| Have transformer, will build - Click HERE for Original Thread |
| still4given |
I am the proud owner of this transformer.
I bought it by mistake for my ESP Project 101. It is too large for that project and now I am left wondering if there is a DIY project that can make use of this trannie. If you know of one, please let me know. Perhaps it will be my next project.
Thanks, Terry |
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| still4given |
Do you mean the Aleph X?
I looked into that thread but it seemed that it is still under development. Are there PCBs availible for that design?
I've heard realy good things about the Aleph amps. I wouldn't mind tackling that next if it's not too complicated.
Thanks Terry |
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| moamps |
Hi,
with this transformer (1000VA/2X56V) you can build a high power amplifier in Class AB (ca. 2X250W/8ohm). Normally, I would not see much point in building such a high-power amp for home use.
However, if you set primary winding to 230V, you'll get half the secondary voltage, which turns this transformer into a pretty good choice for, say, a Pass amp in Class A. Depending on power supply implementation (voltage losses), you could build A2, A5 or a high-power version of AlephX.
Before you decide to build a Class A amp, you should test the transformer for the intended purpose.
Detailed information and an overview of all the complexities involved in building such an amplifier can be found at www.passdiy.com (check out the gallery section).
I believe there are some PCBs circulating on the forum. Ask around. (I wouldn't know).
Regards,
Milan |
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| grege |
Hi still4given,
I think most of us use bridge rectifiers so the DC output voltage is greater the the AC secondary voltage, but if you use a full-wave rectification using just two diodes the DC output voltage is actually less than the AC seondary voltage. I can't remember the formula but I think it was .6 or .7 of the secondary. I have read some prefer full-wave over bridge rectification. So I think you could use this transformer for your original project and power a gainclone off the 17v secondaries. |
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| joensd |
I´d go with moamps suggestions to wire the primaries in series leaving you with 28VAC which gives~40VDC+.
With that rail voltage you can simply build anything as it is quite a "standard" voltage. That includes P101 as well.
That said the transformer will be oversized for the purpose (unless you go class A) but it will also give great "regulation". |
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| still4given |
| quote: | Originally posted by moamps
Hi,
with this transformer (1000VA/2X56V) you can build a high power amplifier in Class AB (ca. 2X250W/8ohm). Normally, I would not see much point in building such a high-power amp for home use.
However, if you set primary winding to 230V, you'll get half the secondary voltage, which turns this transformer into a pretty good choice for, say, a Pass amp in Class A. Depending on power supply implementation (voltage losses), you could build A2, A5 or a high-power version of AlephX.
Before you decide to build a Class A amp, you should test the transformer for the intended purpose.
Detailed information and an overview of all the complexities involved in building such an amplifier can be found at www.passdiy.com (check out the gallery section).
I believe there are some PCBs circulating on the forum. Ask around. (I wouldn't know).
Regards,
Milan |
Hi moamps,
I am not very experienced with DIY amps but of the amps I own, Hafler DH200, Hafler P230, Soundcraftsmen PCR800 & Soundcraftsmen S860, the S860 is the best sounding and the most powerful. It's supposed to be 240wpc @ 8ohms.
I mainly use these in my studio for reference. Sometimes they are played fairly loudly. I drive JBL 4425's, 4412" and Yamaha NS1000's.
Anyway, perhaps the amps I have are not as efficient as the Aleph amps. They are in excess of 100wpc.
May I assume that if I run this trannie at lower voltage that I would have greater VA?
I'm not sure I'm experienced enough yet to tackle the Aleph X. Seems like most folks are tweaking them as they go. I would be better off with a design that is proven I think. I know that I don't have enough understanding to start tweaking someone's design.
Blessings, Terry |
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| jacco vermeulen |
I am a bit surprised by the responses.
You may have noticed that transformers can get hot !
A 1000VA is designed for delivering that power for the rated voltage.
The core of the toroid has flux large enough to transform 1000VA.
Normal engineering means that primary and secondary windings are dimensioned in accordance with the voltage and power rating.
Meaning that the secondary windings are good for nearly 9 amps at 56 volts.
Derating the voltage by putting 110 volts on 230 volt primaries may lower the secondar output voltage, the secondary windings are still only good for 9 amps.
Reduce the input voltage by half, out comes half of the power, 500VA max !
And that does not make real sense, why buy a 1000VA transformer if you are going to use only half of that.
Transformer windings are isolated well enough for way beyond a thousand volts.
Putting 220 volts on 110 volt primaries is more realistic than the reverse strategy.
As the toroid is able to deliver 1000VA the output current is half of the design current for which the secondary cross sections are dimensioned.
56 Volts is good for at least 250 watts, place a small voltage transformer in series with the big one to feed the front stage of the amplifier and you are talking way beyond 300 watts.
Bridge the amps and you have a 500+ amp, strong enough to drive a serious subwoofer.
Overhere people have built 1000 watt amplifiers, plenty of designs available for those who feel the need.
If you decide to go for a smaller power amplifier, unwind the secondaries to whatever you need.
Put 110 on 220 primaries, extract a thousand watts and you might end up with an nice burning toroid by Christmas time ! |
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| AndrewT |
Hi,
Run your tranny at half volts if you want.
You cannot exceed the VA rating except for short term overloads.
With 1000va to play with, it will cover all except a large classA.
Are you able to confirm the current rating of all the windings?
It will give you more flexibility if you can series the 15vac onto the the high voltage. But if they are only low current then separately rectify & then stack on top of main output as a driver regulator feed.
regards Andrew T. |
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| still4given |
| quote: | Are you able to confirm the current rating of all the windings?
It will give you more flexibility if you can series the 15vac onto the the high voltage. But if they are only low current then separately rectify & then stack on top of main output as a driver regulator feed. |
Here's what it says in the add;
You are bidding on a new 1000VA toroidal transformer. It is precisely made for high-end power amp or equipment. It has very low power loss and magnetic leak. Labeled input 115 / 230 VAC 50/60 Hz (single coil with center tap), outputs 55VAC x 2 (dual coils), and 15VAC x 2 (dual coils)at 5A.
You would probably know if that meets the requirements better than me. What do you think?
Blessings, Terry |
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| moamps |
| quote: | Originally posted by still4given
I mainly use these in my studio for reference. Sometimes they are played fairly loudly. I drive JBL 4425's, 4412" and Yamaha NS1000's.
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Hi Terry,
If you wish to build a high-power amp for your recording studio, then the Leach Superamp might be just the thing. Pass amps work in Class A (which means that their efficiency is low), and they are intended mostly for home high-end setups.
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May I assume that if I run this trannie at lower voltage that I would have greater VA? |
Generally, no. In practice, you get 60-70 percent of nominal power.
Regards,
Milan |
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| moamps |
| quote: | Originally posted by jacco vermeulen
[B]I am a bit surprised by the responses. |
Likewise.
| quote: | | You may have noticed that transformers can get hot ! |
You may have also noticed that Terry was advised to TEST the transformer before trying anything, which in itself means that this is not meant as the optimal solution but just an option worth exploring. I have connected 380V primary voltage transformers to the 230V network with no overheating problems. In modern transformers, core overload is of much greater concern than coil current overload, in my experience.
