I don't know why you can't see the attachment, it is well visible in my Mozilla Firefox.
If you read what we discussed in that thread you can get some understanding about voltages and power. Datasheet is the must read material.
Gu-50 was designed for 14,000 hours of life in military equipment when used in specs, including temperature. If 2 or more parameters are on the edge of maximal values the plant would not accept complains.
Here is the graph that specifies max power dissipation depending on ambient temperature.
If you read what we discussed in that thread you can get some understanding about voltages and power. Datasheet is the must read material.
Gu-50 was designed for 14,000 hours of life in military equipment when used in specs, including temperature. If 2 or more parameters are on the edge of maximal values the plant would not accept complains.
Here is the graph that specifies max power dissipation depending on ambient temperature.
Attachments
Yes, the humble and much maligned TDA2030....no one on the chip-amp forum will go near one of these ;-)
But.. I am planning to try this circuit too.. just saw the circuit a day back too 🙂
Here is a nice schematic
Hello nomiconxp
Here is a very nice schematic with two stage. It look like I must get used to if I want two stage these amp will need inter stage transformer.
Also D3A not to long time a go it was 6-7Euro now cost double.
Let see how much will cost a pair OT transformer with shipping..
Right now I work on a lot of project speakers, amplifiers , preamp(tube and SS).
The problem I think the longer I wait the parts will cost more & more.
Do you think the D3A is oscillate? I read a couple place ,last year I wanted to build a preamp (WOT) with these tube.
Thanks
Greetings gabor
Hello nomiconxp
Here is a very nice schematic with two stage. It look like I must get used to if I want two stage these amp will need inter stage transformer.
Also D3A not to long time a go it was 6-7Euro now cost double.
Let see how much will cost a pair OT transformer with shipping..
Right now I work on a lot of project speakers, amplifiers , preamp(tube and SS).
The problem I think the longer I wait the parts will cost more & more.
Do you think the D3A is oscillate? I read a couple place ,last year I wanted to build a preamp (WOT) with these tube.
Thanks
Greetings gabor
Attachments
Good morning to everyone!!
gaborbela the schematic you showed me is a good one..
I have never tried interstage transformer..
Mine works with a coupling cap.
Why go and spend so much money on the inter??
One thing also i learned from the university is that the more transformer you have in a signal path! the more it effects the sound....
That is why you need a transformer that cost 400 euros...
I don't know if i will ever use them...
gaborbela the schematic you showed me is a good one..
I have never tried interstage transformer..
Mine works with a coupling cap.
Why go and spend so much money on the inter??
One thing also i learned from the university is that the more transformer you have in a signal path! the more it effects the sound....
That is why you need a transformer that cost 400 euros...
I don't know if i will ever use them...
The testing i've done with them! it was a very simple tube..
I tried it in a preamp and give very good and loud sound!!!!
Amplification factor is 77! 🙂
In my headphone amp where i have the 12GN7A witch is close to the D3A
I cannot put the volume greater than 30%.
I even tried it on my PP KT88 Amp and the sound was excellent!!
I tried it in a preamp and give very good and loud sound!!!!
Amplification factor is 77! 🙂
In my headphone amp where i have the 12GN7A witch is close to the D3A
I cannot put the volume greater than 30%.
I even tried it on my PP KT88 Amp and the sound was excellent!!
Hello nomiconxp
I do not want to spend on inter stage transformer! That is what I wrote earlier, better to use that money on good quality parts..
I thought if we go with two stage we need inters stage transformer!
I just find these schematic created by Andrea Ciuffoli.
So all two stage GM70 need a preamp. I like as simple as possible but only until it not degrade the sound of the amp!!!With 3 stage not always need a preamp.
I'll wait to see your (whole) schematic.
Greetings gabor
I do not want to spend on inter stage transformer! That is what I wrote earlier, better to use that money on good quality parts..
I thought if we go with two stage we need inters stage transformer!
I just find these schematic created by Andrea Ciuffoli.
So all two stage GM70 need a preamp. I like as simple as possible but only until it not degrade the sound of the amp!!!With 3 stage not always need a preamp.
I'll wait to see your (whole) schematic.
