tubelab.com said:
My Gal an I hit a lot of estate sales, Which are also becoming equally Ebay aware to the point of being obscene.
They Look up completed listings based on highest completed price, Then print it out and tape it to the items for sale. And expect to get Rare Mint condition prices for used, and often DOA JUNK!
At public auctions locally, We only encounter 1 company who's ring man try's to motivate bids bragging " Come On Folks, These are 250.00 on Ebay, Who will start the bid at $200.00.
I shout out " This isn't EBAY, and I bid 5 bucks! " 3 Times I have nearly butted heads with that guy LOL he cringes when I arrive now, Knowing that he is going to be low balled, And if nobody else bids well, That's auctions!
That's were I get a lot of Consoles and organs, Out here at public estate auctions, They can hardly give them away because "A" nobody wants them, & " B " NOBODY wants to haul them or move them.
I have been known to drive 400 miles 1 way for Tubes though, That's how I ended up with 12,000 tubes for under 300 bucks.
Like you said, Drive well off the beaten path and prices drop exponentially with mileage.
There are a lot of old Mom N Pop TV shops out there, Closed, Hidden in storage buildings, Basement and the likes. My Gal is nearly an expert at locating them now.
Gene
This is why I came back here. I'm among buddies, brothers and favorite cousins.
About 2 years ago I started dodging forums. Because of politics and the tantrums I would pitch. With a belly full of razor blades. I was, and am not, a happy boy. It is good that the political topic is dropped. Maybe I'll push it a little and say that Democrats are my 2nd favorite political target.
I checked back through the Sinbin. Thank you all for me not being there. I am a standard issue hippie and not supposed to scrap but I've been swarmed upon and toted out of my home saloon, several times, because of drawing a bead on bigshot's nose... because of politics.
Read The Bible, Voltaire and his stepson Twain. It's always been this way.
Glad to be back.
I know this is a nonlinear spot to say this, but linearity is an abstract concept, you understand.
About 2 years ago I started dodging forums. Because of politics and the tantrums I would pitch. With a belly full of razor blades. I was, and am not, a happy boy. It is good that the political topic is dropped. Maybe I'll push it a little and say that Democrats are my 2nd favorite political target.
I checked back through the Sinbin. Thank you all for me not being there. I am a standard issue hippie and not supposed to scrap but I've been swarmed upon and toted out of my home saloon, several times, because of drawing a bead on bigshot's nose... because of politics.
Read The Bible, Voltaire and his stepson Twain. It's always been this way.
Glad to be back.
I know this is a nonlinear spot to say this, but linearity is an abstract concept, you understand.
Wow dude,
If you're not happy... figure out why. Then do something about it. Don't think about it... don't discuss it... do something... life's too short
The more I learn... the less I know. There's a beauty in that... embrace it.
As far as politics are concerned... leave it to the poilticians... what do you have to gain or lose?
I thought this was about audio.
If you're not happy... figure out why. Then do something about it. Don't think about it... don't discuss it... do something... life's too short
The more I learn... the less I know. There's a beauty in that... embrace it.
As far as politics are concerned... leave it to the poilticians... what do you have to gain or lose?
I thought this was about audio.
Wow, now this threads really gone a stray
Back to my transformers, haha actually more of a a build question, I know this might seems like a silly question, But, In selecting caps for the build that's underway right now. I am curious. Does the uf rating on the cap lower available voltages as it is increased.
Say the schematic says 2x16uf/450V in parallel and 2 more 16uf/450's.
Is using 1-40uf/450V to replace the first 2- 16's that are in parallel taboo? Now, If I use all 40uf/450V's to replace the other 16's will this reduce voltage or mess anything up??
schematic
Gene
Back to my transformers, haha actually more of a a build question, I know this might seems like a silly question, But, In selecting caps for the build that's underway right now. I am curious. Does the uf rating on the cap lower available voltages as it is increased.
Say the schematic says 2x16uf/450V in parallel and 2 more 16uf/450's.
Is using 1-40uf/450V to replace the first 2- 16's that are in parallel taboo? Now, If I use all 40uf/450V's to replace the other 16's will this reduce voltage or mess anything up??
schematic
Gene
Oh Hey SHHHHHHHHHHHHHHHHHH be verwe verwe qwuiet nobody say "powitical"
An externally hosted image should be here but it was not working when we last tested it.
The 5U4GB data sheet says 40 muF. is OK up to 900 VRMS end to end on the rectifier winding. You should be fine, but don't use a larger value.
5U4GB Data Sheet
With the max. allowable 40 muF. in the 1st position, I'm concerned that the resistor does not provide enough protection for the 5U4 against turn on surges. If that resistor is replaced by a choke (1.5 H. is adequate) you can do pretty much what you like in the 2nd and subsequent postitions.
