Search found 32 matches

by Tables_and_Tubes
Tue Jul 06, 2021 2:02 am
Forum: Aesthetics, Look & Feel
Topic: Engineers Amplifier and VTA PH-14
Replies: 2
Views: 71

Re: Engineers Amplifier and VTA PH-14

Absolutely stunning work! I am a sucker for silver faceplates and you really set them off against the zebrawood. How do you like Pete's "EA"? On paper it looks great. A nice mix of distortion cancellation circuitry. The harmonic structure on the FFT's on his website look really good. I am ...
by Tables_and_Tubes
Mon Jul 05, 2021 1:54 am
Forum: General Solid State Audio Discussion
Topic: Pioneer SX 750 went silent
Replies: 4
Views: 95

Re: Pioneer SX 750 went silent

I would also disconnect the wiring from pin 8 on the AWR 100 board. Then you can test that section of the transformer for interwinding shorts (from primary to secondary) and for shorts to ground.

Dan
by Tables_and_Tubes
Sat Jul 03, 2021 7:20 pm
Forum: Discussion on Oscilloscope Video Series
Topic: What am I Seeing Here?
Replies: 16
Views: 723

Re: What am I Seeing Here?

Speaking in generalities is always dangerous, but the "typical" input impedance of many SS amplifiers will run in the range of 22-47K ohms. 50K ohms would be a fairly low input impedance for a tube amplifier. 100-250K ohms would be the expected range on most modern tube amplifiers. Of cour...
by Tables_and_Tubes
Wed Jun 30, 2021 11:23 pm
Forum: General Tube Audio Based Discussion
Topic: Strange Hum in Volume Pot
Replies: 7
Views: 205

Re: Strange Hum in Volume Pot

Make sure that your RCA input connectors are isolated from the chassis. Don't just trust the little washers, make sure by measuring with a meter. To test, you will need to disconnect the main chassis ground at the circuit board by the "AC GND" connection. The bare metal connecting to your ...
by Tables_and_Tubes
Wed Jun 02, 2021 8:00 pm
Forum: Audio Bench & Dummy Load Setup, Test Equipment, Etc.
Topic: Variac input voltage?
Replies: 4
Views: 251

Re: Variac input voltage?

I purchased the little 5A blue variac from Circuit Specialists. The digital voltage readout is fairly close (although I monitor the voltage separately) and the unit performs well. The price is right and if you are a first time buyer, there is a discount. https://www.circuitspecialists.com/variac-var...
by Tables_and_Tubes
Sun May 30, 2021 9:40 pm
Forum: Share Your Latest Project
Topic: 6BM8 "tiny amp" + Video Series
Replies: 14
Views: 679

Re: 6BM8 "tiny amp"

Hi Stephe,
Do you have a link to the cool little tube socket trim rings that you are using in the build?
Thank you!

Dan
by Tables_and_Tubes
Thu May 13, 2021 1:29 pm
Forum: General Solid State Audio Discussion
Topic: Marantz 2235B transisitors
Replies: 12
Views: 574

Re: Marantz 2235B transisitors

Ideally, they should be matched under the conditions that they will see in the circuit (voltage and current), with a test jig and scope,but I just use my Peak Atlas to weed out the strays. So, pick out four that are as close as possible with your tester and that will work. I bet Cory S is happy that...
by Tables_and_Tubes
Thu May 13, 2021 3:39 am
Forum: General Solid State Audio Discussion
Topic: Marantz 2235B transisitors
Replies: 12
Views: 574

Re: Marantz 2235B transisitors

Since H701-H704 are your differential input pairs, they will need to be matched as close as possible. After mounting, put a dab of thermal grease between them (or you can use JB Weld) and then heat shrink the bodies together so that they will thermally "track" with each other.

Dan
by Tables_and_Tubes
Thu May 13, 2021 3:32 am
Forum: Share Your Latest Project
Topic: 6BM8 "tiny amp" + Video Series
Replies: 14
Views: 679

Re: 6BM8 "tiny amp"

Cool! I will be watching this one with interest. It would be a great little desktop/bedroom amplifier for driving my modified PSB "Super" Alpha's! Looks like the power supply will need to source around 100ma (?) and, of course the 6.3V @ 1.56A for the heaters. A nice little L-R-C supply wi...
by Tables_and_Tubes
Sat May 08, 2021 2:50 am
Forum: Great On-Line Content
Topic: Power Supply Simulation
Replies: 2
Views: 276

Re: Power Supply Simulation

Awesome little program! I use it all the time.

Dan