Search found 758 matches

by jjman
Tue Feb 12, 2008 9:39 pm
Forum: Trainwreck Discussion
Topic: relationship of cathode voltage to noise?
Replies: 21
Views: 3063

Re: relationship of cathode voltage to noise?

I'm not understanding Vk=4.42. And the plate voltage is higher than v1a? It sounds like v1b is running way hot? Double check the K resistor and cap on it. Maybe the cap is shorted? You could remove it while diagnosing at idle. I would think a shorted cap or 270 ohm k resistor could cause excess hiss...
by jjman
Tue Feb 12, 2008 9:17 pm
Forum: Technical Discussion
Topic: OT and tube type
Replies: 2
Views: 800

Re: OT and tube type

Or hook an 8ohm speaker/cab to the 4 ohm tap.
by jjman
Fri Feb 08, 2008 12:39 am
Forum: Trainwreck Discussion
Topic: Clone vs real deal... mp3?
Replies: 59
Views: 11379

Re: Clone vs real deal... mp3?

I prefered x thru the speakers but y thru the headphones. Close enough for me.

My trannies arrived yesturday so I'm now ready to start on mine so I can join the club. 8)
by jjman
Mon Dec 31, 2007 12:03 am
Forum: Technical Discussion
Topic: Finally Finished 2x6550 Head w/Tube FX Loop
Replies: 22
Views: 3501

Re: Finally Finished 2x6550 Head w/Tube FX Loop

I'm liking that type of knobs for my upcoming build. Where did you get them? Are they Tele type knobs?
by jjman
Thu Dec 27, 2007 3:04 am
Forum: Technical Discussion
Topic: Other than Sprague Filters
Replies: 12
Views: 3503

Other than Sprague Filters

I saw a thread where a “mystery” cap was inside a Sprague that was cut open. Who knows if it was real or not. And they are more expensive than the others. I think I see Illinois brand in use often? Either way, I’m wondering if other-than- Sprague brands have been holding up well in guitar amps. I’m ...
by jjman
Tue Dec 25, 2007 4:17 am
Forum: Trainwreck Discussion
Topic: PTP ?
Replies: 12
Views: 1939

Re: PTP ?

I'm ignorant on Ken's designs so indulge me. So he built his Wreck series all point to point? No terminal strips or boards? I'm fairly new too but all the clones and actual heads I've seen are on boards. I'm not looking to clone and I like PTP for fairly simple designs with not too may components. ...
by jjman
Wed Dec 19, 2007 1:09 am
Forum: Technical Discussion
Topic: BF Deluxe Reverb issues...
Replies: 2
Views: 802

Re: BF Deluxe Reverb issues...

Scratchy pot is a sign of DC on it. Are there wires under the board that you can't see to what they are attached? Normally there would be. Maybe some are hooked up wrong.
by jjman
Sat Dec 15, 2007 10:12 pm
Forum: Trainwreck Discussion
Topic: PTP ?
Replies: 12
Views: 1939

PTP ?

Has anyone seen a PTP/Standoff layout executed in a TW? Any taboos with such an approach? More microphonic possibilities?
by jjman
Fri Dec 14, 2007 12:19 am
Forum: Trainwreck Discussion
Topic: Got me an express
Replies: 25
Views: 4351

Re: Got me an express

Expressed another way: Bias Voltage : The negative voltage applied to the grid which is not what you generally measure or care about. Idle current : milliamps of current going thru the tube with no signal. This is what you generally measure and always care about. One way to measure is to read the vo...
by jjman
Thu Dec 13, 2007 3:00 am
Forum: Trainwreck Discussion
Topic: 25Watt power resistor?
Replies: 4
Views: 1173

25Watt power resistor?

Watzup with that 25watt 1k resistor in the power supply in the Express? It dissipates much less wattage, no? Probably less than 1watt I would think. Is it similar to the reasons for using high wattage resistors on screens which also dissipate very low wattage? (Don’t want them to blow during shorts ...
by jjman
Thu Dec 13, 2007 2:47 am
Forum: Trainwreck Discussion
Topic: Trem-wreck?
Replies: 5
Views: 1334

Re: Trem-wreck?

Hey statorvane Thanx for the link. Although schematic heaven is down again, I found it from a google on the Kalamazoo. It’s shown attached to a cathode biased setup and I’m still open minded on whether to go cathode or fixed (or switched) bias on mine. I’m very new to TW’s and still need to learn th...
by jjman
Mon Dec 10, 2007 12:10 am
Forum: Technical Discussion
Topic: Agency Certification, RoHS--Question for the Pros
Replies: 27
Views: 3905

Re: Agency Certification, RoHS--Question for the Pros

I’m a skeptic and a cynic. (Thus the fart comment alluding to the fear about the affect of cow farts on the world.) However, I think the y2k thing is a true success story. The fact that almost nothing bad happened showed that the world recognized and took the problem seriously. The goal was to avoid...
by jjman
Sun Dec 09, 2007 5:20 am
Forum: Technical Discussion
Topic: Black Face Deluxe Reverb Problem-Voltages
Replies: 19
Views: 4008

Re: Black Face Deluxe Reverb Problem-Voltages

It looks like there is/was an issue with the heater center tap. The filament pins' ac voltages (to ground) should be the same, but your voltage list showed them differing.

What do they show on the power tubes?
by jjman
Sun Dec 09, 2007 12:19 am
Forum: Trainwreck Discussion
Topic: Ac15/trainwreck inspired amp...
Replies: 11
Views: 2495

Re: Ac15/trainwreck inspired amp...

If you might ever want to use both channels for the same signal they would be out of phase from entering different sided of the PI. If one is delayed (wet only) than you’d have no problem with phase cancellation. Otherwise, you might want to bring both channels into the same side of the PI with mixi...
by jjman
Sat Dec 08, 2007 11:30 pm
Forum: Technical Discussion
Topic: Agency Certification, RoHS--Question for the Pros
Replies: 27
Views: 3905

Re: Agency Certification, RoHS--Question for the Pros

If I travel to Europe do I have to document that I won't fart? This could be a problem for me. 8)