Increased PSU capacitance yields a stiffer B+ rail. If you like the sound of B+ droop in a guitar amp, extra capacitance may not "float your boat".
Eli Duttman said:
Understood, I noticed on this particular schematic Vs many others by fender in that era, They increased that 1st resistor from 5K to 10K, The units following this one had chokes. I guess its a trade off kind of affair on droop / cap thing, more droop, less sustain?
I am running a 5E3 Deluxe that has 3X40 uf with the 5K 1st resistor right now, Not saying it will not mess up, But no problems thus far.
I have really been pouring the coals to this build, I started this morning with a blank chassis, And I am 40% wired! Would be further but my gal insisted I go Xmas shopping a few hours
Gene
Trout said:
Sorry, a brief moment. I just came in, overcome with our buddy "Bill" who is convinced that he is going to hell because he killed a little kid. Even though the boy and his 12 or 13 year old friend shot Bill's friend dead and messed up Bill, to be put back together with titanium.
It's too much. Bill was drunk and hollering. We had no rope to tie him up with. And nothing to glue his *** to the floor, like Spanky would have done. You tell me. All we could do was give him his car keys back and pray that he didn't show up in the news.
Let the damned thread go astray. Let me go to Texas.
I'm not a lightweight, I've been on the wrong end of the pistol a couple of times and I walked up and took one away from a waterhead who did not understand that when my sister says, "it ain't working", she means exactly that.
Out of here again. Another couple of years. Too emotional, I just cannot maintain some comfy illusion. With what's going on, I'm not digital-ready. See ya.
PSUD2
@Trout
If you haven't dowloaded Duncan's Power Supply Designer (PSUD2) yet, give it a try. It's a great help with designing power supplys and in choosing pwr trannys.
www.duncanamps.com/psud2/index.html
Wayne
@Trout
If you haven't dowloaded Duncan's Power Supply Designer (PSUD2) yet, give it a try. It's a great help with designing power supplys and in choosing pwr trannys.
www.duncanamps.com/psud2/index.html
Wayne
Output transformer redesign help
I have the duncan amps program; it's really cool. But, I would like to shift the conversation to the subject of an amp's output transformers. Specifically the subject of re-design, and transformer quality.
As far as transformer re-winding is concerned, I am confident that I could do it, (especially w/the magnetics design handbook availible on The Texas Insturments webpage) because I am already experienced in AC Motor re-winding and redesign. But all of my knowledge is industrial; I'm wondering what makes an output transformer "high end". What makes tranformer quality go beyond the formula "Turns in primary/Turns in secondary=V primary/V secondary"?
I don't have any projects on the agenda, but I was considering building my own amp sometime soon; and I was thinking that I would transplant and redesign the transformers from my current amp; if the cost should end up being less vs. the cost of brand new transformers.
So, what makes a transformer "high-end"?
I have the duncan amps program; it's really cool. But, I would like to shift the conversation to the subject of an amp's output transformers. Specifically the subject of re-design, and transformer quality.
As far as transformer re-winding is concerned, I am confident that I could do it, (especially w/the magnetics design handbook availible on The Texas Insturments webpage) because I am already experienced in AC Motor re-winding and redesign. But all of my knowledge is industrial; I'm wondering what makes an output transformer "high end". What makes tranformer quality go beyond the formula "Turns in primary/Turns in secondary=V primary/V secondary"?
I don't have any projects on the agenda, but I was considering building my own amp sometime soon; and I was thinking that I would transplant and redesign the transformers from my current amp; if the cost should end up being less vs. the cost of brand new transformers.
So, what makes a transformer "high-end"?
Sir Trefor,
Do you have access to the Radiotron Designers' Handbook 4th ed.?
The chapters there are somewhat dated as some of the magnetic materials have changed (pretty much the same for audio though), but otherwise the methods are sound.
Material choices aside;
You extend the bottom range of a transformer by increasing inductance... more turns and therfore more iron
You extend the high frequency performance by interleaving the primaries & secondaries... your goal there is to minimize the leakage inductance.
Interleaving the windings increases the capacitive coupling between the primary & secondary... so a comprimise is in order.
Capacitive coupling may or may not be an issue in an OPT... depends. Shields can be placed between the layers to reduce coupling but this adds capacitance to ground and consumes space in the bobbin that you would like to fill with copper.
All of these things lead to a bigger transformer... hence, why the better ones are usually bigger. You could certainly improve the performance of transformer by rewinding it... in the end you will have to settle for less power though.
I am sure someone here knows of link to the Radiotron book. I know it can be purchased in electronic format. It will have an angle that the TI site night not... TI is pprobably all about switching power supply stuff??
Do you have access to the Radiotron Designers' Handbook 4th ed.?
The chapters there are somewhat dated as some of the magnetic materials have changed (pretty much the same for audio though), but otherwise the methods are sound.
