Casey,
Parts Connexion is a source for the high PIV Schottkys.
If the SiC parts are too costly, don't bother with FREDs. Keep the 10 nF. snubber and use UF5408s, which cost $0.44 ea. from Mouser (stock # 625-UF5408).
On the NTC front, you choose between protecting the filaments and preventing cathode stripping. With B+ above 400 V., cathode stripping draws my attention. FWIW, I have a Jim McShane overhauled H/K Cit 2. that's quiet at turn on and easy on the "finals". It uses NTC devices on the rectifier winding. A stock Cit. 2 emits a clang from the power trafo at turn on and is known to "eat" tubes.
Parts Connexion is a source for the high PIV Schottkys.
If the SiC parts are too costly, don't bother with FREDs. Keep the 10 nF. snubber and use UF5408s, which cost $0.44 ea. from Mouser (stock # 625-UF5408).
On the NTC front, you choose between protecting the filaments and preventing cathode stripping. With B+ above 400 V., cathode stripping draws my attention. FWIW, I have a Jim McShane overhauled H/K Cit 2. that's quiet at turn on and easy on the "finals". It uses NTC devices on the rectifier winding. A stock Cit. 2 emits a clang from the power trafo at turn on and is known to "eat" tubes.
Hello poobah,
😀 😀 😀
Feel free....It actually makes sense (sorta) in the "Air Cooled Volkswagon" context (vee-wee is a term of endearment reffering to a VW). It wasn't until the next morning after signing up that I realized what I had done...note to self..don't pick a handle for anything while enjoying libations🙂
Eli,
Alrighty then..this comes across with conviction. I have read them being recommended elsewhere...what gives?
I'm confoosid..first I assume NTC=inrush limiter, second, I 'm fuzzy on the cathode stripping angle , wouldn't putting it on the primary prevent it as well as on just the filament winding ?
Casey
😀 😀 😀
Feel free....It actually makes sense (sorta) in the "Air Cooled Volkswagon" context (vee-wee is a term of endearment reffering to a VW). It wasn't until the next morning after signing up that I realized what I had done...note to self..don't pick a handle for anything while enjoying libations🙂
Eli,
Alrighty then..this comes across with conviction. I have read them being recommended elsewhere...what gives?
I'm confoosid..first I assume NTC=inrush limiter, second, I 'm fuzzy on the cathode stripping angle , wouldn't putting it on the primary prevent it as well as on just the filament winding ?
Casey
Eli,
Now I'm REALLY confused. Parts Connexion is selling HEXFREDS.
From there website...
...please help...my head's starting to hurt
Casey
Now I'm REALLY confused. Parts Connexion is selling HEXFREDS.
From there website...
...please help...my head's starting to hurt
Casey
I should have looked at everything, and put all these questions in one post..sorry.
Eli,
I downloaded the data sheet, and see this is a soft recovery device. I have read that snubbers can actually make things worse with similiar soft recovery devices (SiC Schottky, HEXFRED)..something to do with compounding winding capacitance issues I think..Whats the skinny ?
I'm sure I am testing your patience now..thanx for hangin' in there
Casey
Eli,
I downloaded the data sheet, and see this is a soft recovery device. I have read that snubbers can actually make things worse with similiar soft recovery devices (SiC Schottky, HEXFRED)..something to do with compounding winding capacitance issues I think..Whats the skinny ?
I'm sure I am testing your patience now..thanx for hangin' in there
Casey
Casey,
ALL PN junction diodes, including FREDs, exhibit a reverse recovery spike. "Standard" parts, like the 1N5408, are quite noisy. Ultra Fast diodes, like the UF5408, are a big step up from their "1N" counterparts. FREDs are a little less noisy than UF diodes, but I've not seen anything on snubbing them. With snubbing, UF diodes are quieter than unsnubbed FREDs at a lower cost. The 10 nF. part in the OEM 500C schematic does a decent job of squelching the SS noise. The H/K Cit. 2 uses the exact same setup. Hop over to Audio Asylum and search the Bottlehead Forum archives for RRSF. You'll pick up more than a few hints on how to "silence" UF diodes.
