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NAD功放评测和NAD 304合并式功放评测合集

出一个9.9新的NAD304功放

得过欧洲大奖和无数好评的NAD304,9.9成新机,连新机的清香味道都还在,所有原厂包装和说明书(全洋文)都在`使用时间不超过三小时,现在包

装好放着,1650元包华宇,图梢后上~~QQ:511317238

NAD发明专利柔性剪峰Soft

Clipping电路革命性令纯电晶体制作扩音机散溢出叫发烧友如痴如醉的甜美而柔媚之天文数字价位胆机才有的风韵!

当年what hi-fi 250英镑级别的5星功放。

“柔性剪峰”(Soft Clipping)是一个相当有用的功能，您可以选择开启或关闭此功能。一般人都有这样的经验：如果功放音量开得比较大，或音

乐电平起伏较大，功放的输出超过其额定功率，会产生削波失真，声音变紧、生硬、失真。而NAD的Soft Clipping电路正是通过适当减小输出

功率等办法来保持波形的完整，减少失真。如果只以适中功率使用NAD功放，则可关闭此功能；反之也可以开启，既可保护音箱，又可保护自己

的耳朵。

“气囊功率”(Power Drive)也是NAD的特色线路，这是NAD于上世纪80年代和90年代著名的Power Envelope电路技术的进一步发展和

改进，它能在瞬间高输出的情况下提供更强大的电源供给，使功放的大功率输出更稳定，驱动力更强，低频更出色。Power Drive电路与Power Envelope电路相比，效果更为显著，同时整体失真更小。

NAD 304 - Best SS amp ever?

I'm being silly, of course, but my experience with this integrated amp has been really baffling. I'll give a brief historical outline

I. Bought one in 1994 on the strength of Corey Greenberg's utterly excited "this is real high end audio for $300!" review in Stereophile (btw, this review isn't anywhere online that I can find). After owing it for a few days, the skeptical retailer asked me if it sounded as "glorious" touted? Well, powering my lil' Dahlquist DQ-16s, the answer was YES!

II. In 1995, something went wrong and I needed a repair. That was the old "green circuit board" version. Borrowed a Quad Amp and Preamp...maybe a 405 with matching preamp? Sounded big and warm.

III. Got the NAD 304 back with new Blue circuit board. Sounded way bigger, more dynamic, and clearer than the Quad set-up. Loved it! had to sell it off later that year to help with some debt.

IV. Bought one in 2008 for $175. I'm using it to power Triangle Zerius 202s.

I know, not the first combo you'd imagine, right? Sounds very clean and not lacking tonally, but now I'm looking for more dimensionality and palpable presence. I have tried using more powerful NAD amps, a high-powered Adcom, and I'm currently trying a Parasound HCA-750A. Everything sounds...ordinary. To be fair, the Parasound has warmed up and is starting to sound pretty good, but it doesn't exactly blow the 304 away.

Am I going to going to have to look at much more expensive gear? Tubes, maybe? Some of the amps I've tried have been very affordable, but the Quad and the

Adcom were kind of ridiculously high-priced IMO, and the 304 was hands-down the winner in those shootouts.

Has anyone else had a similar experience - and if so, what did you finally choose upgrade with?

Joelv(System | Threads | Answers | This Thread)

08-28-08

Responses (1-13 of 13)

Click title to read one, or click date to read all below it.

08-31-08To rephrase the question, have you ever upgraded from an n ...Joelv

09-03-08I am using one with a video system in the living

room-tryed ... Dred

09-03-08Right on, dred, thanks for sharing your experience! the

304 ...Joelv

10-10-08Nad amps are pretty good deal for the money and i agree

with ... Hieule5

10-10-08I owned a 304 for quite a few years, then passed it down

to ... Kbarkamian

10-13-08: Joelv

You know, I'm using the 304 as a pre-amp now. After a few months with my Triangles, I am hearing the 304's limitations... namely rolled off extreme highs and lows. Shortly after writing this, I spent some serious listening time with the Parasound amp and realized that it was pretty great, if a little "hard" sounding in my system.

I'm curious about the 315Bee and the 325Bee as well. I assumed they would

be only marginal improvements, but a remote control would be awesome.

I'm curious about the B&K ST-140 (the older, 70WPC one), the ST-120, and the newest Parasound Zamp. I've also heard some great things about the Onkyo

A9555 Class D integrated.

