Amp design speculations (warning:google translator req)

[Coconutout]

hey guys. this is probably not the best place to ask such a random question but... i'm trying to buy a diy amp from taobao and would like to know your opinion on the models i'm listing below. i was able to get a rough translation via google but even with that all the technical jumbos i cannot seem to get through.
i'm just needing to know which amp might sound 'tubier' and warmer which are the characteristics i'm preferring. i was hoping someone might be able to get a general idea of their sounds from the components listed on the ads.

amp 1

amp 2

[Coconutout]

amp1 ad translated -

GAO Wen-amplifier sounds warm and thick, music, taste good, but the driving force is not very strong, controlling sounds premature.

To this end we have installed additional JRC5532 op-amp type of non-equilibrium transfer balance circuit, you can also use OPA2604, OPA2134 op amp such as the voice for different styles. JRC5532 used here compared with the sound control is better than the OPA2604 and 2134, the sound seems more clean. Although the relatively high frequency in the 2604 sweet, but too much low-frequency mixing (only limited to the machine with the situation, other lines can not be generalized).

Each channel uses two high-road of the original text of the main amplifying circuit for a balanced amplification, which is the choice of materials presented a relatively high demand, 2 the corresponding components are subject to strict matching, the materials used will be an ordinary high-Wen machines 2 times. This is also the most of the power amplifier is not a major cause of a balanced amplification is only seen in some high-end models.

Each output tube we have only used a pair of Toshiba A1943/C5200, each channel is 2 pairs. Even so, the rated power per channel is also 150W, which benefited from the use of a balanced amplification. While reducing the difficulty of matching the output tubes, the sound of the flavor will not be compromised.

The machine did not use my usual super-A optocoupler bias, but rather follows the original line of high bias class AB bias to keep the original sound characteristics.

Prototype out of power after 5 hours of listening, feeling warm voice to maintain the original style of fullness, as the spring inside the sunny vibrant. Low dive some unexpected, listening to very percussion atmosphere. Suitable for more delicate and pretty with a neutral or sound boxes.

The new machines are now available to special to satisfy you Shaoyou, the machine uses a pre-E cows (because of the limited number of cattle), will be replaced by ring out exhausted cattle, then will and declarations.

Size: 430X102X380

Weight:

SNR: "= 110DB (unplugged boot signal lines, speaker is very quiet, closely aligns horn noise is not heard)

Rated Power: 150WX2

Frequency response: 2HZ-100KHZ (-1DB)

[Coconutout]

amp2- (even more of a jumble...)

e can see that there are two sets of schematic bias circuit: R18. VR3. Q42 is the most constant voltage power amplifier bias circuit. Q19.Q20.U1 composition is the machine using the opto-current dynamic bias. The principle of constant-voltage bias is to give the output tube for a fixed bias, when the signal is in positive half weeks, the output level of the upper arm-power tube bias increase in bias due to fixed restrictions, lower arm power tube bias will be decline in order to maintain the same total bias. When the bias voltage drop below the transistor turn-on threshold, the power tube will go into the cut-off. This signal is a half weeks and negative half-cycle changes back and forth, allowing the upper and lower arms along the output power transistor turn-on and cut-off rotation. This leads to what we have said, or switch-crossover distortion. Constant voltage bias the output tubes according to the static work of the state is divided into Group A, Class-AB, B. A fixed bias voltage relative to the comparison of high, relatively wide range of signal amplitude and switching there is no crossover distortion, but after more than a certain power (more than A bias range). Also with the Class-AB and B, like the crossover and switching distortion. To get the larger A power have to further improve the bias or the bias current and operating voltage, then the costs will increase exponentially. A working temperature stability relies on the physical heat transfer coupling. Bias needs 10-20 minutes to stabilize, but also static balance. In the dynamic, as a result of the delayed effects of the physical heat conduction, static current becomes unstable generate dynamic drift. A voice of pure good is true, but the high-cost, low-cost, high-power, high heat, or is inhibited.

