steenoe said:
Please update the IRF9610 in the psu BOM also, I noticed that the wrong type is persisting😉 You list IRF610's for all the fets in the supply. The Negative rail, really needs an IRF9610🙂 Just to avoid mistakes![]()
Marc, if I understand you correctly, you have like 12V AC, Lets say 11V just to be sure. That nets you something like 15,4volts after rectification and before the regulating fet which eats like 3 volts!! You are pretty close to starving the Zenerstring with that voltage!
Variations in the main supply might starve them, and you really do not want that, believe me😉 You could swap out the P-channel fet with a BJT which doesnt throw off so much voltage🙂 You are pretty close to the minimum voltage that I would use!
Steen🙂
Thanks!
I understand. Any suggestions on a suitable T0-220 BJT I could use? I really would like to use this trafo. It looks pretty nice, the size is right, and most importantly, IT"S FREE!
Who cant understand that😀 😀 Yep you are right, I often struggle to find ways of putting some hardware to use too😉 Thats part of the fun, isnt it? I think a TIP36C will do the job just fine. You could even use a TIP35C for the positive rail also, that would net you a few more volts there too🙂 Please check the transistors I mention, this is right off my head😀 I might have got the NPN mixed up with the PNP😀 I have used those transistors on several occasions with good result. They are quite generic, so should be easily obtainable🙂IT"S FREE!
As far as I recall, the pinouts are just the same as the IRF's!
Steen🙂
Looking thru my parts bin I found 5 shiny new ON MJE15031 ... I think they will do just fine...Whadya think🙂 OH..IT'S FREE.😉
😀 😀 I would just pop them in🙂OH..IT'S FREE.
Seems that they can take the heat😉
Steen 🙂
Hi all-
I'm wondering if this preamp will be OK to use with a store bought amp (non-Pass) with respect to input impedence?
Thanks,
Jim
I'm wondering if this preamp will be OK to use with a store bought amp (non-Pass) with respect to input impedence?
Thanks,
Jim
Re: Dale Resistor Kits
Hi Brian,
Does this mean that I missed the chance for the Dales upgrade?
Thanks, Terry
BrianDonegan said:I just added an item to the order page for the Dale resistor kits. It includes Dale RN60 versions of all 42 2/5W resistors in the regular kit. Price is $8. Shipping is covered by the board or kit shipping. Have fun.
BTW: I plan on shipping all the board only orders on Monday, so if you are one of those and want the resistors, now would be a good time... 😉
Hi Brian,
Does this mean that I missed the chance for the Dales upgrade?
Thanks, Terry
Not at all. I was just mailing out the board-only orders, and wanted to be sure to get resistors in for those who wanted them. I will keep resistor kits in stock, so you can order them any time.
Member
Joined 2002
BrianDonegan said:Not at all. I was just mailing out the board-only orders, and wanted to be sure to get resistors in for those who wanted them. I will keep resistor kits in stock, so you can order them any time.
Are you mailing out mine ? Also id like to buy a few parts to compleet the kit can you email me ?
BrianDonegan said:Not at all. I was just mailing out the board-only orders, and wanted to be sure to get resistors in for those who wanted them. I will keep resistor kits in stock, so you can order them any time.
OK, so how do we go about paying for the Dales so nothing gets delayed and we get our complete kits soon? Are you gong to post a price. I hate to think I will have to pay shipping for a second order because I didn't pay for the Dales in time.
Blessings, Terry
EDIT: Hopefully you can come up with something by tomorrow. I am going on a cruise starting Friday and will be gone for a week.
Hi Terry-
I posted something about it here.
Just go to the order page on the site and you will find the resistor upgrade kit listed for $8. If you already ordered boards or a kit, there is no need to pay shipping again.
I hope to start shipping kits next week, but it will depend on a few things coming together. One of the things that may cause a holdup for some kits is a backorder on the output caps. I originally ordered 100 of the Jantzen caps from PE, and recieved 75. The backordered caps are scheduled to arrive at PE on 2/1. I have since ordered another 100, and hopefully they will get enough to cover that as well. At this point I don't think there are enough kits sold for this to be a problem for anyone, but it could cause a slight delay of a few days.
