Another construction
Actually 2 new constructions.
The audiophile friend and I have struck an agreement. I help him and his son build a unit (stereo) each and he gives me my amp back. That's fair .......I guess.
Anyway I'll post construction progress including variations as well as photos. We are supposed to start this Tuesday night.
Cheers
Actually 2 new constructions.
The audiophile friend and I have struck an agreement. I help him and his son build a unit (stereo) each and he gives me my amp back. That's fair .......I guess.
Anyway I'll post construction progress including variations as well as photos. We are supposed to start this Tuesday night.
Cheers
Hi Quasi,
To answer your question. I generally use exact replacements, or suitable subs if the exact part is not available or inconvenient. The parts are either moved around in the amp to obtain matches, or new parts simply matched and installed. No magic involved.
If you have read many of my posts then you know I don't believe in the part of the day. I do believe in the original designer unless things are obviously not right.
The first reports took me by surprise. I could see the amps were more stable with temperature with regard to DC offset and bias. THD was sometimes lower. DC offsets were within mV of calculations. I felt they sounded better, but never expected the average customer would notice. This is especially true when the amp came in for repair and I talked the guy out of "upgrades".
Certainly not everyone noticed. I then would just try and figure out who might mention this and who wouldn't notice at all. Guys who buy on nameplate never notice. Does that say anything?
-Chris
To answer your question. I generally use exact replacements, or suitable subs if the exact part is not available or inconvenient. The parts are either moved around in the amp to obtain matches, or new parts simply matched and installed. No magic involved.
If you have read many of my posts then you know I don't believe in the part of the day. I do believe in the original designer unless things are obviously not right.
The first reports took me by surprise. I could see the amps were more stable with temperature with regard to DC offset and bias. THD was sometimes lower. DC offsets were within mV of calculations. I felt they sounded better, but never expected the average customer would notice. This is especially true when the amp came in for repair and I talked the guy out of "upgrades".
Certainly not everyone noticed. I then would just try and figure out who might mention this and who wouldn't notice at all. Guys who buy on nameplate never notice. Does that say anything?
-Chris
Hi quasi,
lol lol lol I am harmless. I may bruse from sheer volume of words, but that is about my limit
So not to worry and even if I lived beside you you need not feel worried about me.
I am so glad you worked out a deal to get your amps back. Still sounds liek the deal is you will not have your amps returned until at least one stero pair amp is built. I am reading your agreement being a case that two stereo amps are to be built. I know I will be interested in the progress of the build. I will have some questions during the built. The questions were already asked, but will be much easier to answer during your build/measurement phase rather than take a built amp apart to measure. Next weekent I will find the questions I had andpost a post with links to the questions. Who knows I mayu have more questions What a shock!
I am not concerned with the difference between the hFE you found on your 546's vs the few I sampled in the store. You had the "B" version, and the store I was in had the "C" version, ergo the difference in values. Quasi, sorry you did not need to measure so many samples. In the store I tend to spot check 3-5 before I have a feel for the range of values/batch for the device. I find that to be sufficient for my needs before I buy any no matter the quanity. The BC550C was on my shortlist to consider or use in place of the 2SC1845 in the event I could nto find the 2SC1845. The store has had the BC550 tray empty for several months.
I assume you mean Vceo when you say Vce. If that is case I have been mindful to use at least the rating of a part you used or greater. I still have not been able to sort out the voltages and PD of the various parts of the circuit thanks fo your answering my questions to how to calculate. I have no problem with the ohms law math, it is the odd variables that play in some of the circuit elements so I can calculate. The reason was in part to enable me to select alternate transistors and see what effect suggested resistor changes that have been made on the thread and any alternate transistors might have as well. I going to see if I can find a Linux based circuit simulation program just to find out these basic I and V values so I can validate alternate parts. That said I have chosen the route to at least match or exceed altrnate parts available locally in the absense of knowing how to calculate the "finer" elements that affect the I and V each part sees or causes another part to see.
Here is where I am at so far the transistors thus far for the amps I will build:
1) I will use either the 2SC1854E or 2SC2240BL for the input pair T1/T5. I have enough quanity of both that I can use. I will likely use the 2SC2240BL unless there are those that have strong reasons to suggest I do otherwise.
2) Instead of the BC456's for the input stage T2/T3 I will use 2SA970's. The 2SA970's are compliments to the 2SC2240's, well regarded devices for low noise and available at the store.
3) For T4 I will use a 2SA970 to be consistant with the input stage use of 2SA970's for T2/T3.
4) As I mentioned in a prior posting I like to use a TO-126 (or TO-220) for T8. Sorry I cannot recall what you call the fucntion of T8. I know it's purpose is thermal tracking of the output devices so the output devices are less inclined to get into a thermal runaway condition for the output devices. That said I have shortlisted to two possible devices based reviewing many datasheets once I searched the stock of the store from what they carried. The really short shortlist is either a 2SC2911 as first choice, or 2SC3502 as second primary choice. I have 5 other possibilities on the shortlist. The deciding points to decice on the 2 primary possible choices were the hFE rating, range and flatness. If anyone has any opinions to my alternate choice for T8 feel freel to jump in and speak your thoughts.
5) Sadly the store only has a few MJE340's, and good quanity of MJE350's, so I am still researching what alternates I can use. I have a list of parts the store carries. I still have to research the spec sheets to sort out any possible alternates.
6) For the output devices I will use IRFP140, IRF740, IRF540N, and APT4025BN's depending on the task and power supply for the amp. I have IRFP450's I can use to compare differences to the output devices I will use. For full range amp I find the APT4025BN an attractive looking device. I all of these except the IRP540N. Where I will purchase the IRF540N has a quanity of >20,000 in stock so I have no worry to purchase those right away. I bought up the last 25 IRFP140's as they were an attractive output device for a few amps I like to try as first amps.
