AKSA said:
Hugh,
Thanks for the suggestion. The prices on Toshiba devices were so
low it sounded almost like a joke. However, they do give me the
impression of selling only to OEM customers. Maybe somebody has
tried ordering small quantities for private use?
For reference:
www.peacock.com.sg
AKSA said:
Hugh,
great tip!
BTW do I understand that they will also sell in small quantities, for instance to a DIY:er..?
After visiting Peacock I tried to search for KEC's homepages but couldn't access non of them found on internet.
Not even DatasheetCatalog.com could access KEC and retreive datasheets regarding KEC transistors, does anybody know the status for the company?
Do their transistors live up to their counterparts regarding spec performances or should this brand be avoided?
Christer,
I agree with you, either I don't understand ELFA's policy these days regarding transistors...
/Michael
Ultima Thule,
If you tried to click on the manufactureres logos, then yes, only
the Toshiba link seemed to work. These are however obviously
not links to the companies, but to Peacocks inventory lists for
what they have in stock from each company. I could not find any
info about what quantities the prices applied to. If it were prices
for single or very small quantities it was very very good.
If you tried to click on the manufactureres logos, then yes, only
the Toshiba link seemed to work. These are however obviously
not links to the companies, but to Peacocks inventory lists for
what they have in stock from each company. I could not find any
info about what quantities the prices applied to. If it were prices
for single or very small quantities it was very very good.
Christer said:
Oh.., of course I used Google too...
but you'r right, it was only Toshibas link that worked on Peacocks...KEC Not working!
KEC HQ Not working!
KEC world map Works but reffering link to KEC korea don't work!
Nada....
After 4:th page on Google I give up!
But this is anyhow not an important matter, I'm not relying upon KEC..!
Maybe Peacocks prices were stated for big volume purchases as usual with far east traders...?
Hopefully Hugh do have any insight in the matter!:
By accident I found this german supplier
http://www.heldt-electronic.de/
who managed not to get easily found by search engines.
In its stock list
http://www.heldt-electronic.de/2.htm
next to all Japenese transistors mentioned in this thread can be found. For some devices an explicit hfe class is given, Korean second source is identified etc. Looks good on screen.
I haven't done any business with them yet, so I cannot give further judgement.
Regards,
Peter Jacobi
http://www.heldt-electronic.de/
who managed not to get easily found by search engines.
In its stock list
http://www.heldt-electronic.de/2.htm
next to all Japenese transistors mentioned in this thread can be found. For some devices an explicit hfe class is given, Korean second source is identified etc. Looks good on screen.
I haven't done any business with them yet, so I cannot give further judgement.
Regards,
Peter Jacobi
Guys,
Yes, you are largely correct. Large quantities; in my case nothing short of 1000. But they will sell by the 100, so if you want 100 - not unreasonable for a DIYer - they will deal.
Their logos are not marvellous, I agree, but their wonderful business efficiency and reliability is worth the trouble.
I buy my Toshibas there, but also a few other types. They also sell United Chemicon caps at excellent prices.
Cheers,
Hugh
Yes, you are largely correct. Large quantities; in my case nothing short of 1000. But they will sell by the 100, so if you want 100 - not unreasonable for a DIYer - they will deal.
Their logos are not marvellous, I agree, but their wonderful business efficiency and reliability is worth the trouble.
I buy my Toshibas there, but also a few other types. They also sell United Chemicon caps at excellent prices.
Cheers,
Hugh
Japanese transistors
I recently bought some Sanken and Sanyo power devices from profusionplc in the UK. The transistors seem to my untrained eye to be originals. They also have a limited number of small signal types from Sanyo availiable, and they offer free shipping, apparently no matter how little you buy!
I recently bought some Sanken and Sanyo power devices from profusionplc in the UK. The transistors seem to my untrained eye to be originals. They also have a limited number of small signal types from Sanyo availiable, and they offer free shipping, apparently no matter how little you buy!
AKSA said:
Hi Hugh,
what U think about 2SC1505 like substitution for 2SC1819?
