Seeking quality PP pre/mono power project (long)

[LowRedMoon]

For the past several weeks, I've searched the digital ether for designs for the following:

1. Push-pull valve mono power amps
2. A valve preamp to match them

So far, I've found a few schematics, a few expensive kits and a few excellent theoretical resources. In my quest, I've realized, and accepted these obvious facts:

1. I posess the skill and understanding required to build a working, safe and reliable valve rig.
2. I certainly do not command the level of knowledge necessary to design my own circuit or adequately modify someone else's circuit to suit my audio desires - yet.

I've read numerous posts on this site. Though they were packed with vital and valid information, I did not find exactly what I am looking for. I've tried to piece all the bits together myself, but have decided that a humble, direct post to you, the tube kings and gods, who hold the very information I seek in synaptic closeness, is a needed task for helping me decide a path.

...note to self...I need to quit writing as though I'm submitting these words to my English professor in 2 hours...

Basically, I'd like to hear about some designs that are well regarded among builders and listeners, and that work well together.

For those of you who are still with me, here we go.
The rest of this post is simply data that will help you help me. I greatly appreciate your efforts. I seriously mean it. In the future, I will bear your good deeds in mind, when some annoying little snot-nosed greenhorn dares to suckle at my mighty tete of knowledge.

Agenda:
Build a push-pull rig that is powerful unough to push my 91 dB-rated Monitor Audio Silver S8 speakers (a recent upgrade from my previous S6es). The setup should produce more musically satisfying sound than my current Marantz 3250b/300DC pre/power combo (circa. 1978, solid-state).
I have considered an SET setup because of the seductive opinions I've read about their luxurious sound, but I need to be able to crank the volume at any given time. I'm young. I like to get down.
It's not necessary to push the speakers to their limit, but well enough to fill an 18'x18' area, and occasionally saturate it.
Cursory Monitor Audio S8 specs: Moitor Audio Silver S PDF

Musical Tastes:
- Tubey analog Rock
- Female vocalists, Female Folkalists
- Jazz, Blues
- Classical
- Any artful blending of the above categories
- The occasional techno freak-out (that's right, techno)

Budget:
This is a tricky one. I'd like to say something like $500, but who really follows a budget when they're caught up in their passion?

Available Tools:
- Soldering tools
- VoltOhmMeter
- Metalworking tools
- Woodworking tools
- Dual-trace oscilloscope
-- Am hoping to buy a benchtop power supply soon

Skills:
- I can solder quite well
- I can read schematics and understand, at a fundamental level, what is going on

Experience:
Anna, Sarah, Natalie, that girl in the blue skirt at Dan's party...uh...right - stick to the subject...
- Two SS opamp phonostages
- several guitar effect pedals
-- It's a very short list, I know - and mere beans compared to the amps being discussed. But I am very confident that I can manage this project. I take my time. I triple check. I measure things. I have fully read the Tube Noob thread and am aware of the seriousness of tube current. I should also mention that I am awaiting both Jones Valve Amplifier books as I type this.

I'll be on the road from Friday to Sunday, so I won't be able to respond to your replies immediately. Don't mistake my absence for fleeting enthusiasm. I am very serious about getting this project rolling.

Again, Thank You.

[navin]

Originally posted by LowRedMoon
For the past several weeks, I've searched the digital ether for designs for the following:

1. Push-pull valve mono power amps
2. A valve preamp to match them

why a preamp. do you have a tunrtable. if your signal sources are high level (CD etc..) then maybe you can dispense with the preamp altogether.

I have heard the Silver 8 with the Prologue 2 from Prima Luna. This is a KT88 amp. I also heard the Prologue 1 which is a EL34 amp. I prefered the KT88 with the Silver 8.

Extrapolating on the above another tube you could try is the 6550. when my Brother in Law swtiched from the EL34 to the 6550 (using a different speaker) I prefered the 6550.

One option is to build a power amp (like the Ella Consonance) that can use either EL34, KT88 or 6550 (change of bias required) and you can then experiment.

Now while we are talking about EL34 I am also working on a similar project and have fewer skills and tools than you. See "EL 34 schematic confusion" thread. I suspect the 6SL7-6SN7 can drive the KT88 and the 6550 as well.

[LowRedMoon]

why a preamp. do you have a tunrtable. if your signal sources are high level (CD etc..) then maybe you can dispense with the preamp altogether.

