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BNR_1

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    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    3 hours ago, RealMarkDeneen said:

     

    WOW - - what a great post!

    You are good to go with the rectifier he put in. It is a replacement for the original and it is best when mounted to the metal chassis. AOK!

     

    You actually got the pins and molex too! Very well done! That tool back when I bought it was about $75 -- I no longer have it.

     

    Sounds like you are going to stay with the SS rectifiers in place of the 12X4?

     

    And yes, the LMXXX at 6.4 is perfect - all good there.

    So, are you back in business with a working unit now?

     

    Cheers,

    Mark

    Hi Mark:

     

    I was fortunate that my friend has the tool for the KK pins.  If not, I would have probably done what you recommended and that is removing the header pin and solder the wires directly to the PCB.  But with the new Molex connector and pins it works perfect.  I am back in business listening to music.

     

    Does the sonic quality improve with the 12X4 rectifier?  All I have as a point of reference is with the SS diodes in lieu of the 12X4 tube.  Is it difficult reversing it?  Also, I read others doing the SS diode mod.  Do you know why anyone would have performed such mod versus simply leaving it with a tube? 

     

    BTW, thanks for confirming that my brige rectfier is sufficient.

     

    Regards

    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    If anyone is curious or has a similar issue with the Molex connector or crimp this is what I ordered from Digikey and it worked perfect.  This is for the connector with the 3 wires - red, green & green.

     

    Molex connector - Part #WM2103-ND; Molex product #0009503051, 5 pin rectangular connector

    Molex pins - Part #WM2300-ND (18 to 24 AWG); Molex product #0008500106, KK2478 series

     

    I ordered by check so I avoided shipping and handling fees.  It took about 1-1/2 weeks from the time I dropped off the check and order form into the mailbox.

     

    Just remember the Molex KK pins require a certain tool to crimp.  Fortnuately for me, my friend had the tool.  I guess you could carefully use other wire crimpers and solder the wire to the KK pin for added isurance.  Or as Mark suggested, remove the header pin from the PCB and solder the wire directly from the transformer to the PCB.

     

    Regards

    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    On 5/13/2023 at 12:04 PM, RealMarkDeneen said:

    Hi--

    Yes, I think your green winding voltage is fine. It's the pins. You can fix the pins, but it might make more sense (knowing what we know now about the pins/molex trouble), to remove the molex header from the PCB and just solder the transformer to the PCB. Yes, that makes it harder to replace, but I don't think I ever replaced a transformer, so low risk of that.

     

    If you do replace the spring pins don't rely on the crimp. Solder the pins to the wire.

     

    Maybe you can send me a pic of the area around the Molex. I'd like to make sure the blue caps and big cement resistor are ok. And (sorry if you told me already), but have you replaced the bridge rectifier yet? If not, read back through this thread and there is good documentation on what to buy and how to replace it. It is a major weak spot of the unit. They cook, burn and fail at about the 5 year mark. Bad choice of parts on my part. But, it's pretty easy to remedy.

     

    The BBX has one more tube than the Peach. Four versus 3. Probably a little higher current in total, but I'm guessing because the rectifiers have failed much more often on BBX than Peach.

     

    Keep me posted...

    Mark

     

     

    Hi Mark:

     

    Got some good news.  I replaced the Molex connector & pins.  My friend is into pinball machines and fortunately he has the tool to crimp the pins.  I purchased new pins and molex from Digikey.  As an added insurance, as Mark suggested, I also soldered the pin besides crimping.  It works wells.  All powered up.

     

    I noticed that my unit does not have the LM350K, but LM338K.  With the new Molex & crimps, it reads 6.485V DC.  Spot on to the to 6.5V as by design.

     

    I am at least the 3rd owner of this unit, and the seller I purchaed it from did not have much info on the work done by the prior owner(s).  But the tube recitifier was replaced with diodes and the bridge rectifier was removed from the PCB and mounted (bolted) to the chasis.  This was likely to improve heat transfer.  I was able to determine the type - GBPC2501.  There was another marking, but I could not make it out.  N1S0435 or N180435 or NJS0435.  Anyway, this series of codes did not matter on google.  The GBPC2501 popped up on a number of electronic stores.  Is this the stock unit or a replacement?  I looked it up on Digikey and it has a peak reverse voltage of 100V and an average rectified current of 25A.

