70s Ampeg V4B In For RESURRECTION | Rift Weekly Update

[@BCEpedals]

Very interesting behavior from that ampeg! I’m always learning chunks of knowledge, techniques, and so on from your videos!

[@jamesrobinsonjr.9384]

Hi Chris, that 6k11 tube is called a compactron tube, usually three triodes in one tube.

[@rumblinggroover6065]

Hi Chris, nice to see my old Ampeg ‘Oswald’ being brought back to life. The suspense was killing me watching the voltage rise. Great video, can’t wait for the next instalment ❤

[@projekct_amk]

Love that drum solo.. I hope your percussive interlude hasn't upset anyone :P Love the AMPEG P4B PCBs have silk screened the component values on the top side for ease of reading. I have to say, you always convey a great passion for your work, Thank You Chris, keep em coming!

[@enchantederic3792]

You had me, or the Ampeg, had me on the edge of my seat at a few points there! Would not have expected that from bench work ... Fine work, and clearly well experienced craft wisdom. I learned something about electronics here, thanks for that. Oh, I played with a hundred watt version of the Ampeg V4B, as a combo, like (6) 10" speakers in a closed back cab if I remember correctly.Back then I mostly played strats through twins and 50 watt Marshals in the early 80's punk era. But the Ampeg was too intense for me. Powerful shrill upper mids voiced which would take someones *ears* right off.

[@MichaelSmith-rn1qw]

The 11 pin compactron tube was commonly used in old television sets. My 1976 Fender Super Twin Reverb uses a 6C10, which is 3 12AX7 triodes. They are becoming very hard to find (and expensive). Someone has actually designed a plug in converter to use two 12AX7s (leaving one triode not connected).

[@davidlovellbass4761]

That’s really interesting, can you remember who made the 6C10 converter?

[@regaldf.9493]

It's actually 12-pin, and as it contains two high-mu and one medium-mu triodes, it would suit better to substitute it with one 12AX7 and one half-used 12AT7.

[@MichaelSmith-rn1qw]

@@davidlovellbass4761 I thought I had replied yesterday, but it seems to be gone. Do a search for "the telecaster forum" and then do a title search for "super champ 1983 - optimizing". See the discussion and photos/schematic on page 2 of that thread.

[@hoagieman37]

New subscriber and enjoying your videos. I'm just a hobbyist but I've worked on a lot of V4's and the like, they have a lot of quirks depending on which model you get. I'm sure you'll discover this on your own but just want to warn you that the can caps are isolated from chassis ground and carry B+ voltage on them. If you didn't order insulated caps, you'll need to insulate them after installation. Excited to see how you approach the repair and if you run into any of the quirks as I've mentioned.

[@playpaulbee]

Excellent thank you for sharing this, I am just giving my old Ampeg GU12 combo some TLC, they do like to be used regularly, or like a car, at least turned over for a bit. It's possible that V4B is an actual export model, built to run at 240v, I don't think back they they used a different back panel, just put a 240v sticker over the US voltage, also it doesn't have the polarity switch that you see on a lot of Ampegs, just a bit dangerous in the UK! A mate of mine had a none export that came from Canada, it had a separate step down transformer with it, that we got our amp guy to squeeze into the cabinet, making it heavier than an SVT, but a great amp!

[@aluminati9918]

Great run through of the Ampeg! I have the V4 Guitar version from the same year. Wonderful amp, but expensive to maintain. Fairly complex amps compared to the Marshalls of the day. Mine is converted to run 6L6s.

[@andyhightides]

Identical to my V4-B with the white rockers, which I've been told puts it around 1975. I bought mine 20 years ago in Canada for $675 with a 2x15 Dean Markley cab. I took it to my province's most renowned tech, and 7 months later, it was up and running. Maybe 8 years ago, I got it in my head that it needed new power tubes. I took it to a local "tech", and he put a set of JJ's in it, and it has never really given me the same feel that it had before. In passing, the "tech" said he had to disconnect the NFB to get a wattage measurement, and preferred the sound,so he left it disconnected. Always sounded a little suspicious to me, but it runs 3 nights a week, and sounds better than any other bass amp I've tried. It starts to break up between 11 and 12 o'clock with all eq flat.

