tube pre and tube power amp

[tiguan]

hello all

I am a newbie in tube amps and started to read the threads in the forum. My friend who is good at electronics and diy and me (no knowledge in DIY) are planning to make for him and myself
tube pre and tube power amp set.

I am planning to make as well the following speakers
PRELUDE

We are planning to make amps which we are gonna use forever with possible upgrades in the future. Therefore our budget will be shaped based on your recommendations.
Could you please recommend;

1. What should be the power of the amp which can work with the above speaker
2. Schematics for pre amp and power amp (SE)


thanks in advance

 

[Loren42]

hello all

I am a newbie in tube amps and started to read the threads in the forum. My friend who is good at electronics and diy and me (no knowledge in DIY) are planning to make for him and myself
tube pre and tube power amp set.

I am planning to make as well the following speakers
PRELUDE

We are planning to make amps which we are gonna use forever with possible upgrades in the future. Therefore our budget will be shaped based on your recommendations.
Could you please recommend;

1. What should be the power of the amp which can work with the above speaker
2. Schematics for pre amp and power amp (SE)


thanks in advance

How efficient are the proposed speakers (dB/WattMeter)?

How loud do you expect to listen to these speakers?

 

[Eli Duttman]

I read the "Prelude" as being 90 dB. efficient and its crossover is complex. That definitely mitigates against a no NFB SE setup.

Paul Joppa has provided us with a useful rule of thumb. In a "typical" listening space, each amp section/speaker combo should be capable of a peak SPL (1 M. distance) not less than 102 dB. Applying Joppa's Rule to 90 dB efficient speakers tells us that at least 16 WPC are needed.

Push pull EL34 class tubes or 7591s easily produce the requisite power. For a SE setup, the only realistic option I can come up with is a full pentode mode KT88 that employs regulated screen grid B+, along with plenty of NFB in 1 form or another.

Unless phono is part of the equation, a separate preamp is not really needed. Get the gain structure right and a simple passive volume control combined with source selection capability in the same enclosure as the power amp circuitry works very well. In short, build an "integrated" amp.

 

[rotaspec]

The speaker designer recommends 100w, and indeed most of the SPL graph is below 90dB/2.83v/1m.
So it needs a powerful amp to attain high volumes.
Not too many designs suitable for first builds are going to be in this category.

 

[tiguan]

Actually I do not listen too laud music. Generally listen Jazz, Blues and Classic.

I am in correspondence with Mr Gravesen. Yes he is recommending a powerful amp. 100 w for Solid State.
And crossover is as well complex. I was thinking some revisions on the cabinet and he recommended better not to touch any dimension and shape.

But I have big expectations from Audio Technology drivers matching with tube amp and this will put my system to an another point. Which I do not need to change forever.

 

[aardvarkash10]

it seems your objectives are at odds with your choice of equipment.

 

[grhughes]

Your speakers are medium efficient

I'd look for some speakers above 95db/1w/1m (Klipsch Heresey- LaScalla-Belle, EV sentry IV, Altec 604 Altec A7-500, Tannoy MG). If you're a beginner, then I would certainly start off by buying something already built like a Heathkit WM5 or Dynaco MK3 power amps and try to improve it by making mods. Once you're learned what makes good sound then you could maybe brave a full DIY build from scratch. Without that knowledge base, I wouldn't wish it on my worse enemy. We are always dis-advantaged by what we don't know. Pick up a copy of VALVE AMPLIFIERS and BUILDING VALVE AMPLIFIERS by Morgan Jones. Ray

 

[tiguan]

Thanks all. It has shaped more for me. I will not hurry up.