Ah! Cinch Jones! Thank you! I've been racking my brain trying to remember what those were called. This other amp I have has a 10-way on it and it is quite nice.
The connectors I have used in the past are Molex Sabre connectors. The 7.50 variety are rated at 1000VDC, 18A continuous, 5000VAC max. I got mine from Mouser.
So I got home from work and I removed both of the CL90s from the primary side of the transformer leaving just the two after the HV bridge rectifiers. Plate voltage now is 601volts, screen voltage is 144volts. I switched out the speakers to a set that is a bit more efficient compared to the 81db/1watt Ratshack speakers. An older 3way pair of Technics speakers I got for free, they are "rated" at 91db/1watt. A big difference and much louder. I honestly think at this point it is marginally louder than my SSE with KT88s. I plan to try substituting the 6DK6 drivers for a set of higher gain tubes such as a 6GU5. Also wired a volume pot and hooked up my Panasonic DVD player and cranked some Sevendust for a while.
Now as for the connectors, I actually have four brand new sets of Cinch Jones connectors I got in a lot of parts from an estate sale. I just had no idea what they were called. They appear to be older than what they offer now as these have a metal housing but they should work just fine providing I keep everything well insulated.
Now as for the connectors, I actually have four brand new sets of Cinch Jones connectors I got in a lot of parts from an estate sale. I just had no idea what they were called. They appear to be older than what they offer now as these have a metal housing but they should work just fine providing I keep everything well insulated.
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Use a connector with additional pins that are unused to allow you to increase the pin to pin spacing for pins that are used.
This is SOP in the industrial controls industry to meet agency spacing requirements.
This is SOP in the industrial controls industry to meet agency spacing requirements.
I need to read up on this alittle. the speakon connectors have insulation rated at 4kv, but contacts rated at 250vac. Could the 250vac on all these connectors be the break voltage? aka pulling the plug while the unit is on and not arc? Kinda like relay/switch ratings?
I asked the speakon people directly on this and got this response:
I asked the speakon people directly on this and got this response:
I got a hand full of NOS ones at a hamfest. The ones that were made for the end of a cable have a metal shell. I used an 15 pin version on the 845SE, with a chassis mount female on the power supply chassis and a male on the end of the umbilical cable. I didn't know the ratings so I put the HV wire in one corner and didn't use adjacent pins. There is a wire carying 450 volts DC for the Tubelab SE board and + / -300 VDC for the PowerDrive board. All heaters are DC and each supplies have individual returns. Each supply is individually floating and are tied together only at the star point in the amp chassis. This amp is about 6 years old and has been reliable but doesn't see much use due to the heat that it puts out. Picture of the connector on the end of the cable.
Line voltage is 120.9 volts. I know its winter but the AC is on. Temp has been in the mid 80's for the last few days. B+ is 620 at turn on before tubes heat up. After 5 minute warm up B+ is 605 volts at idle. Put on Elton John "Love Song" and set the volume rather loud. B+ went down to 603 volts. Elton is a wuss, go I cranked some Mark Knopfler as loud as I dared push the new efficient speakers. It was LOUD. B+ went down to 595 volts. Return to idle B+ is again 605 volts. Bias currents are 32.2 mA, 29.7 ma, 31.8 mA. and 29.8 mA. Don't remember exactly where I set them but the OPT's that I am using (cheap guitar amp OPT's that sound good) like a little imbalance, so the imbaance is intentional (set with a distortion analyzer). 2nd picture is amp and speakers from last weekends Back Yard Speaker Lab.
Please ignore the clutter on the table and the exposed lethal voltages. I am the only one in the house right now. Amp, speakers, and mess will all be removed and safely hidden before Sherri comes home.
3rd picture is next set under construction in this weekends Back Yard Speaker Lab. They are much smaller and will never see this amp. Two nice weekends in a row. Lets hope for a 3rd. Next weekend is the Orlando Hamfest (200 miles north of here). Last year it was 40 degrees and raining on Friday, 25 degrees and very windy on Saturday.
