The unit is pretty, nice selection of parts, nice enclosure
for sure this stimulates our imagination... sound may be very good too...and increased by our imagination.
Pretty unit.... i would be happy watching the schematic.
hehe..everybody will be happy.... was it posted?.... i have jumped from the beginning to the end, as i perceived people enjoying a good play about.
Good thread...has a nice spirit....interesting a rich guy having a kitchen 15 feet distant from the pré amplifier...this is a very poor house here..
ahahahahha
regards,
Carlos
for sure this stimulates our imagination... sound may be very good too...and increased by our imagination.
Pretty unit.... i would be happy watching the schematic.
hehe..everybody will be happy.... was it posted?.... i have jumped from the beginning to the end, as i perceived people enjoying a good play about.
Good thread...has a nice spirit....interesting a rich guy having a kitchen 15 feet distant from the pré amplifier...this is a very poor house here..
ahahahahha
regards,
Carlos
X, I agree that I am a poor guy, BUT I do own a CTC Blowtorch. Maybe, it is because I designed the insides, that I can afford the unit. The price to you, my friend is: 5,000,000 yen + shipping. Perhaps, you would want one? 😉
Hi jbaudiophile,
I think you'll find that we mostly agree on audio subjects. I keep some new ceramic cpas around of HF bypass work and the odd RF job. Same for Carbon comps. Most of my old stock had drifted way out of spec so I threw the lot out. I buy them as I need them. They should have a "best before date" on them. 🙂
Hey Carlos,
Good to see you in this noisy thread. There is a great deal of info to be had if you read carefully.
Hi John,
I'd love to check out a Blowtorch. I am looking for a preamplifier to replace my Marantz 3650. This is a much better unit than people give it credit for. It's a very hard act to follow. The switches are killing it. I'll ask Carlos what he thinks of your Blowtorch then. 😉
I'm not wealthy either, far from it! A new 'scope is required before I consider buying any audio gear. They ain't cheap! Will you be showing up at the "The Burning Amp Festival"? It might be nice to meet you in person.
-Chris
I think you'll find that we mostly agree on audio subjects. I keep some new ceramic cpas around of HF bypass work and the odd RF job. Same for Carbon comps. Most of my old stock had drifted way out of spec so I threw the lot out. I buy them as I need them. They should have a "best before date" on them. 🙂
Hey Carlos,
Good to see you in this noisy thread. There is a great deal of info to be had if you read carefully.
Hi John,
I'd love to check out a Blowtorch. I am looking for a preamplifier to replace my Marantz 3650. This is a much better unit than people give it credit for. It's a very hard act to follow. The switches are killing it. I'll ask Carlos what he thinks of your Blowtorch then. 😉
I'm not wealthy either, far from it! A new 'scope is required before I consider buying any audio gear. They ain't cheap! Will you be showing up at the "The Burning Amp Festival"? It might be nice to meet you in person.
-Chris
Hi, Anatech,
"Burning amp festival" ??? Should be a quite good idea (and funny to run... With sub-threads : best cap explosion, best finger burning,...). LOL !
20 years ago, I was tweaking with my fresh Curtis Class A amps (60W), and doing my best to have the idle current fixed... Was called out by my wife for a few seconds... When back, the PCB was deep burnt (could see the glass fiber tissue in !!!), and the 5W wirewound resistors were almost vaporized... I just missed the flames, but had the smell...
Quite the contrary to John's... Amps odours came to the kitchen...
Anyway, Blowtorch is quite "tank built", and little agressive air would go in... Perhaps an idea here??? What about neon/helium/... filled cases ???😀 WOW !
All the best,
Jbaudiophile
"Burning amp festival" ??? Should be a quite good idea (and funny to run... With sub-threads : best cap explosion, best finger burning,...). LOL !
20 years ago, I was tweaking with my fresh Curtis Class A amps (60W), and doing my best to have the idle current fixed... Was called out by my wife for a few seconds... When back, the PCB was deep burnt (could see the glass fiber tissue in !!!), and the 5W wirewound resistors were almost vaporized... I just missed the flames, but had the smell...
Quite the contrary to John's... Amps odours came to the kitchen...
Anyway, Blowtorch is quite "tank built", and little agressive air would go in... Perhaps an idea here??? What about neon/helium/... filled cases ???😀 WOW !
All the best,
Jbaudiophile
Good ceramic capacitors
In his capacitor sound series, Cyril Bateman wrote :
---COG : temperature coefficient : +/- 30 ppm [...]
COG ceramic provides the most stable capacitor value over long time periods and temperature excursions. It is frequently used as a capacitance transfer standard in calibration labatories [...]
For small, low distorsion up to 10 nF, my personal choice would be COG ceramic, also including discs up to N750, extended fois/PS and extended foil/PP, with the leadout wires soldered to the eletrodes.---
His measurements for a 10 nF class 1 COG ceramic at 100 or 1000 Hz, with a signal of 4 Vrms and 18 BV bias across it gave an total harmonic distorsion of 0.00009%. In the same conditions, a class 2 X7R gave 0.14495%.
In his capacitor sound series, Cyril Bateman wrote :
---COG : temperature coefficient : +/- 30 ppm [...]
COG ceramic provides the most stable capacitor value over long time periods and temperature excursions. It is frequently used as a capacitance transfer standard in calibration labatories [...]
For small, low distorsion up to 10 nF, my personal choice would be COG ceramic, also including discs up to N750, extended fois/PS and extended foil/PP, with the leadout wires soldered to the eletrodes.---
His measurements for a 10 nF class 1 COG ceramic at 100 or 1000 Hz, with a signal of 4 Vrms and 18 BV bias across it gave an total harmonic distorsion of 0.00009%. In the same conditions, a class 2 X7R gave 0.14495%.