2SC1819M * (from Matsushita) - TV C output, npn
Vcbo, Vceo=300V, Icmax=0.1A, Pc=15W
Hfe=50-250 (Vce=50V, Ic=5mA)
Vce(sat)=1.5V at Ic=50mA, Ib=5mA
Ft=70MHz at Vce=30V, Ic=20mA
Cob=5pF max
Case leads - B, C, E
2sc1505 - NEC
TV CHROMA AND SOUND OUTPUT AMPLIFIERS NPN TRANSISTOR
Vcbo, Vceo=300V,
Icmax=0.2A,
Pc=15W
Hfe=40-200 (Vce=10V, Ic=10mA)
Vce(sat)=2V at Ic=50mA, Ib=5mA
Ft=80MHz at Vce=30V, Ic=10mA
Cob=4.5pF max
Case leads - B, C, E
Hi,
a good VAS transistor is usually low in Cob.
Some of the earlier suggestions are high Cob (upto 30pF).
Check the data sheet for a Cob between 2pF and 6pF @ 10Vce.
I think the lower the better. Then you can add a stable Miller compensation capacitor to tailor the open loop HF response and HF feedback.
I have used
2sa1360/c3423
2sa1380/c3502
successfully and they seem to perform well considering their relatively low cost.
2sa1210, 2sa1407, 2sa1540 would be good but more expensive alternatives.
These VAS types also make good pre-drivers if you adopt triple stage darlingtons for the output.
a good VAS transistor is usually low in Cob.
Some of the earlier suggestions are high Cob (upto 30pF).
Check the data sheet for a Cob between 2pF and 6pF @ 10Vce.
I think the lower the better. Then you can add a stable Miller compensation capacitor to tailor the open loop HF response and HF feedback.
I have used
2sa1360/c3423
2sa1380/c3502
successfully and they seem to perform well considering their relatively low cost.
2sa1210, 2sa1407, 2sa1540 would be good but more expensive alternatives.
These VAS types also make good pre-drivers if you adopt triple stage darlingtons for the output.
look out for low output capacitance..
I have two absolute faVorite vas stage transistors at the moment, 2sa1145 and 2sa1360 PNP, NPN compliment is 2sc2705/2sc3423.. both pnp have an output capactitance of2.5pf and npn 1.8pf, what is the difference between these, nothing except for their power dissapation.. I finally received my backordered 1360/3423 and the 1360 sounds just like the 1145. I have used bd140/2sb631/mje15031 in the vas and none of them sound as good as the toshiba parts. I use a 47pf silver mica miller cap in this application in my amplifier
my 2 cents
Colin
I have two absolute faVorite vas stage transistors at the moment, 2sa1145 and 2sa1360 PNP, NPN compliment is 2sc2705/2sc3423.. both pnp have an output capactitance of2.5pf and npn 1.8pf, what is the difference between these, nothing except for their power dissapation.. I finally received my backordered 1360/3423 and the 1360 sounds just like the 1145. I have used bd140/2sb631/mje15031 in the vas and none of them sound as good as the toshiba parts. I use a 47pf silver mica miller cap in this application in my amplifier
my 2 cents
Colin
HEXFET IRF610 IRF9610 etc. for VAS transistor choice & performance!
Hi, stegmaie
AKSA, here told us, as I get it:
##################################
1. Speed and
2. low base/collector capacitance is important.
3. The higher the beta, the more the open loop gain of the amp,
and the more is the feedback factor.
Generally, this is good.
4. So try to find a device no slower than 100MHz and
5. a beta of 60 minimum.
6. IMHO, the voltage amp is the pivotal stage in a power amplifier.
7. keep temperatures low for reliability.
Hugh
##################################
Personally me lineup,
have found some interesting results
by using TO-220 HEXFET for doing VAS job (Voltage Amplify Stage)
It is interesting to see that Nelson Pass is one of the few,
that actually has done some work and dares to use HEXFETs (like IRF610 IRF9610 etc etc)
for Other stages than OUTPUT.
He has also shown that IRF610 can do good as a Single Voltage Amplifier
in his famous one transistor preamp BOZ.
( He also has used HEXFET / MOSFET for input in some of his amplifiers. )
AKSA opinion:
the voltage amp is the pivotal stage in a power amplifier.
Exactly
.... and too often overlooked.
_______________________________________________________________
How does for example IRF610 qualify for Hugh's hints above:
1. Speed .... they are fast!
2. Collector-Base capacitance ... acceptable, I think. I am no expert here.
Is cob the number we would look for?