Greetings gabor
only if it works 😉
may be a daft question 😱 but have you built any tube amp before this 😕
still, all the presented tech info here is certainly interesting and of value
Hello
Yes I did at the start of my DIY adventure, about 17-18 years a go.
Later I did upgraded some factory built commercial amp also, Philips some European here unknown brand..
Also I owned Revox tube mono blocks and many other tube stuff.
Also I work on two tube preamp now!
I believe with a little help I can build it.
Everybody started one day, not? Not all DIY-ers are technician or engineer.
I built lot of SS amp, I worked in a TV shop just to learn electronics..
Greetings gabor
Yes I did at the start of my DIY adventure, about 17-18 years a go.
Later I did upgraded some factory built commercial amp also, Philips some European here unknown brand..
Also I owned Revox tube mono blocks and many other tube stuff.
Also I work on two tube preamp now!
I believe with a little help I can build it.
Everybody started one day, not? Not all DIY-ers are technician or engineer.
I built lot of SS amp, I worked in a TV shop just to learn electronics..
Greetings gabor
@gabor
Your story sounds like mine, I am not a technician nor an engineer and I did work in a TV shop to learn electronics and it was around 20 years ago... On the other hand, tubes are pretty new to me. I have built more than 10 different SS amps before this and numerous other SS projects.
I have learnt a lot from the forum, and discovered a lot about tubes through testing and experiments. Do your research and be ready to listen to those who know more and have more experience designing circuits with tubes they are familiar with. No one is trying to put you down when they warn you about high voltages, they just do not want to lose a new friend with the same interests as they have.
Anyway, happy experimenting 🙂
Your story sounds like mine, I am not a technician nor an engineer and I did work in a TV shop to learn electronics and it was around 20 years ago... On the other hand, tubes are pretty new to me. I have built more than 10 different SS amps before this and numerous other SS projects.
I have learnt a lot from the forum, and discovered a lot about tubes through testing and experiments. Do your research and be ready to listen to those who know more and have more experience designing circuits with tubes they are familiar with. No one is trying to put you down when they warn you about high voltages, they just do not want to lose a new friend with the same interests as they have.
Anyway, happy experimenting 🙂
Hello quikie22
Thanks for the kind words.
I do my home work, I do as much research as possible.
I know most of the people on the forum want to help.
Now 99% sure I will go with GM70 tube.
I did work in the TV shop about 4 years a go. I used to live next to the repair shop.
I built at least 12-15 SS amplifier some tube amp preamp.
Also I work 3 years with electrician mostly residential but sometimes in factory to with 360V.
When we work residential usually we work under power. I got shocked a couple times but so did my boss.
One of the most important rule when we work with high voltage keep one hand in your pocket.
I'm insured, saved (I'm a believer) I do not afraid to die. Of course I do not want yet , I'm just 41 years old..
Do you have schematic with 3 stage. It would be great if we could use the amp with out a preamp.
Greetings gabor
Thanks for the kind words.
I do my home work, I do as much research as possible.
I know most of the people on the forum want to help.
Now 99% sure I will go with GM70 tube.
I did work in the TV shop about 4 years a go. I used to live next to the repair shop.
I built at least 12-15 SS amplifier some tube amp preamp.
Also I work 3 years with electrician mostly residential but sometimes in factory to with 360V.
When we work residential usually we work under power. I got shocked a couple times but so did my boss.
One of the most important rule when we work with high voltage keep one hand in your pocket.
I'm insured, saved (I'm a believer) I do not afraid to die. Of course I do not want yet , I'm just 41 years old..
Do you have schematic with 3 stage. It would be great if we could use the amp with out a preamp.
Greetings gabor
I have built several iterations of amps based on this chip. On the chipamp forum, the LM1875 is preferred over the 2030. Seems that it sounds better than the 2030. 2030 is considered more "mid-fi" than hi-fi. Both are same package, and are almost drop-in replacements for each other.
Personally, the 2030 sounds ok, but is dependent on the parts used around it. There are several threads comparing the two on the chip amp forum
GM70 Copper plate
Hello
Here is a test after someone set up his amplifier with graphite plate and switched to copper plate.
