montesquieu's STA100

[montesquieu]

Yes, that would be interesting! I would imagine the Sondex, being all valve, would be closer to the STA100 in sound... I'm curious to hear what, if any, difference the FET solid-state inputs make to the sound, seeing as the rest of the TT circuit is very similar to the STA100.
Also, to quote a post here "the output transformers in the TT100 were wound for 4-8 ohms - much more sensible for modern speaker loads than the 8-16 ohm/100v setup of the original STA100" - but I'm not sure if that applies to Tom's RR STA100 anymore, as I guess it's been somewhat modernized?

Yes indeed Will had new transformers wound which I believe were based on the TT100 transformers - I never heard it with the original 100v line transformers as one was found to be slightly faulty and I had them replaced at the outset when it was originally serviced.

David is coming round on Thursday so he may be able to give a view, though different sources and speakers so it may be hard to discern quite what is doing what.

The KR KT88 is reasonably priced. 596 Euro plus VAT for a quad from Best300B.

My bet is they'll be worth every penny and will transform the amp for the better.

Thanks Justin I thought they were more expensive than that I'll investigate.

[User211]

I really think they will be worth a go, Tom. All the KR valves I have tried have been nice.

I think they have priced it right since amps that use KT88s generally use at least a quad of them. And they want a chunk of that US power amp tendency to use a lot more than that!

I firmly believe that a large part of the difference between a good valve power amp and an appreciably better one is down to the output valve quality.

[AD Audio]

Hi All,
Will told me he wound /winds the new transformers with only a 6 ohm tap. That still gives max power at 8ohms and works better with modern speakers.

Yes, I'm looking forward to some early impressions on Thursday and happy to host a bake off at a later date.
David

Sent from my ONEPLUS A5000 using Tapatalk

[Radford Revival]

The transformers in Tom's and Peter's amp are my own special design and can be set for 4, 8, or 16 ohms (though maximum power transfer happens around 3, 6 and 12 ohms) but are an absolute nightmare to wire up!

"4", "8", and "16" ohms is really a rough terminology, usually it means that the said impedance reflects the design centre impedance / often a datasheed suggested value on the anodes. Normally I aim for a slightly lower than the stated value to take into account "difficult" 8 ohm loads etc

[nickbaba]

Thanks for the info, Will - excellent work!

Will had new transformers wound which I believe were based on the TT100 transformers

Interesting... so that should place the STA/TT sound even closer overall, and all things being equal the difference between the valve and FET input stages, if any, should be easier to hear.

[Radford Revival]

Thanks for the info, Will - excellent work!



Interesting... so that should place the STA/TT sound even closer overall, and all things being equal the difference between the valve and FET input stages, if any, should be easier to hear.

They shouldn't sound a million miles apart, given in any well designed amp using valves in its output stage, any residual distortion should be dominated by said output stage and linearised with the use of feedback

[nickbaba]

That's great to know Will, thank you.

My TT100 sounds fantastic to me, that's for sure, and soundwise beats my previous amp, an EAR 890 (hence currently for sale on AoS!).

[Edward]

Tom kindly invited Adam and I over yesterday and we had a wonderful time listening to the STA100.

So after a lovely lunch (thanks Tom! - you should open a restaurant) we sat down and had a few hours with different things. All three of us are familiar with the unique Tannoy/Radford STA25 marriage so were ideally placed to detect the difference the STA100 is able to give. In a word - awesome. Another word - effortless. Last year I had a mini listen to a part finished STA100 at Will's place driving his RFC Raptors so I knew I was in for something special.

The STA100 lift things altogether to another level. It simply breathes music in a totally uncompressed and unrestrained manner. No matter what Tom threw at it the STA100 just picks it up and presents it in a totally natural and open way.

The STA100 is able to take the most delicate or thunderous tracks and present it cleanly without fuss or fanfare. Notes start exactly where they should and stop with natural decay. Huge dynamic passage are almost frightening to the listener but the STA100 just sails through it - never complaining. All obviously helped by the Tannoy setup Tom has. The STA100 has a vice like grip on the Tannoys.

One thing that Tom demonstrated which I don't think I have ever experienced before is playing a mono LP (Cannonball Adderley etc - Somethin' Else) via a mono cartridge and mono SUT. This was completely captivating. The ease and naturalness that was heard completely drew me in and made me feel I was there. Who wants stereo when one can have this incredible sound.

Tom played around with various SUTs and also played some CDs. Vinyl rocks!

Tom wired in my Sugden amp (35w pure class a) and we all agreed that the Sugden played wonderfully and held the Tannoys incredibly well - but alas the STA100 and its valve sound won the day.

Thanks Tom for taking the time and being such a great host.

[Radford Revival]

Very happy to hear the amp is doing its job - many thanks for the positive review of it sounding good in Tom's system Credit for the sound is of course also due to Paul / RFC for his Canterbury cabinets and crossovers.

[nickbaba]

100w Radfords Rule!!