tigerwoodKhorns Posted February 25, 2023 Share Posted February 25, 2023 On 2/24/2023 at 9:00 AM, RealMarkDeneen said: RCA JACKS I have done at least 3 or 4 units in the past with panel mount jacks. I did NOT need to add an extra plate. There is sufficient room on the rear of the chassis above the opening where the rca jack protrude from the PCB. If you cut the upper part of the vinyl label off, there is just the right amount of space. (If memory serves). I know I never added any plate when I've done this in the past. If you do add a plate you will be eliminating some of the cooling. Do you have a picture of this? Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 25, 2023 Author Share Posted February 25, 2023 Here's one with a partial set of jacks. It's the only pic I could find. Plenty of room for the jacks. And then the bottom will remain open. NOTE: Before DRILLING into the back cover the PCB with plastic wrap and tape it down all around the edge so that do drilling chips get lodged under a resistor or something like that. As you can see here, I just drilled right through the label and left in place. Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 25, 2023 Author Share Posted February 25, 2023 Here is a BBX from the inside. Notice that there is plenty of room above the PCB stiffener shelf (where the Cream sits) so drilling through is no issue even with a Cream unit. Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted February 25, 2023 Share Posted February 25, 2023 @RealMarkDeneen I could not remember what the Blueberry looked like on back. Yes plenty of room. Worth taking the time to lay it out and get the spacing just right. I will put this picture in my server when I get back to work next week. I have a Fisher and the top of the case is vented. I will need a plate as I described for speaker terminals, but definitely room in the Blueberry. Quote Link to comment Share on other sites More sharing options...
John Warren Posted February 26, 2023 Share Posted February 26, 2023 I've serviced a Peach II, specifically the filament section that provides AC-DC conversion to source VDC to the small signal heaters. In my case, this was a relatively straightforward effort, a few hours. If your unit stops working and the tubes (except the rectifier) are cold, it may be the power supply sourcing to the filaments. Also, the filaments are in parallel so if two are bright and one dead, suspect the tube, the curcuit is ok. I've documented the servicing here. Juicy Music Peach II Preamp (northreadingeng.com) 1 Quote Link to comment Share on other sites More sharing options...
Rex Everything Posted February 26, 2023 Share Posted February 26, 2023 On 2/24/2023 at 7:07 AM, capo72 said: I did exactly what you describe on my BBX. Several years ago I had issues with the RCA jacks on the board a couple of different times. Mark was no longer working at the time so I decided to tackle the problem on my own; my solution was as you describe. I made a plate to go across the back to hold RCA jacks, then wired to the board as Mark describes. It caused me some other issues, but overall was a good solution. I can try to find pictures of the work I did, or take new ones. I actually made up 2 plates and only used 1 so I have an extra if someone is interested in doing this mod. I'd like to see your pics and I'm interested and may want that if it's still available. I was traveling the past two days and missed this. Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 26, 2023 Author Share Posted February 26, 2023 6 hours ago, John Warren said: I've serviced a Peach II, specifically the filament section that provides AC-DC conversion to source VDC to the small signal heaters. In my case, this was a relatively straightforward effort, a few hours. If your unit stops working and the tubes (except the rectifier) are cold, it may be the power supply sourcing to the filaments. Also, the filaments are in parallel so if two are bright and one dead, suspect the tube, the curcuit is ok. I've documented the servicing here. Juicy Music Peach II Preamp (northreadingeng.com) Well done, John! Thanks for providing that info. I am sure others can use that as a guide. I usually mount the new rectifier on the bottom of the chassis behind the xformer, but your location looks perfectly fine. Cheers, Mark Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 26, 2023 Author Share Posted February 26, 2023 More Heat Relief While we are on the subject of heat. I highly recommend adding a hole pattern to the tops of any wooden box that might have come with your JMA Peach/BBX. Here is what I recently added to my "new Peach". It is simple enough and very effective what I can tell so far. I should put some probes inside and measure, but I haven't yet. Quote Link to comment Share on other sites More sharing options...
Rex Everything Posted February 26, 2023 Share Posted February 26, 2023 20 hours ago, RealMarkDeneen said: Here is a BBX from the inside. Notice that there is plenty of room above the PCB stiffener shelf (where the Cream sits) so drilling through is no issue even with a Cream unit. Absolutely love the color scheme on the face of these early BB's. A good friend had one years ago. The sound mostly but also those looks got me started looking at JM. Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 26, 2023 Author Share Posted February 26, 2023 Yeah, those first ones generated a LOVE/HATE reaction. I was very happy with it - even though it was way toned down from my original prototype look. I built this mockup one weekend and most thought it was way too far over the top. I toned it down. But my heart was always in the more wild colorful playful version. 3 Quote Link to comment Share on other sites More sharing options...
capo72 Posted February 27, 2023 Share Posted February 27, 2023 Let's see if uploading my pictures works. 3 Quote Link to comment Share on other sites More sharing options...
capo72 Posted February 27, 2023 Share Posted February 27, 2023 2 Quote Link to comment Share on other sites More sharing options...
capo72 Posted February 27, 2023 Share Posted February 27, 2023 1 Quote Link to comment Share on other sites More sharing options...
capo72 Posted February 27, 2023 Share Posted February 27, 2023 2 Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 27, 2023 Share Posted February 27, 2023 Merlin Question: If I upgrade my Merlin to use the 6H30 tube (Merlin II?), is the power transformer stout enough for the current? Bruce 1 Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 27, 2023 Author Share Posted February 27, 2023 3 minutes ago, Marvel said: Merlin Question: If I upgrade my Merlin to use the 6H30 tube (Merlin II?), is the power transformer stout enough for the current? Bruce There was only ever ONE transformer used by every JMA preamp. So, yes - no trouble at all. Cheers! Mark Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 27, 2023 Author Share Posted February 27, 2023 23 minutes ago, capo72 said: Let's see if uploading my pictures works. Fantastic. Looks great to me. I see you have some "curl" in your rear label. I peeled those off and then remounted them with Weldwood Contact Cement (the original Weldwood, not the one sold now in California). Also, see my post about adding vent holes to your cabinet. Cheers! Mark Quote Link to comment Share on other sites More sharing options...
Rex Everything Posted February 27, 2023 Share Posted February 27, 2023 46 minutes ago, capo72 said: Let's see if uploading my pictures works. This is like what I'm thinking of. Quote Link to comment Share on other sites More sharing options...
the real Duke Spinner Posted February 27, 2023 Share Posted February 27, 2023 1 hour ago, Marvel said: Merlin Question: If I upgrade my Merlin to use the 6H30 tube (Merlin II?), is the power transformer stout enough for the current? Bruce Good question, Bruce. 🙂 Quote Link to comment Share on other sites More sharing options...
RealMarkDeneen Posted February 27, 2023 Author Share Posted February 27, 2023 6H30 Upgrade The Merlin, BBX, and Peach have individually unique changes for 6H30. Because one of the PSU resistors needs to be changed to reduce plate voltage. Although the upgrade only involves a few parts, it can get tricky due to the many versions of each PCB. The plate & cathode resistors change on that tube socket, and at least one PS resistor. But, to be sure it is right, you have to be able to use a DVM to check voltages, and you may need to "adjust" the size of the plate resistor to match the board version you have. Also, yuo may have to VISUALLY trace the plate load resistor trace on the PCB back to the PS to see which LC is feeding it. Before anyone jumps into that, I will need to do some digging regarding the right voltages. I DON'T have a 6H30 unit here. My Peach is 6DJ8. Cheers! Mark 1 Quote Link to comment Share on other sites More sharing options...
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