Optocoupler bias current through Q19.Q20 base current of the power amplifier tube sampling, through the optocoupler feedback to help implement the base to control the push tube bias to achieve automatic control of output power tube bias. It has the following features:

1: Low Distortion: This circuit is not the current shunt voltage amplification stage. (No general constant-voltage bias of the upper and lower arm resistance) to reduce the voltage level of the load. Optocoupler isolated role of the good. Will not lead to other additional distortion

2: High quality: it is an ideal super-A bias (a non-super-A bias could ratio), bias not close to the cooling pipe, a power output transistor quiescent current has stabilized at the set value. As the temperature rises, the power control the base-level leakage current will increase, this situation will be Q19.Q20 pick up, rapid response to the bias control terminal to reduce bias to maintain the stability of quiescent current. Than the constant pressure of the logistics of multi-speed heat conduction. Dynamic current with the output power varies, but a stop output immediately kept quiescent current setting value, a small drift. It directly controls the output tube output current, the output tubes at any given time there will not produce current flow through the switch and crossover distortion. Response speed optocoupler itself is very fast, we often in the high-frequency switching power supply circuit to see it. Once the output current is beyond the scope of the CPI. Is turned off is the bias tube Q19. Q20 One of the output tubes can also resistor R25. R26 to obtain current and will not shutdown. Because when the Q19. Q20 entering the closed area (at this time there is a certain drop in the R25. R26 to generate current) electro-optical end of optocoupler current decreases, the amount of light decreases, the control end of Induction and improve the bias, thereby enhancing bias to Q19. Q20 exit off loaded state, this process was R25. R26 The existence of the output tubes at any time will not enter the closed area.

We were an ordinary pure A bias and opto-loaded into the dynamic current biasing for the two sets of panels AB comparison (exactly the same as other components parameters) II plate at the end of a cleaner sound, wide dynamic range, resolving power is good, bass guitar like the ability and dive has also increased. Under the relatively large volume, II-type advantage is more obvious in the sound field grand, open. Level of clarity, the high-frequency very moist.

3: High Efficiency: As the quiescent current is relatively small (50-100MA), dynamic current from the signal current superimposed on the quiescent current. Greatly reduced power consumption, heat small. Easy to implement high-power A



The aircraft with the earlier launch of 4000 yuan (large configuration) exactly the same line, reducing the power devices, voltage regulator part of the larger power amplifier on the motherboard, after repeated experiments and with the stereotypes. Larger part of the selection of a fever at all levels, all sound supervisor: the input stage using current Beishoushaoyou respected Audiophile Voices farm management K170/J74. Constant current source selected Toshiba A970/C2240. Hitachi B647/D667 to help implement and promote adoption of the U.S. Semiconductor (ON) MJE15032/15033. Output per channel 2 on the 3 Ken latest HIFI supervisor A2151A/C6011A (parameters: 200V15A160W), signal amplification part of the selection of the United States such as fever, RC DALE.AB piece. At all levels of current have been carefully adjusted. 200W power supply with two liters Long Wan cattle, two-channel fully independent power supply, the main filter for the 8 8200U/71V Panasonic pitched audio special electrolysis. Precision kubota power supply for the input stage and voltage levels to provide high-voltage 76V, output stage voltage of 70V-based machine the outstanding performance of large dynamic ability to lay a solid foundation. Wiring to make a reasonable signal to noise ratio high, electricity close to the speaker can not hear the noise.

The machine sound features: Sound delicate, sweet. Resolving power and control are very good, dynamic range, low-frequency deep, middle and high frequency is very shiny. Overall the sound is neutral approach Shaopian soft. Is a pure cost-effective high-level post.

The basic parameters of this machine: A Power: 100WX2 8 Europe. 150WX2 4 Europe

SNR: "= 100DB

Frequency response: 2HZ-100KHZ (-1DB)

[Johnloudb]

Hmmm....

The second one has a schematic, and it looks like an amp. :T Somewhat complicated and the devices seem to be high quality devices (Toshiba, Hitatchi, On Semi). And the output stage looks very hefty. Interesting that the translator refers to the transistors as tubes. :B

There's no way I can comment on quality though. When you say DIY amp, you mean this is a kit? Won't the assembly instructions also be in Japanese, or Chinese or whatever?