Once I have settled out what top use instead of the MJE340/MJE350's then I can look into case/heatsink solution that will work for my needs and amp needs.
So progress is going forward, slowly and in spots based on available time. I happened by luck out a few weeks back when in a store I am rarely in due to its location and buy solder of a tin/silver/copper content, no lead in it. So I bought it for use in building the amps.
Thanks again for your time and patience with my efforts I am making prior to the start of building phase. So I am very patient as I am sure I have mentioned. The dead phone line problem I had for 3 months and its resulting fallout through me off the rails for over 6 months.
Regards,
John L. Males
Willowdale, Ontario
Canada
19 March 2006 21:00
lol lol lol I am harmless. I may bruse from sheer volume of words, but that is about my limit
So not to worry and even if I lived beside you you need not feel worried about me.I am so glad you worked out a deal to get your amps back. Still sounds liek the deal is you will not have your amps returned until at least one stero pair amp is built. I am reading your agreement being a case that two stereo amps are to be built. I know I will be interested in the progress of the build. I will have some questions during the built. The questions were already asked, but will be much easier to answer during your build/measurement phase rather than take a built amp apart to measure. Next weekent I will find the questions I had andpost a post with links to the questions. Who knows I mayu have more questions
What a shock!I am not concerned with the difference between the hFE you found on your 546's vs the few I sampled in the store. You had the "B" version, and the store I was in had the "C" version, ergo the difference in values. Quasi, sorry you did not need to measure so many samples. In the store I tend to spot check 3-5 before I have a feel for the range of values/batch for the device. I find that to be sufficient for my needs before I buy any no matter the quanity. The BC550C was on my shortlist to consider or use in place of the 2SC1845 in the event I could nto find the 2SC1845. The store has had the BC550 tray empty for several months.
I assume you mean Vceo when you say Vce. If that is case I have been mindful to use at least the rating of a part you used or greater. I still have not been able to sort out the voltages and PD of the various parts of the circuit thanks fo your answering my questions to how to calculate. I have no problem with the ohms law math, it is the odd variables that play in some of the circuit elements so I can calculate. The reason was in part to enable me to select alternate transistors and see what effect suggested resistor changes that have been made on the thread and any alternate transistors might have as well. I going to see if I can find a Linux based circuit simulation program just to find out these basic I and V values so I can validate alternate parts. That said I have chosen the route to at least match or exceed altrnate parts available locally in the absense of knowing how to calculate the "finer" elements that affect the I and V each part sees or causes another part to see.
Here is where I am at so far the transistors thus far for the amps I will build:
1) I will use either the 2SC1854E or 2SC2240BL for the input pair T1/T5. I have enough quanity of both that I can use. I will likely use the 2SC2240BL unless there are those that have strong reasons to suggest I do otherwise.
2) Instead of the BC456's for the input stage T2/T3 I will use 2SA970's. The 2SA970's are compliments to the 2SC2240's, well regarded devices for low noise and available at the store.
3) For T4 I will use a 2SA970 to be consistant with the input stage use of 2SA970's for T2/T3.
4) As I mentioned in a prior posting I like to use a TO-126 (or TO-220) for T8. Sorry I cannot recall what you call the fucntion of T8. I know it's purpose is thermal tracking of the output devices so the output devices are less inclined to get into a thermal runaway condition for the output devices. That said I have shortlisted to two possible devices based reviewing many datasheets once I searched the stock of the store from what they carried. The really short shortlist is either a 2SC2911 as first choice, or 2SC3502 as second primary choice. I have 5 other possibilities on the shortlist. The deciding points to decice on the 2 primary possible choices were the hFE rating, range and flatness. If anyone has any opinions to my alternate choice for T8 feel freel to jump in and speak your thoughts.
5) Sadly the store only has a few MJE340's, and good quanity of MJE350's, so I am still researching what alternates I can use. I have a list of parts the store carries. I still have to research the spec sheets to sort out any possible alternates.
6) For the output devices I will use IRFP140, IRF740, IRF540N, and APT4025BN's depending on the task and power supply for the amp. I have IRFP450's I can use to compare differences to the output devices I will use. For full range amp I find the APT4025BN an attractive looking device. I all of these except the IRP540N. Where I will purchase the IRF540N has a quanity of >20,000 in stock so I have no worry to purchase those right away. I bought up the last 25 IRFP140's as they were an attractive output device for a few amps I like to try as first amps.
Once I have settled out what top use instead of the MJE340/MJE350's then I can look into case/heatsink solution that will work for my needs and amp needs.
So progress is going forward, slowly and in spots based on available time. I happened by luck out a few weeks back when in a store I am rarely in due to its location and buy solder of a tin/silver/copper content, no lead in it. So I bought it for use in building the amps.
Thanks again for your time and patience with my efforts I am making prior to the start of building phase. So I am very patient as I am sure I have mentioned. The dead phone line problem I had for 3 months and its resulting fallout through me off the rails for over 6 months.
Regards,
John L. Males
Willowdale, Ontario
Canada
19 March 2006 21:00
Hi Chris,
I too have to buy from several sources. I limit to local sources as much as I can. Sources for most of the capacitors tend to be various surplus stores in and about the city oddly as they have better parts and better choices. Semiconductors tend to be from one store downtown that is moving as of tomorrow and may not have the same selection at new location, plus Electrosonic. In some ways Electrosonic does not have that much variety and/or far to high minimum quanity order for each part purchased. I shy away from Active Components as they are far too pricey.
