Hi Juanitox!
Nice suggestions - will try most(exept fishing in the COLD Norwegian rivers this time of year - did much of that earlier in life- my family owned a little bit in a nice river).
One thing I forgot - I have two amps(monoblock) with 2 400 watt and 15 - 20 Caddock 50watt different resistors! Enough for a while.
But I will order the spare 2SK82 and the 100000 mF and wait with the Hammond(very heavy and expensive postage).
And I have to take my 2 week offshore-schedule in Telecom from 5 April - then my youngest daughter is into the confirmation middle of May.
So to avoid your prognosed divorce - and not having to stay in the cold river, fishing red-meat salmon - I try build in small amounts 1 hour pr day. And my boxes is mostly OK now - so I will solder resistors and such after 20 april. But also according to my family`s plans(or else.....)
Really looking forward to that day when the first stage is finished - last night I listened to Ryan Adams/Ashes and Fire. On my B1/classdD Amp - and it was like the band was playing in my house.
Wonder how can anything be even more lifelike......
Thanks Juanitox and everyone for suggestions.
Best
Olav
Nice suggestions - will try most(exept fishing in the COLD Norwegian rivers this time of year - did much of that earlier in life- my family owned a little bit in a nice river).
One thing I forgot - I have two amps(monoblock) with 2 400 watt and 15 - 20 Caddock 50watt different resistors! Enough for a while.
But I will order the spare 2SK82 and the 100000 mF and wait with the Hammond(very heavy and expensive postage).
And I have to take my 2 week offshore-schedule in Telecom from 5 April - then my youngest daughter is into the confirmation middle of May.
So to avoid your prognosed divorce - and not having to stay in the cold river, fishing red-meat salmon - I try build in small amounts 1 hour pr day. And my boxes is mostly OK now - so I will solder resistors and such after 20 april. But also according to my family`s plans(or else.....)
Really looking forward to that day when the first stage is finished - last night I listened to Ryan Adams/Ashes and Fire. On my B1/classdD Amp - and it was like the band was playing in my house.
Wonder how can anything be even more lifelike......
Thanks Juanitox and everyone for suggestions.
Best
Olav
Olav,
Here you pay 35 € for postage fee and about 120€ for two hammonds 193v
Tube-Town Online-Store - Hammond Drossel 193V ha193v
Here you pay 35 € for postage fee and about 120€ for two hammonds 193v
Tube-Town Online-Store - Hammond Drossel 193V ha193v
Rethinking
Hi ilimzn,
Thank you for the private insight, so you have a really long history with these parts and I am happy you can contribute some ideas to this thread or a thread of your own.
I hope you do not hesitate a too long time to give us some impression of your prototypes....... after rethinking all!
Hi ilimzn,
Thank you for the private insight, so you have a really long history with these parts and I am happy you can contribute some ideas to this thread or a thread of your own.
I hope you do not hesitate a too long time to give us some impression of your prototypes.......
after rethinking all!
Hi again to all!
This guy has made many SIT`s - some nice - some are strange and complex! Ilimzn may have tried some of them.
And maybe you all probably has seen them before.
Evolve Power Amplifiers
Best
Olav
This guy has made many SIT`s - some nice - some are strange and complex! Ilimzn may have tried some of them.
And maybe you all probably has seen them before.
Evolve Power Amplifiers
Best
Olav
Hi ilimzn,
Thank you for the private insight, so you have a really long history with these parts and I am happy you can contribute some ideas to this thread or a thread of your own.
I hope you do not hesitate a too long time to give us some impression of your prototypes.......
Although I have been 'into SITs' for a long time, most of my experience outside the actual behavior of the parts, is related to much more complex (perhaps needlessly complex) amplifiers, some of which do not really use the SITs to their full advantage. My prototype was a push-pull hybrid, but I have since figured out a better topology to use, and found a different part that may have some advantages which may even be peculiar amongst SITs. Now, if there was only time...