Material choices aside;
You extend the bottom range of a transformer by increasing inductance... more turns and therfore more iron
You extend the high frequency performance by interleaving the primaries & secondaries... your goal there is to minimize the leakage inductance.
Interleaving the windings increases the capacitive coupling between the primary & secondary... so a comprimise is in order.
Capacitive coupling may or may not be an issue in an OPT... depends. Shields can be placed between the layers to reduce coupling but this adds capacitance to ground and consumes space in the bobbin that you would like to fill with copper.
All of these things lead to a bigger transformer... hence, why the better ones are usually bigger. You could certainly improve the performance of transformer by rewinding it... in the end you will have to settle for less power though.
I am sure someone here knows of link to the Radiotron book. I know it can be purchased in electronic format. It will have an angle that the TI site night not... TI is pprobably all about switching power supply stuff??
poobah said:
That's why the TI page is valuable; it has all of the magnetic core information needed to know when re-designing a transformer. Even though you can re-design a trasformer to whatever spec you like, the iron needs to be there; so there is a limit to what you can do with a transformer of a certain size. I imagine you can over-saturate the iron with too many lines of flux just like you can an AC motor core.
Sounds interesting... I'll google it, and check on eBay.poobah said:
I would let some other people reply first. The Radiotron Designer's Handbook 4th ed. is a classic book though... considered a bible many tube nutz. There is all kinds of stuff in it... not just transformers... tubes, math, radio, audio.
I picked up a real one on Ebay for $40 US. I think I saw electronic ones for r$20.
There are certainly more books on just transformer design... see what other say too. Some will say EVERY tube nut should have RDH4.
Remember though, if you rewind for better quality, you lose power... nothing is free! Except advice on DYIAudio.
Cheers,
I picked up a real one on Ebay for $40 US. I think I saw electronic ones for r$20.
There are certainly more books on just transformer design... see what other say too. Some will say EVERY tube nut should have RDH4.
Remember though, if you rewind for better quality, you lose power... nothing is free! Except advice on DYIAudio.
Cheers,
Sir Trefor
On Ebay,
http://cgi.ebay.com/Radiotron-Desig...goryZ378QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
$6
I sure this guy has lot's of copies... might be hard to read and use the charts though... you should ask for some sample pages
Ask for page 219 Fig. 5.13H
Some on Amazon too... $30 and up... make sure you get 4th edition.
Later
On Ebay,
http://cgi.ebay.com/Radiotron-Desig...goryZ378QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
$6
I sure this guy has lot's of copies... might be hard to read and use the charts though... you should ask for some sample pages
Ask for page 219 Fig. 5.13H
Some on Amazon too... $30 and up... make sure you get 4th edition.
Later
If you go to the web site of forum member "GEEK" the entire RDH4 manual is available for download. The link is in the upper right hand corner of the page. There is loads of information in that book, however the book was written for engineers. Some of it is pretty technical.
http://geek.scorpiorising.ca/
Basically if re-designing an OPT, you are trying to minimize parasitic losses, and extend the frequency response. Loss is reduced by using a better grade laminations, and wire. A really high end transformer will use silver wire to reduce resistive losses. Frequency response is improved on the low end by increasing the primary inductance. It is improved on the high end by reducing unwanted capacitance, and leakage inductance. However these terms tend to be mutually exclusive, so every transformer is always a compromize. Be prepared to experiment a few times to get a good sounding transformer. From my experience, a push - pull transformer is easier than a single ended transformer, and the "success window" gets smaller as the power level goes up.
My attempts at a 100 watt SE transformer proved disastrous, so I had one built by a transformer winder who makes excellent 10 watt SE transformers. It was far better than mine, but not good enough for HiFi. It will make a serious guitar amp though.
One more observation. I tried using Kapton tape for the insulation between windings. It killed the high frequency response. The dielectric constant of Kapton is much higher than paper, which makes the distributed capacitance go way up.
http://geek.scorpiorising.ca/
Basically if re-designing an OPT, you are trying to minimize parasitic losses, and extend the frequency response. Loss is reduced by using a better grade laminations, and wire. A really high end transformer will use silver wire to reduce resistive losses. Frequency response is improved on the low end by increasing the primary inductance. It is improved on the high end by reducing unwanted capacitance, and leakage inductance. However these terms tend to be mutually exclusive, so every transformer is always a compromize. Be prepared to experiment a few times to get a good sounding transformer. From my experience, a push - pull transformer is easier than a single ended transformer, and the "success window" gets smaller as the power level goes up.
My attempts at a 100 watt SE transformer proved disastrous, so I had one built by a transformer winder who makes excellent 10 watt SE transformers. It was far better than mine, but not good enough for HiFi. It will make a serious guitar amp though.
One more observation. I tried using Kapton tape for the insulation between windings. It killed the high frequency response. The dielectric constant of Kapton is much higher than paper, which makes the distributed capacitance go way up.
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