Some parts I still will need for the amp like heaksinks, case and such will be a challenge. Toroids I happened to pick up in surplus store and sadly either higher output voltage than I need and some lower than I need voltage and not enough currenty output. The larger ones have lots of current ability. So by and large I been at mercy of working a project as parts become available. This can make a project a very long time to come to any final result. For this amp project I feel a greater chance of success in completeing due to the simple design and flexibility of parts one can use. Once I have the transistors I will be happy as the capacitors other than for PSU filter I can find are respectable types source via various surplus stores about the city. The challenge part to source is PSU capacitors. I am willing to pay $0.10-0.30 extra for a bit higher quality transistor, but I am not paying big $ for PSU filter capacitors.
I have modest amp power needs. Ideally amps that are about 60-100W for full range speakers, and 15W/30W/120W for active T/M/W when I can go active crossover. By and large I think I share same sense of part use and costing as quasi has. I also feel as a DIY project I can spend time doing matching of all the parts in hopes it will help in final result. If not, so be it, but at least the effort and opportunity likely will enable the final result to outdo equipment far more expensive. I think quasi has found out how even a modest effort can have such a great final result. The proof is his audiofile friend likes what his ears hear from a DIY design and project. I know I have some interesting elements I want to use in the building process. DIY will allow me to include certain supporting functions to the actual base amp I choose.
Chris, I recall you are retired and your profession was electronics repair. You, quasi and many others on diyAudio are way ahead of what little I know about amplifier/pre-amp and such. Suffice I know just enough to be "dangerous" as my postings are a testament to.
I do not use credit cards and even the well know mail order places expect a minimum order nonsense credit card or cheque pay method. Added to this they will only ship via courier which is unacceptable on several counts, the most being the rude brokerage charges the courier companies charge. So I have had to spend some time looking at alternate parts. As it turns out I have been lucky with some transistors I been able to locate for quasi's design. I do the hFE measurement spot checks as the primary store I have found a few fake device types and their store claims they have no idea of their part sources. The hFE has helped me screen out some problem devices.
If I recall you are in Georgetown from some post or your profile I looked at some months back. Willowdale is actually Toronto. I just like Willowdale as was the original postal address some "years" back. I never used the City of North York when transistion from Township/Borough to City, and then the forced provice merge into Toronto.
Regards,
John L. Males
Willowdale, Ontario
Canada
19 March 2006 23:57
I too have to buy from several sources. I limit to local sources as much as I can. Sources for most of the capacitors tend to be various surplus stores in and about the city oddly as they have better parts and better choices. Semiconductors tend to be from one store downtown that is moving as of tomorrow and may not have the same selection at new location, plus Electrosonic. In some ways Electrosonic does not have that much variety and/or far to high minimum quanity order for each part purchased. I shy away from Active Components as they are far too pricey.
Some parts I still will need for the amp like heaksinks, case and such will be a challenge. Toroids I happened to pick up in surplus store and sadly either higher output voltage than I need and some lower than I need voltage and not enough currenty output. The larger ones have lots of current ability. So by and large I been at mercy of working a project as parts become available. This can make a project a very long time to come to any final result. For this amp project I feel a greater chance of success in completeing due to the simple design and flexibility of parts one can use. Once I have the transistors I will be happy as the capacitors other than for PSU filter I can find are respectable types source via various surplus stores about the city. The challenge part to source is PSU capacitors. I am willing to pay $0.10-0.30 extra for a bit higher quality transistor, but I am not paying big $ for PSU filter capacitors.
I have modest amp power needs. Ideally amps that are about 60-100W for full range speakers, and 15W/30W/120W for active T/M/W when I can go active crossover. By and large I think I share same sense of part use and costing as quasi has. I also feel as a DIY project I can spend time doing matching of all the parts in hopes it will help in final result. If not, so be it, but at least the effort and opportunity likely will enable the final result to outdo equipment far more expensive. I think quasi has found out how even a modest effort can have such a great final result. The proof is his audiofile friend likes what his ears hear from a DIY design and project. I know I have some interesting elements I want to use in the building process. DIY will allow me to include certain supporting functions to the actual base amp I choose.
Chris, I recall you are retired and your profession was electronics repair. You, quasi and many others on diyAudio are way ahead of what little I know about amplifier/pre-amp and such. Suffice I know just enough to be "dangerous" as my postings are a testament to.
I do not use credit cards and even the well know mail order places expect a minimum order nonsense credit card or cheque pay method. Added to this they will only ship via courier which is unacceptable on several counts, the most being the rude brokerage charges the courier companies charge. So I have had to spend some time looking at alternate parts. As it turns out I have been lucky with some transistors I been able to locate for quasi's design. I do the hFE measurement spot checks as the primary store I have found a few fake device types and their store claims they have no idea of their part sources. The hFE has helped me screen out some problem devices.
If I recall you are in Georgetown from some post or your profile I looked at some months back. Willowdale is actually Toronto. I just like Willowdale as was the original postal address some "years" back
. I never used the City of North York when transistion from Township/Borough to City, and then the forced provice merge into Toronto.Regards,
John L. Males
Willowdale, Ontario
Canada
19 March 2006 23:57
Hi John,
I was just wondering as I have to re-source many of the parts I buy. Electrosonic lost Motorola as a supplier. That hurt them (for me) Active, or whatever they are called now is expensive. They normally do not have what I need these days. My favorite supplier of caps and resistors (plus Japanese IC's and transistors) closed his doors due to the drop in the after market service business. That's a shame for every person in the area. His parts were always real.