The Parts Connexion site is a little tricky, as it uses tabs. At the home page, click on parts and components. At the parts page, click on semiconductors. At the bottom of the S/C page there are a set of tabs. Click on diodes. Scroll the diodes page down. The next to last item, Cree CSD-05120A, is what you are after.
ALL PN junction diodes, including FREDs, exhibit a reverse recovery spike. "Standard" parts, like the 1N5408, are quite noisy. Ultra Fast diodes, like the UF5408, are a big step up from their "1N" counterparts. FREDs are a little less noisy than UF diodes, but I've not seen anything on snubbing them. With snubbing, UF diodes are quieter than unsnubbed FREDs at a lower cost. The 10 nF. part in the OEM 500C schematic does a decent job of squelching the SS noise. The H/K Cit. 2 uses the exact same setup. Hop over to Audio Asylum and search the Bottlehead Forum archives for RRSF. You'll pick up more than a few hints on how to "silence" UF diodes.
The Parts Connexion site is a little tricky, as it uses tabs. At the home page, click on parts and components. At the parts page, click on semiconductors. At the bottom of the S/C page there are a set of tabs. Click on diodes. Scroll the diodes page down. The next to last item, Cree CSD-05120A, is what you are after.
Eli,
Thanx for the explanation, I'll check out the Cree's with my new navigational directive 🙂. I'll also check out the Asylum.
So..just as one issue get ironed out, a much bigger one rears its ugly head.
I was figuring out my powersupply R/C network, when I discovered that the OEM phono and line, circuits together only draw a hair under 4 ma....Thorsten's Phono draws 30 ma. After running the numbers on the extra current, the only way I can do this is to lower the output bias...not good.
After much deliberation, I have decided to go with a stand alone phono-pre. I will bypass the OEM phono section so that I can use its input's... Probably the better solution anyway.
Casey
Thanx for the explanation, I'll check out the Cree's with my new navigational directive 🙂. I'll also check out the Asylum.
So..just as one issue get ironed out, a much bigger one rears its ugly head.
I was figuring out my powersupply R/C network, when I discovered that the OEM phono and line, circuits together only draw a hair under 4 ma....Thorsten's Phono draws 30 ma. After running the numbers on the extra current, the only way I can do this is to lower the output bias...not good.
After much deliberation, I have decided to go with a stand alone phono-pre. I will bypass the OEM phono section so that I can use its input's... Probably the better solution anyway.
Casey
valveitude said:
Casey,
A stand alone phono stage is fine, but it will take some time. You will be involved with PSU construction and chassis work for starters.
The RCA passive circuit I uploaded earlier in this thread is an evening's work for a veteran builder, like you. The RCA circuit draws about the same current as the Fisher OEM. That will get you going with better sound than the OEM circuit quickly.
Eli,
True enough, but I'm a month out minimum before my turntable is ready anyway. I already have the iron and most of the caps for the PSU, and I have a hobby machine shop so the case(s) are no big deal.
Definitely in the wings as plan "B". I'll see how things progress, and if the phono stage is lagging behind the rest of the work, I'll go this route.
After reading through the "Kofi Anan in B+... Plus" and "DC Phono" theads several times, I think I've got a good bead on Thorsten's thought process regarding this design..and I like it. That combined with the glowing reviews by people who have built it, I know anything short of me trying it myself, will cut into the joy of playing my system, as I wonder "what if".
Casey
True enough, but I'm a month out minimum before my turntable is ready anyway. I already have the iron and most of the caps for the PSU, and I have a hobby machine shop so the case(s) are no big deal.
Definitely in the wings as plan "B". I'll see how things progress, and if the phono stage is lagging behind the rest of the work, I'll go this route.