Copper plate version of GM-70[/B
Recently I bought the COPPER plate triodes. about 5 x the price of graphite ones. (USD 200 a pair, new and mint, made in 1982. The year of "almost nearly" Soviet intervention in Poland)
The first thing that stroke me was (no, not a 900 V shock) the light. These triodes probably emit the brightest filament light of all tubes in the world. Like 40 watt bulbs, but much warmer, reddish from the copper plate deflection. Looking into this light is magical, like into a fireplace.
The sound is good, maybe 10 % better in mids, equal in highs, and 50 % weaker in the bass.
It may be my amp operating points being not optimal for this tube, but "internet people" agree - weaker bass and better mids. This is closer to 300B sound. For me - overall net change is negative. I absolutely love the graphite GM70. So I can have a spare pair of copper for the hell of it, but for every day operation I am gonna stick with the graphite.
Maybe on lesser speakers - like mini monitors - the bass issue would not matter, but mids would be better enough with copper.
Probably if someone from the beginning use copper plate and all the set up and parts matched to the cooper plate would sound better that to.
But why, the graphite plate cost 1/4 than the copper plate.😉
Greetings gabor
Hello
Here is a test after someone set up his amplifier with graphite plate and switched to copper plate.
Copper plate version of GM-70[/B
Recently I bought the COPPER plate triodes. about 5 x the price of graphite ones. (USD 200 a pair, new and mint, made in 1982. The year of "almost nearly" Soviet intervention in Poland)
The first thing that stroke me was (no, not a 900 V shock) the light. These triodes probably emit the brightest filament light of all tubes in the world. Like 40 watt bulbs, but much warmer, reddish from the copper plate deflection. Looking into this light is magical, like into a fireplace.
The sound is good, maybe 10 % better in mids, equal in highs, and 50 % weaker in the bass.
It may be my amp operating points being not optimal for this tube, but "internet people" agree - weaker bass and better mids. This is closer to 300B sound. For me - overall net change is negative. I absolutely love the graphite GM70. So I can have a spare pair of copper for the hell of it, but for every day operation I am gonna stick with the graphite.
Maybe on lesser speakers - like mini monitors - the bass issue would not matter, but mids would be better enough with copper.
Probably if someone from the beginning use copper plate and all the set up and parts matched to the cooper plate would sound better that to.
But why, the graphite plate cost 1/4 than the copper plate.😉
Greetings gabor
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Hello
Here is the whole website about that GM70.
I would be delighted to find a schematic like these with 3 stage so no need for a preamp.
With separate preamp more connectors , RCA cables etc.
I think the schematic originally posted on the website not correct.
I see 3 tubes on the amplifier plus the rectifier tube.
At the schematic only has 2 tubes🙁
Can someone explain these??
GM- 70 amplifier mono
Greetings Gabor
Here is the whole website about that GM70.
I would be delighted to find a schematic like these with 3 stage so no need for a preamp.
With separate preamp more connectors , RCA cables etc.
I think the schematic originally posted on the website not correct.
I see 3 tubes on the amplifier plus the rectifier tube.
At the schematic only has 2 tubes🙁
Can someone explain these??
GM- 70 amplifier mono
Greetings Gabor
Hello singa
Yes you right! Because he wrote about a 3th powerful tube to drive the GM70 i got confused.
In the schematic there are 2 tube rectifiers supplying different voltages.
Now I took a look at the PS and I see it.
Thanks
Greetings.. gabor
Yes you right! Because he wrote about a 3th powerful tube to drive the GM70 i got confused.
In the schematic there are 2 tube rectifiers supplying different voltages.
Now I took a look at the PS and I see it.
Thanks
Greetings.. gabor
Hello
I think one of the most important parts to get the right transformers for start these project.
If nomiconxp some reason can't help us with transformer we can probably can order from Edcore but we need all the info about the transformer.
I think we need a special transformer here!
I see Andrea used Tango and Bartolucci transformers but those are $$$$ pricy!
Greetings gabor
I think one of the most important parts to get the right transformers for start these project.
If nomiconxp some reason can't help us with transformer we can probably can order from Edcore but we need all the info about the transformer.
I think we need a special transformer here!
I see Andrea used Tango and Bartolucci transformers but those are $$$$ pricy!
Greetings gabor
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