I didn't retire as much as I sold my business (for the same reasons). That and I was too busy servicing rather than experimenting and designing. That took the fun out of things. There where very very products that interested me in service as well, just mass production, unrepairable plastic stuff. I am currently becoming very busy as old customers discover where I am now. I'm going to have to do something or I'll end up with another service shop, I'd rather not.
Ordering mail order is okay. Most of my suppliers had minimum orders. I guess I just got use to it. Just give up John and order a bit extra of the things you normally use.
-Chris
I was just wondering as I have to re-source many of the parts I buy. Electrosonic lost Motorola as a supplier. That hurt them (for me) Active, or whatever they are called now is expensive. They normally do not have what I need these days. My favorite supplier of caps and resistors (plus Japanese IC's and transistors) closed his doors due to the drop in the after market service business. That's a shame for every person in the area. His parts were always real.
I didn't retire as much as I sold my business (for the same reasons). That and I was too busy servicing rather than experimenting and designing. That took the fun out of things. There where very very products that interested me in service as well, just mass production, unrepairable plastic stuff. I am currently becoming very busy as old customers discover where I am now. I'm going to have to do something or I'll end up with another service shop, I'd rather not.
Ordering mail order is okay. Most of my suppliers had minimum orders. I guess I just got use to it. Just give up John and order a bit extra of the things you normally use.
-Chris
Hi Chris,
One of the issues with most of the surplus stores is they grossly overcharge for their "surplus" components. Let me give you two simple examples of the more common items one can purchase. First is a 50 ft. F-F RJ11 extension cable. Surplus store price $5.00, Dollar Store $2.00. Second example is a KBPC5010 sealed with metal casing bridge rectifier, $8.00 Surplus store, $3.25 electronics store (moving as of today) 3 doors down same side of street. Now on the latter example a Diodes Inc GBPC3510 $2.75 (Qty 1, one of few can order Qty 1) Bridge Rectifier from Electrosonic $2.74. The Diaodes Inc version is far better than the more generic KBPC parts of electtonic or surplus store. So my point is although the surplus stores carry some stuff, they generally charge rude prices. Sadly the electronics store passive parts selection is limited and expensive. On the semiconductor side stocking is so unstale, parts often are not restocked for months at end. Case in point I never worried about the MJE340 stock (Motorola) for months, then upon checking last week next top nothing, yet the MJE350 stock quanity remained about same. So I cannot buy the MJE3x0's as I need then in similar quanities as it could be months until I know they have more stock of the MJE340's.
With respect to the mail order, the problem with minimum order is often I need to have a few of a part to test and evaluate first. Second is, unlike most diy types here, I have just a few specific projects that from most part (no pun intended) that have limitied order needs that are far from the minimum. I do not have the time to experiment as many on diyAudio may have or make time for. So I do lots of research for something of interest and if something exists that will meet my needs then I will determine if I can get the parts for it. Many times I am unable to get the required parts so project is archived in case I luck out.
The courier deliverly only option for mail order is just not acceptable to me based on many past experiences, UPS is very bad, and even after my several experiences with UPS over a year, the UPS problems continue over 5 years after fact. The problems seem to be very unique to UPS Canada. From my experience postal delivery was the most reliable and straight forward no matter if small item or a very large test instrument. Informed US sellers were very aware of the big problems with UPS Canada, however on the flip side UPS US was just great and stable. I had the added enlightenment of dealing with UPS at the central ontario hub in Toronto. Suffice to say it was a very disappointing eye opener top see the pathology problems keep repeating.
It has been a few years since I had reason to use Electrosonic. I did find it odd when I looked up last year that Electrosonic did not carry any Motorola nor OnSemi products. In fact, I was really shocked and had no idea why. I know Electrosonic carried Motorola parts, but could not tell you how long long ago that was. It was a great disappointment Electrosonic does not carry Motorola nor OnSemi semiconductors. It also appears much of the stocking of IRF parts is subject to some stiff minimum quanity orders and long long lead times (several weeks) as Electrosonic does not carry many of the parts on hand anymore.
Active (Future Electronics is parent company based in Montreal if I recall correctly) has always been just plain overpriced of their items for much of the products they carry for years. I really have no clue how they stay in business.
So for now Chris I will muddle with my "treasure hunt" method of finding parts. For you I think you need a more stable source of parts at reasonable pricing. With my experience to date, minimum quanity aside, Electrosonic, Mouser, Newark, and Digikey seem to be far better prospects from stability of stocking and pricing for what you will need. Most of the places I source from have more a one time stocking, or very infrequent restock of parts. Oftentimes the electronics parts store will take several months to get more stock in and when does could be a generic off shore company version of part or if lucky a brand name. Usually the former more than latter as well as many fake possible parts for transistors. I have spent some time weeding out fake or poor generic offshore versions of a part.
Chris, I hope that answers a bit more about the few places locally I frequent few times a month to luck out on some part I need after bearing it out for 6-12+ months if at all. I only wish I had closer access to the "Quasi" store
I hope you find a way to disappear from your former customres so you may do what you wish after selling your business.
Regards,
John L. Males
Willowdale, Ontario
Canada
20 March 2006 20:48
20 March 2006 20:56 Typo corrections
One of the issues with most of the surplus stores is they grossly overcharge for their "surplus" components. Let me give you two simple examples of the more common items one can purchase. First is a 50 ft. F-F RJ11 extension cable. Surplus store price $5.00, Dollar Store $2.00. Second example is a KBPC5010 sealed with metal casing bridge rectifier, $8.00 Surplus store, $3.25 electronics store (moving as of today) 3 doors down same side of street. Now on the latter example a Diodes Inc GBPC3510 $2.75 (Qty 1, one of few can order Qty 1) Bridge Rectifier from Electrosonic $2.74. The Diaodes Inc version is far better than the more generic KBPC parts of electtonic or surplus store. So my point is although the surplus stores carry some stuff, they generally charge rude prices. Sadly the electronics store passive parts selection is limited and expensive. On the semiconductor side stocking is so unstale, parts often are not restocked for months at end. Case in point I never worried about the MJE340 stock (Motorola) for months, then upon checking last week next top nothing, yet the MJE350 stock quanity remained about same. So I cannot buy the MJE3x0's as I need then in similar quanities as it could be months until I know they have more stock of the MJE340's.
