Bought mine in May 2020, works perfectly right from the start 'til today, no hum at all, great sound, I'm very satisfied and definitely would by it again.
I just put a mercury magnetics Output transformer designed for a fender 160-ps PA system in my V4B and it was an incredible difference. I’m going to add a choke to help with the ripple issue
OK, so I finally got the schematics and tube bias instructions from Ampeg - thanks Ampeg. But most importantly, I did my first professional studio recording using the direct output to my mixer - no hum, excellent sound envelope - wow, now I feel much better about this amp.
Bias instruction (at your own risk, use all high voltage precautions): connect load to amp, turn R16 bias pot fully CCW, turn master control fully CCW, turn on power and wait 2 minutes, turn on standby, nothing plugged into inputs, wait another 10 minutes, measure VDC across R12, adjust R16 until you measure 450mVDC - measure VDC across R13, R14 and R15 - should read between 400mVDC and 500mVDC . Service should only be performed by an ISCET Certified Journeyman or Master Electronics technician. If you use New Old Stock tubes, you will need to make sure to buy a matched quartet. Same is true if you buy a new set of tubes. Again, perform this task at your own risk and use all safety precautions like electricians gloves, proper insulated leads, a proper DVM, and the keep one hand in a pocket rule so you can't conduct across your heart.
Hi, the contacts from R12, 13, 14 and 15 on my Amp are covered with some kind of white glue or silicone. Do I have to stab through it with the test leads from the multimeter or am I missing something? I know that the comment ist pretty old, but maybe I'll get an answer anyway.
October 2014 update: hum problem finally solved. I replaced all of the twin triodes (e.g. phase splitter/inverter and preamp tubes) with NOS Siemens tubes. The hum heard at the speaker outputs is now at an acceptable level. Disappointed this amp escaped the factory quality control with obvious hum. I am now playing this amp almost every day - great tone.
It's because there are no more quality modern made tubes. NOS is your only choice and the older the better. Every tube being produced today are made with inferior materials and it's like putting 4 bald tires on your vehicle if you can get a matched quad that doesn't have any grid leakage, they might last 9 months. All tubes are junk right now.
thanks for the video! I saw anther video that said the Standby Switch was too close to the circuit board, and that was causing the hum? Im no expert. thanks again
I just recently got a b from the 90s. As a small bias pot adjustment inside, how do you check the bias on this with new tubes in it without taking it to a tech?
You know this is really sad. This amp is very expensive . and built like crap. What happens now! Do you get your money back. I always wanted an V4B and after this video i decided not to get one. Thanks for this video. I learned alot .
The amp I use most often when recording is my Peavey VB2, but I do like to play for fun through the Ampeg as well - it's just that the hum prevents great recording from it. Thanks for watching!
Hi, I'm working on an Ampeg V-4B and I'm having trouble finding the schematic, I usually find the vintage schematic, but what I'm working on is manufacturing 2006. Can someone help me with the schematic if I have or know of a location that I can download.
So James, I am thinking on buying this one. I already have a PF800 running true a SVT810 70's (stock with (3) blown speakers that I want to restore in january) anyway my set up runs fine but I want the PF as back up. headroom wise or volume wise how loud can be pushed? Tone seems Ampeg so thats no t the issue. but you seems to have knowledge of the build quality on this one.
100 watts RMS (Ampeg V4B) compared to 800 watts RMS (PF800 Mosfet) is unlikely to sound different in most situations. Unless, you are playing to an audience greater than 500 people and/or want to shake the walls down. Check out my review of the V4B vs. Peavey VB2 ... I like the VB2 much better and it costs a lot less money. I opened the Peavey, and I think the build quality on the Peavey is very high.
I wouldn't say it's crap, but I would say it is overpriced. I think Ampeg will have a hard time selling these at retail price with them not made in the USA.
Must be nice to know how to work on your equipment. I just know enough NOT to try to work on a tube amp. For electronic newbies for myself: Don't try this at home!
Well, it's been a couple of weeks and Ampeg decided NOT to send me schematics and tube bias instructions - probably because of this video. I have been using the amp everyday and the hum drives me crazy. I recommend you do not buy this product
Bought mine in May 2020, works perfectly right from the start 'til today, no hum at all, great sound, I'm very satisfied and definitely would by it again.
Year later and still working flawlessly and it still sounds fantastic
I just put a mercury magnetics Output transformer designed for a fender 160-ps PA system in my V4B and it was an incredible difference. I’m going to add a choke to help with the ripple issue
This guy is clueless. I would ignore this vid!
thanks for this video.. I was going to order 2 . I had a 74 ...10 years ago..damn I should have kept it.
Thanks for watching!
We will do that, hopefully this week.