As for the SITs not being utilized with theri particular triode-like advantage, it may be due to the fact that they appeared when engineers were already taught that tubes were a thing of the past, and semiconductors were the future. I would guess that not having dealt with triodes, many would have missed the point of a SIT.
In fact, I can give you an example - Sony has a small VFET/SIT, 2SK63/79 (same part, different case) which they used in some of their amps in the phono section, as the second stage - the first being a special low-noise BJT that operates on very low currents. In this design the SIT was really only used as a FET due to it's high input impedance, to interface with the megaohm output impedance of the previous stage. It also provided a reasonably low output impedance for a two-stage amp - but lacked in gain (it's a design with RIAA network in the feedback loop), because of SIT mu. They could have easily used a largeish JFET and got better results, but there was no such part being made in-house. Paradoxally, this part was ONLY used in that position before they stopped making it, so it was never really used 'properly'. Modifying the design with a small MOSFET in it's place (now commonly available) signifficantly improves on the original.
Ilimzn thanks for all the info.
I think the point about variability in the parameters due to the power supply fluctuations points to the need either for a current source or a regulated supply as ilimzn noted (or both).
Ilimzn mentioned something about the high capacitance of mosfet ccs being not ideal for the sit. The ccs with the semisouth r100 is better in this regard since I see that it has half the capacitance of i.e. the irfp240. Correct?
What about a simple programmable ccs based on the LM338 regulator? It is not fashionable but would it sound as good as a single fet? Or does the ccs not contribute so much to sound quality?
I think the point about variability in the parameters due to the power supply fluctuations points to the need either for a current source or a regulated supply as ilimzn noted (or both).
Ilimzn mentioned something about the high capacitance of mosfet ccs being not ideal for the sit. The ccs with the semisouth r100 is better in this regard since I see that it has half the capacitance of i.e. the irfp240. Correct?
What about a simple programmable ccs based on the LM338 regulator? It is not fashionable but would it sound as good as a single fet? Or does the ccs not contribute so much to sound quality?
Have nice Easter Holidays Mike!
I have 7 different input caps In front of my SIT.......they all sound different....not easy to decide......I will switch to and fro til I can't do anymore....
I tried Panasonic ECQ, Ero1813MKT, Obbligato gold, Russian KP75 paper oil, Cornell Dubilier KP, Elna Silmic always 10uF......
And I compared with my BJ2 to get a similar or better sound balance and in this Bj2 are two Elnas, one in the negative input and one going to the upper Semisouth.
So the result was programmed .......the Elna Silmic as input cap for the SIT gave the same sound of course....
You will laugh......
The Cornell KP had the most impressive attack and accuracy but was to sharp over the time, the Russian made wonderful colors but was a bit to soft...
The Panasonic was very balanced.... The ERO too soft, the Obbligato was the loudest and had a very big image with much bass and highs, but all the film caps sounded a bit tamed against the Elna...
My last film cap try will be the Clarity caps Nelson used in BA-3 and maybe in SIT-1 ....
They are ordered and I will see...Have all nice Easter days!
And I compared with my BJ2 to get a similar or better sound balance and in this Bj2 are two Elnas, one in the negative input and one going to the upper Semisouth.
So the result was programmed .......the Elna Silmic as input cap for the SIT gave the same sound of course....
You will laugh......
The Cornell KP had the most impressive attack and accuracy but was to sharp over the time, the Russian made wonderful colors but was a bit to soft...
The Panasonic was very balanced.... The ERO too soft, the Obbligato was the loudest and had a very big image with much bass and highs, but all the film caps sounded a bit tamed against the Elna...
My last film cap try will be the Clarity caps Nelson used in BA-3 and maybe in SIT-1 ....
They are ordered and I will see...Have all nice Easter days!
Same to you!
And, thanks for the capacitor info. I've been very tempted to try some fancy caps myself.
Yes the most horrible moment is when you recognize that they sound all so different...!