Finally, I take no offense at anyone's opinions about the 304 (or any of my gear) for that matter. Taste is taste, and good is good. Cheers!

Joelv(System | Threads | Answers | This Thread)

10-13-08: Kijanki

Joelv - my brother has NAD (I don't remember model #) and he replaced stock jumpers (thick U shaped bars) between pre and power amp with Audioquest Python jumpers (6" $25). It opened rolled off top end.

Kijanki(System | Threads | Answers | This Thread)

10-13-08: Mapman

What do you use for source units? Cd/digital or phono or both?

Mapman(System | Reviews | Threads | Answers | This Thread)

10-13-08: Kbarkamian

I'm not sure if the source question was directed to me, but I'll chime in...

Original source I used was a Playstation1 while I saved money. Upgraded that to an NAD 523 changer. Huge improvement. From the 523 to a Rega Apollo. Even bigger improvement. The 304 was good enough to show definite differences each time. Even non-hifi guys heard big differences.

Original turntable was a Technics SL-BD2 with Grado Blue. Upgraded that to a Pro-Ject 1Xpression. Added a Dynavector 10x5 and Speed Box. The only piece I didn't hear through the 304 at one point or another was the 10x5.

Regarding the 304 to 320BEE...

Everything is improved. Lows, mids, highs, noise. etc. Not a night and day difference IMO, but an overall improvement. You lose a phono stage. Gain a remote and 15 solid watts. Those 15 watts may seem insignificant on paper, but they become very obvious when driving speakers louder, in a larger room, more difficult speakers, etc.

I thought the price was well worth it for the 320BEE. I haven't heard the 315BEE. I heard very little difference between the 320BEE and 325BEE. Personally, I'd save a few bucks and get the right 320BEE over a 325BEE.

If no good ones were available for the right price, then get a 325BEE.

Kbarkamian(Answers | This Thread)

10-18-08: Joelv

My sources are: SONY DVP-NS715P as a CD / DVD player, Technics SL1200 with KAB Fluid damper and Cardas arm rewire w/several cartridges :)

I replaced the jumpers with 20" of Kimber PBJ which is different, though not an obvious improvement.

I can also say that the phono stage on the 304 is not quite as robust sounding as the one on the 7100 (at twice the retail cost)... which, while I'm at it, has anyone here used the Bellari phono stage? $250 and Stereophile Class B rating from Michael Fremer... is it really that good? I'm skeptical.

I miss Lonnie Brownell's reviews. I found that his and, previously, Corey Greenberg's reviews were aligned with my own tastes more than anyone. I also have a soft spot for Sam Tellig.. but I'm way off topic here. :)

I'm unemployed, so no new gear for me for awhile. Anyone need a recording engineer?

-Joel

Joelv(System | Threads | Answers | This Thread)

10-19-08: Phasecorrect

The Nad 3155 intergrated is very highly regarded...and more difficult to find(maybe ebay but thats a whole other post)...at any rate...NAD amps are phenominal value for the money...they sound big, bold, and very in control...much more like a high powered hi-end amp...I also have heard nightmere stories regarding QC issues concerning their CDPs...just

my .o2....

Phasecorrect(Reviews | Threads | Answers | This Thread)

04-06-09: Joelv

An update: My stalwart 304 has developed some problems -

flakiness/fuzzyness/intermittent cutting out in the right channel. I understand capacitors and solder joints are usually to blame, so I'm going to have it repaired.

In its stead, I'm using my new Trends TA-10.1, touted as 6 Watts of

giant-killing, audiophile magic.

So far, I'm disappointed, but I am waiting for the batteries to discharge and recharge so I can try that option.

Joelv(System | Threads | Answers | This Thread)

04-13-09: Joelv

OK I just have to update this.

I now feel that the Trends TA10.1 is the best amplifier that I've ever owned. It's in another league, completely, from the NAD. Big sound stage, stable, big images, gobs of detail.

I'm out of town but will likely post a review of this when I'm back. If anyone wants to discuss how awesome the Trends TA 10.1 is, feel free to e-mail. I'm thrilled!

Anubis,

I've read a review somewhere on the net, but can't remember where. It was by one of the major magazines, maybe Stereophile?

I used to own the 304. It's currently anchoring my 14 year old brother's Xbox/iPod/Insignia speaker system (the Insignias that everyone was raving about).