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Reduce the input voltage by half, out comes half of the power, 500VA max ! |
This is true only in case of permanent resistive load. In case of amp power supply, it is possible to achieve greater power without any significant overheating (or similar) problems.| quote: |
Transformer windings are isolated well enough for way beyond a thousand volts.
Putting 220 volts on 110 volt primaries is more realistic than the reverse strategy. |
For want of a more polite way to phrase it, I'll just say this must be one of the dumbest and most dangerous suggestions I have read recently. Here are the test results for the transformer's different primary volatages:
Voltage Test Result:
TEST CONDITION: Apply variable voltage to primary coil (115V terminals) from 100-180VAC. No load on secondary coils.
1. Primary V = 100VAC, Primary I = .04A
2. Primary V = 110VAC, Primary I = .05A
3. Primary V = 120VAC, Primary I = .06A
4. Primary V = 130VAC, Primary I = .07A
5. Primary V = 140VAC, Primary I = .10A
6. Primary V = 150VAC, Primary I = .13A
7. Primary V = 160VAC, Primary I = .30A
8. Primary V = 170VAC, Primary I = .95A
As you can see, increases in the primary voltage result in a significant increase in the "no-load" current (the core is getting saturated). For the primary voltage of 230V, the expected current is over 1.5A, which translates into a "no-load" dissipation of about 350-400W and, consequently, leads to transformer core overheating and meltdown. So much for burning toroids for Christmas.
Regards,
Milan
P.S. Moderators, S.O.S. - newbie overboard :hot: |
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| richwalters |
[QUOTE]Originally posted by moamps
with this transformer (1000VA/2X56V) you can build a high power
However, if you set primary winding to 230V, you'll get half the secondary voltage, QUOTE]
Hi there
With a power toroid with good regulation factor and wound for Bmax at 1.7Teslas, for domestic apps you'll need primary inrush current limiting otherwise the line fuse will regulary Zap on switch-on....Murphies plug-in law......
rich |
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| jacco vermeulen |
Dear Milan,
NO transformer should be applied for a higher or lower voltage than it is intended for.
Applying 230 volts on 115 primaries will get you into trouble, it was mentioned for the arguement sake.
You might as well explain what the outcome will be for the transformer when your suggestion is applied.
It is quite common to unwind transformer secondaries instead of putting half the voltage on primary windings.
That way the primaries get the voltage originally intended for, and the secondary windings can handle the current that comes with it.
You may wish to advise transformer manufacturers to wire their transformers with half diameter secondaries, that should be good for quite a big cost reduction. |
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| jacco vermeulen |
Overhere, toroid transformer manufacturers advise to unwind secondaries.
Of course 115 volts can be put on 230 primaries, and it may even be possible to get 600 to 700VA out of it without any trouble for the core or the windings.
Follow manufacturer layout and stick to 500VA.
Overhere it is dead easy to find a new 500-600VA toroid on the web for les than $30.
Here MSRP for toroids are a lot higher than in the US, i can imagine finding one in the USA for less than $69 is certain.
If Terry wants to build a 600VA amplifier he would do better to sell the 1000VA to someone who needs it, buy a 600VA toroid and get a return from the money paid on Ebay.
I can also imagine that Terry can think of building a Nelson Pass amplifier himself, build a Pass amp seems to be the standard advise from not-newbees.
How i read Terry's question was that he bought a 1000VA toroid and is looking for a design to use a 1000VA toroid, not 500VA, 600 or 700VA.
Advising to operate a transformer at 70% of its capability with 115volts on 230 volt primaries and exceeding the secondary current rating by 60%, instead of looking for the right toroid is not sound advise. |
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| jacco vermeulen |
Suppose Terry would want to build a Pass amplifier, say the Aleph 4.
With a CLC powersupply the transformer would need 40Vac secondary windings.
Unwinding the secondaries from 56 to 40 volts would be a reduction of 28.6 % in voltage.
In accordance with the toroid design, with 28.6 % of the secondary winding taken off, the secondary current can be
18.3 % higher.
The rating for the 56volt secondaries would be 850VA, 150VA is for the 15 volt secondaries.
With 28.6% lower voltage and 18.3% higher current the 850VA reduces to 718VA.
That is more than the maximum expected rating for putting 115 volts on 230 volts primaries.
And, there is no need to exceed manufacturers guidelines.
In reality, the secondary windings are usually already dimensioned for the possibillity of unwinding to a lower secondary voltage.
At 56 volts the secondaries would be good for 7.59 amps for 850VA.
Unwinded to 40Vac the current in the toroid's secondaries for 700VA would be 8.75 amps.
With 28.6% of the secondary windings taken off, the load on the secondaries would be 5% lower than originally at 56 volts.
With 115 volts on 230volt primaries, secondary voltage would be 28Vac, the secondary windings current 12.5 amps at 700VA.
Compared to the 56 volt layout the load on the secondary windings is exceeding the load of the 850VA/56Volt appliance
by 171%. |
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| still4given |
First, I want to say how thankful I am that each of you have given your time to make suggestions here. I have already learned some more about the operation of a toroid.
I want to be in this DIY hobby for the long haul and I know I need to learn all of this stuff to really be successful at it.
I certainly do plan to build a Pass amp some day, but I don't really want to modify this particular toroid for that purpose.
As jacco suggested, I really am interested in an amp design that can make use to this transformer as is. If there isn't one around right now, I'll set it aside and wait until I can find one. I'm not nearly sharp enough right now to start unwinding this thing.
I already have two new E-I trannies in the 40-0-40 category that I bought for my Haflers and didn't need. I was really looking for an amp kit or design that could use this tranny.
It doesn't have to be for use in my studio. I also have a PA system that I could use it in. Maybe even a sub amp?
I was just hoping that someone knew of such an amp design.
Blessings, Terry |
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| jacco vermeulen |
Here is one you may like to take a peek at :
http://www.a-and-t-labs.com/K6_Sw_Amp
It uses the familiar irfp9240/240.
I am building Susan Parker's subwoofer with double 16" speakers.
When it is finished i am thinking of building this amp to power it.
With a regular powersupply of course.
Interesting about the design is its flexibility i think.
Have a really peacefull Christmas, Terry.
jacco. |
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| richwalters |
I've done it for 40 years and still alive.......with tubes
best luck...
rich| quote: | | I want to be in this DIY hobby for the long haul and I know I need to learn all of this stuff to really be successful at it. |
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| moamps |
| quote: | Originally posted by jacco vermeulen
NO transformer should be applied for a higher or lower voltage than it is intended for.Applying 230 volts on 115 primaries will get you into trouble, it was mentioned for the arguement sake. |
Actually, what you wrote was:
| quote: | | Transformer windings are isolated well enough for way beyond a thousand volts. Putting 220 volts on 110 volt primaries is more realistic than the reverse strategy. |
I'm glad that you now admit this "realistic" strategy will get people in trouble. Let me repeat it once again, for newbies' sake, connecting 220V to 110V primaries WILL get you in trouble, BURN the transformer and even DAMAGE YOUR HEALTH. The "reverse" strategy, on the other hand, works just fine in theory as well as in practice and has not hurt anyone so far.