Hi Reinhard,
---How can he measure 0,00009 % distortion?---
Cyril Bateman wrote a whole project about that in Electronics World and made PCB's available as well as a complete CD-rom with many of his designs.
Its THD meter uses a very low distorsion sine generator based on a Linsley-Hood design, a notch filter and a simple sound card with FFT software. The limit of measurement is about 0.00005%.
---How can he measure 0,00009 % distortion?---
Cyril Bateman wrote a whole project about that in Electronics World and made PCB's available as well as a complete CD-rom with many of his designs.
Its THD meter uses a very low distorsion sine generator based on a Linsley-Hood design, a notch filter and a simple sound card with FFT software. The limit of measurement is about 0.00005%.
-60dB passive notch (tuneable twin Tee) -> 4 stages of low noise amplification w bandbass filtering 50dB@100Hz, 20dB@20kHz -> analyzer
We discovered problems with distortion in ceramic caps about 34 years ago.
Tektronix accidently found that a measurement modification to the 577 curve tracer showed the ceramic problems clearly. They showed this to me in Feb. 1974. I told Bruel & Kjaer within the year, and a section was added to a technical paper showing the distortion. Later, in 1978, I presented an IEEE paper 'Omitted Factors in Audio Design' that showed distortion in both tantalum and ceramic caps. Walt Jung was at that IEEE conference and took note. It took many years for people to try, and even admit that there was a problem with typical ceramic caps. The better ceramic caps are EXPENSIVE, VERY LARGE, AND SMALL VALUED. Therefore, they are not often used. Their greatest asset is low tempco.
I have avoided using ceramic caps for the last 34 years, once that I realized that it was a source of 3 separate distortions: Normal IM or Harmonic, DA, and 'Non-return to zero' distortion. A person has to be almost reckless or non-caring to use these caps in critical audio pathways. The fix is to use a different type of cap with lower distortion.
The best caps are usually polystyrene and teflon, but they cost real money, and take space. Another alternative is to design the caps out of the series path and use servos to keep the output, DC stable.
Tektronix accidently found that a measurement modification to the 577 curve tracer showed the ceramic problems clearly. They showed this to me in Feb. 1974. I told Bruel & Kjaer within the year, and a section was added to a technical paper showing the distortion. Later, in 1978, I presented an IEEE paper 'Omitted Factors in Audio Design' that showed distortion in both tantalum and ceramic caps. Walt Jung was at that IEEE conference and took note. It took many years for people to try, and even admit that there was a problem with typical ceramic caps. The better ceramic caps are EXPENSIVE, VERY LARGE, AND SMALL VALUED. Therefore, they are not often used. Their greatest asset is low tempco.
I have avoided using ceramic caps for the last 34 years, once that I realized that it was a source of 3 separate distortions: Normal IM or Harmonic, DA, and 'Non-return to zero' distortion. A person has to be almost reckless or non-caring to use these caps in critical audio pathways. The fix is to use a different type of cap with lower distortion.
The best caps are usually polystyrene and teflon, but they cost real money, and take space. Another alternative is to design the caps out of the series path and use servos to keep the output, DC stable.
There was a nice article (Picking capacitors, Jung/Marsh).
Ceramics depend on material used, they are often non-linear. This is a problem, especially in feedback application. Also, when designing active filter, avoid any ceramics!!
Ceramics depend on material used, they are often non-linear. This is a problem, especially in feedback application. Also, when designing active filter, avoid any ceramics!!
Lineup gives sample of this article in post #129
PICKING CAPACITORS
The authors would like to acknowledge private discussions with John Curl and J. Peter Moncrieff on the subject of capacitors in audio circuits and how they might influence subjective testing.
Regards
Eric
PICKING CAPACITORS
The authors would like to acknowledge private discussions with John Curl and J. Peter Moncrieff on the subject of capacitors in audio circuits and how they might influence subjective testing.
Regards
Eric
Do you remember the tantalum capacitor craze of the mid to late 70's. Never could understand that.
-Chris
-Chris
Tantalum was the capacitor of choice in the '60's and 70's. They were cheap, small, reliable, low leakage, and worked well with DC bias on them, for the most part. The ONLY reason tantalum is not used so much today is because the price of Tantalum went way up, because of civil wars, etc. Also, the Japanese started to make very good aluminum caps, to replace tantalum.
Tantalum MUST be DC biased, otherwise absolutely unusable in signal path. Tantalum is the most non-linear capacitor, it is worse in distortion terms than aluminium electrolyte!
Hi John,
Most product I saw on the bench misused these parts. They had a distinct sound to be sure. "They" are attempting to bring newer production tantalum capacitors back into the marketplace.
Funny you should mention new electrolytic capacitors. Often when I service an older product, the older cap is superior to the new manufacture capacitor in the better brand products (Marantz for example). So I have to be careful what I replace.
Any opinion on "Oscon" types? I know you have done a lot of study on capacitors.
-Chris
Most product I saw on the bench misused these parts. They had a distinct sound to be sure. "They" are attempting to bring newer production tantalum capacitors back into the marketplace.
Funny you should mention new electrolytic capacitors. Often when I service an older product, the older cap is superior to the new manufacture capacitor in the better brand products (Marantz for example). So I have to be careful what I replace.
Any opinion on "Oscon" types? I know you have done a lot of study on capacitors.
-Chris
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