I replaced the 304 with a 320BEE. My only reason was kind of stupid - I wanted a remote control. If this helps, tonally they sound very similar. The 320BEE is a little more refined, but the 304 seems to have a flatter frequency response to my ears.

The phono input is very good. To be honest, I thought it was somewhat better than the NAD PP2 phono stage.

I've hooked up a lot of different speakers - from totaly garbage 'White Van' speakers to some power hungry NHT towers. While I was in college and a few years afterward, a lot of friends used my 304 as a reference amp, hence the multitude of speakers tried. It never had a problem with any speaker attached as long as I didn't try to make it do impossible things.

Depending on your room size and speaker efficiency, it may or may not have enough power. In an average sized room, I had no problems driving my PSB Image T55 towers or PSB Century 500i to loud levels.

Keep in mind that any 304 amp probably 15 or so years old. Depending on use or lack thereof, care taken for it, etc., your results may vary quite a bit. Mine (now my

brother's) is very well taken care of.

The only fault that I've ever encountered was the solder joints for the inputs. My father being the master mechanic that he is says that they weren't soldered very well. He resoldered the phono and cd inputs for me. Never had any other problems.

What else can I tell you... I'm not too sure. Feel free to ask any questions.

Anubis

Bronze Member

Username: Anubis

Birmingham, West Midlands England

Post Number: 60

Registered: May-06 Posted on Thursday, February 22, 2007 - 11:13 pm:

Thankyou, Stu. I found that very helpful, as a matter of fact.

I'm still weighing one 304 against many others, including a C357, which I simply can't afford now.

There is also a 716 surround amp. I'm used to very simple, 2 channel sound. It will probably bid up to more than the deposit for a new one anyhow.

Then my 'sensible voice' starts up with "get the 3155 - its got to be better than your old 3225PE..!" Not necessarily, though... Hard choice, without being able to listen.

Then perhaps I could always make-do with that old 3130, I could have: ?49 +postage on a 'Buy It Now'.

Ah... I dunno. I've had to go away and cool off from it all. I can't decide which will be best for me. Oh for the buying power, to just walk into a showroom...

The thing that turns me on, is when you find a gem; Like with my old 3020... But I've simply outgrown it's limitations.

Cheers,

Stu Pitt

Gold Member Username: Stu_pitt

Irvington, New York USA

Post Number: 1584 Registered: May-05 Posted on Friday, February 23, 2007 - 01:33 pm:

What do you have right now? The 3225PE I presume?

If you own that and it's in operable condition, most of the ones listed will probably be a lateral move IMO.

If you don't have anything right now and need a temporary band-aid, pretty much any of them will suffice, as long as they can drive your speakers. They all have the a similar house sound.

The C352 would hands down be the best of the bunch IMO.

If you're looking for a short term replacement and loved your 3020, the 304 will probably run closest. It'll most likely have the limitations the 3020 did. Its 35 wpc. If you need specs on any NAD gear, search around the NAD website. I believe they have old brochures with specs on PDF format in the Support section.

I'll be out of town and away from the computer for a few days. If you need more help, let me know.

Anubis

Bronze Member

Username: Anubis

Birmingham, West Midlands England

Post Number: 65

Registered: May-06 Posted on Friday, February 23, 2007 - 03:26 pm:

Yes, I have the 3225PE, which is broken. I have a 3020 standing in in the living room, but when the 3225 was operational, the 3020 was on computer/art studio duty.

To be honest, Stu, your comments speak volumes to me, compared with a mere list of specs. Because most tech talk is chinese to me, I find that by reading (honest) reviews, where a tester has listened critically and mentioned both low and high points, gives me the best idea about a piece of gear.

Of course, silly as it sounds, I've avoided the BEE models and I think this is down to the fact they've all too often been laid against the C357, whose general reputation is of the best NAD can provide in this price bracket.

I still sometimes wonder about what a new C320 BEE would do for me, in reality. I can get this, possibly the entry level, new, for around ?200.

Nuck

Gold Member Username: Nuck

Post Number: 5986 Registered: Dec-04 Posted on Friday, February 23, 2007 - 07:07 pm: V, does that 320BEE come with a phono?

Anubis Posted on Friday, February 23, 2007 - 10:01 pm:

I'm not sure, although noticing after a certain point, NAD simply stopped putting internal phono stages into their amps, I would not be

Bronze Member

Username: Anubis

Birmingham, West Midlands England

Post Number: 66

Registered: May-06 surprised to find it doesn't.

