Hi Jay,
I missed it somehow, otherwise I would have included the missing components on my PCB. I knew about the feedback circuit back in the ESP P61 days even before I had purchased my original AKSA 8 or 9 years ago. As I didn't realise Hugh had posted his schematic, and the P61 was withdrawn from ESP's website I didn't mention that part of the circuit.
The original ESP P61 AKSA used a diode string for thermal compensation, but my old AKSA version 1.6 used a transistor. I am not sure if Hugh sold any AKSA 55 kits with the diode string.
regards
I see some designers recommending the 1407/3601 in preference to the 1406/3600.
Slightly higher Cob in return for 150mA capability.
Cob 3.2pF @10Vce vs 2.3pF @ 10Vce
I could not find a source of 1407 I could afford.
Slightly higher Cob in return for 150mA capability.
Cob 3.2pF @10Vce vs 2.3pF @ 10Vce
I could not find a source of 1407 I could afford.
Hi Andrew,
I bought some A1407/C3601 from RS-online Australia, the price is reasonable
Sanyo | Semiconductors | Discretes | General Purpose Transistor | PNP Small Signal |2SA1407E
I also found out that Sanyo Semiconductor is now owned by On-semi:
ON Semiconductor Completes Acquisition of SANYO Semiconductor from SANYO Elec...
The press release did not mention audio transistors: "With the addition of SANYO Semiconductor, ON Semiconductor expands its product portfolio, adding new capabilities ranging from microcontrollers and custom Application Specific Integrated Circuits (ASICs) to integrated power modules and motor control devices for the consumer, automotive and industrial end-markets."
Cheers, Stanley
UK RS does not list 2sa1406, 1407, 2sc3600, 3601.
I wonder if Aus RS would ship to UK?
How much is australian $ 1.14 worth? 78cents seems very cheap !!!!!
I wonder if Aus RS would ship to UK?
How much is australian $ 1.14 worth? 78cents seems very cheap !!!!!
Hi Andrew, 78c IS pretty good! and buy buying 25+ you should be able to do matched pairs.
today's exchange rates: (what $1 AU will get)...
One Australian Dollar (AUD) equals:
Bank Spot Buy Bank Spot Sell Country Currency Code T/T Cheques or T/C Notes T/T or Drafts T/C or Notes
USADollarsUSD1.06401.06941.08051.02291.0090
United KingdomPoundsGBP0.65970.66370.67520.62670.6159
so taking the worst exchange rate there they would be ~53p each 🙂
sorry that table looked fine in preview but came out wrong once posted...
If they don't ship to the UK I can get them for you and post them.. Aus post isn't that cheap though so you could probably double the cost once the postage is added. (the good thing is that locally RS ships all orders free if ordered online, and I don't believe there is a minimum purchase amount for that offer. I have a number of things in the cart already that I need to get off my backside and push the purchase button 🙂
Tony.
today's exchange rates: (what $1 AU will get)...
One Australian Dollar (AUD) equals:
Bank Spot Buy Bank Spot Sell Country Currency Code T/T Cheques or T/C Notes T/T or Drafts T/C or Notes
USADollarsUSD1.06401.06941.08051.02291.0090
United KingdomPoundsGBP0.65970.66370.67520.62670.6159
so taking the worst exchange rate there they would be ~53p each 🙂
sorry that table looked fine in preview but came out wrong once posted...
If they don't ship to the UK I can get them for you and post them.. Aus post isn't that cheap though so you could probably double the cost once the postage is added. (the good thing is that locally RS ships all orders free if ordered online, and I don't believe there is a minimum purchase amount for that offer. I have a number of things in the cart already that I need to get off my backside and push the purchase button 🙂
Tony.
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Tony,
You could buy ten of them, stick them to a piece of cardboard with tape, and send in a conventional envelope to UK for $1.80.
Now that's a bargain for Al, I can see his ears glowing red already......
Hugh
You could buy ten of them, stick them to a piece of cardboard with tape, and send in a conventional envelope to UK for $1.80.
Now that's a bargain for Al, I can see his ears glowing red already......
Hugh
Hi Hugh, yes I was thinking of your trick as I posted it, though I thought the postage would be more expensive! I haven't even started to use the transistors yet 🙁 I'll get the other projects done eventually, then there will be some fun to be had with the Baksa 🙂
Tony.
Tony.
Nah, just an even brighter shade of pink. 😀
New schematic should be up in a bit, just tidying up.
