Transistor claims? is it real or is it "snake oil"? - Page 1
Forum section: electronics / projects

author: mw2000
author_rank: Newbie
timestamp: June 29, 2019, 10:49:04 pm
content: Hi everyone!I hope my question about a transistor is in the right place.This is about something called a "Max-Mod" and the regular "TIP36" regulator transistor that comes in radios when they are new.This is my first post and I am hoping that I can "ask some experts" about this thing that several radio shop is trying to sell me as an add-on to a radio I want.I got into electronics a year ago and I have been reading a lot of posts here and the information is overwhelming!I have one more year of high school and I am really considering electronics as the direction I go in.Dave's videos on choosing equipment to buy and how to set it up have been really helpful to me while I shop.I also like to talk on CB radio and I was looking at getting a newer radio like a Stryker SR-955.I keep reading and hearing from other CBers that these radios need new regulator transistors like a Max-Mod or they will overheat.This Max-Mod transistor replaces a TIP36 transistor in the power supply.I want to start working on radios but the small parts in them are a little too hard for me right now. I will probably break the radioI am trying to understand some of the claims being made that seem to be in dispute depending on who you ask.• Most Radios See a 10% Increase in Peak Power Levels• Runs 40% Cooler than Stock RegulatorsThere is a critic of this transistor and has done some tests and says they can't perform like this.There is another person that appears to be more of a televangelist than a radio repair person that is pushing to sell these really hard.He put a video up on YouTube where he ran the transistor without a heatsink and timed how long it got to 200 degrees.Then he switched it for the original one and did the same thing.Here are my questions because this test where he ran it not mounted to a heatsink seemed crazy to me!Is this the right way to test something like this? I thought the transistor would pop by not being on a heatsink?One of these transistors is physically a lot larger than the other one. Doesn't that affect the test?Can you really get up to 10% more power from your power supply by changing a transistor?Can it really run 40% cooler just by changing a transistor? Why wouldn't the radio just come with it?I emailed one of the guys that calls these "snake oil" transistors and he told me a few things that I wanted to verify.He told me that the transistor in question is "turned on hard / saturated" in FM and SSB modes and that it won't generate much heat at full power anyway.Another thing is that the only reason the larger transistor ran cooler in air was because of the "reduced thermal resistance" of the larger package?In some other tests I saw they were mounted normally on the heatsink and the temperatures were virtually identical to the original TIP36 transistor.He said that's because it's still producing roughly the same amount of heat as the original transistor?This guy sent me some ohms law calculations and the math was right but was it? Mentioned some other equations called thermal ohms law?The big question is, are the Max-Mod transistors really producing 40% less heat and 10% more power than the TIP36 transistors or are they "snake oil"?How can we find out when there seems to be so many people selling these that say they work?Are the people that call these "snake oil" just wrong or are the sellers just trying to take your money?I will keep reading and trying to learn but I think this is over my head.I thought it was snake oil but it took longer to get hot without a heat sink so I am torn now.Thanks everyone !!!

author: wraper
author_rank: Unknown
timestamp: June 29, 2019, 11:03:17 pm
content: Snake oil. Heat dissipated and output power will be the same as long as it does not break operation of the device. If used without heatsink, it will be colder than transistors in smaller package since it has larger area for heat dissipation. This is some off the shelf transistor with custom marking. I guess some Chinese cheapo since it's easier to get those custom marked at factory."Datasheet":http://www.servicedocs.com/ARTIKELEN/50700283190001.pdf

author: wraper
author_rank: Unknown
timestamp: June 29, 2019, 11:15:40 pm
content: Quote from: mw2000 on June 29, 2019, 10:49:04 pmThose people need their overheated brain replaced.

author: mw2000
author_rank: Newbie
timestamp: June 29, 2019, 11:54:12 pm
content: The guy that thinks they are snake oil said that both transistors are going to be subject to the same rules.He told me that they will dissipate about 30 watts of heat if there is a 5 amp load on it.His values were 14 volts in, 8 volts out, and 5 amps for the 30 watts of heat.He did say this was an example of how to get an idea how much heat the transistor will produce.Does that make the equation ( 14 - 8 ) * 5?P = V * I? is that correct?How about the extra power? He (jokingly I think) told me that it can't do that unless it drew additional power from the space time continuum?Can you get this extra power any other way?

author: wraper
author_rank: Unknown
timestamp: June 30, 2019, 12:17:50 am
content: Quote from: mw2000 on June 29, 2019, 11:54:12 pmNope. According to it's datasheet, even collector-emitter saturation voltage (voltage drop across fully opened transistor) spec is exactly the same as TIP36. So you cannot get even barely more voltage out of it even if it stays fully open.