After reading through the "Kofi Anan in B+... Plus" and "DC Phono" theads several times, I think I've got a good bead on Thorsten's thought process regarding this design..and I like it. That combined with the glowing reviews by people who have built it, I know anything short of me trying it myself, will cut into the joy of playing my system, as I wonder "what if".
Casey
Casey,
You previously mentioned a need for a replacement volume control. A $2.35 Alpha RV24B-10-15R1-A55 dual 500 KOhm log. taper pot. from Mouser (stock # 313-2420-500K) will get you up and running QUICKLY.
There is a potential for trouble when the time for installing stepped attenuators comes. The phono and tuner circuits of the receiver need to work into a high impedance load (think 500 KOhms). While PSU current availability is limited, a few, not 30, extra mA. should be OK. Buffer the internal sources with JFETs running Id = 1 mA. Low cost MPF102s are adequate for this job and are easily obtained, including R/S.
You previously mentioned a need for a replacement volume control. A $2.35 Alpha RV24B-10-15R1-A55 dual 500 KOhm log. taper pot. from Mouser (stock # 313-2420-500K) will get you up and running QUICKLY.
There is a potential for trouble when the time for installing stepped attenuators comes. The phono and tuner circuits of the receiver need to work into a high impedance load (think 500 KOhms). While PSU current availability is limited, a few, not 30, extra mA. should be OK. Buffer the internal sources with JFETs running Id = 1 mA. Low cost MPF102s are adequate for this job and are easily obtained, including R/S.
Eli,
Ya, the 500k criteria does limit my options..I had already looked at the Mouser Alpha, but there is another problem...the Fisher has a switched pot (power). I am looking at putting together a attenuator, and reserving the first position to control a relay for power switching..I may just go with the cheapo Alpha as a "temp" solution though.
I like the fet buffer idea though. I am looking at setting up the switching so that in the "phono" position the phono-pre drives the balance/volume control directly (a "Phono Direct" position). As it has a 2k output impedance, it doesnt need a buffer. I would leave the aux and tuner going through the tone stack, so I just need the 1 buffer after the last 'AX7 before the balance control if I were to lower the 500k requirement down to something more "real".
I have yet to play with fets, could you point me to a follower circuit I could adapt to my needs ?
Casey
Ya, the 500k criteria does limit my options..I had already looked at the Mouser Alpha, but there is another problem...the Fisher has a switched pot (power). I am looking at putting together a attenuator, and reserving the first position to control a relay for power switching..I may just go with the cheapo Alpha as a "temp" solution though.
I like the fet buffer idea though. I am looking at setting up the switching so that in the "phono" position the phono-pre drives the balance/volume control directly (a "Phono Direct" position). As it has a 2k output impedance, it doesnt need a buffer. I would leave the aux and tuner going through the tone stack, so I just need the 1 buffer after the last 'AX7 before the balance control if I were to lower the 500k requirement down to something more "real".
I have yet to play with fets, could you point me to a follower circuit I could adapt to my needs ?
Casey
Casey,
With either the low cost Alpha pot. or a stepped attenuator, the loudness contour function is disabled for want of taps on the volume controls. Mount an on/off switch (toggle or push button) of appropriate diameter in the hole used by the OEM contour switch.
Setting up source followers is EASY, as "N" channel JFETs get wired up in a manner analogous to a tube. Think heaterless pentode. 😉 Use a 68 nF. I/P coupling cap. and a 1 KOhm Carbon comp. gate stopper. The drain is connected to B+. The source is connected to a 6.04 KOhm bias resistor. A 560 KOhm gate resistor ties the I/P cap./stopper junction to the "bottom" of the bias resistor. A load resistor computed to yield a 1 mA. drain current when added to the bias resistor connects the junction of the bias and gate resistors to ground. Use the next smallest "standard" value, as the FET has a small internal resistance that's been ignored. Cap. couple the source to the load.
With either the low cost Alpha pot. or a stepped attenuator, the loudness contour function is disabled for want of taps on the volume controls. Mount an on/off switch (toggle or push button) of appropriate diameter in the hole used by the OEM contour switch.
