BassmanPaul

Personally the only Latin I learned was Pig Latin!!

When I decided to leave tube amps behind I was using a self designed and built 150W amplifier. I got to designing a SS amp in the pre - stereo power format. 200W/channel at 2Ω. As it was a dual Mono design and had two power transformers it was heavy!

The amp I use today is a Stereo Class D power amp. I built a two channel tube pre-amp to drive it.  I can pick up the rack case it's mounted in with two fingers. Add to that it sounds adorable!!

Paul

Getting back to the original subject of which version to build I would suggest the B15NF. It's the version I own and I love it. Mine still has the original CTS 15" driver which I preferred over the Altec and JBL 2225 I tried in the cabinet.

Using the Octal preamp tubes makes construction easier 'cos of the larger sized socket. To get the best out of the build you must use quality components. The transformers are vitally important. Cheap out here destroys your chances of good tone from the finish project. 

If you decide to use a tube rectifier: GZ34/5AR4 you should add a fast action silicon diode  in series with each plate/anode. This increases the PIV of the rectifier and curbs flashover within the tube. I had to do this with my unit for the same reason.

I wish you luck with the build and if I can be of help please ask.

Paul

On 03/01/2021 at 16:35, Hellzero said:

 

I'm always astonished to read these kind of comments that are simply insulting, but having seen your location, I fully understand your superiority complex, don't worry.

Sorry for derailing your thread @JapanAxe, but I really can't stand this stupid sectarianism.

You've just made an insinuation about someone I have known for many years. He is ALWAYS courteous  and nothing but helpful. Here in Canada we have problems once in a while between folk living in Quebec and folk living in other provinces. Translations can certainly cause difficulties until sorted. Your poor reaction is a comment on you and not on @agedhorse

As an example of his knowledge read through the thread on the Mesa TT800. He designed both it and the Subway series.

On 15/12/2020 at 15:07, 40hz said:

You are a gentleman and a scholar. Thank you so much!

Well he does design amplifiers for Mesa after all! LOL

Don't mess around with cap values - it's too easy to get lost that way. If the 'lil' amp uses a 12AX7/ECC83 try swapping it out for a 12AT7/ECC81. You could also try a 12AU7/ECC82. These are all pin compatible but each has less gain that the one before. See if one will suit your purposes better.

On 31/12/2020 at 04:05, Hellzero said:

Indeed, all modern 6L6 have a Glass Container. 😉

The 'G' refers to a glass container. The letter following defines the variant. For instance I have, somewhere, a pair of 6L6WGB which is an earlier industrial version and not as capable as the GC. I tried those in a Marshall JTM45 and they worked well. The 5881 and 7027 are similar tubes.

When I got to North America I was actually surprised by how many different tubes could be amalgamated under the 6L6 banner. It's why it's important to state the full description for American tubes.

On 28/12/2020 at 06:09, Chimike said:

Ha, 

Well , it might be worth looking at the later SB12 circuit, using 6L6's, as that appears to be what you are describing . I often use an SB 12, and they are fabulous sounding, and lighter than my old B15 !

Just being picky but accuracy in this line of business is important:  The tube needed is a 6L6GC. The 6L6 is an earlier variant usually metal cased, think WWII, and completely unsuitable for a bass amp.

IMO a scope and a signal generator are vital tools. They are how you can see if your amplifier has any spurious artifacts hiding where you can't see them.

I haven't used an AVO since the Sixties but they always give me the warm fuzzies when I think of them. These days Fluke digital meters have replaced them.

You seem to be aware of the pitfalls so I'll wish you luck with the build. What are you doing about a chassis?

Paul

Just for interest, how many tube amplifiers have you successfully built? 

Do you have the tools and test equipment necessary to ensure proper operation of the completed build?

There is a lot of stuff that you need to be aware of for your safety.

I'm not trying to put you off necessarily but these things do run on LETHAL voltages.

On 22/12/2020 at 06:33, Emmol said:

Oh man!!! I am Italian!!! and I struggle a lot with this word... In italian is PRATICA, and it would be easier saying practice then...but I always write practise. So sorry.

 

You're forgiven then!! LOL

Have a wonderful holiday season and a very happy new year! With a bit of luck 2021 will be a better year the world over!!!

45 minutes ago, BreadBin said:

Yes, class D is just a different type of power supply. Lighter and more efficient, but the subject of many debates especially with regard to heft 

Actually it's a different type of amplifier. Often the power supply will be a Switch Mode design to cut down weight.

If your power amp is Class D it's certainly NOT digital. D was just the next letter assigned to a next developed amplifier topology.

It's analogue. 

On 17/12/2020 at 13:28, BillyBass said:

So if people in Canada have never heard of JJB, who do you worship then?

That bloke from Rash with the big nose?

When I worship it surely is a little higher than Geddy! LOL

On 16/12/2020 at 14:33, PaulThePlug said:

Jean Jacques Burnell... The Stranglers

Thank you. I now know who you are talking about. 

18 hours ago, Lozz196 said:

😲

Come on guy - I've been out of the country since 1973!! LOL

Enjoy your new toys!

I must admit that the Mesa TT800 is an amp I'd like to own. From what I have read it's a nice combination of new and vintage tonalities.

Just for interest who is JJB? 

Daisy chaining, amp to speaker 1, speaker 1 to speaker 2 is still a parallel connection. The result is 4Ω.

If you can get by with a comparatively low powered amp an SVT might fit the bill.

As long as you don't get a volume surge above 200 odd watts! You can run a 5W speaker from a 1KW amp as long as you don't drive it past that 5W rating! 

You could use the amp section to power a bass cabinet - say a 2x10 of some kind.

Having looked on-line both cabinets are 8Ω therefore 4Ω when run in parallel. the Amp will supply 325W into that impedance. Split equally between the cabinets each one will see 162.5W. Your baby cabinet will be fine!

You need to tell us what impedances are in play here.

Amp: 325W into what impedance?

Cab 47: What impedance?

Cab 27: what impedance?