Zero Zone Cary SLP-90 clone Preamp

[meako]

Just want to share this little gem. A preamp claimed to be based on the Cary SLP-90. This really sounds very good. Highs are very detailed. The mids has this texture and body to it. The lows are very solid and punchy. Currently using 4 black plate 5814a tubes.

My system,
Advent/1 Speakers
NAD 3130
FX-Audio DAC-X6
Monoprice RCA cables

Also waiting for my new upgraded Quad 405 to do some further listening test.

https://fb.watch/iQ69GFj4Zd/

 

[bkatbamna]

The box looks the same as the ones that they say are the Conrad-Johnson circuit and the Marantz 7 circuit. The one that I have is the Marantz. It is a black box about the same size with remote. The maddening thing about it is that there is no way to tell which of the 4 inputs is selected. At least the one in the picture has a light to show which input is selected.
Funny enough, the one that I have does have a light to show which input is selected but.....it is facing the back of the panel and there's no way to see it without the top being off. LOL

 

[meako]

I think the cases, power supply, input selector boards are all the same in most of the clone preamps. The actual preamp boards are the ones that are different. I opted for the SLP-90 board cause it uses four 12au7s and I have four 5814a tubes in hand. From what I can here in my setup, I made the right choice.

Additionally, it seems to me that this SLP-90 board is very similar to the tubes4hifi SP-12 preamp which I believe got very good reviews. The only difference I can see is the latter uses tube rectification and this preamp does not.

 

[mprince]

I just picked one of these up with (4) Psvane ECC-82 tubes. Solidly built, love the sound but not liking the excess output gain into my Adcom GFA-545 amp.

I've got some Rothwell Attenuation Plugs on the way to install on the amp inputs, but for now my DAC is in preamp (variable loudness) mode set at -25 and I actually have removed my SUT (+26db) from my phono stage, so running a LOMC directly into a MM phono stage and then to the preamp. Sounds weird but it works and allows me to move the volume knob past 7:00 to get normal listening levels.

 

[zackthedog]

I just picked one of these up with (4) Psvane ECC-82 tubes. Solidly built, love the sound but not liking the excess output gain into my Adcom GFA-545 amp.

I've got some Rothwell Attenuation Plugs on the way to install on the amp inputs, but for now my DAC is in preamp (variable loudness) mode set at -25 and I actually have removed my SUT (+26db) from my phono stage, so running a LOMC directly into a MM phono stage and then to the preamp. Sounds weird but it works and allows me to move the volume knob past 7:00 to get normal listening levels.

Bear in mind that the Cary had knock-down pots for each channel before the master volume pot, for balance and gain reduction. Same with the SLP-98. It's pretty much a requirement for those preamps, otherwise the gain is way too high. I run my SLP-98 with the individual pots at about half volume.

 

[mprince]

Glad to report some Rothwell attenuation plugs have solved my "problem", really liking this preamp so far.

 

[gadget73]

maybe worth a read before buying one

Zero Zone tube preamp putting out DC? | Audiokarma Home Audio Stereo Discussion Forums

last page is where things start getting interesting. No solution as of this post but at least a diagnostic that may lead to one.

 

[meako]

maybe worth a read before buying one

Zero Zone tube preamp putting out DC? | Audiokarma Home Audio Stereo Discussion Forums

last page is where things start getting interesting. No solution as of this post but at least a diagnostic that may lead to one.

This seems to be for the Conrad Johnson based preamp and not the Cary one.

This Cary preamp is available at Tubes4Hifi as the SP10-B if a US based warranty is needed.

 

[rotel75]

I just got a similar SLP-90 clone. This one has relay controlled volume, LED input/vol display and a simple remote control. It consumes about 27W idle and in use.
It's my first tube device ever . If I would change the PSVANE ECC82 tubes, would I have to get 2 matched pairs or a set of 4?

 

[mcgjohn]

Just want to share this little gem. A preamp claimed to be based on the Cary SLP-90. This really sounds very good. Highs are very detailed. The mids has this texture and body to it. The lows are very solid and punchy. Currently using 4 black plate 5814a tubes.

My system,
Advent/1 Speakers
NAD 3130
FX-Audio DAC-X6
Monoprice RCA cables

Also waiting for my new upgraded Quad 405 to do some further listening test.

https://fb.watch/iQ69GFj4Zd/

this company makes several preamps based on circuits from other preamps such as the Marantz 7, CJ and others. They all appear to use the same case with different circuit boards. They can sound really good for not a lot of money. On some versions a person may want to double check all the solder connections before plugging it in.

I bought one of these for a friend. The power supply caps were loose rattling around inside the chassis. Had to remove the board and solder them in before powering up.