I think this would be a really ambitious project, even if the with english instructions. Not to dissuade you.

Are you in China? I think I remember you mentioning that in the RBR kit thread.

[Coconutout]

yes i am stuck in china... and these are built diy amps that the seller specializes in. the first amp doesn't specify at which ohm it outputs 150w. if this is for 4ohm, is 50 watts difference the most i can expect to lose at 8ohm?

[Alaric]

Having to guess , I'd go with the EI transformers and Class A bias for a "tubey" sound. If the translation is understood (by me) amp 2 is a copy of a Goldmund amp? You could do worse.

[Hdale85]

http://www.audio-gd.com/enweb/en-amp.htm Check out some of this stuff, believe they are based in China? So shipping should be reasonable and my friend has purchased several of their products and had very very good luck with them.

[Brian Kingsbury]

The aircraft with the earlier launch of 4000 yuan (large configuration).....Larger part of the selection of a fever at all levels....using current Beishoushaoyou respected Audiophile Voices farm management

Gotta love google translator.

Doug came up with a pretty good suggestion but you might also try checking out Australian DIY websites. There's a pretty big DIY scene there and I'd imagine shipping wouldn't be too slow or expensive. You could at least read/understand their descriptions and be able to ask for help from the supplier. There's also a couple of ebay stores based in China that sell some good kits and seem to have their english down fairly well. I dont' know if I'm allowed to name them on here but you can shoot me a PM if you want.

[stgdz]

I was into the Diy audio scene, hell I even built my own gainclone.

Its not worth it, amps are so cheap now especially used one.

[Hdale85]

Diy isn't generally about cost.

Anyways I thought he just wanted to buy a built amp.

[A9X]

As someone who has designed and built a lot of tube amps for stereo, MI and worked on a lot more of all varying topologies, I have no idea what 'tubiness' means. Different tubes and/or different topologies do sound different to a degree, but I have not found an overwhelming commonality between them.

[Alaric]

As someone who has designed and built a lot of tube amps for stereo, MI and worked on a lot more of all varying topologies, I have no idea what 'tubiness' means. Different tubes and/or different topologies do sound different to a degree, but I have not found an overwhelming commonality between them.

I would guess high low-end distortion , pleasant sounding (mildly distorted) mids and clean highs. Big soundstage. I'm currently looking for a good solid state phono amp to compare with my Bellari , on the "tubey" subject!

[Coconutout]

i'm currently enjoying the 'amp1' which i received earlier today. and for about $180 i paid for in chinese yuens, i must say it is the best deal i've ever come across, easily besting nad 2200 and a sherwood am7040 mosfet that both had higher price tag than what this seemingly insignificant diy amp cost. while it doesn't have a the literal distortion of the mosfets, this amp is still 'tubier' in every other aspect. thick el34 type bass, pleasantly rolled off highs, and liquid smooth mids. main traits of charm for this amp to me is that it sounds smooth and thick, thick obtuse bass. imaging is not a strong point but dynamic is. so the soundstage still has that 3d magic. i can almost imagine that the music is coming from a high powered el34 tube amp with full telefunken sets. i do have some big problems with it though now that i'm done praising the pros. the transformer hums! on top of that, its leaking a transformer oil smell... i hope its not pcb! i'd like to know how long you think it might take for the smell to go away and if it's difficult or not to upgrade the transformer to odorless and hum-less one. thanks.

[Alaric]

If you click on the Parts Express banner at the top of this page you'll find a good selection of transformers , and using the HTGuide link helps this site.

[Johnloudb]

I had some power resistors in my preamp that smelled a bit when they were first burning in, but that went away. So, hopefully the smell you're talking about will go away and hopefully doesn't indicate some problem.

[stgdz]

Diy isn't generally about cost.

Anyways I thought he just wanted to buy a built amp.

well let me restate that again dougie, my parasound 2 channel took a poop and I am now looking at scraping the amp but using the transformer to build a two channel, 500w each, amp from these guys.

http://classdaudio.com/