3. Open loop gain ... guess it could be higher ....
But the relation Power Drive / Energy OUT is great!/
4.Ft .... >=100MHz transistion frequency. I am sure it has got it.
7. Temperture ..... No problem. IRF610, TO220 for example, can take power.
200-400mA at 30-40 Volt shouldn't be impossible
_______________________________________________________________
If you are interested in follow exploration in this matter:
To use HEXFET and other MOSFET for VAS, running at higher currents,
.... you'd be sure not to miss out our forum topic here:
Experimenting ... Volt Stage Hybrides
I will post some findings, according to amount of interest shown.
My major publishing & final Amplifiers' Toplogy, however, will be aimed for my own websites exclusively.
My special thanks to Hugh 'AKSA' Dean for sharing his personal opinion
lineup
stegmaie said:
Hi, stegmaie
AKSA, here told us, as I get it:
##################################
1. Speed and
2. low base/collector capacitance is important.
3. The higher the beta, the more the open loop gain of the amp,
and the more is the feedback factor.
Generally, this is good.
4. So try to find a device no slower than 100MHz and
5. a beta of 60 minimum.
6. IMHO, the voltage amp is the pivotal stage in a power amplifier.
7. keep temperatures low for reliability.
Hugh
##################################
Personally
me lineup,have found some interesting results
by using TO-220 HEXFET for doing VAS job (Voltage Amplify Stage)
It is interesting to see that Nelson Pass is one of the few,
that actually has done some work and dares to use HEXFETs (like IRF610 IRF9610 etc etc)
for Other stages than OUTPUT.
He has also shown that IRF610 can do good as a Single Voltage Amplifier
in his famous one transistor preamp BOZ.
( He also has used HEXFET / MOSFET for input in some of his amplifiers. )
AKSA opinion:
the voltage amp is the pivotal stage in a power amplifier.
Exactly
.... and too often overlooked.
_______________________________________________________________
How does for example IRF610 qualify for Hugh's hints above:
1. Speed .... they are fast!
2. Collector-Base capacitance ... acceptable, I think. I am no expert here.
Is cob the number we would look for?
3. Open loop gain ... guess it could be higher ....
But the relation Power Drive / Energy OUT is great!/
4.Ft .... >=100MHz transistion frequency. I am sure it has got it.
7. Temperture ..... No problem. IRF610, TO220 for example, can take power.
200-400mA at 30-40 Volt shouldn't be impossible
_______________________________________________________________
If you are interested in follow exploration in this matter:
To use HEXFET and other MOSFET for VAS, running at higher currents,
.... you'd be sure not to miss out our forum topic here:
Experimenting ... Volt Stage Hybrides
I will post some findings, according to amount of interest shown.
My major publishing & final Amplifiers' Toplogy, however, will be aimed for my own websites exclusively.
My special thanks to Hugh 'AKSA' Dean for sharing his personal opinion
lineup
Hi Lineup
What are your thoughts about cascoding a BJT with a FET for the VAS? This way the BJT can have lower voltage(faster), lower power(higher beta), (could even be SMD) cascoded to FET as a common gate? This might minimalize the signal gate drive from the input stage required for the FET to operate at faster speeds.
What are your thoughts about cascoding a BJT with a FET for the VAS? This way the BJT can have lower voltage(faster), lower power(higher beta), (could even be SMD) cascoded to FET as a common gate? This might minimalize the signal gate drive from the input stage required for the FET to operate at faster speeds.
It's certainly a good transistor for extreme VAS use. However, I think you mean Ft = 500, even though the table only specifies 400. Sanyo Hfe spec. (depending on grade) could vary from 40-320 though I think it's unlikely there are many NOS or pulls from TV sets greater than 200. HTTP 301 This page has been moved
Quite high Ic max and as a result Cob has been compromised. @10V Cob >6pF
Most parameters are plotted for Ic>4mA.
It looks like you need to get most of it's operation such that Ic never drops much below 6mA. This might indicate highish bias ~10mA to give a range from 6mA to 14mA.
Nice high knee in the SOA for a 120Vce0 device, 60Vce for the full 8W.
Most parameters are plotted for Ic>4mA.
It looks like you need to get most of it's operation such that Ic never drops much below 6mA. This might indicate highish bias ~10mA to give a range from 6mA to 14mA.
Nice high knee in the SOA for a 120Vce0 device, 60Vce for the full 8W.
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