 

[ceylon]

i have that board and PT i bought from roy mottram. mine hums like a hornet, so i removed the PS caps and am hoping to re-assemble some time. sometimes i could kill that hum by switching the preamp on and off. without the hum, mine sounded fantastic.

 

[Lavane]

The Zero Zone M-7 preamp board I bought Is very quiet. The board, bag of parts, and the transformer cost me under $60. With the input selector, volume control and other bits the whole thing came in under $100. I used an aluminum plate I had on hand to mount everytning to. They did send the wrong regulator for the heater voltage. Same part number, but different letter at the end. It was a .5 amp. I ordered the 5 amp version of the regulator and the heaters lit up.

 

[ceylon]

The Zero Zone M-7 preamp board I bought Is very quiet. The board, bag of parts, and the transformer cost me under $60. With the input selector, volume control and other bits the whole thing came in under $100. I used an aluminum plate I had on hand to mount everytning to. They did send the wrong regulator for the heater voltage. Same part number, but different letter at the end. It was a .5 amp. I ordered the 5 amp version of the regulator and the heaters lit up.

hella sweet build, @Lavane !

 

[Lavane]

hella sweet build, @Lavane !

Thanks. Yours has to be a grounding issue I would think. That or a bad filter cap? I just used everything that came with the board kit. All the caps and resistors tested fine. Those red Chinese "Audiophiler" coupling caps aren't that bad. I found this long list of film cap tests and these caps came in just above Solen's in performance supposedly.
I used tye same brand in a pair of Realistic Nova 7B speaker crossovers I modified using the "VL" mod approach used for the bigger 8B's.
I alao added a bypass cap across the woofer, an inductor coil to force the woofer to roll off where it was running full range before, and reversed the phase of the two tweeters. It really woke these overly warm sounding speakers right up.

 

[ceylon]

Yours has to be a grounding issue I would think.

i think so, too.

That or a bad filter cap?

i cant make sense of the grounding. as seen from the top of this board, theres a star ground that goes nowhere but the input.

so i gouged out the plastic and soldered a ground lead to the metal. ill attach that to the chassis when i re-assemble. i also bought all new PS caps. its cheap enough to cover every base, so...why not?

I just used everything that came with the board kit. All the caps and resistors tested fine. Those red Chinese "Audiophiler" coupling caps aren't that bad. I found this long list of film cap tests and these caps came in just above Solen's in performance supposedly.
I used tye same brand in a pair of Realistic Nova 7B speaker crossovers I modified using the "VL" mod approach used for the bigger 8B's.
I alao added a bypass cap across the woofer, an inductor coil to force the woofer to roll off where it was running full range before, and reversed the phase of the two tweeters. It really woke these overly warm sounding speakers right up.

 

[Lavane]

i think so, too.

i cant make sense of the grounding. as seen from the top of this board, theres a star ground that goes nowhere.
so i gouged out the plastic and soldered a ground lead to the metal. ill attach that to the chassis when i re-assemble. i also bought all new PS caps. its cheap enough to cover every base, so...why not?
View attachment 3353309

It is hard to follow those traces for sure because the board has traces on both sides.
To follow traces your constantly flipping the board over to see where it goes.
I'm still not sure what the second regulator does on my board. One with the trimmer next to it is for the heaters. The other, . Yours looks like it has a heater voltage regulator for and trimmer for each channel? And that one in the middle, . Maybe it does the same thing as the one in mine does, whatever that is. B+ regulation maybe?

 

[ceylon]

It is hard to follow those traces for sure because the board has traces on both sides.

top side is ground scheme; bottom side is signal path, maybe signal path and B+

To follow traces your constantly flipping the board over to see where it goes.
I'm still not sure what the second regulator does on my board. One with the trimmer next to it is for the heaters. The other, . Yours looks like it has a heater voltage regulator for and trimmer for each channel? And that one in the middle, . Maybe it does the same thing as the one in mine does, whatever that is. B+ regulation maybe?

well, youre guesses are certainly better than mine

 

[mcgjohn]

i have that board and PT i bought from roy mottram. mine hums like a hornet, so i removed the PS caps and am hoping to re-assemble some time. sometimes i could kill that hum by switching the preamp on and off. without the hum, mine sounded fantastic.

if the hum is that loud you may have a cold solder joint or lose ground. May not hurt to reflow all the solder connections.

 

[ceylon]

its easily at listening volume, and it doesnt always happen. sometimes its there when i turn it on, and sometimes it aint. when the hum appears with the preamp being switched on, switching the preamp on and off a few times often makes it go away.

if the hum is that loud you may have a cold solder joint or lose ground. May not hurt to reflow all the solder connections.

not sure there is a ground--see above.

good idea.

i removed all the power supply caps. i may as well reflow every joint, too.

 

[Ken Boyd]

I am building the Cary AE-1 version. It uses the 6SN7 tubes. I modified mine to put the tubes on the outside on top.