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You have to put that into context. They have to go through various certification processes and so I think that is why 250VAC is the target. I imagine it is an expensive process involving all types of humidity levels and so forth. Then there are the lawyers....
The connector also needs to handle that voltage at the contact's full current rating. Our application tend to be rather current-limited, at least for any length of time.
So in conclusion, I also legally cannot recommend you use those connectors. You should not use any connectors. You should not build that amp.
Well my plugs look just like the one George posted but are only six contacts. I plan to put the filament wires and safety ground on one and the Plate, B+, C- and board ground on the other. I have a couple of ideas on how to keep myself from getting them mixed up. I think it will work out just fine.
George how do your portable table saw? I currently don't have room for a fullsize one at my town home and I get tired of having to run out to our warehouse to use the one out there. I have been planning to purchase a portable unit or else try to snag one of our old Makita ones from the shop and tune it up.
George how do your portable table saw? I currently don't have room for a fullsize one at my town home and I get tired of having to run out to our warehouse to use the one out there. I have been planning to purchase a portable unit or else try to snag one of our old Makita ones from the shop and tune it up.
Florida is very inconsistent. I grew up there, and there would be times I came back for Christmas and it would be 85F. However, on one particular Christmas when I visited, the temperature was 19F on Christmas day. We were still semi-rural and had a well to supply our water, and the pump froze, so my poor dad was out tinkering with the pump in that beastly weather. Forget about getting any parts. When I got back to Cali, it was a sane 65F.
I was wondering a bit about the WAF for those speakers, though they're not too bad looking.
I was wondering a bit about the WAF for those speakers, though they're not too bad looking.
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I was wondering the same. Perhaps they could be fashioned into matching grandfather clocks! 😉 j/k...
Sherri has been away from this house since Thanksgiving. She knows I am making speakers but has not seen these, nor any pictures. They will not pass the WAF test as is. This I am sure of. If she doesn't totally reject the idea, I may try to veneer them to match the decor, and ditch the old radios with Silver Iris drivers. If that is unacceptable I will make dollys for them and roll them out when I feel like cranking up some tunes, then stash them out of site when not in use.
The little guys I am building now are for my lab / work room. No WAF approval needed, the door stays closed when she has friends over.
I grew up in Miami and moved to Ft. Lauderdale when I was 20. I have never lived anywhere else. It is consistent for about 9 months of the year. It is either hot, or hotter with high humidity. This summer we had 45 consecutive days of 90+ degrees. It seems that I have a harder time with the heat as I am getting older. From mid November through February it can be 85 degrees one day and 20 degrees the next. This winter has had more freezing days than in recent history. All the oranges and strawberries were frozen. Many farmers lost their crops. For the past 20 days or so it has been in the high 60's to mid 80's. It can't last much longer......
We have a 5HP monster saw in the evening woodshop class. Unfortunately the class is only 1 night a week and there is always someone using it. I got this portable saw on a black Friday sale at Home Depot 3 years ago for $279. At that price it is a no-brainer and I would do it again. It normally sells for $499, and I am not sure I can justify that given my limited use. It folds up and stands on end in the garage only occupying about about 4 sq ft of floor space. It is on wheels for easy movement, but it weighs 100 pounds if you need to lift it into a car or truck.
I already had a cheap table saw similar to the one that Harbor Freight sells for $100 to $130. I gave that one away after plugging this one in for 5 minutes. The HF thing is a POS compared to this one. I have had no issues with this saw, it works great and the fence is accurate and stays put when locked. So does the blade angle and height. The HF does neither. The miter gauge that comes with the saw is typical and OK for most jobs, but I couldn't make accurate 4.9 degree angle cuts on a large piece of plywood last Sunday so that's where I stopped. We have one of these in class. I gotta git me one of these:
http://www.amazon.com/Incra-MITER1000SE-Miter-Special-Telescoping/dp/B0007UQ2EQ
Well I am pretty confident I can start on the chassis this weekend. I have had this thing playing without a hitch. I adjusted the bias today and it was holding steady at around 36ma per channel. I have a different set of driver tubes coming so I will give those a try and report back. They should perform similar to the 6GU5s. So far this has been a great project. I am tempted to wire up some octal sockets and try the set of 6bq6gas that I have stored away.....tempting but I really should resist.