Which is a shame, because the big selling factor for NAD is VFM. As the amps have become more powerful and ISC came in, they've dropped the stages.

Still, I trust that they'll be worth it in many ways.

Anubis

Bronze Member Username: Anubis

Birmingham, West Midlands England

Post Number: 67

Registered: May-06 Posted on Friday, February 23, 2007 - 10:03 pm:

Actually, damn it... I seem to recall now that it does... I'd have to check.

Stu Pitt

Gold Member Username: Stu_pitt

Irvington, New York USA

Post Number: 1585 Registered: May-05 Posted on Saturday, February 24, 2007 - 11:13 pm:

None of the current NAD integrateds have an internal phono stage. They have an input called "disc," but its not a true phono input. They label it that way so you can connect an external phono stage to it. I run mine with a PP-2. It suffecient for me for now. When I re-do the system, it'll definitely be replaced.

If your budget is tight, the 320BEE could be the way to go. If your budget can stretch it, the 352 is easily worth the added price. It sounds much more natural and doesn't have the frequency response bumps the 320BEE has. The 372 may be better than the 352, but if you don't need the extra power it may not be worth your time.

Just some food for thought.

Anubis

Bronze Member

Username: Anubis

Birmingham, West Midlands England Post Number: 75 Posted on Thursday, March 01, 2007 - 02:28 am:

I wouldn't look at either of the BEE models, since my review sources tell me these are the entry level amps in the NAD range and therefore may be coloured slightly, to accept a cheaper range of speakers.

I wouldn't consider buying a C357 new, because at it's current RRP, it's way above budget. The C352 is something of an improvement over the older C350 (more on this in a moment!) and would seem to more than adequately fulfill my requirements for neutrality, soundstaging and

Registered: May-06 bass control. Only problem is that a new one is more than I can afford

right now and second hand, well - they are shooting up above my

current budget... So...

I'm about to become the proud owner of a once award winning...

C350!

In very nearly mint condition, too!. Box, manual, fully working

remote.

Considering I was looking for a rough patch for a broken 3225PE,

along the lines of 3030 and 3130, as you might imagine, I'm very

excited, awaiting it's arrival!

Anubis

Bronze Member

Username: Anubis

Birmingham, West Midlands England

Post Number: 76

Registered: May-06 Posted on Thursday, March 01, 2007 - 02:34 am:

Oh - and what I've saved, I shall put towards an outboard phono stage in future. I can wait for now, to hear my vinyl - while I use CD and all those other useful inputs. I think it's better to be patient and build the system back up, slowly, than to try and cram everything into a small budget at once.

合并式功率放大器解读

镇江高专ZHENJIANG COLLEGE 毕业设计(论文) 合并式功率放大器 Combined type power amplifier 系名：专业班级：学生姓名：学号：指导教师姓名：指导教师职称： 2013 年05 月

目录摘要 ....................................................... 错误！未定义书签。引言 (3) 第一章设计方案 (4) 1.1总体方案 (4) 1.1.1放大器的功能 (4) 1.2总体框图 (5) 第二章电路设计 (5) 2.1电源电路 (5) 2.2合并式功率放大器................................. 错误！未定义书签。 2.3前置放大器 (7) 2.4音调控制电路 (10) 2.4.1功放原理 (14) 2.5音频功率放大电路 (15) 2.6运行结果分析 (20) 2.7保护电路 (20) 第三章总体仿真 (27) 3.1仿真 (27) 3.2PCB板设计 (27) 3.3印制电路板的制造 (28) 第四章安装与调试 (29) 4.1元件的安装 (29) 4.2电路的调试 (29) 4.3性能指标 (29) 总结 (30) 致谢 (31) 参考文献 (32) 附录 (33)