     

    I compared it to the unit you recommended from Digikey 641-1381-ND (GBPC5006-G).  This unit has a peak reverse voltage of 600V and an average rectified current of 50A.  I assume regardless if my bridge rectifier is original or replaced but it may not be adequate compared to your recommendation.  Any thoughts?

     

    Regards

    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    On 5/5/2023 at 6:46 PM, RealMarkDeneen said:

    Hi--

    For the green winding you set the DVM to AC Volts. Put one lead on each wire. You should get about 18V or something like that - I can't quite recall but something like that.

    Now then, if you do that by slipping the probes into the white molex connector, you might NOT get a valid read because on some units the spring terminal crimp goes bad and you won't get any volltage reading. If such happens, you have to unplug the green wires, "re-crimp" the spring lug, re-insert them and try again. It is VERY RARE for the green winding to be burnt out, but not too rare for the spring lug to go bad.

     

    Now, to check the LM350, just set your DVM to DC Volts, and place the black lead on the ground terminal of the chassis and touch the red lead to the top side shell of the LM350 which sits inside the 2" square black heat sink. This reading MUST BE at least 6.1VDC and can be as high as 6.5. If you get a reading like 5V, or 4.5V, that means the mounting has loosened up. There are four bolts holding it down. You have to retighten the 4 bolts to a "firm setting" but don't go crazy and tighten so much that the PCB flexes!! Be careful. That should bring the voltage back up to the proper range.

     

    If you need more email me directly at aroadrunner@protonmail.com. We'll get it figured out!

    Cheers,

    Mark

     

     

     

    Hi Mark:

     

    Well I checked the voltage across the two green wires from the transformer and read 13.52V AC.  As you indicated it was not that easy to read due to the DMM probes into the Molex.  It is not 18V but is the 13.52V AC within the proper design range?

     

    Due to an existing issue with one of the green wires (loose in the Molex connector), I could not get a read on the LM350.  The spring clip for the green wire is broken and loose so I don't get a good contact with the Molex connector inserted and gold pins on the PCB.  The tube filament does not light up.

     

    My next task is to replace the clips and Molex for the red, and two green wires.  The green wires due to the filament do draw a lot of current.  The Molex connector (brownish & scorch) looks similar to the images posted by Rex Everything (02.22.2023).  John Warren posting (02.26.2023 northreadingeng.com) shows that his measurements for X7-X8 (Peach II schematic) was 2.9 to 3.2 A.  I assume the Blueberry Extreme is similar.

    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    On 5/5/2023 at 6:46 PM, RealMarkDeneen said:

    Hi--

    For the green winding you set the DVM to AC Volts. Put one lead on each wire. You should get about 18V or something like that - I can't quite recall but something like that.

    Now then, if you do that by slipping the probes into the white molex connector, you might NOT get a valid read because on some units the spring terminal crimp goes bad and you won't get any volltage reading. If such happens, you have to unplug the green wires, "re-crimp" the spring lug, re-insert them and try again. It is VERY RARE for the green winding to be burnt out, but not too rare for the spring lug to go bad.

     

    Now, to check the LM350, just set your DVM to DC Volts, and place the black lead on the ground terminal of the chassis and touch the red lead to the top side shell of the LM350 which sits inside the 2" square black heat sink. This reading MUST BE at least 6.1VDC and can be as high as 6.5. If you get a reading like 5V, or 4.5V, that means the mounting has loosened up. There are four bolts holding it down. You have to retighten the 4 bolts to a "firm setting" but don't go crazy and tighten so much that the PCB flexes!! Be careful. That should bring the voltage back up to the proper range.

     

    If you need more email me directly at aroadrunner@protonmail.com. We'll get it figured out!

    Cheers,

    Mark

     

     

     

    Thank you Mark for the quick reply.  I will test my pre.

     

    Regards

    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    On 2/23/2023 at 8:31 AM, RealMarkDeneen said:

    Hi--

    Can you do a few voltage checks?

     

    1. Check AC voltage across the two green wires. Should be around 20VAC or so. If not "bad transformer".

    2. If that AC is ok, check the DC volts on top of the LM350. That is the large TO-3 device sitting in the middle of the 2" square heat sink on top of the PCB. That should be 6.3VDC +/- 1/2V. If NOT, you will need to replace the bridge rectifier which can be seen in the first photo. It is the 1" square black part near the long white resistor.