| quote: | | It is quite common to unwind transformer secondaries instead of putting half the voltage on primary windings. |
Unwinding secondaries is not a highly recommended procedure for newbies. It takes a lot of patience, some additional tools and equipment and good knowledge of transformer design. In this particular case, I suspect it may be necessary to fully unwind 2x15V (and thus loose that voltage) before unwinding any part of the main secondary winding. Not to mention the hassle of putting back on the plastic isolation, which is well over any newbie's head.
| quote: | | You may wish to advise transformer manufacturers to wire their transformers with half diameter secondaries, that should be good for quite a big cost reduction. |
Manufacturers have to choose the most suitable wire diameter for a particular design. Their choice is dependent on the transformer's load schedule, operating temperature, mechanical and electromagnetic core characteristics, copper purity and so on. Thus, for example, there are transformers manufactured to work under constant nominal load as in halogen lamps. They usually have overdimensioned wire diameters but underdimensioned saturated cores because the core-parameter is of no particular importance for the operation of halogen lamps. On the other hand, there are transformers manufactured for "audio" purposes, which have underdimensioned wire diameters (because there is no constant nominal load) and overdimensioned cores that are never saturated in order to avoid THD and EMI-RF noise. It is quite rare to find toroidal transformers with overdimensioned wires and cores and an electrostatic shield between the primary and secondary windings. In fact, this is why I usually do advise local transformer manufacturers on how to wire transformers for me.
| quote: | | With a CLC powersupply the transformer would need 40Vac secondary windings. Unwinding the secondaries from 56 to 40 volts would be a reduction of 28.6 % in voltage. In accordance with the toroid design, with 28.6 % of the secondary winding taken off, the secondary current can be 18.3 % higher. |
Nominal current is determined by the wire diameter and vice versa, and in this case it is 7.6A. Nominal current has nothing to do with the number of secondary windings. I would really like to know how you came up with a current increase of 18 percent.
| quote: | | At 56 volts the secondaries would be good for 7.59 amps for 850VA. Unwinded to 40Vac the current in the toroid's secondaries for 700VA would be 8.75 amps. With 28.6% of the secondary windings taken off, the load on the secondaries would be 5% lower than originally at 56 volts. |
Again, I do not get your calculations. This is how they should be done:
For secondary voltage 40Vx2, nominal power is 80x7.6A=600VA.
For secondary voltage 28Vx2, nominal power is 56x7.6A=425VA.
P=k x Vsec.
It follows that the percentage nominal power reduction equals percentage nominal voltage reduction.
Speaking of Alephs, Aleph4 needs about 3A per channel. So, for 2 (stereo) channels this is 6A, which is below the transformer's nominal current of 7.6A. Obviously, in case of the Aleph4 the transformer will work WITHIN ITS CURRENT LIMITS and with NO overload risk. This goes for the Aleph 2 as well.
Terry, if you would like to use your transformer as is, consider the Leach Superamp, also known as the double barreled version at http://users.ece.gatech.edu/~mleach/superamp/ .
Regards,
Milan |
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| still4given |
That superamp looks like a good option. Are there still PCB's available? I printed out the pages on the link so I can study them.
Have folks successfully built the Superamp?
Thanks, Terry |
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| jacco vermeulen |
Joe had a spot of luck, from a newspaper add he bought himself a brandnew small block V8 Chevy crate engine.
As he wanted a car to put it in he went to the nearest car dealer.
The car salesman told him he had just what the engine needed: a top of the line 2 seater Pontiac sportscar.
The only thing he had to do was take 4 sparkplugs out of the engine and drop it in: the car's chassis could easilly handle the torque of the V8 but the power output was too much for it.
Joe asked the salesman how much torque he would get out of it with only 4 cylinders running.
No problem, the salesman said, with only 4 cylinders running the engine can be boosted to deliver more torque without any danger of overheating, i promise you !!
Anyway, you only need 3 cylinders to do 60 mph, 4 is more than enough, this engine is just the thing this car needs.
Another customer had been listening, he budged in and told them he had seen a brandnew Vette for sale, just around the corner, the owner told him it only needed a V8 to run.
Hold on, the salesman said : why didnt you say you wanted the engine with all 8 cylinders running !!!
Look here, i have this great Camaro for sale !
The car just came out of the factory, because it is not the latest model is has prooven itself over the years.
That engine is only a bit undersized but it slides in like butter, i promise you !! |
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| acenovelty |
Mornin Terry,
There are no PCB's for the SuperAmp available from Prof. Leach's web site. Got to make your own. Your power supply is going to put out about 75 V +/- which is OK for the amp, but you will not get 300W/channel with this value. According to Prof. L. you will need more than 90V to achieve this output. Bummer.
On the plus side, this is one sweet sounding amp. Working on making my 4th one as a gift for my son. Not really more difficult than making the low TIM Leach amp. Just more parts and bigger heat sinks. And 100V caps are not cheap.
Prosit :drink: |
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| jacco vermeulen |
Kristijan did a pcb design on the Leach amp, why not ask him.
In 2002 someone did an ExpressPCB design for the SuperLeach, you can find him with a search and email him.
BrianGT made one for TO247 devices, you may contact him on his GainClone page.
Otherwise JPG's of the PCB's made can be printed, ExpressPCB software downloaded, the file remodelled according to the JPG print and ordered from ExpressPCB.
Maybe someone is interested both in designing the PCB and getting in on a group buy, i am game for a couple of boards. |
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| still4given |
Hi Prosit,
Wow, 90V. :hot:
Mine should be around 77V if I did the math right. Good thing about it, is that I have a bunch of new 80V 15000uf caps that I would like to use for the PSU. 90V would be too high anyway.
I'd be surprized if I could hear the difference from the other 13V, but maybe. I guess I need to learn how to make a PCB sometime. Might as well be sooner than later, I suppose.
Hi jacco,
That was great! :D
I know, starting with the transformer is a little weird but we all need some sort of inspiration. :D
The funny thing is, when I asked about which amp to build for my first amp, (in another thread), the Leach amp was suggested. Somewhere along the line I ended up buying ESP boards, thinking they were for a Leach amp. :whazzat:
It wasn't until I started building it that I realized how mistaken I was. Oh well, the P101 is supposed to be a great sounding amp too. I should know in about a week when my heatsinks arrive.
Blessings, Terry |
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| djQUAN |
| quote: | | It wasn't until I started building it that I realized how mistaken I was. Oh well, the P101 is supposed to be a great sounding amp too. I should know in about a week when my heatsinks arrive. |
I've just completed my P101 about a week ago and I don't think you will be disappointed with the sound.:D |
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| jacco vermeulen |
Hi Terry,
i gathered that many designers start with the end of the amplifier and work forwards.
Starting with a transformer does not seem bad to me, you certainly found a nice one at Ebay.
But admitted :i like Chevy crate engines. |
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| acenovelty |
Terry,
80V caps are just a bit skinny for a 77V PS. Take a look at the surge rating. Can't be too careful. Caps make a loud noise when they blow. You don't get to see the magic smoke, just lots of white stuff all over everything.:bawling:
Prosit :drink: |
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| jacco vermeulen |
Overhere the minimal margin is 15% over Vdc, for 77 Vdc the caps need to be at least 90 Volt types.
The power company in Holland is allowed to have a margin of
+10 % on the nominal 230 Volt.