[@andyhightides]

P.S. my switches are really loose, but function fine.

[@paulshurmon138]

Good one. Thanks for the video.

[@dontthroworanges]

In reference to your comment about the schematic being included with the amp, ever work on a Traynor? The top of the cabinet is removable giving you easy access to the internals without having to take the chassis out. On the underside of the "lid" they always included a printed schematic as well. Tech's best friend!

[@MyNameWasTecho]

Maybe the hieroglyphics are the start of Canvey Island and B Veryard got bored? Interesting to see inside the Ampeg and love the idea shock mounting the chassis, but would be curious to know whether it has an appreciable benefit or just looks cool? I’d say seeing the slow start up was fascinating rather than boring. Just my opinion 😀

[@shckltnebay]

This is the reason people were shocked at Gibson buying Mesa Boogie

[@henryhunter5026]

Very interesting video. I have an old slope fronted Impact 60watt head which I would like to resurrect having not been switched on for about 15 years. I’m pretty sure that new electrolytic capacitors will need replacing before I even try to power it up. It’s a great sounding amp and is built in the old way with chassis mounted valves and pots with the small components on a long tag board.

[@andrewwilliams5042]

I know this is probably not an option due to shipping costs, but there is a guy in Buffalo, NY, US (Not posting web address unless asked) that carries odd Ampeg parts that I have had good experiences with ordering/receiving parts for my old V2. Great info as always, this one is most interesting though since there isn't much about the early 70's V series tops that I can find.

[@TheMegaRonin]

Hi Chris, and thanks for taking the time to keep us solder sniffers going! Q? Have you come across a post PIMV on an amp with a cathodyne phase inverter? Can you think of any pitfalls with adding one to an amp like a Princeton Reverb. Cheers from Palma de Mallorca!

[@schmolly75]

These Ampeg use 7027 toutput ubes but you can use 6L6GC that are cheaper because Ampeg did't use the pins 1 and 6.

[@PhillipAlcock]

Question from a player, not an amp expert.. Why do the 2 inputs have the same resistor? Or another way, what makes one HI and the other LO?

[@regaldf.9493]

It seems, through the contacts in the input jacks the two 68k are in one case connected in parallel for 34k and in the other case it's one on its own in the signal path.

[@ChrisHopkinsBass]

Describe yourself by valve numbers - I’m definitely a 6k11 😂

[@peteqwerty51]

Hi Chris, thanks for posting your interesting and informative videos. I wondered if a heat sensitive camera would help diagnose faults is an amp by showing resistors etc getting hotter than they should? Pete T

[@shawndesjardins3841]

I so miss my 1971 Ampeg V2 but my back doesn't. Sadly it had plenty of issues that i couldn't afford to get fixed and didn't know how, so i sold it for far too cheap. Damn i made a lot of bad decisions with equipment over the years.

[@ryanchamblee2758]

Hey Chris. Really enjoying the channel. What’s your thoughts on the Victory amps. I have a Victory V40 Deluxe combo. I’m in the states. I checked the bias per the manual and found one side was reading around 31ma and the other 29ma. When I went to adjust the bias pot to try and get closer to 34ma (bias point per the manual). I found the pot was already turned fully clockwise at max. The bias will not increase more than what my reading above was. Is this normal? Maybe lower output tubes? They appear to be the original JJ6L6 tubes. Also I have an old Ampeg G-18 solid state little combo with a 2 prong power chord. Is a two prong chord still dangerous on a solid state amp?

[@JohnClemence]

Hope you’re going to change that mains plug Chris.

[@kmetal83]

I hate those old Ampegs with the shock mounted chassis. Such a bitch to work on lol. I don't envy you. Cheers, wonderful channel.

[@alanpecherer5705]

Looks to me like a Brit transformer was kind of bodged into the space occupied by the US original part. I don't think the mod was badly done, at least as far as I can examine it from your video. But I surely do not think it was factory-done.

[@MilesICBarker]

Canvey?