Setting up source followers is EASY, as "N" channel JFETs get wired up in a manner analogous to a tube. Think heaterless pentode. 😉 Use a 68 nF. I/P coupling cap. and a 1 KOhm Carbon comp. gate stopper. The drain is connected to B+. The source is connected to a 6.04 KOhm bias resistor. A 560 KOhm gate resistor ties the I/P cap./stopper junction to the "bottom" of the bias resistor. A load resistor computed to yield a 1 mA. drain current when added to the bias resistor connects the junction of the bias and gate resistors to ground. Use the next smallest "standard" value, as the FET has a small internal resistance that's been ignored. Cap. couple the source to the load.
I'm yelling UNCLE !!
I "built" the tone section/line amp in LTSpice to see how much gain ,if any, I would lose if I just bypassed it...
...31 freakin' dB, thats how much...dang.
Clearly, ol' Avery distributed the gain throughout the amp, there is no "line" between pre and power amps.
So...I can either gut the can, and build a new amp, or I can leave the topography alone, and do the passive component upgrade route and buttress up the power supply. I choose "B". As I mentioned earlier, I have lived with vintage Fisher before( thats why I bought this one), and phono section aside, they sound amazingly good.
I've learned a lot in this thread, so the energy wasn't wasted.
Thanks go out to all who contributed...particularly Eli.
Casey
I "built" the tone section/line amp in LTSpice to see how much gain ,if any, I would lose if I just bypassed it...
...31 freakin' dB, thats how much...dang.
Clearly, ol' Avery distributed the gain throughout the amp, there is no "line" between pre and power amps.
So...I can either gut the can, and build a new amp, or I can leave the topography alone, and do the passive component upgrade route and buttress up the power supply. I choose "B". As I mentioned earlier, I have lived with vintage Fisher before( thats why I bought this one), and phono section aside, they sound amazingly good.
I've learned a lot in this thread, so the energy wasn't wasted.
Thanks go out to all who contributed...particularly Eli.
Casey
We aint dead, yet. That 'pile article said the OEM phono section has about 20 dB. of gain. Add in the "tone stack" and it's 51 db. The RCA phono stage has about 45 dB. of gain. So, 6 dB. have to be found to implement phono direct. Steve Eddy has done some excellent work using step up microphone trafos for gain. A FET follower after the RCA phono circuit would provide the low impedance drive a trafo needs. A 1:2 step up mic trafo would provide the extra 6 dB. needed. IIRC, the ideal load for the mic trafos is about 15 KOhms. So, the volume/balance controls in the receiver will not cause a loading problem.
Also, bring the AUX I/P directly to the volume control circuitry. The 2 V. O/P of a CDP should "push" the driver and "finals" to full power and clipping, without any additional gain.
Eli,
Now how did I miss that ? It certainly puts a different light on it, guess I’m back in the game. I really appreciate your wading into the ‘pile to extract that info.
6 dB is easier to get than that…
…6 dB is exactly the insertion loss of a stock balance. By replacing the pot with a 11 or 13-pos. rotary, I can build a series ladder that is directly connected to the vol. control in the center position, and attenuates the opposing chn. as you turn “up” the chn. you need to lift.
In addition, the Fishers I’ve had in the past (if I remember right, it HAS been 25 yrs.) had very aggressive gain anyway, clipping at around 12 to 2 o’clock.
Let me ask you straight out..do you feel that the RCA’s RIAA is equal too, or better than Thorsten’s ? I have not heard either, so I can’t say. What I can say, is that I appreciate Thorsten’s logic regarding this design, as I understand it. First, by putting the blocking cap behind all the eq components, the caps are dc “soaked” minimizing dielectric absorption issues. Second, by keeping the impedance high in the middle by biasing the 6DJ8 with a “grid leak” resistor of 10 megs, the size of the caps are small, again minimizing capacitor nasties, and allowing the use of silver/mica’s throughout. And finally, again because of the “grid leak”, no E-L-E-C-T-R-O-L-Y-T-I-C-S. All that AND an output impedance of 2K…seems like a winner to me.
