barchetta,
Here's a link where transistor troubleshooting was discussed using the Diode function. Your pictures speak a thousand words though.
Sometimes we need to humble ourselves and not dismiss others outright. There's a lot to learn from one another.
http://www.diyaudio.com/forums/showthread.php?s=&postid=434288&highlight=#post434288
Here's a link where transistor troubleshooting was discussed using the Diode function. Your pictures speak a thousand words though.
Sometimes we need to humble ourselves and not dismiss others outright. There's a lot to learn from one another.
http://www.diyaudio.com/forums/showthread.php?s=&postid=434288&highlight=#post434288
Blues said:
Yeah that thread for a beginner like me is not enough information.. photos DO speak a thousand words.. for example: one might take for granted that one knows what a diode symbol looks like! My photos help in that regard.
Regarding lots to learn... yes, I do agree.. but some would be more helpful to this community if they learned how to communicate without sounding so insulting..
Example: this thread STARTED with people ridiculing me for questioning the tech quote on this amp.. the word ridiculing is pretty accurate.. read the posts. after all of this; I think they were absolutely right that the quote was good (this is making a few assumptions however).. because if the $480 for the transistors INCLUDED matching them and they were original not fake Motorola's $480 is not too terrible.
So.. communicating that to me would have been a hell of a lot easier of they were just NICE about it.
So yeah, we can all learn if we are willing to listen to one another.. I am not the only one who feels this way about those posts or I would probably not use this example BTW...
So while this is off subject it is still interesting.. I know I for one struggle with communication every single day.. I am no expert and I do indeed suck at it (which is sorta the breed that would hang around here if you think about it).. 🙂
blah blah blah.. back to my little project.. 🙂
Okay and ANOTHER thing.. searching is not always easy!!
I am trying to figure out which is the correct transistor again! Jon from vintage rattled off a MJ# and I thought there was only one good combo so I did not document the # thinking I would pick it up here.. so I found all these refrences to the proper transistors for my 400a!!
mj150022/24 (posted by Steve but I think its a typo and should be (mj15022/24)
MJ15023/25
MJ15003/4
MJ15025/24
Are all of these right? I am looking at data sheets and my head is starting to spin!
I JUST WANT TO ORDER MY PARTS!
Steve is very busy today and is not going to come and save my butt.. so if someone else can great!hehehehee
Funny: I came directly off ebay looking for thresholds and also broken amps suitable for a Aleph poject case and read this message.GRollins said:
I AM SICK.
Hi barchetta,
Great, you're back. I am pretty happy about that.
I will appologise to you right here and now. I was upset about your view of a tech over charging and the amp being not worthwhile. I was trying to get my point across that most good techs do not overcharge (and actually undercharge). You didn't seem to accept that point of view so I went for shock value.
If Nelson would like to suggest a good replacement part. I would tend to recommend MJ15003 and MJ15004 for these. The cascode arrangement suits a lower VCE device and you don't want it too fast.
I'm just going to hang back and allow the rest of the membership to give you some more excellent help and advice.
-Chris 😉
Great, you're back. I am pretty happy about that.
I will appologise to you right here and now. I was upset about your view of a tech over charging and the amp being not worthwhile. I was trying to get my point across that most good techs do not overcharge (and actually undercharge). You didn't seem to accept that point of view so I went for shock value.
If Nelson would like to suggest a good replacement part. I would tend to recommend MJ15003 and MJ15004 for these. The cascode arrangement suits a lower VCE device and you don't want it too fast.
I'm just going to hang back and allow the rest of the membership to give you some more excellent help and advice.
-Chris 😉
Hi barchetta,
MJ21195 and MJ21196 might work but they are not really suitable for this amplifier design.
Edited to retain information from a deleted post.
MJ21195 and MJ21196 might work but they are not really suitable for this amplifier design.
Edited to retain information from a deleted post.
anatech said:
Apology accepted and I throw one back right at you. Please accept it?
Based on my search Mr. Pass has not gone on record accept to say that any t03 with a 4mhz bandwidth will work.. and I frankly do not blame him if he does not go on record... its smart.
So I am going to need the help from you guys.. Anybody disagree with Chris's recommendations? I'll look for em now.. thats even more important.. gotta find them.. MJ14022/24 are available @ like $4.50 each.. not bad.
Hi barchetta,
No problem. I am completely okay with everything.
