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Old 5th March 2013, 08:14 PM   #21
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Originally Posted by DF96 View Post
Sad to see a reputable company like Ohmite now producing 'audio grade' wirewounds. I guess business is business, though.
Quite the contrary . A good company with real manufacturing get paid for producing a quality product and cutting out the snake oil salesman's markup by using the saleman's terms for there properly produced quality product . This is the highest level of good when the people who design and build thing are the ones who get paid. If that takes using snake oil salesman terms to accomplish SO BE IT.
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Old 5th March 2013, 08:40 PM   #22
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Thanks ITPhoenix. I've been working with many musicians in studio and on stage and I have to admit they are really " golden ears " listeners.
Back to yours PSU, CRC topology " sounds " better than CLC in transistors amps, based on my personal experience.
And to get better results ( God don`t leave me alone right now, please ) OVERSIZED capacitors are usefull to have a good " kick" in bass/midbass frequencies.

ciao
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Old 5th March 2013, 10:05 PM   #23
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Originally Posted by bicefalo View Post
Thanks ITPhoenix. I've been working with many musicians in studio and on stage and I have to admit they are really " golden ears " listeners.
Back to yours PSU, CRC topology " sounds " better than CLC in transistors amps, based on my personal experience.
And to get better results ( God don`t leave me alone right now, please ) OVERSIZED capacitors are usefull to have a good " kick" in bass/midbass frequencies.

ciao
Yes, and DC heaters feeding the preamp tubes supposedly increases bass response from what I hear. This is one of the things I think are missing from the average treble guitar amp.

And the other is about 300Hz and up but only on the upper registers; ~ fret 8 and up. There is too much in my head right now, but I believe there was something about that in the reservior thread; that using smaller "fast" caps at the end of the chain, and in fact placed right on the output terminals, may help with upper frequencies in some respects, but I forgot.
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Old 5th March 2013, 10:20 PM   #24
DF96 is offline DF96  England
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Quote:
Originally Posted by ITPhoenix
DC heaters feeding the preamp tubes supposedly increases bass response from what I hear.
I would be amused to see an 'explanation' of that!
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Old 5th March 2013, 10:51 PM   #25
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Originally Posted by DF96 View Post
I would be amused to see an 'explanation' of that!
I would settle just to see it! There are myriad claims, often with no documentation, or in this case, even an explanation. But I keep seeing this common denominator in all these "schemes". A change in just one component may affect the entire amplifier in various ways. So perhaps it's not the fact the heaters are DC, but what happened to the rest of the circuits by doing so.

To the best of my knowledge, most all-tube bass amps have AC heaters. Or at least the ones that do, sound awesome. I liked the Sunns from the 1970s fed by Richenbachers, but I never ventured to find out if the one I heard was SS or tube. All I knew was that if I decided to play bass, that was the setup. Or if I had the money, one of the Ampeg "necktie blowers".

I am going with DC heaters for the reason that there will be switches at each socket for the two different kinds of heater connections (at least that's the plan). I expected complications around the switches where there is no choice but to separate the wires. And also, it appears DC heaters are used on all the good, tube preamps. Why? I don't know.
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Old 5th March 2013, 11:20 PM   #26
GoatGuy is offline GoatGuy  United States
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ITPhoenix,

Stuff which is repeated over, and over, as if it is gospel, often (and more often than not!) is nowhere near as patent as its advocates attest.

The original question was "what is that 1 ohm 17 watt wire-wound resistor doing in series with the 560 nF power supply distal capacitor? There have been a number of answers, but the best were along the lines of a high-frequency snubber. Indeed - if the amplifier sections are prone to HF (radio frequency) oscillation, then a whole lot of oscillation can travel down those power-supply wires. If the power supply has "naked caps" along the chain, they can aggravate - increase - the RF feedback problem. Having a moderately resistive cap could serve to quench RF oscillation before it gets carried away.

Apart from that though, it serves little to no other purpose. It might very slightly take the edge off the most spiky treble passages ... if the wiring from power supply to that last distal capacitor is long, and of thin-gauge wire (intentionally having a very low resistance element in series with the main power supply!) I've done this before, with results that are surprisingly good. But by no means am I advocating it. It takes careful calculation, and actually finding the right kind of wire to do the job in just the right way.

There is absolutely NO difference between the bass-response of tubes heated with A/C or D/C power, so long as the tubes are correctly heated to the right level. (It is surprising just how many tube amplifiers, especially mass-produced-for-guitarists ones have insufficient heater supplies.)

DC filament heating is a modern trend that has buckets of snake oil supposing magnificent features but which in the end don't show up in fact. And, like all trendy things, since the public really doesn't know, but are influenced by marketing fantasies ... "follow-the-leader-ism" is the norm. Anyone remember when all turntables had tall spindles where one could [horrors!] stack LPs to DROP onto each other automatically? Oh my, was that a bad idea.

Even some of the higher end stereo had 'em. BECAUSE "Ma and Pa Kettle" didn't know any better, and wanted what had been highly touted in the 1950s. Automatic, like juke boxes, washing machines and dishwashers. 8 tracks in cars. 8 tracks everywhere, in glorious low-def mono.

