Awesome. I’ve always wanted to hear those amps and how they would compare to say my quicksilver mid mono amps. I’m sure the vrds would be better but I’m wondering by how much.
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Anyone still running a Juicy music blueberry?
- Thread starter pjrengineer
- Start date
MRL_Audio
RIP 2022
There's a ton of info on these on the Klipsch Forums. Craig made far more VRD's then NBS units. Guess that's why it took me so long to finally secure one. They are selling for close to or more than folks paid so they are obviously holding their value. Makes the purchase a relatively comfortable affair.
Hey PJR. Would you mind sharing your opinion between the BB and your Mc MX? Now that you made the investment in the BB would you have done it all over again given that you have a MX? I also noted in your photo that the RCA connectors are still attached directly to the PCB. My understanding is that this was originally done to reduce noise. But on the other hand it is somewhat of a vulnerability especially for those that tend to swap cables often or have heavy cables hanging and stressing the connection. Care to share for keeping the OEM connections?
Thanks
Thanks
I enjoy the mx110z more because of the more solid feel of the controls and the tone controls. I also listen to a fair amount of fm on it. The juicy music has a little more open sound maybe? They are both world class preamps when restored like mine have been. The mx110z is my main setup. Every time I think of selling the juicy music I end up forgetting about it because it also sounds so good.
Check the simple stuff first. Tubes. Connections. Etc.
wiggle the connections.
Report back.
Im running a BBEWC that I picked up from an AKer a couple of years ago . Using the NOSValves VRD stereo amp sorta like MRL_Stereo. I love it. First tube preamp I’ve ever owned so maybe I just don’t know how good I have it. I believe this one was maxed out as far as mods go, not the Super tube mod though but has SS rectification/ power supply?
There is a low level hum and on of the RCA jacks is a bit wiggly and there’s some tube hiss here and there . I’m using a combination of Amperex and Mullard tubes.
the MC phono stage with Jensen step up transformers is sweet with Lyra Delos cartridge. Is there a better built in phono stage than this thing has? I have nothing to compare it to other than I had a Black Cube for a while with a different cartridge and everything else in my system was different so I can’t judge apples to apples but this thing sounds so good...
There is a low level hum and on of the RCA jacks is a bit wiggly and there’s some tube hiss here and there . I’m using a combination of Amperex and Mullard tubes.
the MC phono stage with Jensen step up transformers is sweet with Lyra Delos cartridge. Is there a better built in phono stage than this thing has? I have nothing to compare it to other than I had a Black Cube for a while with a different cartridge and everything else in my system was different so I can’t judge apples to apples but this thing sounds so good...
Thanks for the initial tips.
This is what I checked. Fuse is good. Check for continuity since the internal fuse wire is so small and my eyes do not have perfect vision. I also checked the switch at the switch. Same way...continuity. Works.
I examined the connection from the power transformer to the circuit board. There are 7 wires that go to a plastic harness. The plastic around the 2 green wires display heat issues. The plastic harness for the two wires are brown. But the plastic does not appear to be cracked or melted away. Just brown from heat stress.
The tube filaments do not light up and neither does the standby switch light.
This unit does not have the tube rectifier. It has diodes that were installed before I purchased it. I believe it was also installed prior to the previous owner, but I am not 100% sure. I used this preamp on a regular basis for the past 3 years. Other than replacing the line stage tube all was good.
I checked the voltage at the IEC and it read 120 volts. I also checked the voltage at the fuse body. With power, switch on and in stand by mode, the voltage showed a low value in mV. I should have written it down, but it was low.
Visually, there does not seem to be anything wrong but obviously there is something that is not right.
This is what I checked. Fuse is good. Check for continuity since the internal fuse wire is so small and my eyes do not have perfect vision. I also checked the switch at the switch. Same way...continuity. Works.
I examined the connection from the power transformer to the circuit board. There are 7 wires that go to a plastic harness. The plastic around the 2 green wires display heat issues. The plastic harness for the two wires are brown. But the plastic does not appear to be cracked or melted away. Just brown from heat stress.
The tube filaments do not light up and neither does the standby switch light.
This unit does not have the tube rectifier. It has diodes that were installed before I purchased it. I believe it was also installed prior to the previous owner, but I am not 100% sure. I used this preamp on a regular basis for the past 3 years. Other than replacing the line stage tube all was good.
I checked the voltage at the IEC and it read 120 volts. I also checked the voltage at the fuse body. With power, switch on and in stand by mode, the voltage showed a low value in mV. I should have written it down, but it was low.
Visually, there does not seem to be anything wrong but obviously there is something that is not right.
Herb ward fixed mine. Not sure he’s willing to take on another one though. It’s a true pita to work on.
Have you started checking voltages in the power supply section? Check the diodes too.
No, I have not other than what I posted in #29 above. I did not want to poke around much, but may have no choice. Kind of difficult without a schematic or input from others as to where to probe and what is the appropriate voltage read.
RHThatcher
New Member
Bringing an old thread back to life... Does anyone know where to get info technical / service on the Juicy Blueberry Extreme with Cream? I had one from 2007-2018, sold it, and just bought it back. It was "one that got away".