FULL DISCLOSER: I put a good part of my Russian military surplus order together with this circuit in mind. For example, I ordered a 395-piece silver/mica capacitor assortment, with 5-10 pieces of each value from a couple of puffs to 10nF. The idea being to closely match the caps. (well…that and to be flush with silver/micas).
As far as fet followers go, I admit to being a slowly recovering “sand-state” bigot. I have just about convinced myself to try a CCS in a power amp design, and I have no problem with a SS power supply, but I’m afraid, I’m a ways off from actually putting it in the signal path of my analog. I was contemplating a follower when all that would go through it was AM/FM, and those funny little discs with all those tiny long/short pits. Slapping one on the “Tape Out” is ok as well.
One of my criteria’s for this project is to keep the original functions as close as I can, and any changes to be reversible, when possible, so as not to affect resale value if I ever decide to sell it. In that spirit, I am considering a series ladder attenuator (ya I know..there are better ways, but it would be a bunch better than stock), this would provide for the loudness tap. I would then use the full counter-clockwise position to control a relay to power the unit. As far as a lower resistance volume control, I don’t see that as bad in of itself, and since the attenuator will be a custom build, I will keep it at 500k, eliminating the need for a follower after the tone stack.
As for the “Phono-Direct” , I will use the “Tape Head” position and inputs. By hardwiring the stock phono circuits eq. ,it will free up a set of contacts to control the line/tone circuit bypass. I have some dandy gold plated reed relays that I think would work well for this.
Ok I’ll shut up now.😀
Casey
Now how did I miss that ? It certainly puts a different light on it, guess I’m back in the game. I really appreciate your wading into the ‘pile to extract that info.
6 dB is easier to get than that…
…6 dB is exactly the insertion loss of a stock balance. By replacing the pot with a 11 or 13-pos. rotary, I can build a series ladder that is directly connected to the vol. control in the center position, and attenuates the opposing chn. as you turn “up” the chn. you need to lift.
In addition, the Fishers I’ve had in the past (if I remember right, it HAS been 25 yrs.) had very aggressive gain anyway, clipping at around 12 to 2 o’clock.
Let me ask you straight out..do you feel that the RCA’s RIAA is equal too, or better than Thorsten’s ? I have not heard either, so I can’t say. What I can say, is that I appreciate Thorsten’s logic regarding this design, as I understand it. First, by putting the blocking cap behind all the eq components, the caps are dc “soaked” minimizing dielectric absorption issues. Second, by keeping the impedance high in the middle by biasing the 6DJ8 with a “grid leak” resistor of 10 megs, the size of the caps are small, again minimizing capacitor nasties, and allowing the use of silver/mica’s throughout. And finally, again because of the “grid leak”, no E-L-E-C-T-R-O-L-Y-T-I-C-S. All that AND an output impedance of 2K…seems like a winner to me.
FULL DISCLOSER: I put a good part of my Russian military surplus order together with this circuit in mind. For example, I ordered a 395-piece silver/mica capacitor assortment, with 5-10 pieces of each value from a couple of puffs to 10nF. The idea being to closely match the caps. (well…that and to be flush with silver/micas).
As far as fet followers go, I admit to being a slowly recovering “sand-state” bigot. I have just about convinced myself to try a CCS in a power amp design, and I have no problem with a SS power supply, but I’m afraid, I’m a ways off from actually putting it in the signal path of my analog. I was contemplating a follower when all that would go through it was AM/FM, and those funny little discs with all those tiny long/short pits. Slapping one on the “Tape Out” is ok as well.
