Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 7:26:15 GMT
Does anybody believe that the Class A HA would have sounded any better if the 2 toroidal transformers in the external case were fancy screened types,and if there was a reasonable amount of spacing between the PSU and the HA, and the case of the HA was metal ?
Alex
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 8:54:11 GMT
C'mon Alex..........................boys  and their toys...............  give us boys a break. After all..........................birthdays are only once a year......................and dear old Santa also. Then there's " never look a gift horse in the mouth"  Alan |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 9:00:20 GMT
Alan Don't blame me . Blame that guy from the Sunshine State who is always sniffing around for bargains .  Regards Alex |
|
mrarroyo
Been here a while! 
Our man in Miami!
Posts: 1,003
|
Post by mrarroyo on Nov 28, 2011 11:24:30 GMT
^ What have you been smoking lately Alex?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 11:27:28 GMT
Does anybody believe that the Class A HA would have sounded any better if the 2 toroidal transformers in the external case were fancy screened types,and if there was a reasonable amount of spacing between the PSU and the HA, and the case of the HA was metal ? Alex Hi Alex well the answer is er...... no but I'm wondering if putting the HA/PRE and 15W transformers in the same box (if i have space) if it may help prevent interaction between the two sets. anyhow now't wrong with just a little over kill between friends. however i still doubt it's going to make much difference SQ wise. i did have a fixed amount to spend on the birthday thaaang so decided to go for the double screen just for piece of mind. i did spend a quite memorable birthday in the sunshine state (the first warm birthday I've had) so it's going to be great to have the company of the Queensland posse for this hot build. take care |
|
|
|
Post by jeffc on Nov 28, 2011 11:28:07 GMT
I've been struggling to find ANY suitable transformers advertised locally and was thinking I might have to get some custom wound, which I'm guessing would get expensive becasue then I'd be tempted to get them quadruple shielded I just lucked finding this one, and being "On Sale" was a bonus . I thought hell, it might be OK, but to be sure I better check. Thanks for confirming "its a toroidal transformer" Alex ;D Alan, Santa (AKA....... the Aust Post parcel delivery lad) delivers me little gifts all year round and the boss here would only buy 1.5 kg transformers so she could drop them from a great height onto my head   cheers.. jeffc |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 11:40:57 GMT
Hi Shaun
Inside my 2U rack case I have the big dual primary windings toroidal for the Class A itself, as well as the 2 x 18-0-18 30VA transformers for the HA/preamp. The new PSU PCBs from Will are likely to be smaller than the original SC designed PSU PCBs,
so it may be possible to fit the 4 transformers in a simliar sized case.
Regards
Alex
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 11:42:24 GMT
Smart arse Yanks ! ;D
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 11:44:41 GMT
Hi Jeff
''the boss here would only buy 1.5 kg transformers so she could drop them from a great height onto my head''
just add a crash helmet to the Xmas list ;D ;D ;D
that way you can have the transformers without fear.
take care
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 11:56:25 GMT
Hi Shaun Inside my 2U rack case I have the big dual primary windings toroidal for the Class A itself, as well as the 2 x 18-0-18 30VA transformers for the HA/preamp. The new PSU PCBs from Will are likely to be smaller than the original SC designed PSU PCBs, so it may be possible to fit the 4 transformers in a simliar sized case. Regards Alex Hi Alex thanks for that info one PSU case would be fantastic and help keep the box count down to a minimum. i have a U2 HIFI 2000 disipante case in mind for the PSU just for the sake of matching the 15W case. Santa's looking into that for me now. so I'm hoping with a little imagination that they will all fit nicely. and a quick question if i may on the speaker protection board I've had a look at the SC one supplied by Jaycar and it states that it runs on 22-70v. will it need to be modded to work @20v. also from reading the post that Will linked to you've modded its sensitivity so some clues on that would be really helpful. are there and sonic penalties when using the speaker protection circuit. yes silly questions but I'm curious. take care |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 15:02:36 GMT
