Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim
Yes, and they are usually crumbling... I believe it's 5 ohms. On Monday, July 31, 2023 at 09:01:59 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
Cant find it on schematic. 5u4 goes bonkers and glows bright. Lous hum. On Monday, July 31, 2023 at 09:08:33 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Yes, and they are usually crumbling... I believe it's 5 ohms. On Monday, July 31, 2023 at 09:01:59 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
I just looked at my 1454 schematic and it shows 7 ohms. On Monday, July 31, 2023 at 09:24:59 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Cant find it on schematic. 5u4 goes bonkers and glows bright. Lous hum. On Monday, July 31, 2023 at 09:08:33 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Yes, and they are usually crumbling... I believe it's 5 ohms. On Monday, July 31, 2023 at 09:01:59 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
Does it say how many watts it is? Looks like maybe a 10 watt one or so. I have one of those big fold-out schematics for a 1448 and just doesnt show it. Mine reading about 12 Meg ohms would likely cause it to draw way too much current, wouldnt ya think? On Monday, July 31, 2023 at 09:26:47 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: I just looked at my 1454 schematic and it shows 7 ohms. On Monday, July 31, 2023 at 09:24:59 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Cant find it on schematic. 5u4 goes bonkers and glows bright. Lous hum. On Monday, July 31, 2023 at 09:08:33 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Yes, and they are usually crumbling... I believe it's 5 ohms. On Monday, July 31, 2023 at 09:01:59 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 7/31/23 18:33, Jim McClave via Jukebox-list wrote:
Does it say how many watts it is? Looks like maybe a 10 watt one or so. I have one of those big fold-out schematics for a 1448 and just doesnt show it. Mine reading about 12 Meg ohms would likely cause it to draw way too much current, wouldnt ya think?
No. Current is inversely proportional to resistance for the same input voltage. At 12 megohms it's essentially an open circuit and you'll get extremely low current, meaning that the tweeter won't get any signal and you'll lose high-frequency response. This resistor burning out isn't the cause of the overload and hum, but it may have been the result of it if the amplifier is oscillating at a high frequency. The square sand-block power resistors about an inch long are 5 watts, those about 2 inches long are 10 watts. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Ok , thanks for the info Jay, Ill dig into it some more and let you know what I find. Its not the square resistor , I know what you mean. Its the rough sandy kind just shaped like a big capacitor. On Monday, July 31, 2023 at 09:41:45 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:33, Jim McClave via Jukebox-list wrote:
Does it say how many watts it is? Looks like maybe a 10 watt one or so. I have one of those big fold-out schematics for a 1448 and just doesnt show it. Mine reading about 12 Meg ohms would likely cause it to draw way too much current, wouldnt ya think?
No. Current is inversely proportional to resistance for the same input voltage. At 12 megohms it's essentially an open circuit and you'll get extremely low current, meaning that the tweeter won't get any signal and you'll lose high-frequency response. This resistor burning out isn't the cause of the overload and hum, but it may have been the result of it if the amplifier is oscillating at a high frequency. The square sand-block power resistors about an inch long are 5 watts, those about 2 inches long are 10 watts. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 7/31/23 18:01, Jim McClave via Jukebox-list wrote:
Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim
It's in series with the ground connection of the tweeter. Schematic shows that it should be 5 ohms. Likely opened due to an overload or high frequency oscillation. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Why cant I find it on the schematic? Am I overlooking something? Indications I get are a loud hum when the jukebox scans or when selecting a record. and the 5U4 power tube starts overloading like crazy. On Monday, July 31, 2023 at 09:11:08 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:01, Jim McClave via Jukebox-list wrote:
Hi all , is there supposed to be a power resistor betwwen pins 2 and 5 of the speaker female plug on the amp? Miine has one , the brown sandy kind, thats reading about 12 meg ohms. The schematic just shows a straight wire between 2 and 5 . 2 goes to ground. Thanks, Jim
It's in series with the ground connection of the tweeter. Schematic shows that it should be 5 ohms. Likely opened due to an overload or high frequency oscillation. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 7/31/23 18:23, Jim McClave via Jukebox-list wrote:
Why cant I find it on the schematic? Am I overlooking something? Indications I get are a loud hum when the jukebox scans or when selecting a record. and the 5U4 power tube starts overloading like crazy.