5 % is added for the increase in voltage of the transformer without a load.
That is the absolute bare minimum, taking in account that simultaneous power surge and zero load is unlikely and caps have a safety margin.
The data of your transformer states 63.5 Vdc at zero load, that is already nearly 90 Vdc.
If the voltage wandwidth of your local power company is 10 % too the minimum you will need for that transformer are 100 Volt capacitors.
Often enough power companies accidentally go beyond the 10 percent margin, so many would go for even higher than 100 Volt types. |
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| BobEllis |
| quote: | Originally posted by acenovelty
Terry,
80V caps are just a bit skinny for a 77V PS. Take a look at the surge rating. Can't be too careful. Caps make a loud noise when they blow. You don't get to see the magic smoke, just lots of white stuff all over everything.:bawling:
Prosit :drink: |
Not to mention that the smell of boiling capacitor juice doesn't go well with other holiday scents.
:clown:
Bob
/who got to watch hot electrolyte squirt all over his kitchen table/ |
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| fish4u |
| quote: | Originally posted by djQUAN
I've just completed my P101 about a week ago and I don't think you will be disappointed with the sound.:D |
pre can you rate it pls? better than leach?thanks.. |
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| still4given |
Ok. A word to the wise is sufficient.
I'll buy more caps. :xeye:
Hi djQUAN,
I think I read you had a bit of a hum problem. Did you get that figured out? I'd like to take advantage of what you've learned before I start putting this P101 together if I can.
Thanks, Terry |
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| moamps |
| quote: | Originally posted by still4given
[B]..Mine should be around 77V if I did the math right. Good thing about it, is that I have a bunch of new 80V 15000uf caps that I would like to use for the PSU...... |
Hi,
Capacitors for the Leach Superamp should be rated 100V. In the picture below are the capacitors I'm intending to use for my Superamp project.:cool:
Regards,
Milan |
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| Tensop |
| quick q: 2 transformers, with the primaries connected to each other in series will equal half the effective voltage across each transformer yes? but will derate each transformer to half the maximum loading on the primary side? eg, 2x 500va transformers in series will only be capable of safely delivering 500va? |
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| acenovelty |
Ummm,
I think the voltage remains the same, the current (A) doubles in this type connection. Please correct me if I am wrong, somebody,....anybody?
Prosit :scratch: :drink: |
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| jacco vermeulen |
| Jan Dupont-ACD still has the Leach clone on his site, probable that he can deliver PCB's. |
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| jacco vermeulen |
| quote: | Originally posted by moamps
below are the capacitors I'm intending to use for my Superamp project. |
| quote: | Originally posted by moaps
Normally, I would not see much point in building such a high-power amp for home use. |
? |
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| moamps |
To answer your ? - audio is both my profession and my hobby, which means that I do not build audio equipment for home use only.
Regards,
Milan |
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| still4given |
| quote: | Originally posted by jacco vermeulen
Jan Dupont-ACD still has the Leach clone on his site, probable that he can deliver PCB's. |
Maybe I'm not looking properly but I couldn't find any PCB's for the Leach on his sight.
Seems like most folks are making their own. Is there any good literature around on how best to make your own PCB's?
I sure wouldn't mind learning how to make them myself.
Thanks, Terry |
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| jacco vermeulen |
Terry,
you just missed this one by Per Anders on the Leach clone a few days ago :
http://www.diyaudio.com/forums/show...&threadid=46824
There is lots of info on PCB-making on PCB software company homepages.
Designing a good PCB takes a lot of practice, making a PCB is rather easy.
Companies like Seno, that produce stuff to make PCB and layouts publish books on PCB making.
Some PCB design programs are freeware, with added features PCB software starts at $30/$40.
These are good for designing simple circuitry on 6"x4" boards.
Just some names that spring to my mind right now :
Orcad(Cadence)
Ultiboard(EWB)
PowerPCB(Pads)
ExpressPCB(same)
Eagle(Cadsoft)
Sprint Layout(Abacom)
Layo1(Baas)- probably just in Dutch
Cadstar(Zuken)
PCBdesigner(Pads)
It is also possible to draw PCB layouts in Autocad or similar, but even the simplest PCB software works much faster.
It takes a lot of hardware to produce professional quality PCB's.
I make my own for audio purposes because professionally produced Teflon PCB's are very expensive.
if someone else did the PCB design and you are able to join a group buy you are far better off i think.
jacco. |
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| still4given |
Thanks jacco,
I have contacted Jens Rasmussen about the group buy. Those are big boards! :eek:
I'll have to do some more follow-up on it before I'm sure. I would like to find a project for this trannie and i like the idea of a big amp. :D
Blessings, Terry |
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| kilowattski |
| Before you go crazy, I would finish the Rod Elliot amp you are presently working on. This hobby can be expensive if you start many projects and finish none. |
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| still4given |
| quote: | Originally posted by kilowattski
Before you go crazy, I would finish the Rod Elliot amp you are presently working on. This hobby can be expensive if you start many projects and finish none. |
I know how that can go. I have only a couple of parts yet to get. They should arrive Monday. I also need to get some more aluminum for the chassis. I thought I had what I needed but couldn't find it. Today being New Year's day, none of the metal suppliers were open.:xeye:
Probably have to wait until Monday for those too. I should have it together by mid week. Really looking forward to hearing it. I will probably build a stereo P101 when it is done for the rear two channels. Depends on how much better it sounds than my Soundcraftsmen amps. Otherwise I'll just use one of the Soundcraftsmen amps for that.
I've also thought about using the bigger tranny to make a variable power supply by using it with my variac. We'll see. If I can find a good amp design to use it I'll probably still build it.
Blessings, Terry |
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| TVP |
hey ...
I'm a PCB designer and more than willing to help ... I was lurking here to find some ideas and more I look at it .. I think a generic chassis design would be of the greatest benefit to diyaudio ...
let me know
thanx
TVP |
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| kilowattski |
TVP,
I could not agree more. It seems that the electronics portion of a project is cake compared to the mechanical portion. I built a Zen IV amp and building the boards and wiring took all of about 8 hours but the chassis took about 3 months of Saturdays at a neighbors machine shop. Granted, some of the time was spent learning how to use a Bridgeport, but it still seemed to take forever. Below is a picture of the chassis. It sure would be nice to have a chassis I could purchase easily. Most of the chassis you can purchase are in Europe or the Far East. |
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| jacco vermeulen |
I doubt that you will ever buy a complete chassis of the same quality you built.
But you are right that it is a waste of energy if every DIY artist needs to go though the learning process of machining.
I grew up between machinery, a chassis like cowanrq built i would never do myself because of the time involved.
If offered at a reasonable pricetag and within reach i would certainly buy such chassis.
Ready built original Aleph style chassis like the one offered from Asia look non-DIY and can be made affordable, those i can imagine to be attractive for a great number of amp builders, in the US and the fossil continent.:clown: |
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| TVP |
hey all ....
sorry about the tangent topic , I can't start my own yet :(
I've been thinking about the chassis idea long before I started a amp design ... I've been doing this so long, I guess it's always how I've done it . I can ALWAYS make a PCB fit a chassis, going the other way around never seems to work :\ anyway ....