With respect to the mail order, the problem with minimum order is often I need to have a few of a part to test and evaluate first. Second is, unlike most diy types here, I have just a few specific projects that from most part (no pun intended) that have limitied order needs that are far from the minimum. I do not have the time to experiment as many on diyAudio may have or make time for. So I do lots of research for something of interest and if something exists that will meet my needs then I will determine if I can get the parts for it. Many times I am unable to get the required parts so project is archived in case I luck out.
The courier deliverly only option for mail order is just not acceptable to me based on many past experiences, UPS is very bad, and even after my several experiences with UPS over a year, the UPS problems continue over 5 years after fact. The problems seem to be very unique to UPS Canada. From my experience postal delivery was the most reliable and straight forward no matter if small item or a very large test instrument. Informed US sellers were very aware of the big problems with UPS Canada, however on the flip side UPS US was just great and stable. I had the added enlightenment of dealing with UPS at the central ontario hub in Toronto. Suffice to say it was a very disappointing eye opener top see the pathology problems keep repeating.
It has been a few years since I had reason to use Electrosonic. I did find it odd when I looked up last year that Electrosonic did not carry any Motorola nor OnSemi products. In fact, I was really shocked and had no idea why. I know Electrosonic carried Motorola parts, but could not tell you how long long ago that was. It was a great disappointment Electrosonic does not carry Motorola nor OnSemi semiconductors. It also appears much of the stocking of IRF parts is subject to some stiff minimum quanity orders and long long lead times (several weeks) as Electrosonic does not carry many of the parts on hand anymore.
Active (Future Electronics is parent company based in Montreal if I recall correctly) has always been just plain overpriced of their items for much of the products they carry for years. I really have no clue how they stay in business.
So for now Chris I will muddle with my "treasure hunt" method of finding parts. For you I think you need a more stable source of parts at reasonable pricing. With my experience to date, minimum quanity aside, Electrosonic, Mouser, Newark, and Digikey seem to be far better prospects from stability of stocking and pricing for what you will need. Most of the places I source from have more a one time stocking, or very infrequent restock of parts. Oftentimes the electronics parts store will take several months to get more stock in and when does could be a generic off shore company version of part or if lucky a brand name. Usually the former more than latter as well as many fake possible parts for transistors. I have spent some time weeding out fake or poor generic offshore versions of a part.
Chris, I hope that answers a bit more about the few places locally I frequent few times a month to luck out on some part I need after bearing it out for 6-12+ months if at all. I only wish I had closer access to the "Quasi" store
I hope you find a way to disappear from your former customres so you may do what you wish after selling your business.
Regards,
John L. Males
Willowdale, Ontario
Canada
20 March 2006 20:48
20 March 2006 20:56 Typo corrections
Hi John,
I don't wish to disappear so much as I want time to do my thing too. I enjoy working on good equipment for the most part. I also enjoy helping people out. If there were more good shops out there, everyone would be happy. I also do enjoy seeing some of the old friends I've come to know over the years.
I may start to refer some people to Ontario Audio, but he is very busy too. Besides, I have to fund my hobby. I want a DSO with math. Preferably HP or Tek. That will make my life so much easier and more fun!
-Chris
I don't wish to disappear so much as I want time to do my thing too. I enjoy working on good equipment for the most part. I also enjoy helping people out. If there were more good shops out there, everyone would be happy. I also do enjoy seeing some of the old friends I've come to know over the years.
I may start to refer some people to Ontario Audio, but he is very busy too. Besides, I have to fund my hobby. I want a DSO with math. Preferably HP or Tek.
That will make my life so much easier and more fun!-Chris
Hi Chris,
I understand exactly the rational of you enjoying working on proper equipment and still seeing some of your well liked and enjoyable customers. Oh yes, those hobbies we like that for some reason need money to fund some elements of the hobby. At least your hobby is not nearly as expensive as some other hobbies. I am sure you will find the right balance to suit your needs and interests. You already started and are on right track.
One clear example is your interest in this diyAudio.com forum here with your practical experience such as the hFE matching you made on this thread to just base reading of meter as a relative value and not worry about if meter reading is absolute hFE. Very practical suggestion.
Regards,
John L. Males
Willowdale, Ontario
Canada
20 March 2006 21:51
I understand exactly the rational of you enjoying working on proper equipment and still seeing some of your well liked and enjoyable customers. Oh yes, those hobbies we like that for some reason need money to fund some elements of the hobby. At least your hobby is not nearly as expensive as some other hobbies. I am sure you will find the right balance to suit your needs and interests. You already started and are on right track.
One clear example is your interest in this diyAudio.com forum here with your practical experience such as the hFE matching you made on this thread to just base reading of meter as a relative value and not worry about if meter reading is absolute hFE. Very practical suggestion.
Regards,
John L. Males
Willowdale, Ontario
Canada
20 March 2006 21:51
VERY GREAT WORK QUASI !
I am very interested to your project.
When I foud a lot of time I want to build a variation of yor project with 2 different PCB: one for predrivers, drivers and regulated power supply and one for power FET and dc protection.
Do you have the schematics of dc protection ?
Thank you for all.
I am very interested to your project.