One of my criteria’s for this project is to keep the original functions as close as I can, and any changes to be reversible, when possible, so as not to affect resale value if I ever decide to sell it. In that spirit, I am considering a series ladder attenuator (ya I know..there are better ways, but it would be a bunch better than stock), this would provide for the loudness tap. I would then use the full counter-clockwise position to control a relay to power the unit. As far as a lower resistance volume control, I don’t see that as bad in of itself, and since the attenuator will be a custom build, I will keep it at 500k, eliminating the need for a follower after the tone stack.
As for the “Phono-Direct” , I will use the “Tape Head” position and inputs. By hardwiring the stock phono circuits eq. ,it will free up a set of contacts to control the line/tone circuit bypass. I have some dandy gold plated reed relays that I think would work well for this.
Ok I’ll shut up now.😀
Casey
Casey,
No way am I going to bet against Thorsten. I'm thinking in terms of pragmatic solutions. The RCA circuit is decent and relatively high gain. If you use it to get things going, be sure to change the 2nd gain block to use grid leak bias.
A FET follower is needed for trafo gain. You found the 6 dB. in the level control circuitry. If the impedance downstream from the RCA circuit is 250 KOhms or higher, a buffer is not needed. So, "sand" stays out of the analog playback path. Heck, based on your prior experience with Fishers, the "missing" 6 dB. could be a blessing.
A front panel on/off switch in the contour switch opening IS reversible. I know the ground rules. 😉 Such a switch and the Alpha pot. would make the receiver operational QUICKLY. JMO, get it playing music 1st. After it's operational, begin the improvements.
Let me repeat something I've said before. I'm just another hacker who has some info. to share. You are a better builder than I could ever hope to be. Your turntable project is scary good.
FWIW, I was thinking of a left channel volume control where the OEM balance control is mounted and a right volume control where the OEM volume control is mounted. Separate L/R controls eliminate a set of wipers in the signal path.
No way am I going to bet against Thorsten. I'm thinking in terms of pragmatic solutions. The RCA circuit is decent and relatively high gain. If you use it to get things going, be sure to change the 2nd gain block to use grid leak bias.
A FET follower is needed for trafo gain. You found the 6 dB. in the level control circuitry. If the impedance downstream from the RCA circuit is 250 KOhms or higher, a buffer is not needed. So, "sand" stays out of the analog playback path. Heck, based on your prior experience with Fishers, the "missing" 6 dB. could be a blessing.
A front panel on/off switch in the contour switch opening IS reversible. I know the ground rules. 😉 Such a switch and the Alpha pot. would make the receiver operational QUICKLY. JMO, get it playing music 1st. After it's operational, begin the improvements.
Let me repeat something I've said before. I'm just another hacker who has some info. to share. You are a better builder than I could ever hope to be. Your turntable project is scary good.
FWIW, I was thinking of a left channel volume control where the OEM balance control is mounted and a right volume control where the OEM volume control is mounted. Separate L/R controls eliminate a set of wipers in the signal path.
Eli,
Gotcha, the RCA definitely WOULD be the most pragmatic solution. And getting a vintage unit online relatively quickly is also a pragmatic option compared to the system I originally envisioned. BUT there is only so much pragmatism I can take, and getting the source as “right” as possible, within my budget (an S&B LCR phono would be the shiz-nitty), is a priority. Keeping the phono in the same can has its appeal, but it is no way a deal breaker for me..truthfully it is probably better that it isn’t. It will make the likely future upgrade easier.
If my notoriously bad memory is right..I agree.
Well…if this is true , then I aspire to be “just another hacker”!! More often than not Eli, the threads that I’ve read after doing a search on a topic of interest, has you as one of the main contributors. You sir are a “Geek with a Passion”, a very dangerous combination😀 . I suspect that you have forgotten more about audio circuit design than I know.
I don’t agree with the first part, it took the better part of 10 years of scrapping material, and ruining cutting bits, before my skill set was up to were it is today (still novice level compared to a real machinist, just do a quick search on home machine shops..some of those guys are awe inspiring). As for the second part…thank you..blind luck in some ways, the design was based around the materials available, I was lucky that they happened to be the ”right” materials.
