BassmanPaul

White noise is a product of all active electronics. Some folk are more sensitive to it than others. Same goes for fan noise. In reality, on stage, neither would be audible.

I have built hundreds of amps over the last sixty years. The Ampeg B15 is a very simple build. You should stick to the circuit exactly and use the 6SL7 octal preamp tubes. They have a certain 'something' that adds to the B15 mystic. I have every thing I need including chassis to build six more amps. As winter progresses I'll make a start on the first. I'm thinking of a B15 clone using a pair of KT66s that I've had in my tube stores for years. Time to put them to good use. I already own a B15NF and whilst reconditioning it I ran into Two problems. After installing new caps I experience flash over in the GZ34/5AR4 rectifier. the cure was to add a fast recovery silicon diode in series with each plate/anode of the GZ34. The second was the 6L6GCs red plating in spite of the negative bias being correct. Cure was replacing the 270KΩ grid bias resistors with 100KΩ as per the RCA tube manual. I feel that the amp is sensitive to the 'new' tubes being produced today. Good luck with the build. It's very rewarding when you step out on stage using equipment that you put together with your own hand!!

Unfortunately it's not as simple as that and you might just make things worse. When disaster strikes if the item is of good quality it's worth putting money into it to promote reliability. Remember that flood water also contains sewage. Yuck!!

For some reason I got it into my head the Positive Grid were based in the UK. on checking they seem to be in Las Vegas! LOL

I have never even seen one of Alex's Barefaced cabinets so I cannot comment on that score. I use the Acme Sound B2 three way cabinet. I'm certain that one would cover most gigs but I am conservative with my gear. I stack them on their ends so the divers are vertically aligned. They work better that way all around. Two stacked atop each other of a vertical 4x10 is my go to amplifier system. I always use the pair whenever I gig. Newer drivers are more capable so I bow to BFM's wiser knowledge base. That said I can't imagine being able to successfully play a gig with just one ten.

I fear for your ears. It's no fun being deaf and hearing aids are expensive. My current pair cost six grand!!

I'm sorry for your troubles I really am. I would consider sending it in to the manufacturer for their opinion. Water, especially filthy flood water, is not a healthy thing for any amp class D or no. Water would likely have gotten into the pots and switches. I don't think any manufacturer would gouge you with excessive fees for such an event.

Two cabinets always sound better, fuller than just one.

@sandy_r Thank you for taking the time to help out.

Thank you for the kind words. On April 04 1981 Lionheart played a formal at Toronto's Ontario place. WOW!!! That's 42 years ago! It only seems like yesterday. On an impulse we dangled a microphone over our light trees on each side of the stage. Connected to a cassette recorder we let it run. What came from it was surprisingly good and pretty well balanced. This recording I copied onto my computer and then burned to CD. I got them out and listened to the entire night. LOL It showed just how good John's playing was. His vocals are amazing. He was trained a St Micheal's Choir School here in Toronto. I wish I could post a bit but the files are all too large.

Today I am deeply saddened to hear that the Keyboard player from the best band I ever played with has passed away at the age of 71. We lost our Drummer Dennis to cancer and now John has gone. As a band we shared such adventures going to gig after gig here in the Toronto GTA and across Southern Ontario. The music wa played was wonderful. Our Beatle medley was such fun. Forty five minutes of non stop Beatle music. Rest in peace John. Edit: I know this is the wrong place for this but if anyone could understand how I feel it would be other musicians.

For anyone who plans on working on an amplifier it behooves them to at least learn the basics of electronics. Would you work on a car's engine without learning a bit about it before you start?

With the greatest of respect @Beedster that schematic is about as simple as one could be. I could almost build that blindfolded!!

I broke a sweat just looking at that rack!!

Padded Bra it is then! LOL Forgive my ribald sense of humour.

You'd definitely need an underwire Bra to hold that rack safely! 😊

Just for the fun of it:

Amen to that! Exactly my thoughts too. It took me years to find the sound I was looking for and now I've found it. I sound like a bass and not a fuzzed out low strung guitar!!

I had three sixes all made by Carvin in the US. First was `a white body with a Maple neck and Ebony finger board. I still own that one. Next came a beautiful fretless in Koa with an Ebony neck. The thought of the wide expanse of black Ebony worried me so I had them install fret lines. This is my favourite bass to play. It's still here with me. After surviving my third stroke my wife bought me another bass this time in Walnut. It was incredibly heavy!! This one I sent to my nephew who I discovered plays bass. He is studying at Oxford. He loves the instrument. Sound wise all three suffered a bit with the first and sixth strings. The pickups were standard size Jazz bass and I felt there was not enough magnet under those strings. I had them all changed out for EMG soap bars and they all now sound wonderful!! Being booked for an appearance on Toronto's Breakfast Television I took both the white and the fretless with me. For some reason when It was our time I picked up the fretless! It was the first time I had ever played it in concert. The show went well and later I discovered the clip of our show on YouTube! I was gobsmacked! It's the only video I have of me playing. LOL

I just watched all of the Star Wars movies, not at one sitting I should add!! LOL

When I first went to using rack gear I had a power bar, a Korg tuner, a pre-amp and a 1400W Class AB power amp. Looked great but I could hardly lift it. The system sounded great so I was prepared to accept the weight. I should add: I was a LOT younger then too!!! I started using Snark clip on tuners so the Korg was removed. Through many iterations rack units came and went. Crossovers, EQs, and other units got swapped in and out as time passed. I still have a plethora of these various components hanging around my workshop. LOL My final assembly, in a four space SKB rack case, consists of a 2KW capable Class D power amp and a Tube pre-amp I built to drive it. I can lift the whole thing with just two fingers. It supplies around 1KW into two of my Acme Sound B2 speaker cabinets. It gives me the full 2KW when I use all four of my B2 boxes.

As a fellow six string player what is that gorgeous bass hanging above theMesa amp??

You'll get tired of toting that rack pretty quick! LOL

@Beedster did you try the old saw of linking the Send and Return of the Effects Loop with a signal cable to see if that helps?

You may have no choice but to go to a Class D head in the future. I think you'll find that Class AB amplifiers are going to be less and less available. I really don't understand what the negativity is about Class D amps. All my amps are now Class D from may bass amp to my PA systems. Lack of heft you say? My amp has all the heft that anyone could wish for. Pushing two or four of my Acme Sound B2 three way cabinets I can almost blow the roof off any venue I've used it in.