Golden Gate DAC arrives.

[Audiophile Bill]

Hi Bill,
Have you had a chance to compare 242 to Takatsuki 300B?
Thanks,
Aziz

Hi Aziz,

I have not but have done the Elrog 300b and Kr 300b balloon. I don't like either 300b in the GG and can't imagine any 300b suiting me. Nice mid range sure but rest is miles behind.

 

[abeidrov]

Hi Aziz,

I have not but have done the Elrog 300b and Kr 300b balloon. I don't like either 300b in the GG and can't imagine any 300b suiting me. Nice mid range sure but rest is miles behind.

Thanks, Bill. My concern is a point that Mike just made:the 242 gain adjustment may compromise the sound of the other tubes.

 

[bonzo75]

Thanks, Bill. My concern is a point that Mike just made:the 242 gain adjustment may compromise the sound of the other tubes.

Hi we have tried the other tubes on Lampis not adjusted for 242. In fact most of us had it that way before.

 

[Tango]

Pg. 141. This got to be the longest thread. I now understand why Lampi is very popular. First, it sounds great. Second, you can keep playing tweaking when it starts to sound normal to your ears.

 

[dctom]

As Mike suggested there can be some consequences from the power adjustment, my original 2A3s no longer worked in the GG, but they had already been superseded by my PX4s and are now sold.
On my Lampi there is a switch to toggle between 45,242 or 101D, PX4, 300B. I only have one other set of valves besides the 242s (PX4) and they sound better after the mod than before.

 

[seatrope]

Hi dctom,

Do you know what your gain (maximum output level) in mV is set to?

I just received my new GG, which is a substantial upgrade from my Big7. Although I have not had the chance to sit down for a proper listen yet, it seems like the gain is very low on my 242 optimized GG. I find that for the same sound level as my Big 7 I am at 90-95% of my (passive) preamp volume. The spec sheet says 285 mV maximum output level.

With a 45 Mesh I am pegged to 100% for normal to slightly loud listening levels.

There also seems to be an increase in background tube hash (as a result of my having the volume open almost all the way) from the GG... anyone had similar issues?

Yeang

 

[wisnon]

Hi dctom,

Do you know what your gain (maximum output level) in mV is set to?

I just received my new GG, which is a substantial upgrade from my Big7. Although I have not had the chance to sit down for a proper listen yet, it seems like the gain is very low on my 242 optimized GG. I find that for the same sound level as my Big 7 I am at 90-95% of my (passive) preamp volume. The spec sheet says 285 mV maximum output level.

With a 45 Mesh I am pegged to 100% for normal to slightly loud listening levels.

There also seems to be an increase in background tube hash (as a result of my having the volume open almost all the way) from the GG... anyone had similar issues?

Yeang

I think mine is about 600 to 700v. 285 seems low. I would prefer 550 or so.

 

[marslo]

In my setup KR 242 had to much gain and I couldn't listen to them without fatigue .
PX4 are about right together with KR 5u4g Lampi edition , keep 101d WE replicas as a spare set.

 

[dctom]

The absolute signal vol on my test report (no 24) is 540mV with242. As Norman says 285 seems low.
My pre vol is usually around 1/3 of max, unless recording level is low.

 

[microstrip]

The absolute signal vol on my test report (no 24) is 540mV with242. As Norman says 285 seems low.
My pre vol is usually around 1/3 of max, unless recording level is low.

Pre vol or loudness percent are useless and misleading units. The easiest proper way of checking output level is using a calibrated CD track (the more usual is 1000 kHz at 0 dB) and an AC voltmeter - be careful that many cheap AC voltmeters that are accurate at 50- 60 Hz have an high error at 1000 kHz.

IMHO tubes for SE type DACs should be very accurately matched and well burned-in. Otherwise the DAC would have a strong channel imbalance. In the Metronome C2 tubed DAC I had to select among many tubes to get a .1 dB match.

 

[murphys33]

My initial issue relates to gain too. My preamp was high gain and as such I could hear it loud when the preamp volume was set low. Cranking the tube also results in some background tube noise. The tubes act as antenaes and pick up rf from the surroundings. I sent this back to the factory for the gain to be recalibrate and installed shields around the tubes. You may want to try that.

 

[Legolas]

My initial issue relates to gain too. My preamp was high gain and as such I could hear it loud when the preamp volume was set low. Cranking the tube also results in some background tube noise. The tubes act as antenaes and pick up rf from the surroundings. I sent this back to the factory for the gain to be recalibrate and installed shields around the tubes. You may want to try that.

Why would anyone want more gain than standard 6v balanced? I can understand wanting more if using a passive pre-amp direct to a power amp, and in that case up to 30v is no problem via a passive pot. If used with an active pre-amp it is probably in most cases going to cause issues IMO by overdriving the input stages in an active pre-amp. Can you drop out the Ref 6?