This is where the WAF comes in. I struck a bargain with my lovely bride that I still am amazed with (she knows what this means to me, lucky man am I), that will have my system dominate our small living room. In return, I have assured her of 2 things..1) that it won’t be “butt” ugly (she gets final say on exactly what that is), and 2) it has to be user friendly…I’m afraid the “dual mono” approach fails no. 2.
You have been an amazing help to me Eli, as I suse out what I will, and will not do with this Fisher..finding the OEM 20dB phono factoid in itself rescued it….thank you.
Gotcha, the RCA definitely WOULD be the most pragmatic solution. And getting a vintage unit online relatively quickly is also a pragmatic option compared to the system I originally envisioned. BUT there is only so much pragmatism I can take, and getting the source as “right” as possible, within my budget (an S&B LCR phono would be the shiz-nitty), is a priority. Keeping the phono in the same can has its appeal, but it is no way a deal breaker for me..truthfully it is probably better that it isn’t. It will make the likely future upgrade easier.
If my notoriously bad memory is right..I agree.
Well…if this is true , then I aspire to be “just another hacker”!! More often than not Eli, the threads that I’ve read after doing a search on a topic of interest, has you as one of the main contributors. You sir are a “Geek with a Passion”, a very dangerous combination😀 . I suspect that you have forgotten more about audio circuit design than I know.
I don’t agree with the first part, it took the better part of 10 years of scrapping material, and ruining cutting bits, before my skill set was up to were it is today (still novice level compared to a real machinist, just do a quick search on home machine shops..some of those guys are awe inspiring). As for the second part…thank you..blind luck in some ways, the design was based around the materials available, I was lucky that they happened to be the ”right” materials.
This is where the WAF comes in. I struck a bargain with my lovely bride that I still am amazed with (she knows what this means to me, lucky man am I), that will have my system dominate our small living room. In return, I have assured her of 2 things..1) that it won’t be “butt” ugly (she gets final say on exactly what that is), and 2) it has to be user friendly…I’m afraid the “dual mono” approach fails no. 2.
You have been an amazing help to me Eli, as I suse out what I will, and will not do with this Fisher..finding the OEM 20dB phono factoid in itself rescued it….thank you.
OK, SOAF is important and she who must be obeyed is not to be trifled with. Time for plan "B" in getting the 800C working quickly. Since the front panel is off limits, let's look at the back. You have 2 switched convenience outlets there. A slide switch WILL mount in an outlet's opening. I have a slide switch installed in my H/K Cit. 2 in an opening that had the same sort of convenience outlet. Remove and save an outlet. Disconnect the 2nd outlet. Install a slide switch. If you use a DPST part and switch both sides of the AC mains, you can use the OEM 2 wire power cord with some degree of safety.
Eli,
You know it brother!! At this point, I still can't believe my good fortune of striking the deal that I have. I shan't deviate from my directive of making it bride friendly, for fear of having the whole contract nulled 😀.
Now this I like!! I'll have to make sure there's easy access, and I'll probably go with a rocker (easier), but this will be the plan..egg-suh-lent.
I intend to replace with a proper three wire and ground the chassis via a "69" pair of diodes..another Thorsten gem.
Now a question...What do I look for regarding in-rush limiters. I looked in my mouser catalog , and I couldnt figure out what to look under
Casey
You know it brother!! At this point, I still can't believe my good fortune of striking the deal that I have. I shan't deviate from my directive of making it bride friendly, for fear of having the whole contract nulled 😀.
Now this I like!! I'll have to make sure there's easy access, and I'll probably go with a rocker (easier), but this will be the plan..egg-suh-lent.
I intend to replace with a proper three wire and ground the chassis via a "69" pair of diodes..another Thorsten gem.
Now a question...What do I look for regarding in-rush limiters. I looked in my mouser catalog , and I couldnt figure out what to look under
Casey
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