     

    I will have to provide you the instructions and the part # you need to buy. It is the #1 most common failure in the BBX. Bad choice of parts on my part. However, once fixed it will last a long long time.

    Email me with the results: aroadrunner@protonmail.com

    Cheers

    Mark

    Hello Mark:

     

    To verify the AC voltage for the two green wires do you connect each lead of the DMM to each of the green wires setting DMM to AC?

     

    Can you explain how to test the voltage of the LM350?

     

    Regards

    Maybe You Have A Juicy Question?

    in 2-Channel Home Audio

    Posted

    On 9/25/2022 at 9:12 AM, RealMarkDeneen said:

    @Audible Nectar

     

    Hello old friend! It's great to hear that you are doing so well with your health. Everything gets more difficult the older we get.

     

    Speaking of orthopaedics, I am getting my 6th joint replacement in a couple weeks. My skeleton looks like an erector set in Xrays. But damned, if those orthopods don't do a fantastic - almost unbelievable job - of keeping my wheels rolling! This Frankin-body keeps chugging along. I feel more fit at 74 than I did at 44.

     

    I put a "Peach Documentation Package" together for Dave to give to his tech. It's not perfect, but it should give a technician a pretty good roadmap for making repairs. If you ever need it send my your email via PM and I will email it to you. I'll be doing the same for Tercel and BlueBerry soon.

     

    If I recall the denouement of "Reservoir Dogs" - everyone shot each other at the end!

     

     

    This is awesome.  The designer and fabricator of Juicy Music is here to support his product.  I am anxiously awaiting his info on the Blueberry Preamp.  I am experiencing some issues.  I hope to get this preamp up and running because I enjoyed what it offered for my listening experience.

    Room Size and Volume Level: OK for Chorus or Forte I/II?

    in 2-Channel Home Audio

    Posted

    13 minutes ago, Deang said:

    Tractrix horns in the Forte II's and Chorus II's.

     

    You sit so close, and the speakers so close together -- combined with not being able to get much space off of the wall -- I think the Forte II's will work better for you.

     

    ... or ... just buy some LaScalas. :-)

    I was thinking the limited distance to the wall was one reason working against the Forte II.

     

    Appreciate your input.

    Room Size and Volume Level: OK for Chorus or Forte I/II?

    in 2-Channel Home Audio

    Posted · Edited by BNR_1
    Correct measurements of listening area.

    Hi Folks:

     

    First posting for me.  Been a lurker for most parts.

     

    I am interested in getting a pair of Chorus I or Forte I or Forte II speakers for my listening enjoyment.  I have not listened to neither of these speakers, but read so often the positive feedback on these speakers.  I have an opportunity to purchase one of these speakers.  I will be using a tube amp & preamp to drive the speakers.  Most of the listening will be jazz, blues, and classic rock.  No hard metal, etc.  Most of my listening is done at lower levels.  Levels that you can enjoy the listening while reading.  If the volume knob points to 7 o'clock for zero sound level then my listening levels are usually around 9/10 o'clock.  About 80% of my music is digital and the rest is LPs.   

     

    My dilemma is whether my listening area is too small.  The speakers will be placed near a corner of my living room.  The room is shaped like an "L" lying on its side.  The room is 12 feet deep (shallow leg) by 18 feet, and it opens up to the longer end about 22 feet deep.  The room has an 8 foot  ceiling height.  The face of the speakers will be about 10 feet from my couch along a corner wall and speakers will be about 6 feet center-to-center.  My couch is against a wall, 8 feet long, running parallel to the 18 feet wall.  The room is entirely carpeted.  I can probably afford to have the back of the speakers no further than 6 to 9 inches away from the wall.  I know that matters for the rear passive speakers in the Forte II.

     

    I am leaning towards the Chorus I, but I am concerned that the speaker maybe too large for this room and it will not be driven to the sweet spot for listening pleasures since the volume will be set somewhat low.

     

    I read some of the postings on this forums site and others, but most speak of larger rooms or rooms that are perfectly rectangle or square in shape.  My listening area is a combination living room and dining room ("L" shape). 

     

    Regards

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