Search found 428 matches

by Thermionic Idler
Fri Mar 30, 2018 4:41 pm
Forum: Everyones Projects
Topic: Dieselpunk Preamp of Doom and the Beast with Two Backs
Replies: 199
Views: 22196

Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Partially completed softstart / dc blocking modules. The soft start PCB and its 9V transformer can be seen between the turret boards. The components for the dc blocker (4 diodes, 6 caps) will be mounted to the turrets next. I have already tested the soft start boards to prove they work, cos they'd b...
by Thermionic Idler
Sun Mar 25, 2018 11:34 pm
Forum: Everyones Projects
Topic: Dieselpunk Preamp of Doom and the Beast with Two Backs
Replies: 199
Views: 22196

Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

I don't think I'd have been popular at the pub with this either! My self storage lock-up (well, shipping container) is in the middle of a Chesterfield industrial estate, they don't mind loud hammering on a Sunday afternoon so much.
by Thermionic Idler
Sun Mar 25, 2018 8:30 pm
Forum: Everyones Projects
Topic: Dieselpunk Preamp of Doom and the Beast with Two Backs
Replies: 199
Views: 22196

Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Today, I have been mostly... bashing turrets into PTFE boards. I had to take everything down to the self storage place (a.k.a. my shed) to do it. After bashing the first one in, having drilled out all the holes, Meredith asked me how many I had left to go. When I answered "71", her reaction led me t...
by Thermionic Idler
Sat Mar 24, 2018 11:58 pm
Forum: Solid State
Topic: DIY Transistor Amp Using NVA Boards
Replies: 71
Views: 4572

Re: DIY Transistor Amp Using NVA Boards

And then there are insane nutters like me who decided the whole output transformer question was too hard and went down the OTL path, though admittedly one well trodden by people who know what they're doing (Rozenblit). The whole concept of OTL is wrong on so many levels but I've yet to hear anything...
by Thermionic Idler
Sun Mar 18, 2018 1:29 pm
Forum: News
Topic: FM Switch Off Scrapped
Replies: 12
Views: 1528

Re: FM Switch Off Scrapped

Indeed, although I've not had an FM tuner in my system for years. There is so much online choice now, and it largely doesn't pollute my listening space with crap I don't want to hear.
by Thermionic Idler
Sun Mar 11, 2018 1:52 pm
Forum: Beginners
Topic: Floating signal grounds?
Replies: 13
Views: 1783

Re: Floating signal grounds?

Decision cemented then, on that basis - 0v to safety with a straight piece of wire, no resistors, no thermistors. The galvanic isolation gives me absolutely no reason not to.
by Thermionic Idler
Sat Mar 10, 2018 12:18 pm
Forum: Assorted Stuff
Topic: Next Owston meet 30 june/1 July 2018
Replies: 174
Views: 10523

Re: Next Owston meet 30 june/1 July 2018

Hire the a team to shift the 301! Ha - I think it'll need more than the A-team. Every time I have to move it off the rack I risk landing myself in A&E. The nude VdH with no stylus guard just adds to the fun. We'll likely be using either the Lenco you built for us (though it needs a non-78rpm cartri...
by Thermionic Idler
Sat Mar 10, 2018 11:14 am
Forum: Assorted Stuff
Topic: Next Owston meet 30 june/1 July 2018
Replies: 174
Views: 10523

Re: Next Owston meet 30 june/1 July 2018

Meredith and I should be there on at least the Saturday, hopefully with Steve's old Mets, my completed Beast amps, AMB preamp, source TBA.
by Thermionic Idler
Mon Mar 05, 2018 4:29 pm
Forum: Everyones Projects
Topic: Dieselpunk Preamp of Doom and the Beast with Two Backs
Replies: 199
Views: 22196

Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Do you expect the inside to get above 70C ? It shouldn't get that high, at a guess maybe mid 50's at the very most on a hot day? The idle heat should be about 240 watts a side with a 12 tube configuration (it can be reduced to 8 tube / 175 watts in the summer). It's more that I wanted to ensure a g...
by Thermionic Idler
Mon Mar 05, 2018 2:04 pm
Forum: Everyones Projects
Topic: Dieselpunk Preamp of Doom and the Beast with Two Backs
Replies: 199
Views: 22196

Re: Dieselpunk Preamp of Doom and the Beast with Two Backs

Slow progress of late but last week whilst snowed in, I worked on populating the main circuit boards. Electrolytics are mostly high temp Panasonics, all fast recovery diodes (UF4007, FR605-T), 2W resistors are Vishay CPF series metal films rather than metal oxide, 0.5W are Takman metal films aside f...
by Thermionic Idler
Sat Feb 24, 2018 11:02 pm
Forum: Assorted Stuff
Topic: Nothing In Particular
Replies: 9986
Views: 573881

Re: Nothing In Particular

I'm quite impressed with the Mash here for finding a stock pic with a Garrard 401 in it...

http://www.thedailymash.co.uk/news/life ... 0222144733
by Thermionic Idler
Sat Feb 24, 2018 1:21 pm
Forum: Beginners
Topic: Floating signal grounds?
Replies: 13
Views: 1783

Re: Floating signal grounds?

A 10 Ohm 1 watt resistor between the chassis/PE and signal ground/star. Nelson Pass uses an NTC thermistor in a lot of his designs. That's what I would do too. Hang on though - is that 10R resistance even needed in this case? Won't hurt, but should stop a hum loop, and you've had bother with that t...
by Thermionic Idler
Sat Feb 24, 2018 1:51 am
Forum: Beginners
Topic: Floating signal grounds?
Replies: 13
Views: 1783

Re: Floating signal grounds?

Hang on though - is that 10R resistance even needed in this case? I'm using input transformers, one of their benefits is the breaking up of ground loops. The incoming signal hot and cold phase will be on pins 2 and 3 of the XLR, connected to the floating primary, with pin 1 (shield) connected to cha...
by Thermionic Idler
Fri Feb 23, 2018 11:45 pm
Forum: Beginners
Topic: Floating signal grounds?
Replies: 13
Views: 1783

Re: Floating signal grounds?

Interesting idea about the thermistors, as it happens I have two spare CL-60's. They were originally specified for the inrush current limiting but I've since decided to replace them with an active soft-start circuit per Rod Elliott, which will also more elegantly integrate the remote 12V power-up / ...
by Thermionic Idler
Fri Feb 23, 2018 2:10 pm
Forum: Beginners
Topic: Floating signal grounds?
Replies: 13
Views: 1783

Floating signal grounds?

Hi, I'd like to put a question to the knowledgable if I may. The never ending Transcendent Beast OTL project is moving glacially forward and I've run into something which looks a bit odd to me. As it's a copyrighted design I can't post the schematic, but the circuit signal grounds all tie back to a ...