It looks like there may have been a modification mid-production. Some versions show pin 5 connected to ground via pin 2, others show the 5-ohm resistor. This resistor won't have anything to do with the hum or 5U4 overload. Has the amplifier been rebuilt? If not, it's overdue. Bad filter capacitors are one possibility, or a possible shorted output tube. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications? On Monday, July 31, 2023 at 09:30:40 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:23, Jim McClave via Jukebox-list wrote:
Why cant I find it on the schematic? Am I overlooking something? Indications I get are a loud hum when the jukebox scans or when selecting a record. and the 5U4 power tube starts overloading like crazy.
It looks like there may have been a modification mid-production. Some versions show pin 5 connected to ground via pin 2, others show the 5-ohm resistor. This resistor won't have anything to do with the hum or 5U4 overload. Has the amplifier been rebuilt? If not, it's overdue. Bad filter capacitors are one possibility, or a possible shorted output tube. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 7/31/23 18:36, Jim McClave via Jukebox-list wrote:
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect. With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Okay, back into this amp. problem is definately the amp as I was able to try this amp in another 1448 today, and it has the loud hum and 5U4 starts to glow bright. Im digging around the output transformer and a resistor that I cant find on the schematic. The resistor is riveted to the side and is about 2-3 inches long. like a long block type filter resistor. Has 3 terminals coming off it. Anyone know what the resistance should be on all of them? Also, what would be the correct readings for the primary of the output transformer? I have 3 wires, a blue, red and brown . 2 of the wires go to the 6l6 plates. What should my resistance look like there? My electrolytic filter caps all read ok. Only get this loud hum when the amp powers up to play a record or while scanning. Jim On Monday, July 31, 2023 at 09:53:29 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:36, Jim McClave via Jukebox-list wrote:
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect. With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
I believe Ive found the problem guys. Looks like a bad output transformer. Ive got shorts to ground almost everywhere on it. Primary and secondary. Anyone have any spares laying around? thanks, Jim On Monday, July 31, 2023 at 09:53:29 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:36, Jim McClave via Jukebox-list wrote:
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect. With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
Bickers uses a 30 watt Fender guitar amp output transformer with good results. Mounts underneath out of sight. On Wednesday, August 2, 2023 at 09:01:18 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: I believe Ive found the problem guys. Looks like a bad output transformer. Ive got shorts to ground almost everywhere on it. Primary and secondary. Anyone have any spares laying around? thanks, Jim On Monday, July 31, 2023 at 09:53:29 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:36, Jim McClave via Jukebox-list wrote:
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect. With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
``Thanks Jim, Ill try to contact him. I assume he has a website. Jim On Thursday, August 3, 2023 at 02:44:49 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Bickers uses a 30 watt Fender guitar amp output transformer with good results. Mounts underneath out of sight. On Wednesday, August 2, 2023 at 09:01:18 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: I believe Ive found the problem guys. Looks like a bad output transformer. Ive got shorts to ground almost everywhere on it. Primary and secondary. Anyone have any spares laying around? thanks, Jim On Monday, July 31, 2023 at 09:53:29 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:36, Jim McClave via Jukebox-list wrote:
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect. With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
For 6L6 outputs I use the Hammond 1645 transformer with excellent results! Usually sounds better than original. I think it was Jay Hennigan who originally suggested it to me years ago. Good suggestion. Mauro Sent from my iPhone
On Aug 3, 2023, at 3:43 PM, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
``Thanks Jim, Ill try to contact him. I assume he has a website. Jim On Thursday, August 3, 2023 at 02:44:49 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
Bickers uses a 30 watt Fender guitar amp output transformer with good results. Mounts underneath out of sight. On Wednesday, August 2, 2023 at 09:01:18 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
I believe Ive found the problem guys. Looks like a bad output transformer. Ive got shorts to ground almost everywhere on it. Primary and secondary. Anyone have any spares laying around? thanks, Jim
On Monday, July 31, 2023 at 09:53:29 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote:
On 7/31/23 18:36, Jim McClave via Jukebox-list wrote: Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect.
With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil.
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
_______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 8/3/23 12:53, M De Simone via Jukebox-list wrote:
For 6L6 outputs I use the Hammond 1645 transformer with excellent results! Usually sounds better than original. I think it was Jay Hennigan who originally suggested it to me years ago.
