rather have the lower noise level of the LM4562NA. I'll look at the muses01.

Thanks for your offer, it is kind of you.

Regards

 

[rodman1]

The only difference between LM4562MA &LM4562N Is the type of metallized finish on the actual component lead. This will make no difference to you or your application and either part is fine.

 

[rodman1]

I used MUSES01 when I built mine and never looked back. I never tried any other amps as well.

 

[snaimpally]

I bought a TU-8500 off of someone on this forum and it has Mundorf Mcap Supremes and Muses 01 opamps. I am using it as the preamp for a Buckeye Amp (Hypex NC-502MP) - replacing a Topping Pre90. I am very happy with the sound.

The only thing I wish it had was a remote for the volume. Has anyone replaced the pot with a motorized one?

 

[Steve Morley]

If memory serves, there likely isn't the physical room for one if you want to mount it on the circuit board like the original pot. There are kits available on eBay with motorized Alps pots for not too much. Buy one and see.

Cheers, S.