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Topic: Amp question. (Read 45282 times) previous topic - next topic
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Amp question.

Reply #75 –
I'll wait a bit with continuing on this project 'till i can afford some more gear. I want to get a proper soldering station and third hand, proper pliers, etc.

Meanwhile i hooked up my HP Jornada 568 to RMAA. Here's the results and it nicely explains why a headphone amp makes sense:
Veni Vidi Vorbis.

Amp question.

Reply #76 –
Quote from: HbG on
I'll wait a bit with continuing on this project 'till i can afford some more gear. I want to get a proper soldering station and third hand, proper pliers, etc.

Meanwhile i hooked up my HP Jornada 568 to RMAA. Here's the results and it nicely explains why a headphone amp makes sense:

Hi,
Nice to see you are continuing on your quest for the perfect sound.

Today I got hold of a Luxman LV-111 2 x 70W amp which I found on eBay for 20 euros + shipping. According to the previous owner, its power supply "was burned". On opening the cover, I immediately saw that one of the main electrolytic capacitors was bust. It also had a blown fuse.
Well, the end of the story is that after replacing the capacitor and putting a new fuse in place (with a few tests in between and careful examination with a multimeter), the thing is now playing like a new amp.
I'll take a few pictures and post them here tomorrow.
I have a Yamaha coming on Saturday, also with "something burned". Looks like I'll soon have a collection of amps, each with its own different sound (or not?)!
HbG, when are you going to run your Marantz through RMAA?

Amp question.

Reply #77 –
The quest for the holy grail of perfect sound indeed!  Today I feel slapped in the face by the reality of compression and clipping and poor mastering in general. Bah.

Nice one on the Luxman, i got a tuner of the same brand that i'm very happy with. Any idea what it's worth now that it works?

The Marantz through RMAA.. i can do that tomorrow, but i'll need to know how. Should i take the headphone output, build a voltage devider on the speaker output, or take the preamp output, or the poweramp section, does it make sense to measure it through tape monitor, etc.. I need to look at the schematic some more, I've never done this before.
Veni Vidi Vorbis.

Amp question.

Reply #78 –
Quote from: HbG on
The quest for the holy grail of perfect sound indeed!  Today I feel slapped in the face by the reality of compression and clipping and poor mastering in general. Bah.

Agreed 100%. Nice sound begins with a good recording, and there are many poorly engineered recordings around, unfortunately.
Quote
Nice one on the Luxman, i got a tuner of the same brand that i'm very happy with. Any idea what it's worth now that it works?

I saw some mint LV-110 amps selling for around 100 euros on eBay (basically the same amp with 2x35W). So I would say anywhere in the 110~120 euros range.
Quote
The Marantz through RMAA.. i can do that tomorrow, but i'll need to know how. Should i take the headphone output, build a voltage devider on the speaker output, or take the preamp output, or the poweramp section, does it make sense to measure it through tape monitor, etc.. I need to look at the schematic some more, I've never done this before.

Very simple really:
- Output from your sound card to Tuner input of the Marantz: mini-jack to RCA cable.
- Speaker output from the Marantz to Input of your sound card: you can make that cable with 4 pieces of wire and a mini-jack. Leave the speakers connected or if you want to spare your ears, use a dummy load.

Amp question.

Reply #79 –
I used foobar to apply replaygain data to the mp3 files to get the peak values below 1. It helped, but there was still some clipping in a live version of Led Zeppelin - Black Dog. I think it's only because i started listening for it with the headphone amp that i got sensitive to it. I lost my blissful ignorance.

RMAA test... done. Thanks to a leftover headphone jack i had ripped off a broken pair of 'phones years ago.
My soundblaster Live's unsensitive 2V RMS inputs are coming in handy here. I didn't use a dummy load, i wanted to see if the speakers i have have any influence on the frequency response, which doesn't seem to be the case. This would indicate that the damping factor is high enough for my setup.
For the frequency response i'm limited by my soundcard (looking to get an audigy2), but at least it's higher than my ears will go. Bass is pretty good for a capacatively coupled amp. -3dB at 11.6Hz  Don't have records of any other amps to compare it to though. Is there any website that has RMAA reports of various amplifiers?

Now i'm interested to see who's vintage amp is better!
Veni Vidi Vorbis.

Amp question.

Reply #80 –
Quote from: HbG on
I used foobar to apply replaygain data to the mp3 files to get the peak values below 1. It helped, but there was still some clipping in a live version of Led Zeppelin - Black Dog. I think it's only because i started listening for it with the headphone amp that i got sensitive to it. I lost my blissful ignorance.

RMAA test... done. Thanks to a leftover headphone jack i had ripped off a broken pair of 'phones years ago.
My soundblaster Live's unsensitive 2V RMS inputs are coming in handy here. I didn't use a dummy load, i wanted to see if the speakers i have have any influence on the frequency response, which doesn't seem to be the case. This would indicate that the damping factor is high enough for my setup.
For the frequency response i'm limited by my soundcard (looking to get an audigy2), but at least it's higher than my ears will go. Bass is pretty good for a capacatively coupled amp. -3dB at 11.6Hz  Don't have records of any other amps to compare it to though. Is there any website that has RMAA reports of various amplifiers?

Now i'm interested to see who's vintage amp is better!

Great testing HbG, way to go! 

Now I am really impressed by this 30-year old Marantz 1060!

Look carefully at the THD+noise graphics, you can see that Harmonic Distortion is mainly even order; this is due essentially to the output capacitors and low feedback, and gives the Marantz the sweet sound that some people call "tube sound" (which contrasts with what the same people call "transistor sound", which is described as "harsh").

I don't know of any website that reports RMAA results for vintage amps, but I'll sure be checking mine soon!

Of course it would be very interesting to also test a tube amp, and some opamps.

Anyways, well done. Best post I have read in a while.

Amp question.

Reply #82 –
Quote from: Sebastian Mares on
While testing my iPod Nano 2G, I also tested my Marantz PM310 amplifier that is about 20 years old: http://www.maresweb.de/miscellaneous/Comparison.htm

What do you think?

BTW, what is stereo cross-talk?


Hi Sebastian,
I have the PM450, which is very similar to your PM310 (BTW I have the schematics for your PM310 if you need them).

Crosstalk: Electronics. Undesired signals or sounds, as of voices, in a telephone or other communications device as a result of coupling between transmission circuits.

In this case, how the signal from the left channel affects the right channel and vice-versa. Measured in dB.

Amp question.

Reply #85 –
Yep, I have that too. My PM310 has only one phono input, doesn't have a slider for mids and supports only one pair of speakers. I think (I am actually almost sure) that my amplifier is also from the "new" Marantz.