A table saw is on my list for my next purchase. I have been very impressed with the Ridgid tools I have seen. I really need to build some new Sachiko's for my Fostex 206e that I have had for almost two years sitting on a shelf. Now finding decent plywood locally has been a royal pain. Menards has ok quality baltic birch but the next nearest place that sells high quality wood is about 70 miles away.
A table saw is on my list for my next purchase. I have been very impressed with the Ridgid tools I have seen. I really need to build some new Sachiko's for my Fostex 206e that I have had for almost two years sitting on a shelf. Now finding decent plywood locally has been a royal pain. Menards has ok quality baltic birch but the next nearest place that sells high quality wood is about 70 miles away.
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We don't have Menards, only Lowes and Home Depot. Neither has baltic birch. Baltic birch doesn't seem too common here, I got the woodshop teacher to call his usual suppliers and only one said that they could get it....If we bought a whole pallet. The best that I can get is "sandeply" from Honduras.
Resist, they would be a downgrade from the 6HJ5's. Even the best 6BQ6GA's have 18 watt plates. The 6HJ5 is good for 24 watts. I abuse the 6bq6's because I got bunches of them for an average price of 80 cents each. They are also pin compatible with the 6L6GC and other popular audio tubes if you connect a plate cap to pin 3 of the octal socket.
Wow, I bought one of Pete's boards back when this amp design was first released and it has been sitting on my projects-to-build shelf since then. I came to check on this thread and I see that it has exploded with all kinds of higher wattage variants from George. Pretty awesome stuff really. 🙂
I'm finally getting ready to build mine, I bought tubes and sockets right when I bought the board, but I didn't buy any transformers or the rest of the parts to stuff the board. I have 8 6JN6 for the power tubes and would rather stick with those since I already have them, but, I'm wondering if I would be able to crank a few more watts out of them.
My main speakers are a pair of Econowaves that I built which are ~98Db sensitivity so really, 18W is plenty, but I wouldn't mind having more. Keep in mind that I still consider myself a bit of a novice when it comes to making changes to a proven design. I can solder together a working amp following a plan no problem.
I was hoping that I might be able to squeeze out a few extra watts just by using different output transformers, maybe the Edcor CXPP50-8-6.6K. Will that give me any more power without needing to increase the B+? I'm trying to keep it simple and be able to use the specified power transformer so I don't have to worry about seperate bias supplies or anything like that.
I'm finally getting ready to build mine, I bought tubes and sockets right when I bought the board, but I didn't buy any transformers or the rest of the parts to stuff the board. I have 8 6JN6 for the power tubes and would rather stick with those since I already have them, but, I'm wondering if I would be able to crank a few more watts out of them.
My main speakers are a pair of Econowaves that I built which are ~98Db sensitivity so really, 18W is plenty, but I wouldn't mind having more. Keep in mind that I still consider myself a bit of a novice when it comes to making changes to a proven design. I can solder together a working amp following a plan no problem.
I was hoping that I might be able to squeeze out a few extra watts just by using different output transformers, maybe the Edcor CXPP50-8-6.6K. Will that give me any more power without needing to increase the B+? I'm trying to keep it simple and be able to use the specified power transformer so I don't have to worry about seperate bias supplies or anything like that.
When I cranked the 6JN6s to 500V of B+, I got 60WPC easily. This is my original attempt at a hot rod red board back around post 333, but my ultimate goal were the 6HJ5s. George pointed out that even these smaller sweep tubes are barely breaking a sweat at this voltage.
If you take the dual-winding approach that George is doing now, you can probably get even more with 600V on the plates. I think George said he got 80WPC at 600V on the 6NJ6 before he blew up a capacitor (he was feeding it all the the board back then too). His current approach is much easier on the board and much safer overall.
If you take the dual-winding approach that George is doing now, you can probably get even more with 600V on the plates. I think George said he got 80WPC at 600V on the 6NJ6 before he blew up a capacitor (he was feeding it all the the board back then too). His current approach is much easier on the board and much safer overall.