Hello
I saw some diamond buffer over the net (with very good opinions) and decided to make an amp using diamond input stage.
Work is still in progress I will post schematic at evening time. I still have few issues to get sorted but anyway amp is playing nice and is stable.
My sound card is giveing out - not able to measure thd properly but is giving some picture of it.
The results are bellow.
I saw some diamond buffer over the net (with very good opinions) and decided to make an amp using diamond input stage.
Work is still in progress I will post schematic at evening time. I still have few issues to get sorted but anyway amp is playing nice and is stable.
My sound card is giveing out - not able to measure thd properly but is giving some picture of it.
The results are bellow.
Attachments
Updated verion looks like this. I think there is nothing to coment for now, pictures are saying more then 1000 words. I have changed my soundcard with e-mu 0204 so there will be no problems with artefacts anymore (i hope)
Anyway the amp is playing very nice. If I will have enough time there will be another version with toshiba mosfets at output stage.
Anyway the amp is playing very nice. If I will have enough time there will be another version with toshiba mosfets at output stage.
Attachments
I really do not know if it is any better, diamond buffers they have good reviews so I decided to make an amp of it. It sound really good.
Hi,
have you made extended listening sessions with this amp? and compared to BG1/BG2 minimap?
Have you change 2N5xx1 due the little heat issue?
Marc
have you made extended listening sessions with this amp? and compared to BG1/BG2 minimap?
Have you change 2N5xx1 due the little heat issue?
Marc
Yes I have hanged 2n5xx1 transistors and putted toshibas instead.
I am going to do some listening tests soon. But first impression is that bass is bit deeper than bg1 amp. Hights are very acurate.
First I will have to finish speakers
I am going to do some listening tests soon. But first impression is that bass is bit deeper than bg1 amp. Hights are very acurate.
First I will have to finish speakers
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I was thinking about ccs at the first stage but i decided to put resistor, why ?
--> the output stage is separated from input/voltage amplifier by two diodes, so when the psu voltage at output stage will drop a bit, diodes will not allow to ''drink'' the current from in/vas amplifier back to OP stage. With higher psu voltage only 4 resistor change is required.
--> the output stage is separated from input/voltage amplifier by two diodes, so when the psu voltage at output stage will drop a bit, diodes will not allow to ''drink'' the current from in/vas amplifier back to OP stage. With higher psu voltage only 4 resistor change is required.
Borys do you think if I ad those caps to the circuit can improve the sound??
Marc will you draw the layout of these amp?🙂 Or maybe we should wait until Borys will test thoroughly the amp.
Greetings Gabor
Marc will you draw the layout of these amp?🙂 Or maybe we should wait until Borys will test thoroughly the amp.
Greetings Gabor
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I dont think it would improve the sound, but might theoretically improve stability. The important smoothing is after the diodes.
Gabor
If you would like to add some caps - in this case there would be better to putt caps just beside the collector of output transistor, should improve pulse response. But in practice when using 20-30W there is really no diffrence, on the oscillograms the psu is giving out with square load and high amplitude.
Soundwise - the amp is quite interesting cause is really good for tweaking, small change in currents flow and harmonics spectrum is changing, sound is changing too.
First wersion with 2n5xx1 transistors sounded different to the current with toshibas.
If you would like to add some caps - in this case there would be better to putt caps just beside the collector of output transistor, should improve pulse response. But in practice when using 20-30W there is really no diffrence, on the oscillograms the psu is giving out with square load and high amplitude.
Soundwise - the amp is quite interesting cause is really good for tweaking, small change in currents flow and harmonics spectrum is changing, sound is changing too.
First wersion with 2n5xx1 transistors sounded different to the current with toshibas.
My experience is good to have those caps.
You right close to the power transistors is better.
I tested these caps with a few amplifier and yes it improved the amplifier as far you can even hear it.
Now if the amplifier heavily biased that is another case.
A few people even in Class A like to use caps, my experience is the opposite better with out caps.
Here at these amplifier to decide need to be tested.
It is a very nice amplifier, worth to try some tweak.
Greetings Gabor
You right close to the power transistors is better.
I tested these caps with a few amplifier and yes it improved the amplifier as far you can even hear it.
Now if the amplifier heavily biased that is another case.
A few people even in Class A like to use caps, my experience is the opposite better with out caps.
Here at these amplifier to decide need to be tested.
It is a very nice amplifier, worth to try some tweak.
Greetings Gabor
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What would you recommend that we use instead of the discontinued 649, 669?
None of the modern availability has specs like the originals--The generic is a small signal device in a big box (work great for 2n5551 but not enough current for drivers), or the Hi-Sincerity reproduction part is just 40mhz although it does handle some current. They're not like the Hitachi at all.
Here's a photo to help identify the real Hitachi. <--link
Closest match (in current production) is KSA1220, so would you rather use that or perhaps just use more of the Toshiba drivers?
None of the modern availability has specs like the originals--The generic is a small signal device in a big box (work great for 2n5551 but not enough current for drivers), or the Hi-Sincerity reproduction part is just 40mhz although it does handle some current. They're not like the Hitachi at all.
Here's a photo to help identify the real Hitachi. <--link
Closest match (in current production) is KSA1220, so would you rather use that or perhaps just use more of the Toshiba drivers?
Hi Gabor,
I have done, but Borys as publish one good, mine is with some SMD parts....that's why i don't promote it and it's simple derived from borys one.
Marc
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