As for your transistors, look at Newark and Digikey. These are both excellent mail order houses. Mouser is supposed to be good, but shipping to Canada is brutal with them (UPS or the slowest mail I've seen). I just bought some from Newark that I'll have to match to get a pair.
-Chris
No problem. I am completely okay with everything.
As for your transistors, look at Newark and Digikey. These are both excellent mail order houses. Mouser is supposed to be good, but shipping to Canada is brutal with them (UPS or the slowest mail I've seen). I just bought some from Newark that I'll have to match to get a pair.
-Chris
Anatech:
Yeah digi has them... cheaper yet.. than the ones Steve mentioned.. you are reasonably sure these are plug and play into the 400a then? If so I am ordering right now as soon as I gather all the resistors and caps up on digikey (which is going to be hard for me to do but I will work at it! )
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=61932&Row=614873&Site=US
Yeah digi has them... cheaper yet.. than the ones Steve mentioned.. you are reasonably sure these are plug and play into the 400a then? If so I am ordering right now as soon as I gather all the resistors and caps up on digikey (which is going to be hard for me to do but I will work at it! )
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=61932&Row=614873&Site=US
Hi barchetta,
Failing an opposing opinion from Nelson Pass, that's what I would be buying. I would differ to the guy who designed the amp after all! 😉
-Chris
Failing an opposing opinion from Nelson Pass, that's what I would be buying. I would differ to the guy who designed the amp after all! 😉
-Chris
Okay; I will order those transistors.. they are already in my "cart". 🙂 I'm reading thru steves recommendation on the caps and resistors and trying to understand..
Hi Joe,
I've tested some electrolytic caps and ofter the dielectric absorption is lower on the 85° types compared to the 105 ° types. Any film cap is better than electrolytic as long as it's not physically too big. Any electrolytic is better than solid tantalum. Ceramics are universally bad, but NPO / COG types are the least offensive. Go mica for low values.
Metal oxide resistors are much better than carbon types. Metal film are only needed in the input signal path if you are concerned with noise.
That should make you life a little easier.
-Chris
I've tested some electrolytic caps and ofter the dielectric absorption is lower on the 85° types compared to the 105 ° types. Any film cap is better than electrolytic as long as it's not physically too big. Any electrolytic is better than solid tantalum. Ceramics are universally bad, but NPO / COG types are the least offensive. Go mica for low values.
Metal oxide resistors are much better than carbon types. Metal film are only needed in the input signal path if you are concerned with noise.
That should make you life a little easier.
-Chris
Favor: Can you show me an example of what you would replace one of these with on digi keys site? It would help me understand..
this one is orange:
sprague atom
tvan1304.1
10UF-50VNP
85 degrees C
USA 7704h
this one is Silver
NLW
10-100
10MFD
100WV
105 degrees C
7701
Is there anything special about the silver one?
this one is orange:
sprague atom
tvan1304.1
10UF-50VNP
85 degrees C
USA 7704h
this one is Silver
NLW
10-100
10MFD
100WV
105 degrees C
7701
Is there anything special about the silver one?
Posts have been modified and / or deleted to remove references to an accusation that has not been substantiated at this time. No further references to this will be tolerated.
-Chris
anatech said:
Posts have been modified and / or deleted to remove references to an accusation that has not been substantiated at this time. No further references to this will be tolerated.
-Chris
Umm for the records.. IT WAS NOT ME!!! For once I am innocent..
Okay resistors.. I have all of them but one now.. its the primary resistor used for emitters .22 Ohns (red red silver silver).. and I cannot find them in metal oxide.. I can only find this and I dont know what kind it is!
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=100832&Row=173717&Site=US
HELP...
An externally hosted image should be here but it was not working when we last tested it.
Edit... looks like these are wirewound.. didnt think they were till I saw the guts?
Hi Joe,
Your resistors appear to be carbon composition and would be non-inductive in that case. There are some low inductance wire wound types available. That is the magic phrase "low" or " non inductive". I have also seen wire wound types that look like that, but the split makes me believe they are bulk carbon.
-Chris
Edit: In that picture they are clearly wire wound.
Edit again! : Try these <Darn, search will not return a valid page!> Part number 42JR20E-ND at Digikey.
True ..........
Your resistors appear to be carbon composition and would be non-inductive in that case. There are some low inductance wire wound types available. That is the magic phrase "low" or " non inductive". I have also seen wire wound types that look like that, but the split makes me believe they are bulk carbon.