If you guys are interested ... PLEASE ... start a topic and lets get this going !!! I'd start my own if I could :( ... I'm going to do a rack ANYWAY .... so I'd like to get as many ideas into it QUICKLY !!!!
My idea is to have a chassis with a power supply area (below) and then cards that slide in (top)... heatsink on top of the card cage ... more of a power and heat management system ... but then it can be built as 200watts or 5000watts (multichannel of course) and you can change card/amps to play with ... side by side with ONE power supply system :) Common card layouts for audio in and out .. common power from the back of the cage ...
perf PCBs could be made for true experiments .... common amp designs for testing output devices ???? maybe make the power supply a card too ???? then one could be made for car stereo :)
lots of ideas in my head .... few on paper .... CAD work to start soon :)
let me know
thanx
TVP |
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| BobEllis |
TVP,
Welcome to the forum. Don't forget to check the "I've searched" box in the upper left hand corner of the new thread form. That's bittten me more than once. I don't remember if being under moderation prevents you from starting a thread or not.
Bob |
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| richwalters |
| quote: |
That's bittten me more than once.
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perspectives...I've often contributed bits which ended up in different threads...no intention, sometimes can't be helped when my line up here runs at 30Kbps!
rich |
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| still4given |
Hey guys, I'm almost ready to start putting this thing together. I've been bouncing back and forth between building the Low TIM and the Superamp. The Low TIM would require beefier transistors and more of them and even then, that design has not been tested. Frome what I can tell, several folks have built the Superamp, so that is probably my best option.
I have a question about the TO-3 transistors. Is it OK to use sockets like this or this?
Would I be better off with mica insulators?
I have both styles of transisors for this amp (TO-3 TO-247). I should have the Press-n-Peel sheets and copper clad boards by the end of the week and like to ready to start putting this together.
Thanks, Terry |
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| jacco vermeulen |
For audio purposes sockets are not the best choice.
Besides the thermal issue, with a high power amplifier cooling is an important factor, there is an audio signal going through the contacts.
Microphonics may change contact resistance of the sockets, and influence sound quality.
In time, contact resistance will deteriorate by corrosion and/or
smudge (look at the insides of a ten year old amplifier).
For proper amplifiers sockets are not used at any location, not for small signal devices or operational amplifiers.
If used, commonly the devices legs are soldered in the socket.
The easiest would be mica isolators, Mr Pass told me they are still the number 1 choice.
For TO3's you might consider AluminumOxide isolators, the same shape as the mica isolators, a white color and about 1/8 " thick.
I used them for a hybrid class A amplifier for Hitachi 50/135 Mosfet outputs.
Thermal resistance of AlOx isolators is a lot better than Mica, but a bit more expensive.
Though not strictly necessary some amplifier builders use them, a personal thing i guess.
Thermal grease you will need just the same.
My personal recommendation would be to use solder with a silver percentage.
Soldering with the stuff is great, it looks better and keeps the appearance.
In my view using silver solder minimises the risk of making a bad connection and sound quality is better.
After soldering i clean boards to take the solder resin remains off and put a cover of plastic spray on it. |
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| WorkingAtHome |
Sockets (for TO3s) help isolate the case from the heatsink where screws pass through. I understand and agree that soldered connections are better. I am actually planning on using sockets, but soldering the pins to the socket after the amp is tested and working.
-b |
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| AndrewT |
Hi,
AlO at .125inch is far too thick for effective thermal conduction.
It should be 50 to 100 times thinner.
Sockets in general will reduce the thermal performance of hi power devices. Avoid them if possible.
regards Andrew T. |
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| still4given |
Thanks guys,
I was afraid that the socket might reduce the heat transfer to the heatsink. I had better just stick to the mica pads and grease.
Thanks again,
Terry |
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| WorkingAtHome |
Could someone remind me of how the socket affects the heat transfer to the heatsink? The socket mounts on the opposite side of the heatsink from the device, so the device sits on isolator (pad or mica) the same with or without the socket.
What am I missing?
-b |
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| still4given |
I didn't realize that they were on the opposite side of the heatsink. That makes more sense. I guess the mica pads and grease are still necessary then.
On the Leach there are connections to the case as well. I suppose I would need some solder tabs for the bolts as well.
Thanks, Terry |
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| jacco vermeulen |
| quote: | Originally posted by WorkingAtHome
The socket mounts on the opposite side of the heatsink from the device |
As far as i got the information right torque distribution of the TO3 is more likely to be uneven if sockets are used, resulting in a higher thermal resistance between the TO3 and the heatsink.
The socket goes between the heatsink and the screw that pulls the bolt, and the TO3, to the heatsink.
A regular bolt and screw with an isolator pulls the device more evenly to the heatsink.
As regular habit became to integrate the TO3 connections on pcb's sockets were used more sparsely.
The major downside of sockets would be the unsoldered connection, and in case of the wires plugged in the socket double contacts in the signal way.
I noticed that on the Pass labs F1 large washers are mounted on the output devices, aimed at getting an even better torque distribution. |
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| jacco vermeulen |
| quote: | Originally posted by AndrewT
It should be 50 to 100 times thinner. |
Hi Andrew,
do thin Aluminum Oxide isolators exist?
I have never seen them thinner than the ones i have, i am told they need to be that thick for strength.
At the time i bought them they were 10 times more expensive then Mica, 10 times more difficult to obtain.
If unevenly torqued they tear, so mounting them takes much more care then with mica.
For TO3's mica was listed at 0.30 , Al-Oxide came a bit over 0.20
Cheers,
jacco. |
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| still4given |
OK I've got another question.
This is the transformer I have. It is rated at 55-0-55. When I do the math I get +-77VDC rails. I have a slew of 80V,15000uf, 105C, filter caps. Will these be OK with this transformer?
Thanks, Terry |
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| JensRasmussen |
Hello Terry
Regarding you caps, I think you should use 100V caps for a supply of 1.41*55 – 1.2 = 75V.
Generally you should never apply more than about 80% of the rated voltage to electrolytic capacitors.
\Jens |
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| still4given |
Hi Jens
I was afraid you were going to say that.:bawling:
:D
Aw, what's another $50 anyway?;) It's only money.:dead:
Blessings, Terry |
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| acenovelty |
WorkingAtHome,
"What am I missing?"
Seems you have trouble recognizing balderdash when you read it.
There are no downsides to sockets that are demonstrable.
I betcha if I remove the hubcaps from my wheels, that will get the backpressure off the lugbolts.
Prosit :drink: |
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| WorkingAtHome |
| Sorry, I meant Still4Given. Am i? |
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| acenovelty |
WorkingAtHome,
Hmmm, yup sarcasm is pretty easy to recognize. Pseudo-scientific explainations of Micro-somethings, thermal performance radials and torque adjustments just seem to slip by most folks though. The mil-spec isolators available over here in the local surplus store are just called "teflon" style. Turns out they are indeed teflon. Isn't that the stuff they put on cooking pans? And then there's the folks who swear by Kapton tape. A pin head of thermal grease will spread all the way up the wall if dropped on the floor.
The point of an "isolator" is to electrically isolate the the TO-3 from the heatsink and provide some assistance in transferring the heat from the transistor to the heatsink.
Seems like common sense isn't all that common..
