DIY Audio Projects Forum

I was prepared to listen to a few tracks (Classical) and swap the TJs back in for the Treasures. Four hours later I'm listening to the Treasures and they will be staying longer yet.

Where the TJ are dark and heavy providing great musical weight the Treasures a light and articulated.
Where the the TJs have a big broad sound stage and sort or individual voices and instruments the Treasures produce a razor sharp clearly defined sound stage but tend to bunch individual choir voices as one.
The bass from the TJs is full bodied and very extended (30Hz) the Treasures didn't produce as heavier bass though extension seems to be there (need more listening here).
Voice is weighty and "real" with the TJs - like every singer has massive lungs - with the Treasures voice sounds almost super natural and very finely detailed.

If your system was on the dark side I would go for the Treasures and if your system is on the light side the TJs will provide weight and grunt the Treasures don't have. Where the JTs are an Olympic wrestlers with strength and technique the Treasures an Olympic welter weight boxers, quick and agile. But I'll have them box-on a little longer. They look better in my Dragon anyway.

P.S. 6Moons has a write-up about the Shuguang 50 Treasures 300B-Z and I agree with everything they say especially about sound stage. The Treasures are compared with other high end 300Bs so it is worth a read.

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

I wonder if any one has thought of using two different power tubes in parallel. For example TJ 300B and Shuguang 300B-Z tubes in parallel. I like the sound of both so why not use the two together. You could extract more power from the amp and get the best sound of the two tubes combined.

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

I've heard 'em. Definately not sold on them.

Glad you like 'em

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-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design

I assume you are saying you heard the 300B-Z and did like them or you heard mixed power tubes in an amp and didn't like it?

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

I heard the 300B-Z in two different amps and would take a pair of Electro Harmonix over them.

I'm difficult to please, though

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-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design

I have been putting in a lot of hours with the 300B-Z and are not 100% convinced they are better than the TJs. In the 6moons review Srajan noted resolution and sound stage as the big standouts for the tubes. After reading his article I would agree 100%. These two points hit me within the first few minutes of play (I read his article some nights later). But I have heard the TJ produce as bigger sound stage and very resolved. What I think the TJ have over the 300B-Z is just sheer musical weight. For that reason I will go back to the TJs.

I bought a pair of EH 300Bs to test the amp with. If I get the chance I will take a listen with them in.

Geek: have you listen to the TJ SE Carbon plates?

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

No carbon plates, unfortunately.

A client was going to get some 845's with those plates and have me over for a listen, but to date he hasn't.

Cheers!

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-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design

This requires a look: http://www.audionotekits.com/agrove_interstage.html

I'll assume a 6SN7 could be used. Or could it?

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |

Yes a look is in in order. I do agree with most of what Mr. Grove has to say concerning SE interstage coupling transformers. However his comments about PP interstage and high frequency response I do find a little dubious. After running the calculations I don't see the inter-wire capacitance limiting the upper frequency response anywhere in the audio range. And his comments about design history, especially "Circuit designers became lazier as the physicists and engineers designing the valves improved them...", are way off the mark. But we must remember that he has a product to sell so he needs to talk it up to some extent.

As to Mark's question about the 6SN7 as a driver, I wholly agree with his assessment. Following are the two driver load lines, first for the 6SH7 and then for the 6SN7.These two load lines are first approximations assuming an interstage transformer with the input characteristics of a Hammond 124B transformer and the circuit values given by Mr. Grove in his circuit. From what I see here, I have to say that not only is it possible to use the 6SN7 here but it is a superior choice to the 6SH7. It should have both lower distortion and lower noise. If the Hammond 124B were used in place of the 1:1 transformer indicated then it should make for one quiet and sensitive amplifier.

Anyone out there want to give it a try? (I don't have any interstage transformers lying around.)

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Matt
It's all about the Glass!
http://www.CascadeTubes.com
Cascade Tubes Blog

Matt: Due to the fact I'm about to kick one project from my bucket list (EL34 amp) and now have the speakers I have wanted for a while complete and in use I can add another project. By some strange twist of DIY fate I happen to have a pair of Hammond 124Bs. These are a nickel core inter-stage and a claimed frequency response of up to 15K at a full 5W. Generally when used under max power better frequency response can be gained. They do state 10K primary and 90K secondary.

Matt: I'll assume you are sure the 124Bs are an appropriate choice? The schematic specifies a 1:1 turns ratio. Is that the same for the 124Bs? What makes me want to tackle this project also is a have an inbox pair of Shuguang 300B-Z just laying around idle which I was given. Can't think of a better reason to build the amp. Can you?

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Projects:"Rosso" - E88CC SRPP preamp | "Pass F5 trubo” - dual mono high-end amp | “MWH” - 1920s UX-171A preamp | ”Image” - Low Profile 100W Class D amp |