I opened it up to put tubes in and see 2 traces to the rectifier bridge are lifting. The PCB looks like it took a lot of heat in the area of that bridge. The caps around the bridge also look to be cracked / drying out. Before I power it up I want to fix that up.
While I was waiting for the shipment I wanted to see about any mods or technical details are out there on this preamp, and I found this thread. I'm interested in doing the power supply mod, maxim mods, and 6H30 retrofit. But I can't get any details.
I tried an using an email address I found for Mark D, but it bounced. I tried a call and email to Craig at NOS Valves. No response.
I can DIY this if I had schematics. Does anyone have schematics? Does anyone have this preamp with those mods who would be willing to take a few close up pictures of the boards so I can compare things?
For now I may simply put a bridge rectifier with a snubber circuit on the chassis and run wires where they need to go. That's an easy fix for the obvious issue, and it solves my short term need.
I opened it up to put tubes in and see 2 traces to the rectifier bridge are lifting. The PCB looks like it took a lot of heat in the area of that bridge. The caps around the bridge also look to be cracked / drying out. Before I power it up I want to fix that up.
While I was waiting for the shipment I wanted to see about any mods or technical details are out there on this preamp, and I found this thread. I'm interested in doing the power supply mod, maxim mods, and 6H30 retrofit. But I can't get any details.
I tried an using an email address I found for Mark D, but it bounced. I tried a call and email to Craig at NOS Valves. No response.
I can DIY this if I had schematics. Does anyone have schematics? Does anyone have this preamp with those mods who would be willing to take a few close up pictures of the boards so I can compare things?
For now I may simply put a bridge rectifier with a snubber circuit on the chassis and run wires where they need to go. That's an easy fix for the obvious issue, and it solves my short term need.
herb ward restored mine. I can share pics. It was purchased from ak and I quickly learned the seller didn’t disclose that there was a catastrophic component failure inside. What a joy ride that was but now it’s working in all its glory and I love it.
May help or not but Mark Deneen, the person behind Juicy Music Audio, has recently begun posting again on the Klipsch forum. Here's the thread: https://community.klipsch.com/index...be-you-have-a-juicy-question/#comment-2749491
RHThatcher
New Member
I'm going to reach out to him over there - thanks for the tip!
@pjrengineer - I also would love to see some pix of your repaired Blueberry!
RHThatcher
New Member
Rectifier procedure:
First things first.
Your BBX rectifier needs to be replaced. I did many of these as per the following.
Parts
You need a 25A 50V bridge rectifier like this:
https://www.digikey.com/en/products/detail/onsemi/GBPC25005/1057321
Procedure
- Looking at the rectifier, take a note of all for corner markings. There is one (+) one (-), and two (AC) lugs. Remove the burned out rectifier from the PCB
- Remove the snubbing caps from the PCB
- Clean up all the holes
- Mount the new rectifier to the metal chassis witth near the location of the PCB holes
- Using 16ga wire make leads of about 8" and solder them to the rectifier. Make sure you see the (-) sign and (+) since and the (ac) terminal marking on the new rectifier. Connect these leads to the appropriate +, -, AC, terminal holes on the PCB.
- Remove the large cement board resistor and replace it with a 16ga wire. It's not needed.
- If the two Blue Caps are burnt, misshapen or seem defective in any way, replace them. Any value above what they are is fine. Not very critical.
- Don't replace the snubber caps - - not needed.
- Now test the voltage on the regulator. It is the large silver TO-3 device sitting in the middle of the 2" x 2" black heat sink. Top of regulator is (+), chassis is (-). You should get 6.2VDC to about 6.5VDC. If you get any reading in the 5's, you need to TIGHTEN the regulator screws holding the device to the PCB. Often, the nylon spacers shrink which loosens the whole regulator/heatsink assembly. If you get 0VDC, that regulator will have to be replaced, but I've never seen one fail.
RHThatcher
New Member
Here's my plan so far. I have 2 PCB's being fabricated now and I imagine they'll arrive next week.
Low voltage / filament power supply - I'll be installing a bridge rectifier using a PCB. That PCB will also add a snubber circuit, inrush current limiter (thermistor), and filter stage (cap & resistor). I'll replace the 10W resistor on the PCB with another value. This will give me the inrush current limiter after the bridge, the snubbers to dampen transformer/bridge ringing, and upgrade the current CRC filter to a CRCRC filter before the voltage regulator. The goal of the CRCRC is to get lower voltage with less ripple into the regulator. output from CRCRC needs to be around 7.6V or a little higher. I measured 9.1V with CRC filter. This should make for even cleaner DC and less heat at the regulator. I also have a 25W heatsink on order for the regulator. I've done some modeling in the Duncan PSU designer, let's see how it works out in the real world. Switching to the "super tube" will put even more demand on this part of the circuit. So I want it to be as robust as possible.