When I foud a lot of time I want to build a variation of yor project with 2 different PCB: one for predrivers, drivers and regulated power supply and one for power FET and dc protection.
Do you have the schematics of dc protection ?
Thank you for all.
Thanks Antonix.....I will post short cct protection over the next few weeks.
For Keypunch;
John your post #404 has an error. You specified using a 2SA970 for T4, but this is an NPN transistor. Also you only need low voltage transistors for T2 & T3 so use someting more common and cheaper (unless you have plenty of 2SA970's)
Thanks to Fcrawley for pointing this out.
Cheers
For Keypunch;
John your post #404 has an error. You specified using a 2SA970 for T4, but this is an NPN transistor. Also you only need low voltage transistors for T2 & T3 so use someting more common and cheaper (unless you have plenty of 2SA970's)
Thanks to Fcrawley for pointing this out.
Cheers
quasi said:
Thanks Quasi and Fcrawley,
On my Post #404 noted error. My notes I created for the parts list, comments from the thread and my research on alternates availability as well as the specified part was corret for T4. That being a BC456. I had no alternates as I could find good source of BC546'ss. Seems my "brain circuits" got a bit confused in my memory on the parts list for the transistors. What can I say? I "was not properly biased"
Regarding T2/T3 use of the 2SA970, it is the complement to the 2SA2240. In my way of thinking I thought the 2SA970 was a natural choice as well as being a low noise device. This does not mean it was a smart choice. Enlightenment on my intent to use a 2SA970 fot T4 - pros and cons - are most welcome.
BTW, who is Fcrawley? A person outside diyAudio? The questions are just curious. I am not upset. In part I was curious so I could thank properly.
Regards,
John L. Males
23 March 2006 22:23
23 March 2006 22:39 Typo Corrections
Willowdale, Ontario
Canada
Fcrawley is a new member;
http://www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=66686
I had a good email from him to check the polarity of said transistor.
Cheers
http://www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=66686
I had a good email from him to check the polarity of said transistor.
Cheers
Quasi,
There is no hurry for answer to these questions.
I have simple question re T2/T3. Aside from the 2SA970 you suggested I use a cheaper more common part for I can also buy the specified BC556(C), and BC560C. The simple question is related to the BC560C and 2SA970, Vceo rating of these two ignored, is these any advantage to these two low noice characteristics for T2/T3, or is it better to save them for circuits that need their low noise characteristics? I am assuming in theory yes, so the real qustion is if ther eis a remote sonic advantage?
The same basic question regarding using a low noise alternate for T4 is of any advantage.
I do not have a "store" like you do so I have the option to use alternates to the ones you choose in the event you feel there is some possible advantage. I know your audiophile friend seems very happy with the choices that you used as a whole for the amp you have built. I do not have your level of circuit topology knowledge to know if there is or not any such advantages.
With respect to T8 Vbe, based on local part availabiliity and research of TO-126/T0-220 parts I have narrowed down to what I think are two candidates - 2SC2911 and 2SC3502. The 2SC2911 appears with my limited knowledge and read of the spec sheets appears to be the best choice as a alternate for T8 Vbe with my limited knowledge. The question is if you feel my conclusions are off due to my little knowledge is dangerous. The 2SC2911 is a T)-126 all plastic case with no metal at all, i.e. not even about the mounting hole rear. The plastic only case T)-126 has the advantage of not requiring any thermal insulation to mount to the heatsink. Is there any downside to using a TO-126 all plastic case? I know the BC546 you used is all plastic case, but the TO-92 case is smaller and may be more responsive to sense temperature changes of the heatsink in the method you used to interface to the heatsink.
As a side question regarding the Vbe I have read conflicting information as to or not to mount the Vbe on an output driver or on the heatsink of the output devices. I know your use of the BC546 mounting is in effect to mount on the heatsink and not the output device. A simple answer if has any difference or pros/cons to either approach is all I really need in terms of an answer.
I remember seeing your case layout pic posts, but I am not clear on one aspect of your final case. The question is regarding your final case. Did the case have any ventilation? I ask as the MJE340s/350s are mounted to a heatsink and noted to run very warm normally. I am assuming you had some form of ventiliation so the internal temperature of the amp does not keep rising form the MJE340s/350s heat?
I am still researching alternates to the MJE340/350 parts for two basic reasons. Basically no local availability of these parts and my desire to use a larger dimensioned part to reduce the heat related stress to T6/T7/T9/T10. I am aware of the alternate resistor values you provided to a member to reduce the heat of theses devices a bit. I am trying to determine through research if alternates will be as good as the MJEs and/or if I will ensure a large heat sink solution to help keep the heat stress lower.
The next step for me is to find or use an existing design to use a twenty 3 DB step LED power meter or analogue VU meter circuit, figure out a variant for the PSU inrush limiter, a clipping circuit, choose an input balanced line circuit option and find a case or case design I can build from metal stock, find a appropriate thermal 60C sensor for PSU cut off and a creative heatsink solution before I can get down to build an initial stereo pair. My initial stereo pair would be based on using a 20-0-20 VAC 160 VA secondary toroid. If all goes well I would then build a second 20-0-20 VAC 160 VA based stereo pair. Once I have the finer points of building worked out then I woudl build some amps based on the 44-0-44 VAC secondary 927 VA and 1127 VA toroids.