HI Jeff, like Shaun I thought if I was to house everything in the one case the fancy-pants extras wouldn't catch me with my knickers down.....so to speak. As to case I'll most likely make my own. Building the case for the AKSCHA means I'm not winging it so much for it's big brother as that was a first and really just a prototype for the real thing. Your Dun-Mei case looks good but way to much shekels for me. The material costs .......aluminium.......are zero even get the pop rivets thrown in. Regards, Alan |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 15:19:23 GMT
Hi Alex....et al, I was concerned.....a bit.....that there are only positive versions of the LT1033 series regs, so I cast around a bit and read several hundred lines of bum-ff in various places and eventually arrived at this. Your input would be most welcome. I hope I've got it right. Not sure about the 1.5 amps being enough but probably will be with the dual traffos. Will, apologies for being impetuous and not waiting for your PSU to come forward I don't mean to tramp on your toes. Hands on is the only way I learn. Regards, Alan  |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 16:35:54 GMT
Just to confirm, I'm going to have a go at this one too. So, get ready for the questions What are we all going to do when this project is completed? Syd |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 16:57:45 GMT
Hi Syd, welcome on-board....................there's always the great sounding music you'll be able to listen to. Regards, Alan |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 17:02:19 GMT
Hi Syd, welcome on-board....................there's always the great sounding music you'll be able to listen to. Regards, Alan X2 |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 20:48:05 GMT
Hi Alex....et al, I was concerned.....a bit.....that there are only positive versions of the LT1033 series regs, so I cast around a bit and read several hundred lines of bum-ff in various places and eventually arrived at this. Your input would be most welcome. I hope I've got it right. Not sure about the 1.5 amps being enough but probably will be with the dual traffos. Will, apologies for being impetuous and not waiting for your PSU to come forward I don't mean to tramp on your toes. Hands on is the only way I learn. Regards, Alan Alan The trimpots would need to be 2K or higher. With a 5K you could get an improved action with a parallel 4.7K MF resistor.With a 10K you could use a parallel 2.7K You would also need more wires between cases. 2 x 3 wires using 7.5A or 10A mains cable is more manageable. Alex |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 21:10:34 GMT
Hi Alex,
thanks for the input, I'll update the trimpots, before I post another pic are there any other suggestions you would have..........?
Is 1.5 amp sufficient power for one line or would it be better to go with the 3 amp LT1085CT.
Also are the 1N4004 1amp diodes okay to use with the 1086 1.5a Regs?
Would there be any advantage to upping C1, C2, C3, C4 to 4700uf.
Regards,
Alan
|
|
|
|
Post by jeffc on Nov 28, 2011 21:12:25 GMT
Shaun, Another option for Speaker Protection and Power Soft Start circuits is here. connexelectronic.com/index.php/cPath/43?osCsid=7ntqc7qqvl81g3273lr1j18kh5extra info available by clicking on the products links. I have the the Power Soft Start V3 board in my laptop linear supply and it works a treat. Apparently the voltage requirements for the SP circuit can be adjusted with a couple of parts changes, which Cristi, the cool dude who makes this gear, would do before shipping. Cheap too......which is fitting seeing I seem to be getting a reputation for buying CHEAP STUFF.  CHEAP transformers ordered cheers.. jeffc |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 21:19:00 GMT
Hi Shaun
My speaker protector works fine with 20V, and the new revised article (October 2011) actually says from 20V.
I replaced the 22K to ground with a 47K for slightly improved sensitivity.This would mean operation with a DC level of + or - 1.2V which is more than sensitive enough for a power amplifier.
There is a minor change in the input circuit to improve response time a little.(from around 124mS to 88mS)
It now uses a single series 47K resistor and a single 47uF 50V NP to earth. This just involves a 47uF being removed and a link fitted.
With mine, as the over-temp input can't be used with the Class A due to the continuous higher temperature of the heatsinks,
I cut the track to the over=temp input right next to it's screw terminal and connected a series resistor under the PCB from the +VE side of the relay coil to the terminal.This allows me to connect a "reassurance" green LED on the front panel.You will then see the several seconds switch on delay, and of course the green LED will not be on if the amplifier has a fault condition.
I haven't noticed any sonic penalty with the Speaker protector in line, but I am using 10A wire to and from the relays.