I buy Sanyo components factory direct, at RS price I bet they are fakes or cheap chinese copies. RS are known to sell some fake components and I see they dont show the face of that part, maybe to hide the fact. I could be wrong........
Sng001 could you show a pic of the front of those transistors, I would be able to verify if they are true sanyo.
Sng001 could you show a pic of the front of those transistors, I would be able to verify if they are true sanyo.
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wow, it took over 500 posts to reproduce my TGM1 design 😀
you're gonna like the sound of this one.
you're gonna like the sound of this one.
Hello
Remember guy's to close match the two input transistors for vbe and hfe, it will give a better sound (resolution and soundstage).
Bye
Gaetan
Remember guy's to close match the two input transistors for vbe and hfe, it will give a better sound (resolution and soundstage).
Bye
Gaetan
Sound Buster,
Remove R10B and D1B from the negative rail. The sound quality is superior without them. This I realise is counterintuitive, but I have verified it many times.
Al,
R3 should be 56K, in order to generate 1mA stage current from 62V rails. The pot trims the offset, so this series pair must be right.
Nice job....
Hugh
Remove R10B and D1B from the negative rail. The sound quality is superior without them. This I realise is counterintuitive, but I have verified it many times.
Al,
R3 should be 56K, in order to generate 1mA stage current from 62V rails. The pot trims the offset, so this series pair must be right.
Nice job....
Hugh
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Aren't R10 and D1 to keep the bootstrap from "overshooting" the positive rail ?
As I understand you would not need to do this for the negative (active) rail/vas.
I wonder how this amp would benefit from some cap multipliers ? My sim's show barely adequate PSRR. 🙁
OS
As I understand you would not need to do this for the negative (active) rail/vas.
I wonder how this amp would benefit from some cap multipliers ? My sim's show barely adequate PSRR. 🙁
OS
A1407 & C3601 from RS
Hi homemodder.
I only bought 5 of each from RS. As far as I can tell, they are good transistors.
I built Dr. Bora's Sigma Amp: http://bas.elitesecurity.org/SIGMA-Schematic.pdf with them. The Sigma amp sounds good & I guessed that is what matters.
The parts are E-grade, I measured the Hfe: C3601 ~ 130, A1407 ~ 150.
I guessed that the stock at RS will not last very long given that On-semi now owns Sanyo and the main applications for these transistors are:
· Ultrahigh-definition CRT display.
· Video output.
· Color TV chroma output.
Attached is a picture.
Cheers, Stanley
Hi homemodder.
I only bought 5 of each from RS. As far as I can tell, they are good transistors.
I built Dr. Bora's Sigma Amp: http://bas.elitesecurity.org/SIGMA-Schematic.pdf with them. The Sigma amp sounds good & I guessed that is what matters.
The parts are E-grade, I measured the Hfe: C3601 ~ 130, A1407 ~ 150.
I guessed that the stock at RS will not last very long given that On-semi now owns Sanyo and the main applications for these transistors are:
· Ultrahigh-definition CRT display.
· Video output.
· Color TV chroma output.
Attached is a picture.
Cheers, Stanley
Attachments
OS,
R10 and D1 actually allow the bootstrap to overshoot the positive rail, and with C3 hold the node potential when the positive rail is heavily loaded by hard on NPN outputs.
Yes, barely adequate PSRR. But how important is it to sound quality, that is the question? Does this prevent the amp sounding very, very good? Nah, let it go.....
Hugh
R10 and D1 actually allow the bootstrap to overshoot the positive rail, and with C3 hold the node potential when the positive rail is heavily loaded by hard on NPN outputs.
Yes, barely adequate PSRR. But how important is it to sound quality, that is the question? Does this prevent the amp sounding very, very good? Nah, let it go.....
Hugh
Pinkmouse,
check polarity c10 & c12 , is opposite ?.
so check the gnda on c10, why connected with rail plus ?
check polarity c10 & c12 , is opposite ?.
so check the gnda on c10, why connected with rail plus ?
With "overbuilt" dual mono PS's the outcome would be very good. In a 5 channel HT amp as "modules" with a single PS , one might have issues. For it's use as a entry level audiophile project , go with the dual PS's ... especially If it is ported to 3 pair OP's (way more ripple than any "baby aksa") and asked to drive low impedance loads.
Just to show what a pair of simple 1st order mult's will do (below1 - not bad 🙂 ) is the plain 55 and (below 2) is with multipliers and 1 v p-p ripple.
Just for laughs , (below 3) is with separate front end supplies w/ .25v ripple thrown in for good measure (the real world is not perfect). 😀