-Chris
Edit: In that picture they are clearly wire wound.
Edit again! : Try these <Darn, search will not return a valid page!> Part number 42JR20E-ND at Digikey.
Okay and while I am looking for that.. whats this??
I tried part #'s but nothing.. would help if I knew what the heck it was!
I tried part #'s but nothing.. would help if I knew what the heck it was!
An externally hosted image should be here but it was not working when we last tested it.
anatech said:
Meaning do not replace them? There are 2 per side.. ??? cute little guy... 🙂
figures the most commonly used resistor would be the most expensive.. the emitters will run $40 for this project.. I went with 3 watt vs 2 watt to SAVE a little $$ .. is that okay?
Okay off to the electrolytics...
Hi Joe,
The caps should be fine. Leave them for now.
Sorry, I didn't look at the pricing.
3W are just fine.
-Chris
The caps should be fine. Leave them for now.
Sorry, I didn't look at the pricing.
3W are just fine.
-Chris
Yes another question.. having trouble locating a radial mount 470uf/mfd 16v cap... can I go higher in voltage on caps? Is that just a rating or is it a needed value?
sorry.. this is getting sorta embarassing.. I have been on digikeys site for about 5 hours now. I have 2 more caps to go.. and I am done.. here is what I have so far..
Index Quantity Part Number Description Customer Reference Backorder Quantity Unit Price
USD Extended Price
USD
1 13 MJ15003GOS-ND TRANS PWR NPN 20A 140V TO3 0 3.29000 $42.77
2 13 MJ15004GOS-ND TRANS PWR PNP 20A 140V TO3 0 3.29000 $42.77
3 1 345-1006-ND SILICON GREASE 4 GRAM 0 5.04000 $5.04
4 12 BER122-ND HEATPAD TO-3/TO-66 .005" Q3 0 0.62900 $7.55
5 12 P3.0W-3BK-ND RES 3.0 OHM 3W 5% METAL OXIDE 0 0.47600 $5.71
6 12 P10W-3BK-ND RES 10 OHM 3W 5% METAL OXIDE 0 0.47600 $5.71
7 4 P22W-2BK-ND RES 22 OHM 2W 5% METAL OXIDE 0 0.28000 $1.12
8 20 43FR20-ND RESISTOR SILICONE .20 OHM 3W 0 1.86000 $37.20
9 4 4236PHCT-ND CAP 50V 10UF ELECT AXIAL 0 1.47000 $5.88
10 8 4254PHCT-ND CAP 100V 10UF ELECT AXIAL 0 1.27000 $10.16
11 4 338-1075-ND CAP 20PF 300V MICA RADIAL 0 1.27000 $5.08
Subtotal $168.99
Handling $0.00
Shipping unknown
Sales Tax unknown
Total unknown
sorry.. this is getting sorta embarassing.. I have been on digikeys site for about 5 hours now. I have 2 more caps to go.. and I am done.. here is what I have so far..
Index Quantity Part Number Description Customer Reference Backorder Quantity Unit Price
USD Extended Price
USD
1 13 MJ15003GOS-ND TRANS PWR NPN 20A 140V TO3 0 3.29000 $42.77
2 13 MJ15004GOS-ND TRANS PWR PNP 20A 140V TO3 0 3.29000 $42.77
3 1 345-1006-ND SILICON GREASE 4 GRAM 0 5.04000 $5.04
4 12 BER122-ND HEATPAD TO-3/TO-66 .005" Q3 0 0.62900 $7.55
5 12 P3.0W-3BK-ND RES 3.0 OHM 3W 5% METAL OXIDE 0 0.47600 $5.71
6 12 P10W-3BK-ND RES 10 OHM 3W 5% METAL OXIDE 0 0.47600 $5.71
7 4 P22W-2BK-ND RES 22 OHM 2W 5% METAL OXIDE 0 0.28000 $1.12
8 20 43FR20-ND RESISTOR SILICONE .20 OHM 3W 0 1.86000 $37.20
9 4 4236PHCT-ND CAP 50V 10UF ELECT AXIAL 0 1.47000 $5.88
10 8 4254PHCT-ND CAP 100V 10UF ELECT AXIAL 0 1.27000 $10.16
11 4 338-1075-ND CAP 20PF 300V MICA RADIAL 0 1.27000 $5.08
Subtotal $168.99
Handling $0.00
Shipping unknown
Sales Tax unknown
Total unknown