I'd like to be able to switch between 3 sources (tuner,CD,phono - which I have an external phonostage for). I'd also like to regulate the volume with the preamp.

I prefered the KT88 with the Silver 8.

Why did you prefer the KT88?

[navin]

Originally posted by LowRedMoon


I'd like to be able to switch between 3 sources (tuner,CD,phono - which I have an external phonostage for). I'd also like to regulate the volume with the preamp.



Why did you prefer the KT88?

an input selector and volume pot can make an effective preamp.

The KT88 sounded fuller but i suspect (based on a seperate listening test) that the 6550 would have been nicer still.

However most schematics allow for using interchanging between the EL34, KT88 and 6550. Some use the ECC81/82, some the 6SL7/6SN7 and others the EF86/ECC83.

Now dont get me wrong. there are other tubes out there that might suit your fancy. a 300B or 845 perhaps? :-)

[LowRedMoon]

an input selector and volume pot can make an effective preamp.

I'd like to have a separate monoblock for each speaker, so I think that a preamp would be necessary. Plus, I'd like the experience of building a preamp.

However most schematics allow for using interchanging between the EL34, KT88 and 6550. Some use the ECC81/82, some the 6SL7/6SN7 and others the EF86/ECC83.

I would definitely like a design that allows swapping of different tubes. Since my tube ear is very inexperienced, it would be nice to be able to experiment and hear how different tubes sound.

[navin]

Originally posted by LowRedMoon


I'd like to have a separate monoblock for each speaker, so I think that a preamp would be necessary.

I would definitely like a design that allows swapping of different tubes. .

1. a passive preamp can do the job.
2. look for the schematic of the Ella Consonance I know it allows swapping tubes
3. where in upstate are you. i lived around Fishkill and Stormville in the late 80s.

[Eli Duttman]

I keep repeating in different threads an important rule of thumb. For satisfactory listening levels, a system has to be able to produce 102 dB. SPL peaks. Do the math. 15+ WPC will get the job done, assuming the 91 dB. spec' is honest.

Look here, where issues similar to yours are under consideration.

What sort of budget is available? With lots of cash to spend, PP 300Bs, of the sort Lynn Olsen advocates, are a possibility. Triode wired PP EL34s could be executed for a lot less money.

A passive control center may or may not be suitable. Active electronics are strongly indicated if long interconnects and short speaker cables are envisaged.

BTW, passive preamp is an OXYMORON.

[navin]

Originally posted by Eli Duttman
I...a system has to be able to produce 102 dB. SPL peaks. Do the math. 15+ WPC will get the job done, assuming the 91 dB. spec' is honest.

usually the 91db spec is at 1m. most of listen at about 3m from the speakers hence dont we need a bit more power to hit 102db or does room gain compensate for this difference.

[LowRedMoon]

What sort of budget is available? With lots of cash to spend, PP 300Bs, of the sort Lynn Olsen advocates, are a possibility. Triode wired PP EL34s could be executed for a lot less money.

I'd like to keep my cost around $500. And now that Navin has put it in my head, I'd like to go with a design that allows a few different tube models to be rolled. Being that this would be my first tube amp, I think that flexibility would promote learning.

I would like to use good quality components - resistors, caps, and even transformers. If vast tube rolling options are present, I can start out with more modest tubes and upgrade them in the future.

A passive control center may or may not be suitable. Active electronics are strongly indicated if long interconnects and short speaker cables are envisaged.

My sentiments exactly. I plan to put the monoblocks close to the speakers.

[navin]

Originally posted by LowRedMoon


I'd like to keep my cost around $500. And now that Navin has put it in my head, I'd like to go with a design that allows a few different tube models to be rolled. Being that this would be my first tube amp, I think that flexibility would promote learning.
..
My sentiments exactly. I plan to put the monoblocks close to the speakers.

1. there are some limitaions to this. I mean the same driver/phase splitter can only drive a limited numbr of output tubes. The reason I sugessted the EL34/KT88/6550 switch is that I have seen it being done on a Ella Consonance.

2. Putting monoblocks close to speakers means long cable runs from the preamp. This was something I was also thinking of doing this (hiding the power amp behind the speakers) but wiser counsel prevailed.

the preamp output levels are lower than the power amp output levels so there is greater chance of noise coming at the preamp-power amp wire. It might be nicer to have longer speaker wires and shorter preamp wires.