合并式功率放大器专业班级：学生姓名：指导教师：职称：摘要合并式功率放大器的作用是给负载RL提供一定的输出功率，当RL 一定时，希望输出功率尽可能大，输出信号的非线性失真可能小，且效率尽可能高。由于合并式电路采用直接耦合方式，为了保证电路工作稳定，必须采取有效措施抑制零点漂移。为了获得足够大的输出功率驱动负载工作，故需要有足够高的电压放大倍数。因此，性能良好的合并式功率放大器应由输入级、推动级和输出级等部分组成。按照各级功能及技术要求，首先确定整机电路级数及电压增益分配，而后分别选择设计各级电路元器件及参数。从功放级向前逐级设计。但还是有不足之处；音频的变化范围较小，对电路功能的分析有不够详细。音频功率放大器是一个技术相当成熟的领域，在现代音响普及中，得到很大的发展和应用。音频功率放大器不仅仅是消费产品（音响）中不可缺少的设备，还广泛应用于控制系统和测量系统中。这款功放采用了典型的OCL功放电路，为全互补对称式纯甲类DC结构，功放的每一级放大均工作于甲类状态。输入级和电压放大级采用线性较好的沃尔漫电路，差分管及电流推动管分别为很出名的K170、J74（可用K389、J109孪生对管对换）对管和K214、J77中功率MOS管，功率输出级为2SC5200和2SA1943大功率东芝管并联输出，功率强劲，驱动阻抗2Ω的喇叭也轻松自如，毫不费力。综合运用了我们前面所学的知识。设计完全符合要求关键词：合并式功率放大器双声道 Combined type power amplifier Abstract Combined type power amplifier is the role of provides certain output to load RL,when RL is fixed,want to output power as high as possible,small nonlinear distortion of the output signal,and the efficiency is as high as possible.Because of the complicated circuit adopts a direct coupling mode,in order to guarantee the circuit work stable, effective measures must be taken to suppress the zero drift.In order to obtain the output

带前置合并式广播功放使用的手册

带前置合并式广播功放 AP-200P AP-300P AP-600P AP-1000P 使用手册性能特点： ●3路话筒输入口，2路辅助输入口，2路辅助输出口，最便于组合公共广播系统 ●100V，70V定压输出和4-16Ω定阻（平衡，不接地）输出 ●有默音功能，便于插入优先广播 ●各输入通道独立音量控制 ●高音和低音音调控制 ●5单位LED电平表,易观察输出电平 ●输出短路、过压，过流，过功率保护并告警 ●开机延时保护，避免开机瞬间对喇叭的冲击 ●使用高保真D类放大器设计，具有省电功能，降低损耗功率前面板： ①电源指示灯⑤高音调节旋钮 ②LED电平表及失真指示⑥话筒音量旋钮 ③电源开关⑦辅助音量旋钮 ④低音调节旋钮⑧ 1号(优先)话筒插口注意:第5只LED长亮表示过载失真,应调小有关音量以改善音质和减轻机器负荷。

后面板： ①220V交流保险丝⑤辅助输出口(用于录音或链接另一功放) ②220V交流电源线⑥输出端子 ③MIC2,MIC3话筒插口⑦默音控制旋钮 ④辅助输入1,2插口注意:不能在两个热端之间输出功率。默音功能： Mic 1乃具有最高优先级别之输入插口,由该口输入之信号将抑制其它口输入之信号.抑制的程度可由机器后面板之默音控制器MUTE"调节,调节范围为0 ~ -30dB.出厂时调在-30dB. 安装注意事项： 1、当接通电源并输入信号后，如听到短促报警信号音，即说明输出线路有短路故障，应立即切断电源，排除故障后重新加电。 2、因负载线路有一定的功率损耗，根据现场，应预留足够的功率余量,通常用所接的喇叭功率和乘以1.3倍得出功放的功率。（因广播线材的质量、大小及长短不同，倍数有所不同）3、其它注意事项请参照前面的基本安装注意事项。连接：

用EL34制作的合并式电子管功放(上) 精品

用EL34制作的合并式电子管功放(上)(组图) 电子管功放音色纯真而柔美，谐韵丰富，胆味浓郁，深受广大发烧友青睐。今特推荐一款适合普通家庭使用和欣赏音乐的电子管合并式功放。本机通用性强，制作简便，成功率高，升级换代方便。电子管功放的负载能力很强，当额定输出功率能达到30W+30W时，其音乐功率可达120W+120W，可带动一对中型音箱，完全能满足家庭影院和欣赏各种室内乐的要求。本功放电路采用通用型设计方案，功率放大管可采用6L6、6P3P、EL34、6CA7、KT88、6550等，工作状态根据制作者的偏爱，可分别制成A类或AB类放大形式，电路基本不变，只要调整功放栅极负压与部分元件参数即可。常用功率管作A类与AB类推挽功放应用参考数据表: 图1 一、合并式功放电路简析