Alex
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 21:35:56 GMT
Hi Alex, thanks for the input, I'll update the trimpots, before I post another pic are there any other suggestions you would have..........? Is 1.5 amp sufficient power for one line or would it be better to go with the 3 amp LT1085CT. Also are the 1N4004 1amp diodes okay to use with the 1086 1.5a Regs? Would there be any advantage to upping C1, C2, C3, C4 to 4700uf. Regards, Alan Hi Alan I haven't had breakfast yet,so I am not fully awake yet.  I would prefer to see some of you guys answering these types of questions.There is more than one way to do these things, and I would like to see input from Will,Shaun and others in this area. The original actually uses a single 10A 400V bridge and 4,700uF input capacitors, but diodes like the 1N5404 (or faster could be worthwhile there. Regards Alex P.S. Mine worked O.K. using just LM317T/LM337T due to suitable heatsinking, when a series pass transistor in one PSU went O/C. The LM317T/LM337T are good for 1.5A when suitably heatsinked. Each channel should draw aprox. 1.1A to 1.2A, depending on the actual bias adjustments. |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 21:44:16 GMT
Hi Jeff Their Speaker Protection PCB is not really suitable here due to it's special AC and DC supply requirements,although they can adjust that for you, the trip detect voltage is also higher, although they can adjust that for you too. 10A fuses in the output leads ? YUK! IMO, that's not good for retaining a high speaker damping factor. The SC design is not too expensive, and ideal for this design. e.g. Class A Speaker Protection Module (Part of K 5125) K5124 $29.95 from Altronics. Alex P.S. I won't even go there why they should feel the need for those 10A fuses, which will take a lot more current than 10A to blow, as well as being quite slow to blow. |
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on Nov 28, 2011 22:39:02 GMT
Hi Alex....et al, I was concerned.....a bit.....that there are only positive versions of the LT1033 series regs, so I cast around a bit and read several hundred lines of bum-ff in various places and eventually arrived at this. Your input would be most welcome. I hope I've got it right. Not sure about the 1.5 amps being enough but probably will be with the dual traffos. Will, apologies for being impetuous and not waiting for your PSU to come forward I don't mean to tramp on your toes. Hands on is the only way I learn. Regards, Alan Hi Alan, Good going on the PSU! I know what you mean about the lt1033, but I've done a bit of digging around, and Farnell do them for £3 odd, if we can get 10 bought at a time. Something worth pointing out to others is that the dual +ve reg layout can't be used with CT transformers, and needs to be run from two secondaries. I'd also agree with upping the smoothing cap to 4700uF, 50V (perhaps a nice TSHA?) My thinking on the PSU (from my own perspective) is that I'd feel uncomfortable running the LM317/337 at close to their max output current. I'd prefer using the 3A lt1085 and lt1033, as that allows for a bit of headroom when running at normal bias setting, and allows upping the bias, perhaps, for those headbangers out there ( ) The same thinking goes for the rectifier diodes, I'd be looking at 5-6A minimum diodes so that they don't run hot if running bias higher than normal. Anyone know about a nice bridge rectifier package? The LT1085 can be a funny bugger apparently, so make sure that you pay attention to that after-reg cap value. I'll be forging on with a lt1085/lt1033 myself, but I'm looking forward to seeing your PSU board, which knowing how fast you work, will be on soak test by the end of the week!  Anybody who is going to want the PSU pcb I have made, please feel free to chip with how they feel about basing it on the lt1085/lt1033, rather than on two lt1085 - or other combo's. |
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on Nov 28, 2011 22:45:41 GMT
Just to confirm, I'm going to have a go at this one too. So, get ready for the questions What are we all going to do when this project is completed? Syd Hi Syd, Nice to see you along for the ride! As for what's next, well how about a DIY HD-projector? |
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on Nov 28, 2011 22:48:49 GMT
On the leading traffo question, I'd expect no increase in SQ, but as others have mentioned, knowing that any possible interference has been reduced is good piece of mind for myself.
I know that this power amp will sound good (based on the HA), so it's worth taking care with.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Nov 28, 2011 23:04:53 GMT
Hi Jeff Their Speaker Protection PCB is not really suitable here due to it's special AC and DC supply requirements,although they can adjust that for you, the trip detect voltage is also higher, although they can adjust that for you too. 10A fuses in the output leads ? YUK! IMO, that's not good for retaining a high speaker damping factor. The SC design is not too expensive, and ideal for this design. e.g. Class A Speaker Protection Module (Part of K 5125) K5124 $29.95 from Altronics. Alex P.S. I won't even go there why they should feel the need for those 10A fuses, which will take a lot more current than 10A to blow, as well as being quite slow to blow. Hi Alex the loudsspeaker protection kit is still listed at jaycar as a back catalogue item for Internet order only for half the price that Altronics list it for. www.jaycarelectronics.co.uk/productView.asp?ID=KC5450&form=CAT2&SUBCATID=965#11so if the above is OK then the price is much better. they look like the same kit used in the 20W classA so look good to go. as far as the PSU goes I'd be tempted to go for something close to the original but as will suggested one board per side. all that needs to happen is the power transistor and supporting components removed. maybe some beefier regs but if it ain't broke don't eeerrr. IMHO originality is good but not always necessary or beneficial Hi Alan don't forget to check your mail take care |
|
and their toys............... 
