got a used EZG in beautiful shape serial # starts with U--- so old style oval front- with grove tubes #4's . original likely?
Thought I'd go with the current recommended TS and got a bias rite for the job (always wanted one anyway). The GTs read 28 at 450V- about spec- at about 12N on the bias pot, Sounds good and pretty happy. I realize there are some little estimations the bias rite makes - cathode resistor method etc...
The new TS read 35 at the LOWEST bias pot setting at 452V. I can't go any lower, but I want to- sounds a bit harsh and is definitely louder (good or bad.. ). What's going on? 35 is safe for the tubes OK but at the bottom of the bias pot? with a suggested 28 per Doc's specs?
Are the tubes that different or is the newer model that different. Do I need to send the amp to the doc for upgrade?
Post by headshrinker (Marc) on Nov 23, 2017 11:01:50 GMT -7
My guess is that the new tubes you have are way out of specs. Doc always calls for medium range tubes. Yours sound like high. There are others who know more about the workings of amps though. I've never had a problem using the bias pot on Z amps and being able to get medium tubes to the right numbers.
thanks. Could be - I know this variable exists but haven't run in to it at this level before. I wrote the tube guy to ask. The numbers on the boxes are 47.4 / 2960 and 45.7 / 2910 from his matching process - over my understanding despite a long Bing inquiry last night. (some expressions of plate dissipation and output I gather, but I can't benchmarks for comparisons). The tubes are a bit warmer sounding after a few hours playing (or my ears are numb- it's a loud amp-), but bias readings haven't changed much. I worry I bother you folks as an inexpert hobbyist, but, I have built several guitars, an amp, own 4 others (2 Z's) and tweak tones compulsively best I can over years, so I guess I rate some small bonafides here. I take courage to post again (the lurker exposed). My apologies as applicable for your indulgence. And certainly thanks either way.
new set arrived. Plate current listed as 18.3 and 19.0- much lower. (lower than the medium gain Z recommends as it turns out) Biased to 28 per website - that's 27.4 and 28.6. Voltage read 470 (higher). These are nice looser sounding.-plenty of harmonic content. If there's even order distortion from the small variance in matching I certainly can't tell. Some nice blackface OD sounds at appreciably lower volumes. (celestion gold 12") I didn't need the Z brake to break up the cleans with pick attack. So I learned a lot. The softer rated tubes make a huge difference the character and feel , volume overall may be a bit lower but not much - just some earlier breakup and touch happiness. Whole different amp. Happy. Thanks, z talk. then I added in zen drive. well...
GuitarZ: I'm okay with the AARP letters. You're still living and breathing? What the heck am I to think when a funeral home sends me a free consultation offer? Ouch!
Jun 21, 2019 15:41:26 GMT -7
The Bad Poodle: I bought airline tickets online... now every few days i get emails that read "Your trip is almost here but aren't you forgetting something?? You don't have trip insurance!" and i'm thinking..."is there something i should know about your plane maintenance?"
Jun 21, 2019 16:02:32 GMT -7
GuitarZ: Reminds me of buying my Honda. When they tried to sell me the maintenance package, I said "Is your car not reliable?" Long story short my wife teamed up with the sales lady to buy the maint package. Never again!
Jun 21, 2019 16:16:53 GMT -7
roscoenyc: I have never in my life experienced tube rattle. That said, I've only been playing electric guitar for 49 years.
Aug 2, 2019 6:39:37 GMT -7
The Bad Poodle: What cures tube SHAKE and tube RATTLE? A tube ROLL?
Aug 11, 2019 17:22:10 GMT -7
capofirstfret: I've experienced tube rattle in two different amps that I've had. In both cases I bought the rubber rings from Eurotubes and it fixed it for me.
Aug 14, 2019 12:57:35 GMT -7
roscoenyc: Guitar amps on carpet make me sad.
Aug 16, 2019 5:23:37 GMT -7
The Bad Poodle: Sunshine on my shoulders makes me happy, Sunshine in my eyes can make me cry
Aug 16, 2019 14:12:09 GMT -7
GuitarZ: Thank you for neighbors with gardens. Fresh veggies and no hassle!
Aug 17, 2019 18:12:08 GMT -7
"Z" Steve: Sunshine Superman? Call any vegetable - call it by name!
Aug 19, 2019 11:53:09 GMT -7
GuitarZ: Idiot! I wanted to put a little air on my Zoom H1's circuit board to clear out any residual Deoxit from spraying the input connector. Guess which can I picked up to spray. Yup! Not the air can.
Aug 23, 2019 10:07:40 GMT -7
premiumplus (Dave): I was wondering why a Frisbee gets larger the closer it gets. Then it hit me.
Aug 24, 2019 6:14:55 GMT -7
easyed: Call any vegetable - call it by name! And the chances are good, that the vegetable will respond to you. F-Zappa.
Oct 1, 2019 19:49:10 GMT -7
The Bad Poodle: rutabay-ayga... rutabay-ayga
Oct 2, 2019 12:33:25 GMT -7
"Z" Steve: I'm losing status at the high school - I used to think that is was MY school
Oct 8, 2019 15:01:34 GMT -7
The Bad Poodle: A bunch of pom-pom girls, Looked down their nose at me. They had painted tons of posters, I had painted three. I hear the secret whispers Everywhere I go, My school spirit is at an All time low...
Oct 8, 2019 17:11:32 GMT -7
"Z" Steve: Oh Look! My hair is getting good in the back!
Oct 10, 2019 20:48:05 GMT -7