justinsweber

I may be wrong... Ask Dave... He would know for sure. So much of the credit of ampsandsound goes to Dave's urging.

Yes and no. I think Dave chose different caps for coupling. Russian PIO. I use Wima. Aside form that differance... no.

Thanks guys. The wood work is the efforts of partner. I tried to embed the pics... didnt seem to work... can anyone help?

The PCB is Shannons... but greatly changed... I’ve prob spent the most time reworking the design of this amp. I consider myself a purist... not a fan of pots on amps... Simpler the better. I’ve had to service too many amps in which no one did the requisite adjustments. Though I think the world of Chicago magnetics... I’ve moved away from their use is some cases... Having built alot of kits sourced from Triode of the years... like many... their kits (metal work is great). And the ST-35 offers the most support. I would strongly sugest you order your own parts. Here is a bit of what we have been up to the last 2 weeks.

Schu Kind of you. I do think things are hard for many. I heard this interview on PBS... basically concluded that in the 90s to 2000s the middle class leveraged the income of both heads of family to send their children off to college or buy a home. The reality of 2010s forward has been both heads of house work and that the husband typically has 2 jobs to provide the $ to maintain the middle class dream. Id consider myself a bit more ambitious than many people I know... but I too work too much. (Trying to learn better ways to make the same $ but work less.) About the transformers... If you didn’t own Klipsch Id say Edcor transformers are great...They are cheap by comparison, Their. GXSEs have great power handling and HF extention… but only go to 40hz. The SE-84 uses these outputs with a custom primary impedance and a lot of work with the feedback network. My Tech has those stacked cap and stacked resistor networks that helps to dial in such things. If you want iron that does what it should and can handle big power… Hammond 1600 serious iron is wonderful without being pretentious. They are BIG… will require a braced chassis…. Problem with bracing is it Fs with how you route wires almost always. That said, Great power headroom, goes low, goes high. Transcendar iron is generally my iron of choice. US made, natural midrange, great primary inductance, goes low, goes really high… not big. I always go for lower distortion over power when choosing primary impedances and bias tubes really conservatively. With each of iron I use now… Ive gone to custom impedances to match the BOM of the circuits… just one more way to get a bit more out of it.

Kit... depends on how you consider it... I do buy my PCBs from shannon... I we also have alot of discussion with Shannon, my tech and myself re: changes to the circuit and different parts used. DIYtube makes amazing PCBS which hare well thought-out. That said, building them and getting the performance desired has taken many revisions. The SE-84 is based on Shannon's top-plat and PCB. Specific changes include cathode biasing, feedback value changes and output transformers with different specs... though sources from edcor on this model. Re: mental enclosure inside the wood... I originally was picking up noise. and so tried this simple suggestion and its worked... Ive now moved onto spraying the inside of the wood plinths with RF shielding which has accomplished the same goals. KITS or not... an amp should measure well and try to employ the best build practices… I am not Shindo or Audionote… god I wish I were… I don’t make my own caps or wind my own iron… don’t forage my own chassis. We do buy our own wood, mill it down; finish it to mate to its top-plate. Though I own some of my PCB gerbers outright… I don’t own them all and source from OE supplies who want my business and want to see their ideas get executed well. I ask for the design expertise to aid in building something which is different/improved from their original concept and pay for the advise. I’ve said repeatedly… if anyone wants advise or would like more intimate details of what I use/ how I do it… call me. I have only received 3 such calls which covered cornscala configurations, sourcing for good iron and how to get a similar wood plinth. I don’t think its fair to ask me to place schematics, build of materials and grounding schemes for public consumption… Happy to share to an individual who wants to build for themselves and takes it upon themselves to ask. With each of the amps I sell… they start with someone else’s good idea and good implementation of that idea… I try to then put my spin on it… not just solder it together but chose parts and values which make sense for me, and very often are not what are spec’d. In the end, each amp is bench tested, burned in for a several hours and then listened to. I’m not the most handy with a scope… My tech is… but my Cornscala’s sure as shit are revealing of problems… generally I fight noise floor battles… I want vanishingly low noise, good bass extension, neutral presentation and mid HF that floats… If I can hear it then there is a problem. Re: the orig post… My exp has been circuit, output iron, passive components and grounding to make the largest share of differences on performance. Crapy circuits are real performance killers, but generally will exceed the ability of the iron. Passive components and their inability to remain stable over time or provide reliable/repeatable values has been a historic problem which has gotten considerably better over time. I think there was another post re: building practices… there is own books on this… building practices matter because the physics are non-negotiable and should be respected. Lastly... if asked... I think Petter Millet and Shannon sparks create truely amazing designs worth exploring and builing.

I will not be using a voltage dividing network on this next amp. I wanted as simple a solution as possible… It might not work… but I’m hopeful it will. I didn’t want to take an output tap intended for a speaker and drive it down to be used for phones. The SE-84 takes that approach… I was tying a diffident method. I’ve seen this approach used… as I’m not a phones user I did not evaluate, but when this project is done and scoped… I’ll buy some to listen. The Darling circuit with 8ohm tap outputs ~.750mv… I will see when the transforms get here and are build what it will output given the new output impedances… the napkin math looks very promising but bench testing will tell. The hope is DHT, no feedback and no resistive network… strap the phones to the ¼” socket and call it good. I based my impedances on looking what several headphone manufactures spec for driving sig vs the phone freq response. Who knows… cant what makes it fun.

Ive ordered iron for my 1st dedicated unit with impedances for 32 ohm for grados and alike and 600ohm for the wild stuff... I think 300 ohm was used previously with older designs.

I have my output iron on order for the 1626 SE with 32ohm and 600ohm taps... bing on the phones :-)

It’s a work in progress bringing the 1626 to phones... I’ve ordered transformers with 32ohm and 600ohm tapp, should cover almost all needs. If my calc is correct... 750mv SE no feedback... should be worth a listen. As soon as I get it up in prototype... I’ll ask for an audition.

Apple TV does optical out. I think Joe's DAC will handle. Used Gen 1 Apple TVs have HD and allow for great upgrades. More space plus use if external HD. A used Mac mini would be a fantastic option. I ran one from 3 years ago and upgraded to my current. Went SSD internally and external raid. Mac mini had optimal and USB out. Another option would be to go SSD on your existing laptop and mirror it. Then no reloading. And the. Go external. I've looked into Carbonite for backup. Scary idea backing up 1.5tb of media. But should be done.

Older computer will work great. Load a simple red hat Linux for OS and it can use the USB on your DAC. There is a lot if support for this type solution too. If going with full computer route get as much ram as possible.

Joe You don't need a ton of processing power. I think the best budget solution. Is a used orig Apple TV. Swap out the internal drive for a 1TB and call it good. It will give you optical out. The use a an iPhone, monitor or tv. Best of all. You'll have a good front end and can use a remote.