OK, so I finally got the schematics and tube bias instructions from Ampeg - thanks Ampeg. But most importantly, I did my first professional studio recording using the direct output to my mixer - no hum, excellent sound envelope - wow, now I feel much better about this amp.
Bias instruction (at your own risk, use all high voltage precautions): connect load to amp, turn R16 bias pot fully CCW, turn master control fully CCW, turn on power and wait 2 minutes, turn on standby, nothing plugged into inputs, wait another 10 minutes, measure VDC across R12, adjust R16 until you measure 450mVDC - measure VDC across R13, R14 and R15 - should read between 400mVDC and 500mVDC . Service should only be performed by an ISCET Certified Journeyman or Master Electronics technician. If you use New Old Stock tubes, you will need to make sure to buy a matched quartet. Same is true if you buy a new set of tubes. Again, perform this task at your own risk and use all safety precautions like electricians gloves, proper insulated leads, a proper DVM, and the keep one hand in a pocket rule so you can't conduct across your heart.
Hi,
the contacts from R12, 13, 14 and 15 on my Amp are covered with some kind of white glue or silicone. Do I have to stab through it with the test leads from the multimeter or am I missing something?
I know that the comment ist pretty old, but maybe I'll get an answer anyway.
@@valentino99r yeah I ripped it off
October 2014 update: hum problem finally solved. I replaced all of the twin triodes (e.g. phase splitter/inverter and preamp tubes) with NOS Siemens tubes. The hum heard at the speaker outputs is now at an acceptable level. Disappointed this amp escaped the factory quality control with obvious hum. I am now playing this amp almost every day - great tone.
It's because there are no more quality modern made tubes. NOS is your only choice and the older the better. Every tube being produced today are made with inferior materials and it's like putting 4 bald tires on your vehicle if you can get a matched quad that doesn't have any grid leakage, they might last 9 months. All tubes are junk right now.
How loud was the Hum? My V-4B that I bought 1 month ago, hums at low level like a cooling fan. Is that normal?
thanks for the video! I saw anther video that said the Standby Switch was too close to the circuit board, and that was causing the hum? Im no expert. thanks again
Glad I paid $800 for a vintage V-4b, with original cab. $1,200 seems mighty pricey for a defective product.
Todd, Good find! I paid 7 for a 77 V4 head alone.
first off, what problems are you having???? u just said your not happy and found a few defects???? what defects???
What is the defect? Not sure there is one or that you know what you’re talking about.
I just recently got a b from the 90s. As a small bias pot adjustment inside, how do you check the bias on this with new tubes in it without taking it to a tech?
You know this is really sad. This amp is very expensive . and built like crap. What happens now! Do you get your money back. I always wanted an V4B and after this video i decided not to get one. Thanks for this video. I learned alot .
Thanks for this video, if this is gonna be your back up amp, than what is gonna be your main amp?
The amp I use most often when recording is my Peavey VB2, but I do like to play for fun through the Ampeg as well - it's just that the hum prevents great recording from it. Thanks for watching!
can you compare this with your peavey vb2?
Hi, I'm working on an Ampeg V-4B and I'm having trouble finding the schematic, I usually find the vintage schematic, but what I'm working on is manufacturing 2006. Can someone help me with the schematic if I have or know of a location that I can download.
So James, I am thinking on buying this one. I already have a PF800 running true a SVT810 70's (stock with (3) blown speakers that I want to restore in january) anyway my set up runs fine but I want the PF as back up. headroom wise or volume wise how loud can be pushed? Tone seems Ampeg so thats no t the issue. but you seems to have knowledge of the build quality on this one.
100 watts RMS (Ampeg V4B) compared to 800 watts RMS (PF800 Mosfet) is unlikely to sound different in most situations. Unless, you are playing to an audience greater than 500 people and/or want to shake the walls down. Check out my review of the V4B vs. Peavey VB2 ... I like the VB2 much better and it costs a lot less money. I opened the Peavey, and I think the build quality on the Peavey is very high.
where i can buy one of this amplifier?
I knew these things would be crap. I'll stick with my '73 V4B thanks...
I wouldn't say it's crap, but I would say it is overpriced. I think Ampeg will have a hard time selling these at retail price with them not made in the USA.
I'm pretty sure this is a one off un lucky unit...
Guys, can someone identify the 3 switches ? are dpdt toggle ? i will try to build a pedal based on the preamp of this
Must be nice to know how to work on your equipment. I just know enough NOT to try to work on a tube amp. For electronic newbies for myself: Don't try this at home!
Well, it's been a couple of weeks and Ampeg decided NOT to send me schematics and tube bias instructions - probably because of this video. I have been using the amp everyday and the hum drives me crazy. I recommend you do not buy this product
DO YOU EVEN PLAY IN A BAND? LOL !
Cheap chinese parts.
maybe the techs that build the amps know more than you do! lol !!! just play it man! LOL !!