Prosit :drink: |
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| still4given |
OK, ask a question and get five different answers from five different people. :D
This hobby is nuts. :D
The sockets and sil pads cost more than the transistors. :eek:
I can see why folks strip old amps for parts. :)
Hey I tried the PnP yesterday. It didn't stick to the whole board. How hot do you need to get this? I was afraid of overheating it. Good thing I bought 20 sheets. :D
Thanks, Terry |
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| jacco vermeulen |
| quote: | Originally posted by acenovelty
I betcha if I remove the hubcaps from my wheels, that will get the backpressure off the lugbolts. |
I just use the word "nonsense" instead.
A specialist in aerodynamics can tell you the difference of laminated flow and turbulent flow.
He can explain that using hubcaps on the wheels of your car reduces fuel consumption and may increase driveability.
Whether you regard it as "balderdash" is your choice.
Mica is a lot better than Silicon, by the way.
Mica is a great deal cheaper, less vulnerable, and gives better cooling.
To top it off Mica is used by the majority of the industry.
In my opinion a difference of 0.10 C/W for the connection between output device and heatsink is important.
With one output device the difference of a 0.30 C/W heatsink and a 0.40 C/W heatsink is significant.
You may calculate what the cummulative effect for multiple output devices will be yourself.
Silicon is used by folks who think it is all balderdash anyway, the best thing is to hold the thermal grease totally. |
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| jacco vermeulen |
Some regard the primary function of an isolator to be the transfer of heat.
That is what the connection between output device and heatsink is there for.
Some regard the negative thermal effect of isolator materials of such importance that they skip the isolator completely.
I can name at least 5 manufacturers who bolt the transistors straight on the heatsinks and accept having a potential on the heatsink because they find the thermal resistance of isolators having too great an influence on the thermal condition.
Quite a number of Class A people on the Pass forum use thick anodised heatsinks to get rid of the isolator, just ask Kilowattski.
Sockets and Silicon isolators were invented by the industry to save time, thus save money.
They were certainly not thought of to raise quality.
Anyone who has mounted a TO3 on a heatsink with a mica isolator, thermal grease and isolator rings, knows that it is filthy time consuming labor.
Using a silpad and a socket is much easier.
The major difference between low power and high power amplifiers often is the number of output devices, the Leach amplifier is a good example.
It is not the higher voltage that calls for the need of a higher number, often the same output devices are used.
It is not the higher current that depicts an array of transistors, often 2 transistor in parallel can handle 30 amps or more.
Take a look at the ZapPulse amps, huge power and low output device number.
THE major factor is heat dissipation, more power means higher heat dissipation.
Heat dissipation is completely controlled by total thermal resistance, the division between the number of output devices and the heatsink factor is influenced by the optimal amount of money spent and heatsink dimensions.
Putting few outputs on a very large heatsink is not economical and uses space.
Placing a very large number of outputs on a small heatsink may not be the cheapest solution either.
The required thermal condition can be obtained by an optimal number of output devices and type of heatsink,leading to the lowest amount of money spent.
The optimum is influenced by the ratio of the thermal resistance of transistor, isolator and heatsink.
For many the goals of DIY audio are:
1 saving money
2 obtaining the highest quality
3 enjoying to build yourself
4 doing it better.
Using silpads and sockets is more expensive and sacrifices quality for time saved.
Where is the diy advantage ?
The main reason for output transistor breakdown is overheating.
A major cause for overheated output devices is bad thermal connection between device and heatsink.
In many cases of a bad thermal connection the reasons were insufficient thermal grease and/or a bad torque division on the device leading to bad pressure distribution.
Spending time and interest on isolator issues leads to better thermal connection between output transistor and heatsink.
This in turn leads to an amplifier with a higher performance level.
Some may call that common sense. |
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| jacco vermeulen |
| quote: | Originally posted by acenovelty
The point of an "isolator" is to provide some assistance in transferring the heat from the transistor to the heatsink. |
Now that is what i call Balderdash and it is not even pseudo-scientific.
No one with any knowledge on thermo-dynamics would make such a statement.
Isolators do not only isolate potentials, they isolate heat.
Thus, thermally speaking, isolators are certainly not a helper, they are an obstruction.
The exact reason why the term used in thermo-dynamics is thermal resistance.
Air has a very high thermal resistance, so air is a very good thermal isolator.
Meaning, air does not provide any assistance in transferring heat at all, it is an obstruction for heat transfer. |
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| still4given |
OK, question. On my P101 I used Kapton tape and grease. Different type of transistors though. Will kapton tape work with TO-3 transistors? It's got to me less thermal insulating that mica or sil pads.
What do you think?
Thanks, Terry |
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| WorkingAtHome |
Wow. I had no idea *this* would be such a hot topic. Not like we are talking speaker wire (!) (me use zip cord, btw).
I am going to use silpads on the amp I'm building now, mainly because they won't kill my son if he gets into them (which he will). I figure the Leach is generally a conserv. amp. If I have a heat problem in testing, I can switch to grease/mica to see if it improves anything (you know, DIY style). Just need to shackle the kid for a bit.
As for the main purpose of isolators, it is to isolate electrically. That they isolate thermally is a drawback that is compensated with thermal grease. Not ideal, but it works.
So, other than the "torque" issue, what would be the drawback of sockets if I solder the TO3 pins to the socket (from the back side) after the amp is tested and working? If anything, the socket pins give a better solder point for my wires.
One more point, I would say that the number one cause of transistor failure (in DIY anyway) is not heat. It is accidental shorts.
Okay. everyone smile for a minute, then breath. Now let's build.
-b |
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| jacco vermeulen |
For me it is not such a hot issue, adding another connecting is so thats what i mentioned as the main thing.
When i started with amplifiers i used sockets too for, transistors and opamps.
Because they were available i thought it would be wise to spend money on them.
On top of that i thought it wise to use because it would be safer for the expensive devices, think of static sensitive op-amps.
Later i was told it was better to solder them in the socket for better contact, later still i learned that quality may suffer from any added connection.
So, less is actually more.
I too used silicon isolators, thinking it was better and cleaner.
At the time i had to travel 150 miles to buy the stuff by the sheet in Germany, and it came expensive.
Thermal grease is awfull stuff, i never learned how to handle it and not smear it all over everything and me.
Mr Pass wrote on the F1 thread that he is covered too at the end of the day when he has been building his amplifiers.
I dont think using silicon sheets or silpads instead of mica is a major crime if you are not fighting for every watt, like with class A amplifiers.
Not using thermal grease is not a good choice, not so long ago i checked with Nelson Pass and others, he stated that thermal paste is still the best to use.
Of course bad thermal connection is not the number 1 amp killer but it is a reason for amplifier failure quite often, you can check with professional amplifier technicians on the web.
I agree too that the discussions on cables is a heap of hogwash, i un-subscribed from the thread here because of it.
Terry stated that he would like to learn and he wants to do it right.
In my view his choice of spending money on Kapton and thermal grease on his amplifier from Mr Elliot is money spent wiser than spending it on sockets.
Kapton can be bought on a role or ready made to size for any device, also in TO3 shape.
The Leach Superamp is a big one, it delivers next to 300 watts in 8 Ohms, more than 500 in 4 Ohms, with an adequate powersupply it could be near to 750 watts in 2 Ohms.