Indeed the 1645 (now 1645A) is a pretty good universal 6L6 jukebox output transformer. Without a 1448 amp in front of me it's hard to say if the physical mounting is going to be suitable. This is often the main issue in finding a suitable replacement transformer, especially for those that mount in a rectangular hole through the chassis. Electrically it looks like a good match. Note that neither the original design nor the 1645 have screen taps. CV output of 500Ω vs. 70V is a bit off, but that's rarely used. the original 500Ω is closer to a 25V line at that power level. This is a non-issue unless you're using external CV speakers. There's a company in Italy that is now making direct replacement transformers for a number of jukebox amplifiers but the Rockola 1448 doesn't seem to be among them and I don't immediately see anything similar. I've used their SHFA1 output transformers. They drop right in and work well. https://shop.piemme-elektra.it/Categories/82 -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Bickers is good, but he wants my amp to specially match it up. wont give me the info on the transformer. I can install it myself. On Thursday, August 3, 2023 at 02:44:49 PM EDT, JIM & LAURIE DIRKSEN via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: Bickers uses a 30 watt Fender guitar amp output transformer with good results. Mounts underneath out of sight. On Wednesday, August 2, 2023 at 09:01:18 PM EDT, Jim McClave via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: I believe Ive found the problem guys. Looks like a bad output transformer. Ive got shorts to ground almost everywhere on it. Primary and secondary. Anyone have any spares laying around? thanks, Jim On Monday, July 31, 2023 at 09:53:29 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 7/31/23 18:36, Jim McClave via Jukebox-list wrote:
Yes Jay, rebuilt amp and tubes checked. The schematic im using just shows the pin 5 to pin 2 ground connection. But since mine is reading 12 meg, I believe I see a connection to the field coil, Wouldnt that cause my indications?
Ground is pin 2. Field coil is between that and pin 3. A shorted field could cause the overload. There's also AC line voltage on the speaker jack between pins 1 and 6 as a form of interlock to prevent powering the high voltage without the speaker plugged in. Between that and the field voltage, that speaker plug is threatening to bite the unwary. Treat it with respect. With the machine powered off, unplug the speaker. Measure the resistance between pins 2 and 3 of the speaker plug (not the amplifier socket), black and yellow wires. It should be in the vicinity of 6000 ohms or so. If so, the speaker field is good and your overload is elsewhere. If it's substantially below that, you have a shorted field coil. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/ _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 8/6/23 09:49, Jim McClave via Jukebox-list wrote:
Bickers is good, but he wants my amp to specially match it up. wont give me the info on the transformer. I can install it myself.
Transformer sits on top of the chassis with a rectangular bolt pattern? What are the dimensions of the bolt spacing both in line with the laminations and across them? -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Jay, I think he was talking about matching it up electronically. Jim On Sunday, August 6, 2023 at 02:31:53 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 8/6/23 09:49, Jim McClave via Jukebox-list wrote:
Bickers is good, but he wants my amp to specially match it up. wont give me the info on the transformer. I can install it myself.
Transformer sits on top of the chassis with a rectangular bolt pattern? What are the dimensions of the bolt spacing both in line with the laminations and across them? -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 8/7/23 11:32, Jim McClave via Jukebox-list wrote:
Jay, I think he was talking about matching it up electronically. Jim
I know. The Hammond 1645 looks like a very good fit electrically. If it's also a good mechanical fit, that's pretty much a guaranteed drop-in replacement. Knowing the dimensions will help. Info is not only useful for this repair but others needing it in the future. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
Jay, I have a Stancor A-3311 output transformer. 10K ohms primary, 25W 4,8. 15 . and 500 ohm outputs. I think it was intended for 6v6 tubes. Im thinking of trying it in the 6l6 1448 amp.. Thoughts ? On Monday, August 7, 2023 at 02:49:03 PM EDT, Jay Hennigan via Jukebox-list <jukebox-list@lists.netlojix.com> wrote: On 8/7/23 11:32, Jim McClave via Jukebox-list wrote:
Jay, I think he was talking about matching it up electronically. Jim
I know. The Hammond 1645 looks like a very good fit electrically. If it's also a good mechanical fit, that's pretty much a guaranteed drop-in replacement. Knowing the dimensions will help. Info is not only useful for this repair but others needing it in the future. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
On 8/7/23 11:59, Jim McClave via Jukebox-list wrote:
Jay, I have a Stancor A-3311 output transformer. 10K ohms primary, 25W 4,8. 15 . and 500 ohm outputs. I think it was intended for 6v6 tubes. Im thinking of trying it in the 6l6 1448 amp.. Thoughts ?
It could work. The 70mA current rating seems a little low and 10K impedance a bit high for 6L6s. If the Stancor is substantially smaller and lighter than the original I would be worried. What are the bolt pattern dimensions on the 1448 amplifier original transformer? I'm thinking Hammond 1645A or possibly 1650G would be a better choice. -- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
participants (4)
-
Jay Hennigan -
JIM & LAURIE DIRKSEN -
Jim McClave -
M De Simone