As an aside, just by luck I happend to discover a commerical design receiver locally a couple weeks ago and was on sale for $80.00 CND last week. It is based on the 2SC5200/2SA1943 output power devices (one pair per channel) and 2SB649A/2SD669A drivers. Considering the price for this 100W a channel receiver which also has a toroid power supply lots of heatsinking, but sadly only has 4700uF PSU filtering I choose to purchase it as bridge to an aging stereo amp of 1977 based on one Sony 2SD339 one each side of the rail for each amp. Now you know why I need to build some newer design amps. For the price this $80.00 amp performs very well and seems to have good dymanics and ease of handling of. It also runs very cool whereas the 2SB339 based amp runs warm for same music level demands. This 2SC5200/2SA1943 amp will bridge me some extra time to buidl the quasi mosfet amps. I still have a fair amount of sourcing of other supporting circuits and case/heatsinking yet to do for the quasi amps with varied available time so it may still be 6+ months before I am able to build my first quasi mosfet amp.
I had a mosfet amp design froman early 1990's article, but sadly many of the small signal devices were next to impossible to be found locally. I liked the N based quasi complementary designs, no pun intended. The Holton N-Channel amp was of interest, but seemed to have some stability challenges. That caused me to sit on the fence until the wonderful quasi design of this thread appeared. I also look forward BiPolar varient of the quasi mosfet design. that quasi indicated will start a new thread for. I may elect to try the BiPolar design for lower PSU rail if there is a smaller rail loss seen by the BiPolar output devices.
Regards,
John L. Males
Willowdale, Ontario
Canada
03 April 2006 00:20
There is no hurry for answer to these questions.
I have simple question re T2/T3. Aside from the 2SA970 you suggested I use a cheaper more common part for I can also buy the specified BC556(C), and BC560C. The simple question is related to the BC560C and 2SA970, Vceo rating of these two ignored, is these any advantage to these two low noice characteristics for T2/T3, or is it better to save them for circuits that need their low noise characteristics? I am assuming in theory yes, so the real qustion is if ther eis a remote sonic advantage?
The same basic question regarding using a low noise alternate for T4 is of any advantage.
I do not have a "store" like you do so I have the option to use alternates to the ones you choose in the event you feel there is some possible advantage. I know your audiophile friend seems very happy with the choices that you used as a whole for the amp you have built. I do not have your level of circuit topology knowledge to know if there is or not any such advantages.
With respect to T8 Vbe, based on local part availabiliity and research of TO-126/T0-220 parts I have narrowed down to what I think are two candidates - 2SC2911 and 2SC3502. The 2SC2911 appears with my limited knowledge and read of the spec sheets appears to be the best choice as a alternate for T8 Vbe with my limited knowledge. The question is if you feel my conclusions are off due to my little knowledge is dangerous.
The 2SC2911 is a T)-126 all plastic case with no metal at all, i.e. not even about the mounting hole rear. The plastic only case T)-126 has the advantage of not requiring any thermal insulation to mount to the heatsink. Is there any downside to using a TO-126 all plastic case? I know the BC546 you used is all plastic case, but the TO-92 case is smaller and may be more responsive to sense temperature changes of the heatsink in the method you used to interface to the heatsink. As a side question regarding the Vbe I have read conflicting information as to or not to mount the Vbe on an output driver or on the heatsink of the output devices. I know your use of the BC546 mounting is in effect to mount on the heatsink and not the output device. A simple answer if has any difference or pros/cons to either approach is all I really need in terms of an answer.
I remember seeing your case layout pic posts, but I am not clear on one aspect of your final case. The question is regarding your final case. Did the case have any ventilation? I ask as the MJE340s/350s are mounted to a heatsink and noted to run very warm normally. I am assuming you had some form of ventiliation so the internal temperature of the amp does not keep rising form the MJE340s/350s heat?
I am still researching alternates to the MJE340/350 parts for two basic reasons. Basically no local availability of these parts and my desire to use a larger dimensioned part to reduce the heat related stress to T6/T7/T9/T10. I am aware of the alternate resistor values you provided to a member to reduce the heat of theses devices a bit. I am trying to determine through research if alternates will be as good as the MJEs and/or if I will ensure a large heat sink solution to help keep the heat stress lower.
The next step for me is to find or use an existing design to use a twenty 3 DB step LED power meter or analogue VU meter circuit, figure out a variant for the PSU inrush limiter, a clipping circuit, choose an input balanced line circuit option and find a case or case design I can build from metal stock, find a appropriate thermal 60C sensor for PSU cut off and a creative heatsink solution before I can get down to build an initial stereo pair. My initial stereo pair would be based on using a 20-0-20 VAC 160 VA secondary toroid. If all goes well I would then build a second 20-0-20 VAC 160 VA based stereo pair. Once I have the finer points of building worked out then I woudl build some amps based on the 44-0-44 VAC secondary 927 VA and 1127 VA toroids.
As an aside, just by luck I happend to discover a commerical design receiver locally a couple weeks ago and was on sale for $80.00 CND last week. It is based on the 2SC5200/2SA1943 output power devices (one pair per channel) and 2SB649A/2SD669A drivers. Considering the price for this 100W a channel receiver which also has a toroid power supply lots of heatsinking, but sadly only has 4700uF PSU filtering I choose to purchase it as bridge to an aging stereo amp of 1977 based on one Sony 2SD339 one each side of the rail for each amp. Now you know why I need to build some newer design amps. For the price this $80.00 amp performs very well and seems to have good dymanics and ease of handling of. It also runs very cool whereas the 2SB339 based amp runs warm for same music level demands. This 2SC5200/2SA1943 amp will bridge me some extra time to buidl the quasi mosfet amps. I still have a fair amount of sourcing of other supporting circuits and case/heatsinking yet to do for the quasi amps with varied available time so it may still be 6+ months before I am able to build my first quasi mosfet amp.