It needs adequate cooling ability even if it is class AB.
If you do a thermal calculation and add up the costs you may conclude that money spent on low thermal isolators is good economy, not humpty-dumpty science.
Even Kapton is relatively cheap compared to the thermal costs of high power transistors and heat sinks.
I'd say if sockets are already paid for and are essential for getting a son enthousiastic for building amplifiers then thats the ticket.
My friend and audio tutor worked in the electronics field all his active life, back then he told me that a lot of trouble originates from bad connections, he gave me the advice to solder the legs.
I am still very gratefull to have had someone then who gave me such a lot of professional insight when i knew next to nothing and solid information was hard to come by.
If you make sure the soldered connections are good, an added contact may be relative.
I prefer class A amplifiers, the number of devices i burnt because of failing isolation at biasing time i dread to mention.
Good isolation is very important, i do not have the guts to put them on heatsinks isolated and trust that the anodising layer will do the job.
I use industrial silver stranded coaxial cables as speakerwire,
1/2 an inch thick, bi-wired.
Cheap, and saves me the headache of esoteric talk. I'd rather listen to music instead. |
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| AndrewT |
Hi,
I thought the sockets were in contact with the TO3, but I may be wrong. Someone else said they are on the other side of the heatsink. Can an expert confirm where the TO3 sockets are located?
If the sockets are between the TO3 and the heatsink then I recommend you omit them and use conventional thermal jointing.
Still4given, what thickness Kapton did you use? 0.001 inch(1 thou) is good, 0.006 inch is not so good but ok. Both are better with thermal grease to each contact face.
regards Andrew T. |
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| WorkingAtHome |
Hi jacco-
I agree with everything you just said.
My comment about my son: he is 22months old. Everything goes in his mouth. I found him playing with one of my old t220 heatsinks a few weeks ago - luckily the paste was on the inside, and he hadn't (yet) touched it. It's hard to keep him out of thw workshop, so it's silpads for the near term. Also, I am experimenting a bit with the heatsinks, and it would be much easier to move the TO3s around if I wasn;t always playing with the grease.
Perhaps I will ditch the sockets after I get everything working well. Who knows. I can never leave well-enough alone. ("But if a just tweak that one little thing..." bang!).
Maybe I will have my brother machine some Al covers to go over my TO3's (with grease) to act as both an additional heatsink as well as a strong flange for machine screws. Hmm...
There must be something like that out there..
-b |
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| jacco vermeulen |
TO3's have two legs, and 1 connection to the casing.
As they are mounted on a heatsink, both legs need to go through the heatsink plus two bolts to tighten the TO3 to the heatsink.
Without a socket you will need to isolate both the bolts and the two legs with isolating washers/nipples with varying diameter.
TO3 is something like 0.160 " for the bolt holes , TO3 legs
are 0.063 " thick.
The socket combines all washers/nipples on one plate and is mounted from the other side of the heatsink.
The sockets come in two models ; with or without soldering extensions.
The first mentioned can be thin, the latter has up to 0.2 " thickness.
If you want the experts and a view on a socket, take a look :
www.fischerelectronics.de
For a story on different cooling material, their merits and downsides, and some info on un-even pressure effects read the man himself : Rod Elliot.
He had a tech article on his ESP site about transistor mounting.
Those that like to see a TO3 AluminiumOxide(Al2O3) isolator have a peak at the pic below.
If anyone desires to know what i used them for, and how much heat you would be looking at, he can always ask me. |
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| jacco vermeulen |
He should have a talk with my kid.
Rafael loved to hit the Vifa domes on my DIY speakers as a baby, daddy was sweating with a needle to get the dome shape back out the speaker again every time.
I had to store the dynamic speakers, the Quad ESL's, and my amps for over two years in my hobby room.
I can show you a pic of the class A headphone amp i had to suffer with all that time.
Rafael is 7 now, 3 weeks ago he ran off with a plastic bag containing 100 IRF's. Daddy had a near heart attach again.
:clown:
On the TO3's, there are bolt-on heatsinks for them, undoubtebly Fischer has pics of them on their site.
Musical Fidelity used them on their B200 power amplifier, a derivitive of the A1 integrated.
That one had a bunch of 2N3055 output devices with only a heatsink mounted on top of them, something like a dozen per channel.
Think they are called finger-coolers, with two small holes for the bolts holding the TO3 , and a large one in the middle for the TO3 body to go through. |
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| acenovelty |
Oh please, if you must quote me, at least keep all the quote and in context.
"The point of an "isolator" is to electrically isolate the the TO-3 from the heatsink and provide some assistance in transferring the heat from the transistor to the heatsink. "
Go ahead and solder the wires to the sockets if you must. Then when it is necessary to remove a socket soldered transistor, tell us how much fun it was to desolder your fine work.
Yes the Superamp puts out lots of power and a good electrical connection is required.
Maybe I'll consider soldering the wires to the battery in my car instead of using a connector.
Manufacturers commonly use as few parts as possible to reduce build cost and improve profit. If there is any benefit to you or the amp is debateable. My goodness, what a firestorm.
Prosit |
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| wwood |
Terry,
I use the PnP material with a slightly modified "pouch Laminator". Really slick. Just run the board with the PnP on it thru the laminator and out comes perfectly applied PnP. Resolution is great and works as well as photo processing for me. The laminator is about $130 at office supply stores.
Visit www.pulsar.gs for details on how to do this. Pulsar also sells another material system similar to PnP, but I find that PnP is easier to use and works as well or better. With the laminator it works every time (including the very first time I tried it) and is VERY easy.
Bill |
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| WorkingAtHome |
I haven't used the PnP, so keep that in mind reading this post:
If you are using an clothing iron, you don;t really have to worry about too much heat on the PCB, unless you leave it on there for a LONG time. The iron won't get over 500F (likely not even that hot - doesn;t melt solder I don't think. If it does, maybe I can use one for tinning my boards!) PCSs can take a fair amount of heat in the 800F+ range.
An interesting test would be to put a full-heat iron on a scrap board and see just how long it will take the heat. I'd sure be interesting for when I try the PnP.
-b |
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| still4given |
| quote: | Originally posted by AndrewT
Hi,
I thought the sockets were in contact with the TO3, but I may be wrong. Someone else said they are on the other side of the heatsink. Can an expert confirm where the TO3 sockets are located?
If the sockets are between the TO3 and the heatsink then I recommend you omit them and use conventional thermal jointing.
Still4given, what thickness Kapton did you use? 0.001 inch(1 thou) is good, 0.006 inch is not so good but ok. Both are better with thermal grease to each contact face.
regards Andrew T. |
Hi Andrew,
The Kapton is described as "1 Metre x 25mm x 25um Kapton Tape ". That's what I bought. I should have plenty to make pads for all of the TO-3's on this amp.
Blessings, Terry |
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| jacco vermeulen |
| quote: | Originally posted by wwood
The laminator is about $130 at office supply stores. |
I am told it is offered on Ebay sometimes for far less. |
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| wwood |
I got my laminator on sale at Staples office supplies for $99.