The better moment is when you recognize that they all do some things good and some more bad and that you have the choice that is no choice......
And you tend to look at the components before and after that cap to be neutral, when you begin to realize how many of these components also have to consider you could get crazy by the permutations you have to test....and you begin to relax...
But back to the point really .........astonishing sound change by one cap.
Of course I will try to use "no" cap, the output cap of my UGS is Nelson like an 220uF bypassed by a 100nF MKC (hi ZM ), doing the job alone, I must only put away the 100k after the outputcap because it changes the bias voltage! To lower voltages, means higher current, means hotter SK82.
The better moment is when you recognize that they all do some things good and some more bad and that you have the choice that is no choice......
And you tend to look at the components before and after that cap to be neutral, when you begin to realize how many of these components also have to consider you could get crazy by the permutations you have to test....and you begin to relax...
But back to the point really .........astonishing sound change by one cap.
Of course I will try to use "no" cap, the output cap of my UGS is Nelson like an 220uF bypassed by a 100nF MKC (hi ZM ), doing the job alone, I must only put away the 100k after the outputcap because it changes the bias voltage! To lower voltages, means higher current, means hotter SK82.
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Thanks for that summary generg.
Can you also summarize how that mu follower circuit works?
It behaves more complicated than the simple solution B Mike suggested (CCS with Semisouth)
To give an example, I trimmed the k2 dominant to K3 and the hissing sounds got too sharp. I thought that the sound should get more darker....
So I am still looking for the right mix.....
And when I want to relax after the desperate search I take the simple MIKE CCS because it sounds simply good.
So I cannot say up to now that the MU is better or much better than plain CCS...
Gain Question
Hello-
You guys are doing a great job with this thread. I really don't need another amplifier, but I am really tempted anyway. Perhaps someone can relate.
A few questions:
1) What is the gain of the Hammond Choke version? I thought I saw 6db somewhere, but cannot seem to find it again. The CCS version I believe is 8db.
2) If I wanted to add a simple preamp to this amp, how much voltage swing is OK on the gate of the 2SK82. 5-7 volts OK? I'd like to get a good 10-15V peak output to the speakers if possible. Is that possible with just a 24V supply as in the Hammond Choke version?
3) If I go with the CCS version of this amp, what are the thermal resistance heat sink requirements on the CCS transistor, as well as the 2SK transistor. It looks like Micheal was using a .3 C/W unit from Newark for the CCS, but what about on the 2SK? I'd like to trim down the size if possible. Would a .5C/W on each device be too small?
4) I know its heresy, but I was considering going switch mode on the PSU. Maybe something from here: http://connexelectronic.com? Maybe this: http://connexelectronic.com/product...ucts_id/122?osCsid=86jtb8mjs75lhkg7ut5plrird5
Thanks again.
Hello-
You guys are doing a great job with this thread. I really don't need another amplifier, but I am really tempted anyway. Perhaps someone can relate.
A few questions:
1) What is the gain of the Hammond Choke version? I thought I saw 6db somewhere, but cannot seem to find it again. The CCS version I believe is 8db.
2) If I wanted to add a simple preamp to this amp, how much voltage swing is OK on the gate of the 2SK82. 5-7 volts OK? I'd like to get a good 10-15V peak output to the speakers if possible. Is that possible with just a 24V supply as in the Hammond Choke version?
3) If I go with the CCS version of this amp, what are the thermal resistance heat sink requirements on the CCS transistor, as well as the 2SK transistor. It looks like Micheal was using a .3 C/W unit from Newark for the CCS, but what about on the 2SK? I'd like to trim down the size if possible. Would a .5C/W on each device be too small?
4) I know its heresy, but I was considering going switch mode on the PSU. Maybe something from here: http://connexelectronic.com? Maybe this: http://connexelectronic.com/product...ucts_id/122?osCsid=86jtb8mjs75lhkg7ut5plrird5
Thanks again.
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