I had a mosfet amp design froman early 1990's article, but sadly many of the small signal devices were next to impossible to be found locally. I liked the N based quasi complementary designs, no pun intended
. The Holton N-Channel amp was of interest, but seemed to have some stability challenges. That caused me to sit on the fence until the wonderful quasi design of this thread appeared. I also look forward BiPolar varient of the quasi mosfet design. that quasi indicated will start a new thread for. I may elect to try the BiPolar design for lower PSU rail if there is a smaller rail loss seen by the BiPolar output devices.Regards,
John L. Males
Willowdale, Ontario
Canada
03 April 2006 00:20
Hi,
quasi if while you oversee the building of one of the four amps (two stereo pairs) for your audiophile friend you could measure the in circuit Vceo of all but the output drivers at idle and 1 watt that would be most helpful and the PSU supply rail voltage for these respective set of measurements. If you made any changes to the any of the part values from what is listed in the schematic those differences will need to be noted so one can relate to the measuremeents. When you do these measurements it would be helpful to know what hFE versions (no need to measure the hFE) and maker (Phillips, CDIL, Toshiba, Hatachi, etc) is on the BC5xx and 2SC1845 parts. For example the BC5xx parts usually have an hFE version code of A, B or C and the 2SC1845 has an hFE code of GR or BL. Again no need to measure the hFE of these. If you are using MJE's other than Motorola/Onsemi can you let me know what make was used. I ask for the make as from reading the SPEC sheets of the different makes for the same part and my own experience of sample hFE measurements there are some differences from the SPECS and the sampling has shown differences in the typical hFE values of a part based on who makes the part.
Now if anyone else is bold enough to also provide the above information as well that would be great as well. I will also ensure I provide this information as well here.
I am trying to come up with a quasi specific test board so I can experiment with some different parts and evaluate any possible differences before I settle in on what parts I will use. Some parts will be to test out a few different transistors and output devices as well as previously suggested alternate resistor values for the MJE part heat, different gain, evaluate a couple different PSU line electrolytic capacitor makes and values (Siemens, Nippon mostly, maybe a Rubycon) and a couple if different input section capacitor makes and values. I have an idea how I will be able to make this test jig board, but still have to settle out a few elements and then the actual layout. The reason for this is mostly to evaluate different output device choices (the shortlist hitlist is APT4025BN, IRF740, IRF640N, IRFP140, IRF540(N), IRFP250N, IRFP240, IRFP340, IRF630(N), IRF530(N) compared to the IRFP450) evaluate the use of 220uF to 1000uF for the PSU supply line filter, confirm the alternate Vbe part I will use which may be an IRF to match the output device thermal charactisitics, possible alternate parts for the MJEs, and what effect certain passive part matching has. I know quasi has done much research, testing and enduring of feedback comments to acheive the designthat has very endearing qualities.
As this is a DIY project for me I am doing the special evaluation test jig for three reasons. One is to learn a bit more about the design, second to evaluate certain elements my research/reading over that past year has given as food for thought I like to see if I can evaluate, and thirdly to ensure any alternate parts I choose do not detract from the wonderful results that quasi's design has had.
Regards,
John L. Males
Willowdale, Ontario
Canada
04 April 2006 06:36
quasi if while you oversee the building of one of the four amps (two stereo pairs) for your audiophile friend you could measure the in circuit Vceo of all but the output drivers at idle and 1 watt that would be most helpful and the PSU supply rail voltage for these respective set of measurements. If you made any changes to the any of the part values from what is listed in the schematic those differences will need to be noted so one can relate to the measuremeents. When you do these measurements it would be helpful to know what hFE versions (no need to measure the hFE) and maker (Phillips, CDIL, Toshiba, Hatachi, etc) is on the BC5xx and 2SC1845 parts. For example the BC5xx parts usually have an hFE version code of A, B or C and the 2SC1845 has an hFE code of GR or BL. Again no need to measure the hFE of these. If you are using MJE's other than Motorola/Onsemi can you let me know what make was used. I ask for the make as from reading the SPEC sheets of the different makes for the same part and my own experience of sample hFE measurements there are some differences from the SPECS and the sampling has shown differences in the typical hFE values of a part based on who makes the part.
Now if anyone else is bold enough to also provide the above information as well that would be great as well. I will also ensure I provide this information as well here.
I am trying to come up with a quasi specific test board so I can experiment with some different parts and evaluate any possible differences before I settle in on what parts I will use. Some parts will be to test out a few different transistors and output devices as well as previously suggested alternate resistor values for the MJE part heat, different gain, evaluate a couple different PSU line electrolytic capacitor makes and values (Siemens, Nippon mostly, maybe a Rubycon) and a couple if different input section capacitor makes and values. I have an idea how I will be able to make this test jig board, but still have to settle out a few elements and then the actual layout. The reason for this is mostly to evaluate different output device choices (the shortlist hitlist is APT4025BN, IRF740, IRF640N, IRFP140, IRF540(N), IRFP250N, IRFP240, IRFP340, IRF630(N), IRF530(N) compared to the IRFP450) evaluate the use of 220uF to 1000uF for the PSU supply line filter, confirm the alternate Vbe part I will use which may be an IRF to match the output device thermal charactisitics, possible alternate parts for the MJEs, and what effect certain passive part matching has. I know quasi has done much research, testing and enduring of feedback comments to acheive the designthat has very endearing qualities.
As this is a DIY project for me I am doing the special evaluation test jig for three reasons. One is to learn a bit more about the design, second to evaluate certain elements my research/reading over that past year has given as food for thought I like to see if I can evaluate, and thirdly to ensure any alternate parts I choose do not detract from the wonderful results that quasi's design has had.
Regards,
John L. Males
Willowdale, Ontario
Canada
04 April 2006 06:36