 

[wisnon]

Pre vol or loudness percent are useless and misleading units. The easiest proper way of checking output level is using a calibrated CD track (the more usual is 1000 kHz at 0 dB) and an AC voltmeter - be careful that many cheap AC voltmeters that are accurate at 50- 60 Hz have an high error at 1000 kHz.

IMHO tubes for SE type DACs should be very accurately matched and well burned-in. Otherwise the DAC would have a strong channel imbalance. In the Metronome C2 tubed DAC I had to select among many tubes to get a .1 dB match.

This last point is not an issue for lampi DHT tube dacs. I cant recall a single case of channel imbalance. Pehaps its the auto balancing circuit.

 

[dctom]

Pre vol or loudness percent are useless and misleading units. The easiest proper way of checking output level is using a calibrated CD track (the more usual is 1000 kHz at 0 dB) and an AC voltmeter - be careful that many cheap AC voltmeters that are accurate at 50- 60 Hz have an high error at 1000 kHz.

IMHO tubes for SE type DACs should be very accurately matched and well burned-in. Otherwise the DAC would have a strong channel imbalance. In the Metronome C2 tubed DAC I had to select among many tubes to get a .1 dB match.

I am just giving Yeang a comparison - he is having to turn up his pre amp to all most full vol.

 

[microstrip]

This last point is not an issue for lampi DHT tube dacs. I cant recall a single case of channel imbalance. Pehaps its the auto balancing circuit.

Auto balancing circuit? Interesting. Can you give us a few details on it?

 

[seatrope]

Yes, I know that I should (and will probably) measure a sine wave output at 0 dBFS between my Big7 and GG to give Lukasz an idea of how much to tweak gain. It was the easiest relative but subjective measure that I could provide, which as we all know varies widely with sensitivity of ones speakers, gain of ones amp and preamp, on and on.

The interesting and relevant point here is that, Lukasz told me that he is just setting the gain low as he gets complaints from people that his DACs are too loud. That would not be an issue if the noise floor went down with the lowered gain. But what I am hearing is that the tube hash/noise stays the same between my Big7 and my GG with the different gain setting, at the same volume setting on my preamp (despite the markedly lower music amplitude at the same setting with the GG in).

What this means is that lowering the gain is throwing away your signal-to-noise ratio.... I'm wondering how many GG/Big7 out there are handicapped due to a suboptimal gain setting. I wish there some way that didn't degrade the signal too much (maybe a autoformer or resistor relay?) to adjust your gain. Obviously that's what the built in preamp is after all.

I'm leaning towards having it back to 700mV or thereabouts. My current passive pre (Hornshoppe "Truth") is infinitely stepped and has plenty of down headroom.

Yeang

I am just giving Yeang a comparison - he is having to turn up his pre amp to all most full vol.

 

[Sablon Audio]

It's probably worth pointing out that the Philips/Sony cd player standard from 30 years ago specified an output of 2v rca (4v xlr) and this is typically higher than analogue sources such as tuners or phonostages produce. If running a passive stage or direct from a dac with the inbuilt atenuator, then you need to look at the voltage your power amps(s) need to make full power (aka input sensitivity).

 

[wisnon]

I'm leaning towards having it back to 700mV or thereabouts. My current passive pre (Hornshoppe "Truth") is infinitely stepped and has plenty of down headroom.

Yeang

Just adjust it to 550mv and you should be Golden.

My new speakers are 94db and so with the GG and 242 tubes, I get max SPL already at roughly 45% volume. On my older 90db speakers, I needed 70% volume to have the same SPL. Its a combination of several factors.

 

[microstrip]

(...) The interesting and relevant point here is that, Lukasz told me that he is just setting the gain low as he gets complaints from people that his DACs are too loud. That would not be an issue if the noise floor went down with the lowered gain. But what I am hearing is that the tube hash/noise stays the same between my Big7 and my GG with the different gain setting, at the same volume setting on my preamp (despite the markedly lower music amplitude at the same setting with the GG in).

Yes, the gain, noise and subjective sound quality is a critical compromise in design, particularly in non-feedback circuits. Unfortunately most of the time high gain sounds better than low gain - e.g. many people preferred the old high gain conrad johnson preamplifiers to the next generation having less noise and less gain.

This happens also with solid state - it is why many power amplifiers have excessive gain, exposing the background noise of preamplfiiers and sources when used with sensitive speakers .

 

[wisnon]

Auto balancing circuit? Interesting. Can you give us a few details on it?

No details. I am no techie. Its something he spoke of once when we met...related to ohms law.