Bill |
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| still4given |
I'm not sure what those last two posts have to do with this. :xeye:
Well I made the PCBs. I used the Press-n-Peel sheets. I made a few mistakes. I'll share for those who are thinking of doing this.
First, I cut the boards to the exact size before I ironed on the sheets. This particualar design has traces running right along the sides. I found it really hard to get the trace to stick to the edge like that. I will trim the board to size after I etch it next time.
Second, I didn't get the iron hot enough the first time and so a lot of traces didn't stick. I had to scrub it off redo it with a new sheet.
On the second go around, most all of the traces stuck but there were a few that didn't. I went to Radio Shack and bought a trace pen and filled in the bare spots. That worke fine. The etchant didn't penetrate it.
Then, I didn't read enough about using the Ferric Chloride. I didn't realize it should be heated and that it needed to be agitated. After about 20 minutes I decided I had better look it up. So, I put a flood lamp over it and began rocking the glass tray I was using and finally began to see results.
Here are some pictures of the finished boards. Well, finished being etched. Obviously I still have a lot to do. :D
Blessings, Terry |
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| WorkingAtHome |
Congrats Terry. They look great. Drilling is the fun part...
The two posts you mentioned were related. it's possible to get a laminating machine (used for badges and cars and such) and make an adjustment to the rollers to allow you to pass circuit boards through it with the press and peal. Gives nice even heat and a lot of pressure. $9 isn;t a bad price if you're gonna make a lot of boards (or laminate stuff I guess - would keep the cat from shedding as much).
-b |
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| acenovelty |
Very cool Terry. The boards look real good. Now the fun part drillin and solderin.
Prosit |
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| still4given |
Oops, I missed wwood's first post.
That does look like a pretty cool way of doing it. I'll have to keep that in mind. I'm not sure I will be making enough PCBs to justify it, but I love tools. :D
Thanks for the tip.
Now I have to find some really small drill bits. Any sources?
Thanks, Terry |
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| jacco vermeulen |
First time i tried the P-n-P thing a long time ago it took me multiple attempts to end up with a board that does not even come close to yours. I find it hard to get an even pressure on the foil with a roller.
Means : you are very handy and i am not, or P-n-P has come a long way since TEC foil.
I am hoping for the latter.
I should be building instead of talking :clown:
The flaws on the boards i made with press-on foil i corrected by putting a thick layer of tin over the copper after the drilling.
Its sold in bottles, the pcb in a tray and the stuff just poored over it.
Nice job, Terry |
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| still4given |
Hi Jacco,
Thanks for the support!
I'm not sure we are talking about the same process. This this is not a "press on foil" application. With this system you simply print the pattern onto the blue sheet and when you iron it on to the solid copper clad board only the portion that is printed sticks. I suppose the toner from a laser jet printer has some etchant resistant properties. I know that it is heat sensitive because that's how it is applied to the paper in the first place. At any rate, the etchant doesn't penetrate it so when you dip it, the etching solutions eats away every thing else. It took over a half an hour for the the etching process. Probably because I didn't heat the solution and because I didn't agitate it until about half way through.
Like I said, I had to touch up the image a little before I dipped it because it didn't stick everywhere. Not too much trouble with the little pen I bought from Radio Shack.
I'm looking forward to drilling and adding the componants.
Blessings, Terry |
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| wwood |
Terry,
Another source for drill bits is www.drillbitcity.com. They sell re-sharpened carbide drills in sets that have a useful selection of sizes. The prices are reasonable and the service very good.
Jacco,
PnP has changed quite a bit, actually it is PnP Blue that is special. The original was just a toner transfer system. Now, the toner is used to adhere to the board and to another film is on top of the toner. The result is equivalent to first transfering toner and then putting another layer on top of the toner. The second layer is the key. It seals the toner surface so you get pin hole free resist. The top layer is quite rugged. Resolution is excellent and Terry's results are typical. Using PnP Blue and a laminator is the best approach that I have ever used. Like some one else posted, I have been making boards for a lot of years .... going back to coating boards with liquid resist.
The Pulsar web site gives an interesting etching technique .... soak a sponge with ferric chloride and rub the etchant on the board. They claim very rapid etching. Have not tried it, but it does look interesting.
Pulsar also shows a way to use the toner transfer system with a white film on top to create an equivalent silk screen effect. It works. Best part about the Pulsar stuff is that it is available from DigiKey.
Sorry if this is too off topic,
Bill |
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| wwood |
Hi WorkingAtHome,
Looks like nice stuff! What do you use for a drill press?
Bill |
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| jacco vermeulen |
Overhere a set of drills like on the picture is sold for around $10 on the web.
I checked each one with a magnifiying glass first time i bought a set, the tips looked as good as new.
I use them on a dremel style drilling machine in a stand on a powersupply with speed control, i am almost enjoying to drill holes.
Ooff, the relief.
TEC was just a transparent going through a laser printer.
First the foil had to be ironned on the board, then pressed on with a foam roller.
At the time i cursed my head off each time i tried to remove the foil from the pcb (so to speak). :clown:
Thanks, Bill. |
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| WorkingAtHome |
I picked one of these up about a year ago for just over $100 on sale:
http://www.delta-tools.net/delshopdp8de.html
Good for 99% of the wood and metal working I do. My little brother has an old Wilton floor press that I maight swap it for (needs a little TLC).
Just bought the vice. $65 with shipping. They have a smaller version as well for about $12 less.
-b |
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| jacco vermeulen |
Whats the maximum speed on that drill press ?
I have a floor stand one in my garage the size of Gibraltar, originally from my dads plant.
I spent months behind it from the age of 8, drilling holes in production tools my dad developed.
I have drilled up to 2 inch diameter holes with it in solid steel.
At one time it took 4 square inches of skin off my right hand.
A 10.000 rpm table model delivers very clean holes in pcb's.
A board like Terry's Super Leach would take me half an hour in my hobby room.
How much time would such a board take on a drill press as shown ? |
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| still4given |
Hey Working,
You're not off topic. This thread is about building an amp based on the Transformer that I already owned. Making the PCBs is all part of it. The only shame is that someone who needs to know this stuff may not see it because it isn't part of the thread title.
Hi wwood,
I was ordering the bits while you were posting the link. I probably would have ordered them from there instead. The ones from oselectronics.com look good enough but they charge $8 shipping. Man, I think I've already paid for one of those big brown vans that UPS drives.
I ordered one of those etching tanks while I was there. Now I have to make more. :D
Blessings, Terry |
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| WorkingAtHome |
Not sure of the top speed, I'll check tonight. If I need to I can always swap out the pulleys to speed it up (I have this little 2-inch pully from my table saw motor that should do it).
Also, the only circuit board I have made since I got the drill press measured 2x3cm (12VDC -> 5V 2A car power supply for my MP3 player). That took about 1 minute, but isn;t really representative. Cut it with an Exacto knife.
-b |
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| wwood |
Jacco,
The problem with modifying a "good" floor standing drill press such as you describe or the Delta's to run at 10,000 rpm is that their bearings are not designed to run at the high rpm. When the bearings wear, the quill begins to wobble and eventually you drill ellipses :bigeyes: I know, my floor standing drill press is an example.
For drilling circuit boards I now use a small hobby drill press by Proxxon. Runs at 8000 rpm. Works nicely.
Bill |
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