6V6 line preamp - Page 13

albertli · 17th September 2008, 04:58 AM

Do they sound nice?

Salas · 17th September 2008, 05:15 AM

Nice. Have to listen more to tell you their exact traits.

albertli · 23rd September 2008, 03:30 AM

Salas,

I'm going to make it drive the Pass Lab F4 power amp. Can you tell what kind of gain ( db ) it can provide?

Thanks

Salas · 23rd September 2008, 03:47 AM

15dB or times 5.6

albertli · 23rd September 2008, 05:12 AM

Thanks

Salas · 28th September 2008, 05:04 AM

With a 1V P-P input and about 6V P-P output (volume control at max), this is the distortion it charts. Only second harmonic above the grass. 3rd etc are missing in action. Also, otherwise much possible 50 & 100 Hz hum peaks, are missing in action too with the regulator used.
At half the volume rotation, it gives 0.07% THD and 0.051% IMD. I am not sure if the percentages are right or actually lower (I used an IBM Thinkpad which loops 0.05% by itself), but the shapes are correct.

albertli · 21st October 2008, 02:48 PM

Salas,

I've collected all parts I'll need for the project with 2 very nice nos philips 6v6.
I'd like to make use of all other parts I have in hand. 350-0-350 120ma tranny, cv378, 32H choke and couple 100uf Elna Cerafine and 50k 25w breeder but don't know if the tranny is too big?

Albert

Salas · 21st October 2008, 05:11 PM

Looks like too big for voltage. But there are always resistors to calculate voltage drops to suit. Keep in mind that all you need is a 340V, clean B+ under load. There are many different ways to skin a cat.

albertli · 27th October 2008, 02:46 PM

I'm looking for another tranny for this pre, 300-0-300 sounds more suitable.
Have you ever thought of making it a balanced pre?

Salas · 27th October 2008, 05:58 PM

Yes, its more suitable.

No, I haven't tried to make a balanced pre. My best source is my humble TT with Denon DL-160 through my Jfet Riaa design. Its single ended. But my Benchmark DAC-1 has balanced outputs too, and I can always design a new Riaa which accepts the cartridge balanced for current amplification...hmm don't put new ideas to me. I just finish my experiments on cascoding my Jfet RIAA...

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17th September 2008, 04:58 AM	#121
albertli diyAudio Member Join Date: Nov 2004 Location: Vancouver	Do they sound nice?

17th September 2008, 05:15 AM	#122
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Nice. Have to listen more to tell you their exact traits.

23rd September 2008, 03:30 AM	#123
albertli diyAudio Member Join Date: Nov 2004 Location: Vancouver	Salas, I'm going to make it drive the Pass Lab F4 power amp. Can you tell what kind of gain ( db ) it can provide? Thanks

23rd September 2008, 03:47 AM	#124
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	15dB or times 5.6

23rd September 2008, 05:12 AM	#125
albertli diyAudio Member Join Date: Nov 2004 Location: Vancouver	Thanks

21st October 2008, 02:48 PM	#127
albertli diyAudio Member Join Date: Nov 2004 Location: Vancouver	Salas, I've collected all parts I'll need for the project with 2 very nice nos philips 6v6. I'd like to make use of all other parts I have in hand. 350-0-350 120ma tranny, cv378, 32H choke and couple 100uf Elna Cerafine and 50k 25w breeder but don't know if the tranny is too big? Albert

21st October 2008, 05:11 PM	#128
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Looks like too big for voltage. But there are always resistors to calculate voltage drops to suit. Keep in mind that all you need is a 340V, clean B+ under load. There are many different ways to skin a cat.

27th October 2008, 02:46 PM	#129
albertli diyAudio Member Join Date: Nov 2004 Location: Vancouver	I'm looking for another tranny for this pre, 300-0-300 sounds more suitable. Have you ever thought of making it a balanced pre?

27th October 2008, 05:58 PM	#130
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Yes, its more suitable. No, I haven't tried to make a balanced pre. My best source is my humble TT with Denon DL-160 through my Jfet Riaa design. Its single ended. But my Benchmark DAC-1 has balanced outputs too, and I can always design a new Riaa which accepts the cartridge balanced for current amplification...hmm don't put new ideas to me. I just finish my experiments on cascoding my Jfet RIAA...