图2 图2 电子管合并式功放电原理图图2为电子管合并式功放电原理图。输入电压放大级采用目前最流行的SBPP电路，由双三极电子管6N11担任，该管屏流与跨导值大，屏极线性范围宽，输入动态范围大。输入的音频信号由下管栅极输入，工作于共阴极方式；上管工作于共栅极方式，经放大后的音频信号由上管阴极输出。本输入级的特点是：输入阻抗高，输出阻抗低，因此，本前级放大具有传输损耗小，抗干扰性能好，频率响应特性好，特别是高频特性极佳，高频瞬态响应特性好的优点。倒相放大级采用长尾式倒相电路，将输入级的音频信号直接耦合至倒相级。这样不但拓宽了频响；同时又减少了因极间耦合电容带来的相位失真。本电路由双三极电子管6N1l 或6N6来担任。上管为激励管；下管为倒相管。两管共用阴极电阻，并具有深度电流负反馈的作用，故稳定性能好，相移失真小，共模抑制能力强。对上管来说是串联输入；对下管来说是并联输入。当有音频信号输入时，利用两管阴极的互耦作用，使屏极与阴极电流均随之变化，由于两管屏极负载电阻的阻值相同，两管输出电压的幅值相等，而两管屏极的输出电压方向相反，从而完成了倒相放大工作。值得注意的是：前级输入放大管与倒相级放大管的阴极电位均接近100V，所以在选用双三极电子管代用时不能忽视，因为一般的双三极电子管，其阴极与灯丝之间的耐压均不超过100V，超过此极限电压时，将会导致灯丝与阴极间的击穿。故比较适合使用的双三极管有：6Nll、6N6、12AX7、12AU7等。此外，还必须注意的是倒相管栅极对地电容的容量可从0．1—0．22μF，耐压400V 以上，不允许有丝毫的漏电，否则将会影。向倒相级的工作状态，因此必须选用高质量的CBB电容为最佳。

后级功率放大器与合并式放大器后级放大部分的特点

后级功率放大器与合并式放大器后级放大部分的特点北京百宝城科技有限公司关于后级功率放大器与合并式放大器做了详细的解析，希望可以帮到广大的影音爱好者。功率放大驱动部分的主要功能就是进一步放大经前级处理的信号，进而转换成模拟信号驱动整个音箱系统。由于AV放大器是采用晶体管放大的方式，放大模组与电子管放大器相比，具备体积小、发热量低、电流输出大的特点。按照输出级工作方式的不同可以分为A、B、AB、D、G与H等多种工作方式，其中AB类与D类放大器常见于家庭影院放大器之中。这几类放大方式各具特点，而且后续所推出的每一种放大方式都能依据原有类型的缺点进行改进。例如，A类拥有优秀的线性表现，失真低，但功耗大。B类改良了功耗的问题，却引来了失真大的问题。AB、G、H则是在低失真与低功耗之间取得平衡，D类则是通过数字放大处理的方式改良传统模拟放大的不足。

AB类放大是AV放大器常用的一种方式，综合了A类与B类两方面的特点，效率高于A类放大器，失真小于B 类放大器。在工作特性上，AB类放大器引入了非线性工作点，让信号接近于零时两个晶体管导通，大信号时，转向B类的工作方式。这里讲讲A类和B类放大电路的一些特点。A类放大方式出现的时间最早，其工作特性是输出级晶体管始终处于导通状态。这类放大器的优势在于具有极佳的线性输出，信号失真低，缺点是工作效能低，仅为20%～30%，其余部分都转化为热能，需要搭配大型的散热装置。因此，A类放大器会非常庞大且重量十足。B类放大方式是为了克服A类方法在效率上的不足而研发出来的。其工作特性是使用了双晶体管，每个输出级的晶体管仅在信号波形半个周期内导通，分别用于正负周期。B类放大方式的特点是在效能上取得相当理想的效果，发热量低，但是缺点也明显，会出现交越失真，线性并不出色，失真严重。

用EL34制作的合并式电子管功放调整

用EL34制作的合并式电子管功放（上）电子管功放音色纯真而柔美，谐韵丰富，胆味浓郁，深受广大发烧友青睐。今特推荐一款适合普通家庭使用和欣赏音乐的电子管合并式功放。本机通用性强，制作简便，成功率高，升级换代方便。电子管功放的负载能力很强，当额定输出功率能达到30W+30W时，其音乐功率可达120W+120W，可带动一对中型音箱，完全能满足家庭影院和欣赏各种室内乐的要求。本功放电路采用通用型设计方案，功率放大管可采用6L6、6P3P、EL34、6CA7、KT88、6550等，工作状态根据制作者的偏爱，可分别制成A类或AB类放大形式，电路基本不变，只要调整功放栅极负压与部分元件参数即可。常用功率管作A类与AB类推挽功放应用参考数据表: 一、合并式功放电路简析