Have fun, don't get wrapped up in the falderal, and keep your first attempts SIMPLE. No dried lizards, no sacrificing of chickens at midnight, no skeins of garlic kept in shoeboxes in the electronic-parts cabinet.

GoatGuy
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Old 5th March 2013, 11:21 PM   #27
GoatGuy is offline GoatGuy  United States
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ITPhoenix,

Stuff which is repeated over, and over, as if it is gospel, often (and more often than not!) is nowhere near as patent as its advocates attest.

The original question was "what is that 1 ohm 17 watt wire-wound resistor doing in series with the 560 nF power supply distal capacitor? There have been a number of answers, but the best were along the lines of a high-frequency snubber. Indeed - if the amplifier sections are prone to HF (radio frequency) oscillation, then a whole lot of oscillation can travel down those power-supply wires. If the power supply has "naked caps" along the chain, they can aggravate - increase - the RF feedback problem. Having a moderately resistive cap could serve to quench RF oscillation before it gets carried away.

Apart from that though, it serves little to no other purpose. It might very slightly take the edge off the most spiky treble passages ... if the wiring from power supply to that last distal capacitor is long, and of thin-gauge wire (intentionally having a very low resistance element in series with the main power supply!) I've done this before, with results that are surprisingly good. But by no means am I advocating it. It takes careful calculation, and actually finding the right kind of wire to do the job in just the right way.

There is absolutely NO difference between the bass-response of tubes heated with A/C or D/C power, so long as the tubes are correctly heated to the right level. (It is surprising just how many tube amplifiers, especially mass-produced-for-guitarists ones have insufficient heater supplies.)

DC filament heating is a modern trend that has buckets of snake oil supposing magnificent features but which in the end don't show up in fact. And, like all trendy things, since the public really doesn't know, but are influenced by marketing fantasies ... "follow-the-leader-ism" is the norm. Anyone remember when all turntables had tall spindles where one could [horrors!] stack LPs to DROP onto each other automatically? Oh my, was that a bad idea.

Even some of the higher end stereo had 'em. BECAUSE "Ma and Pa Kettle" didn't know any better, and wanted what had been highly touted in the 1950s. Automatic, like juke boxes, washing machines and dishwashers. 8 tracks in cars. 8 tracks everywhere, in glorious low-def mono.

Have fun, don't get wrapped up in the falderal, and keep your first attempts SIMPLE. No dried lizards, no sacrificing of chickens at midnight, no skeins of garlic kept in shoeboxes in the electronic-parts cabinet.

GoatGuy
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Old 5th March 2013, 11:32 PM   #28
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Quote:
Originally Posted by ITPhoenix View Post
I would settle just to see it! There are myriad claims, often with no documentation, or in this case, even an explanation. But I keep seeing this common denominator in all these "schemes". A change in just one component may affect the entire amplifier in various ways. So perhaps it's not the fact the heaters are DC, but what happened to the rest of the circuits by doing so.

To the best of my knowledge, most all-tube bass amps have AC heaters. Or at least the ones that do, sound awesome. I liked the Sunns from the 1970s fed by Richenbachers, but I never ventured to find out if the one I heard was SS or tube. All I knew was that if I decided to play bass, that was the setup. Or if I had the money, one of the Ampeg "necktie blowers".

I am going with DC heaters for the reason that there will be switches at each socket for the two different kinds of heater connections (at least that's the plan). I expected complications around the switches where there is no choice but to separate the wires. And also, it appears DC heaters are used on all the good, tube preamps. Why? I don't know.
Preamps use dc heaters to reduce noise on them . With a bass amp if you lift the ac up about 45 volts above the cathode voltage it will be very quiet for your use. much easier then dc the heaters . dead quiet is not as big a thing in a bass amp as it is in a preamp. As for better bass with dc heater whow . Think I need so popcorn for that answer. That is some high grade snake oil not found in at least any first second or third world countries.
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Old 6th March 2013, 12:16 AM   #29
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Originally Posted by Triodethom View Post
Preamps use dc heaters to reduce noise on them . With a bass amp if you lift the ac up about 45 volts above the cathode voltage it will be very quiet for your use. much easier then dc the heaters . dead quiet is not as big a thing in a bass amp as it is in a preamp. As for better bass with dc heater whow . Think I need so popcorn for that answer. That is some high grade snake oil not found in at least any first second or third world countries.
Well, reduced noise was another consideration. That is one of my design criteria. I always detested the slightest amount his or hum when it was quiet in the room. Granted, that's off the deep end, but who has the authority to determine what my cloud should be?

Thank you for that input.
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Old 6th March 2013, 12:48 AM   #30
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Originally Posted by ITPhoenix View Post
Well, reduced noise was another consideration. That is one of my design criteria. I always detested the slightest amount his or hum when it was quiet in the room. Granted, that's off the deep end, but who has the authority to determine what my cloud should be?

Thank you for that input.
Are we speaking of play back amps or performing bass amps ? The farther down the line the amplification stage is the less the noise of the heater matters. Since about 1950s elevated heater voltage has been shown to lower that hiss you speak of .

Last edited by Triodethom; 6th March 2013 at 12:50 AM.
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