High voltage - I made a board to convert from the 12X4 tube rectifier to solid-state rectification. Again, I'm adding a snubber circuit and inrush current limiters. I'm also adding a bleeder resistor to drain of power supply capacitor voltage on power down. I'm going to use ultra fast diodes. I also added 2 more filter stages to the already very robust power supply. Swapping from tube to solid state means I need to drop ~20V to make up the difference between tube and solid state. These 2 extra filter stages and a change to one existing resistor should get the voltages to where they need to be. I have a few different resistors coming that I can use to do final tuning.
Once this power supply is tip-top I'll need some more info from Mark to get to the "super tube" mod and the "maxim" mods.
I will likely add a thermistor between IEC earth ground and chassis ground. This is a hum breaker / ground lift solution that I learned from doing First Watt / Pass Labs clones.
I'm not sure how fast this will go. I have a day job and a few paid solid state and tube scratch build & mods in my queue. Those come first, then I'll get to the personal projects. Stay tuned.
Low voltage / filament power supply - I'll be installing a bridge rectifier using a PCB. That PCB will also add a snubber circuit, inrush current limiter (thermistor), and filter stage (cap & resistor). I'll replace the 10W resistor on the PCB with another value. This will give me the inrush current limiter after the bridge, the snubbers to dampen transformer/bridge ringing, and upgrade the current CRC filter to a CRCRC filter before the voltage regulator. The goal of the CRCRC is to get lower voltage with less ripple into the regulator. output from CRCRC needs to be around 7.6V or a little higher. I measured 9.1V with CRC filter. This should make for even cleaner DC and less heat at the regulator. I also have a 25W heatsink on order for the regulator. I've done some modeling in the Duncan PSU designer, let's see how it works out in the real world. Switching to the "super tube" will put even more demand on this part of the circuit. So I want it to be as robust as possible.
High voltage - I made a board to convert from the 12X4 tube rectifier to solid-state rectification. Again, I'm adding a snubber circuit and inrush current limiters. I'm also adding a bleeder resistor to drain of power supply capacitor voltage on power down. I'm going to use ultra fast diodes. I also added 2 more filter stages to the already very robust power supply. Swapping from tube to solid state means I need to drop ~20V to make up the difference between tube and solid state. These 2 extra filter stages and a change to one existing resistor should get the voltages to where they need to be. I have a few different resistors coming that I can use to do final tuning.
Once this power supply is tip-top I'll need some more info from Mark to get to the "super tube" mod and the "maxim" mods.
I will likely add a thermistor between IEC earth ground and chassis ground. This is a hum breaker / ground lift solution that I learned from doing First Watt / Pass Labs clones.
I'm not sure how fast this will go. I have a day job and a few paid solid state and tube scratch build & mods in my queue. Those come first, then I'll get to the personal projects. Stay tuned.
Attachments
Last edited:
RHThatcher
New Member
I just wrapped up my mods.
Added High Voltage Mod - Removed rectifier tube, added new solid state rectifier PCB with snubbers, inrush current limiters, bleeder resistor, and additional filtration. I tweaked values in the power supply resistors to match the voltages I measured before doing mods. Through some modeling and optimization (PSU Designer 2, build, measure, add to spreadsheet, calculate, tweak, repeat) I figured out the ideal new power supply resistor values for a 6DJ8/6922 in position V4 and for the 6H30.
Added Low Voltage Mod - Removed old bridge, added new bigger bridge/filter PCB with inrush current limiter, additional filtration. I updated the 10W CRCRC filter resistor values to spread the voltage drop before the regulator. This way the heat is spread around between 2 10W resistors and the regulator/heatsink. And the ripple is minimized before the regulator, giving it a cleaner signal to start with. I changed the to higher rated regulator heatsink. In hindsight, this was probably not necessary because the dissipation at the regulator is appx 5W with 1R2 10W resistors in LV supply.
Updated to 6H30 in position V4 including cathode bypass caps.
Added CL60 between IEC and Chassis Ground. This is a classic ground loop / hum breaker technique I learned building First Watt Clones.
It sounded great on the bench - now I need to get it into my real system!
Added High Voltage Mod - Removed rectifier tube, added new solid state rectifier PCB with snubbers, inrush current limiters, bleeder resistor, and additional filtration. I tweaked values in the power supply resistors to match the voltages I measured before doing mods. Through some modeling and optimization (PSU Designer 2, build, measure, add to spreadsheet, calculate, tweak, repeat) I figured out the ideal new power supply resistor values for a 6DJ8/6922 in position V4 and for the 6H30.
Added Low Voltage Mod - Removed old bridge, added new bigger bridge/filter PCB with inrush current limiter, additional filtration. I updated the 10W CRCRC filter resistor values to spread the voltage drop before the regulator. This way the heat is spread around between 2 10W resistors and the regulator/heatsink. And the ripple is minimized before the regulator, giving it a cleaner signal to start with. I changed the to higher rated regulator heatsink. In hindsight, this was probably not necessary because the dissipation at the regulator is appx 5W with 1R2 10W resistors in LV supply.
Updated to 6H30 in position V4 including cathode bypass caps.
Added CL60 between IEC and Chassis Ground. This is a classic ground loop / hum breaker technique I learned building First Watt Clones.
It sounded great on the bench - now I need to get it into my real system!