I posted something about it here.
Just go to the order page on the site and you will find the resistor upgrade kit listed for $8. If you already ordered boards or a kit, there is no need to pay shipping again.
I hope to start shipping kits next week, but it will depend on a few things coming together. One of the things that may cause a holdup for some kits is a backorder on the output caps. I originally ordered 100 of the Jantzen caps from PE, and recieved 75. The backordered caps are scheduled to arrive at PE on 2/1. I have since ordered another 100, and hopefully they will get enough to cover that as well. At this point I don't think there are enough kits sold for this to be a problem for anyone, but it could cause a slight delay of a few days.
Brian,
It looks like there is still one discrepancy on the BOM's. The Power Supply parts list shows 2 24 V Zeners and 2 75 V Zeners. The Excel spreadsheet shows 2 18 V Zeners and 2 12 V Zeners. My understanding was that the circuit uses 75 V Zeners and 18-24 Volt Zeners.
Could you double check and confirm the intended values?
It looks like there is still one discrepancy on the BOM's. The Power Supply parts list shows 2 24 V Zeners and 2 75 V Zeners. The Excel spreadsheet shows 2 18 V Zeners and 2 12 V Zeners. My understanding was that the circuit uses 75 V Zeners and 18-24 Volt Zeners.
Could you double check and confirm the intended values?
I am going on a cruise starting Friday and will be gone for a week.
Sorry, OT, but what kind of cruise?
BrianDonegan said:Hi Terry-
I posted something about it here.
Just go to the order page on the site and you will find the resistor upgrade kit listed for $8. If you already ordered boards or a kit, there is no need to pay shipping again.
I hope to start shipping kits next week, but it will depend on a few things coming together. One of the things that may cause a holdup for some kits is a backorder on the output caps. I originally ordered 100 of the Jantzen caps from PE, and recieved 75. The backordered caps are scheduled to arrive at PE on 2/1. I have since ordered another 100, and hopefully they will get enough to cover that as well. At this point I don't think there are enough kits sold for this to be a problem for anyone, but it could cause a slight delay of a few days.
Hi Brian,
OK, I paid for the upgrade. Hopefully you can get those included with my kit and it won't put me in the back of the line. 😀
It would be very cool if the kit was waiting for me when I return.
Blessings, Terry
chipco3434 said:
Sorry, OT, but what kind of cruise?
Hi Chipco,
My wife and I are going on a cruise to the Caribbean. We fly to Florida on Friday, hop the ship on Saturday and return on Thursday. We've never done anything like this before so we are very excited with anticpation. It was very difficult reving myself up to come to work today.
Blessings, Terry
still4given said:We fly to Florida on Friday, hop the ship on Saturday and return on Thursday.
I see there is still a rocker left in you, Terry.
Be gentle on swinging that boat !
Boards Arrived
The boards and resistors arrived in the mail today. Look really great. Had not noticed until now just how short the traces are on the preamp. Excellent layout. Looks like a busy weekend.
Craig
The boards and resistors arrived in the mail today. Look really great. Had not noticed until now just how short the traces are on the preamp. Excellent layout. Looks like a busy weekend.
Craig
Sorry to repeat a question..either it got glossed over or...maybe... nobody knows the answer
"Also, will a 6.2v zener work as D1 (instead of a 6.8v) as just mentioned by Russ/Brian? This I have no clue....
is that value critical?
Also..not to be a pain🙂 , whadya guys think about 67v AC for the + side psu feed..too high? or can I get away with it?
~94vdc after rect ?
?
Thanks in advance...
Marc:

"Also, will a 6.2v zener work as D1 (instead of a 6.8v) as just mentioned by Russ/Brian? This I have no clue....
is that value critical?
Also..not to be a pain🙂 , whadya guys think about 67v AC for the + side psu feed..too high? or can I get away with it?
~94vdc after rect ?


Thanks in advance...
Marc:
Hi Marc, I am affraid I am not confident enough to answer either question yet. 🙂 But I think the voltage you described is pretty high, but with big enough heatsink on that rail you might be OK. I will let those more knowlegable about the circuit than I answer for certain.
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