图1 电子管合并式功放电原理图图l为电子管合并式功放电原理图。输入电压放大级采用目前最流行的SBPP电路，由双三极电子管6N11担任，该管屏流与跨导值大，屏极线性范围宽，输入动态范围大。输入的音频信号由下管栅极输入，工作于共阴极方式；上管工作于共栅极方式，经放大后的音频信号由上管阴极输出。本输入级的特点是：输入阻抗高，输出阻抗低，因此，本前级放大具有传输损耗小，抗干扰性能好，频率响应特性好，特别是高频特性极佳，高频瞬态响应特性好的优点。倒相放大级采用长尾式倒相电路，将输入级的音频信号直接耦合至倒相级。这样不但拓宽了频响；同时又减少了因极间耦合电容带来的相位失真。本电路由双三极电子管6N1l或6N6来担任。上管为激励管；下管为倒相管。两管共用阴极电阻，并具有深度电流负反馈的作用，故稳定性能好，相移失真小，共模抑制能力强。对上管来说是串联输入；对下管来说是并联输入。当有音频信号输入时，利用两管阴极的互耦作用，使屏极与阴极电流均随之变化，由于两管屏极负载电阻的阻值相同，两管输出电压的幅值相等，而两管屏极的输出电压方向相反，从而完成了倒相放大工作。值得注意的是：前级输入放大管与倒相级放大管的阴极电位均接近100V，所以在选用双三极电子管代用时不能忽视，因为一般的双三极电子管，其阴极与灯丝之间的耐压均不超过100V，超过此极限电压时，将会导致灯丝与阴极间的击穿。故比较适合使用的双三极管有：6Nll、6N6、12AX7、12AU7等。此外，还必须注意的是倒相管栅极对地电容的容量可从0．1—0．22μF，耐压400V以上，不允许有丝毫的漏电，否则将会影。向倒相级的工作状态，因此必须选用高质量的CBB电容为最佳。

带五分区合并式广播功放使用的手册

带五分区合并式广播功放 PA-8200PS PA-8300PS PA-8600PS PA-9000PS 使用手册性能特点： ●3路话筒输入口，2路辅助输入口，2路辅助输出口，最便于组合公共广播系统 ●100V，70V定压输出和4-16Ω定阻（平衡，不接地）输出 ●有默音功能，便于插入优先广播 ●各输入通道独立音量控制 ●高音和低音音调控制 ●4单位电平表，1单位红色失真灯指示 ●输出短路，过压，过流，过功率保护并告警 ●开机延时保护，避免开机瞬间对喇叭的冲击 ●自带五分区 ●单机即为一套完备的小公共广播系统前面板：

①电源开关⑥话筒音量旋钮 ②电源指示灯⑦辅助音量旋钮 ③低音调节旋钮⑧ 1号(优先)话筒插口 ④LED电平及失真指示⑨分区选择按键 ⑤高音调节旋钮注意:第5只LED长亮表示过载失真,应调小有关音量以改善音质和减轻机器负荷。后面板： ①保险丝⑥辅助输出口(录音或链接另一功放) ②交流电源线⑦功率输出端子 ③CH1-CH5分区输出接各区喇叭⑧功率输入端子 ④MIC2,MIC3话筒插口⑨默音控制旋钮 ⑤辅助输入1,2插口注意:不能在两个热端之间输出功率。默音功能： Mic 1乃具有最高优先级别之输入插口,由该口输入之信号将抑制其它口输入之信号.抑制的程度可由机器后面板之默音控制器“MUTE”调节,调节范围为0 ~ -30dB.出厂时调在-30dB. 安装注意事项：

1、当接通电源并输入信号后，如听到短促报警信号音，即说明输出线路有短路故障，应立即切断电源，排除故障后重新加电。 2、因负载线路有一定的功率损耗，根据现场，应预留足够的功率余量,通常用所接的喇叭功率和乘以1.3倍得出功放的功率。（因广播线材的质量、大小及长短不同，倍数有所不同） 3、其它注意事项请参照前面的基本安装注意事项。连接：性能规格：