author: sleemanj
author_rank: Super Contributor
timestamp: June 30, 2019, 12:23:07 am
content: The Vce Saturation voltage of the "Max-Mod" is the same or even slightly worse than the TIP36, so in saturation if the load is unchanged, and the transistor drops more volts, then the voltage available to the load is reduced - obviously that is not beneficial.The reported hFE of the Max-Mod is supposedly higher than the TIP36, so, maybe, maybe, if the transistor is not being driven into saturation you might get some benefit there in increased current to the load for the same base signal level. But frankly the "specs" of this Max-Mod don't look far removed from a TIP36 datasheet to me.

author: floobydust
author_rank: Super Contributor
timestamp: June 30, 2019, 12:24:03 am
content: ThePalomar Max Modis just a bigger transistor that the TIP36, perhaps2SA19432SA1301 but obsolete. The TIP36 seems to control modulation to the RF power amp driver stage in the very hairy circuit below. I think the only benefit might be the higher beta.The "40% cooler" seems to be a bogus claim in that any transistor there will still dissipate the same amount of heat. So cooler would be due to a little better heat transfer (lower thermal resistance) from the larger transistor package. Is 40% = 5°C cooler?CB radio is a kind of a religion, so there are stories, myths, voodoo and strong opinions. Good luck sorting through it.

author: wraper
author_rank: Unknown
timestamp: June 30, 2019, 12:27:13 am
content: Quote from: sleemanj on June 30, 2019, 12:23:07 amIf you compare worst case MAX-MOD against worst case TIP36. In practice particular specimen of TIP36 could easily have higher hFE than MAX-MOD.

author: mw2000
author_rank: Newbie
timestamp: June 30, 2019, 12:38:32 pm
content: I asked the person that did the videos on YouTube with the transistor off the heatsink about some of the things below and he deleted my questions.I won't get any answers from that guy.I see this morning that there is another one of a 2SA1301?Isn't the 2SA1301 by specifications a lesser transistor than a TIP36 or even the Max-Mod transistor?Can I do this test to find better transistors to use in radios?He says this is how it's done in the real world and I am left wondering about that.How do manufacturers test them?And

author: wraper
author_rank: Unknown
timestamp: June 30, 2019, 01:01:34 pm
content: ^That guy does not even know how to measure temperature properly. Also temperature without heatsink does not mean anything.

author: wraper
author_rank: Unknown
timestamp: June 30, 2019, 01:05:19 pm
content: Quote from: mw2000 on June 30, 2019, 12:38:32 pmThe best is what is used from the factory unless particular radio was not designed properly and has reliability problems. It's just stupid that people who don't understand a shit even consider using this.

author: madires
author_rank: Super Contributor
timestamp: June 30, 2019, 02:21:12 pm
content: It's simply an overpriced and custom labeled transistor from China. A well known local online shop sells the TIP36 for EUR 0.88. The Max Mod is about 10 times more expensive and doesn't improve the performance of your CB. It would have to burn the same amount of power resulting in the same amount of heat to be dissipated. But it provides one benefit, the seller will make more profit when selling a Max Mod instead of a TIP36.

author: wraper
author_rank: Unknown
timestamp: June 30, 2019, 02:29:44 pm
content: Quote from: madires on June 30, 2019, 02:21:12 pmIt also creates market for selling those. As it's fixing what's not broken, thus TIP36 would not be bought to begin with.

author: mw2000
author_rank: Newbie
timestamp: June 30, 2019, 05:52:40 pm
content: I am getting the impression that these transistors either don't do or can't do what they are advertised to do in the first place?Is this a scam?

author: Buriedcode
author_rank: Super Contributor
timestamp: June 30, 2019, 09:06:46 pm
content: Quote from: mw2000 on June 30, 2019, 05:52:40 pmThe last 5 replies give more than impression - they are pretty clear. Re-read them.

author: Buriedcode
author_rank: Super Contributor
timestamp: June 30, 2019, 09:12:57 pm
content: Quote from: mw2000 on June 29, 2019, 11:54:12 pmYes. The amount of power something dissipates (as heat, but in Watts) is exactly that P = V*I where V is the voltage *across* the device (in this case the Collector - emitter) and I is the current *through* it. As it is being used as a regulator, any device with similar specs will work in its place, and all with have roughly the same dissipation - because the regulated voltage isn't going to change, and nor is the current consumption (current through the device). That is how linear regulators work - they "drop" a voltage across them, and keep the output fixed when the input varies. They get rid of this excess energy as heat.So whilst others have said pretty much exactly the same thing, "the guy that thinks they snake oil" is correct. No magic or special transistor will dissipate less power because that is precisely what the part is designed to do in this circuit. Also as others have mentioned - I'm just laying it on thick here - the transistor packaging, and how it is mounted determines how hot it will get dissipating this power.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 01, 2019, 02:11:50 am
content: Someone show this guy the basics of video editing, please!The pair of linked Youtube videos could have been shortened by 90%, and no information would be missing.