[L0rdGwyn]

Always a good day when new transformers arrive. Got my 1:14 MC SUTs along with my new HY69 amplifier output transformers. The outputs are 7K primary and I simplified things a bit with just two secondary taps, 100ohms and 32ohms. I'll have to polish up the brass end bells like I did on the other set. The old transformers are going to burn a hole in my pocket, need to do something with them.

I am rebuilding the HY69 amp yet again. It's the forever amp so it has to be perfect and I decided I need ideal output transformers and it needs to be fixed bias, so it's going to be a three chassis amplifier. One chassis for the AVC, which is already done, one chassis for the power supply, and one chassis for the signal. I'll also be ditching the cathode bypass and going fixed bias with Simpson meters.

Gonna take some time as I need to work on layouts, chassis, and circuit changes to go fixed bias. Hopefully will have the rebuild done and my LCR phono done by the end of the summer.

 

[AnyDave]

Always a good day when new transformers arrive. Got my 1:14 MC SUTs along with my new HY69 amplifier output transformers. The outputs are 7K primary and I simplified things a bit with just two secondary taps, 100ohms and 32ohms. I'll have to polish up the brass end bells like I did on the other set. The old transformers are going to burn a hole in my pocket, need to do something with them.

I am rebuilding the HY69 amp yet again. It's the forever amp so it has to be perfect and I decided I need ideal output transformers and it needs to be fixed bias, so it's going to be a three chassis amplifier. One chassis for the AVC, which is already done, one chassis for the power supply, and one chassis for the signal. I'll also be ditching the cathode bypass and going fixed bias with Simpson meters.

Gonna take some time as I need to work on layouts, chassis, and circuit changes to go fixed bias. Hopefully will have the rebuild done and my LCR phono done by the end of the summer.

So are you going to build a gaggle of other amps with all of the transformers that you've removed from the HY69 amp?

 

[LobalWarming]

Always a good day when new transformers arrive. Got my 1:14 MC SUTs along with my new HY69 amplifier output transformers. The outputs are 7K primary and I simplified things a bit with just two secondary taps, 100ohms and 32ohms. I'll have to polish up the brass end bells like I did on the other set. The old transformers are going to burn a hole in my pocket, need to do something with them.

I am rebuilding the HY69 amp yet again. It's the forever amp so it has to be perfect and I decided I need ideal output transformers and it needs to be fixed bias, so it's going to be a three chassis amplifier. One chassis for the AVC, which is already done, one chassis for the power supply, and one chassis for the signal. I'll also be ditching the cathode bypass and going fixed bias with Simpson meters.

Gonna take some time as I need to work on layouts, chassis, and circuit changes to go fixed bias. Hopefully will have the rebuild done and my LCR phono done by the end of the summer.

At least your QA is assured under the watchful eye of the traffo-cat. What a beauty!

With all the spare transformers, any plans to include transformer sockets for endless traffo-rolling fun?

 

[cats4cans]

So are you going to build a gaggle of other amps with all of the transformers that you've removed from the HY69 amp?

Decoy amps. Have all the tubes light up, and have the output transformers installed, but not connected. Build a little chip amp to hide inside and do the real work. It’ll look pretty though.

 

[L0rdGwyn]

So are you going to build a gaggle of other amps with all of the transformers that you've removed from the HY69 amp?

I have so many transformers from old projects lying around, I could build a fleet of Frankenstein amplifiers with all this stuff!

 

[triod750]

What do they say; 'Do it once, do it right'?
Or; 'Just do it'!
How do you do...

 

[L0rdGwyn]

What do they say; 'Do it once, do it right'?
Or; 'Just do it'!
How do you do...

My version is do it three times. Do it wrong, oops wrong again, then do it right

 

[Svperstar]

I see this thread is up to 451 pages.... I haven't taken the time to read all of that.

Any thoughts on estat amps? What the best is? Or better off using a transformer box?

 

[L0rdGwyn]

I see this thread is up to 451 pages.... I haven't taken the time to read all of that.

Any thoughts on estat amps? What the best is? Or better off using a transformer box?

Sorry estats really aren't my area of expertise.

 

[g0ldl10n]

@L0rdGwyn yo man, just wanted to say thanks for recommending the books - once I got the fundamentals down the subjects this single book goes into which I can now understand to the point of being able to execute them in my proto circuit, well it's just lovely!

I have implemented mu-follower for the input stage on each side (1 twin triode for each channel) which this book goes into detail and I have gotta say, wow!

Now, I can begin to pick this stage apart to dial it in more. Furthermore, once I grab the second book on power supply designs I am sure there are more of these moments to come!

Edit: This line here is what caught my attention and is why I decided to give it a try.

 

[L0rdGwyn]

@L0rdGwyn yo man, just wanted to say thanks for recommending the books - once I got the fundamentals down the subjects this single book goes into which I can now understand to the point of being able to execute them in my proto circuit, well it's just lovely!

I have implemented mu-follower for the input stage on each side (1 twin triode for each channel) which this book goes into detail and I have gotta say, wow!

Now, I can begin to pick this stage apart to dial it in more. Furthermore, once I grab the second book on power supply designs I am sure there are more of these moments to come!

Edit: This line here is what caught my attention and is why I decided to give it a try.

You're welcome. Those two books are great, top recommendation for me for people wanting to get into tube DIY.

 

[g0ldl10n]

You're welcome. Those two books are great, top recommendation for me for people wanting to get into tube DIY.

Have you ever built anything using mu-follower? For me this is a serious game changer to what is possible in terms of SQ.. oh my word.. I am a bit stunned how good this nuclear explosion of caps, resistors, wire and transformers with a bit of protoboard spinkled in on top of a piece of plywood sound using this design. I think I will just call it completed

 

[L0rdGwyn]

Have you ever built anything using mu-follower? For me this is a serious game changer to what is possible in terms of SQ.. oh my word.. I am a bit stunned how good this nuclear explosion of caps, resistors, wire and transformers with a bit of protoboard spinkled in on top of a piece of plywood sound using this design. I think I will just call it completed

I frequently use CCS loads or gyrators to load triodes which are essentially a hybrid mu follower where the bottom triode is loaded by a transistor as opposed to another triode. Surprisingly not many commercial amplifiers utilize these circuits and load tubes with resistors, which is bonkers because it's not that much more expensive and infinitely better.

 

[L0rdGwyn]

I will say though that using a true mu follower is definitely cooler than using a transistor, even if it isn't as high performing. Kinda like tube rectification

 

[L0rdGwyn]

Another thing you could try with a dual triode that accomplishes similar goals to a mu follower is an SRPP stage.