Need new amp build!

[azatplayer]

I have a bunch of parts laying around, and am looking for another project.
What i am interested in at the moment is building something that has most of the attributes of my 5E3, which is really a 5E3x2 and is a great amp, but with a little more headroom and clean push, and a trem. I run a pair of KT66's in it and it loves it!
What i have tho is a pair of trannies i was gonna build a standard 2 hole deluxe with, ones a 180ma 320-0-320 PT also has 260-0-260 taps
the OT is a 8.5k 25 watter with 4-8-16 sec.
Looking at the brown 6G3's, as i HAVE to have trem.
Has me wondering if the longtail PI will give me the desired headroom, and i hear the bias driven trem is pretty sweet.
Also the PT should drive 6L6's ok, and the OT being 25 watts, would take bigger glass, and add a little compression when driven, could be cool.
I am open to suggestions. The Allen hot fudge looks like the ticket, based on folks reviews.
Pretty well the brown deluxe i think with some tweakage.
The amps i have are great, dont really need any more, but would be cool to have a 20ish watter for the more quiet gigs.
I am curious for opinions on 2 things with the 5E3. One, is how much would fixed biasing change its character, the other is how much different a LTP would make it. I really dig what if does, for me tho, that little cleaner push when driven harder would make it perfect.
Cheers!

[tubeswell]

FWIW the 5G9 is an amazing little tweed amp with a LTP inverter and bias-vary trem which has an intensely hypnotic 'slamming' quality.

I built one with a 5k Pr Z Ot, but anything up to 8K would sound good IMHO.
2CW. It uses 300-0-300 on the traditional build, but you could get away with 320-0-320 and zenering down the B+ by 20V. You'd need a 3A rectifier winding for the 5U4G

[tyru007]

Fender Princeton Reverb using 6L6s or 6V6? Similar to the Weber 6A14HP and the Allen Sweet Spot. You get the reverb and the bias tremelo.

[img1837]https://taweber.powweb.com/store/6a14hp_schem.jpg[/img]

[azatplayer]

Hmmm. Both great ideas. Gees 410 volts on the plates of a princeton 6V6, i have another trannie with 350-0-350 voltage that could do that.
With the 5G9, i have a rocket trannie, 5.2k, left over from my rocket to liverpool conversion. Could use that in a pinch to suit bigger glass in a 5g9.
I like the 5g9 at the minute. Im not huge on reverb, but might put a loop in as i like a verb pedal in that way.
I have a swart ast, that is a great amp. If anyone has one here, it gets squishy when driven in a pleasing way, i pulled the mojo speaker out, and have tried 4-5 speakers in it. What i have in there right now is a texas heat. It has given the amp 100 percent more clean headroom, in fact the small clubs i use it in, i have to pedal it to get drive, where the mojo breaks by itself. Amazing difference that speaker made. Its still in there too.

[tubeswell]

If you are going to build the 5G9 then build it with 6V6s. The trem circuit is designed to work with 6V6s idling at about 370 plates. This makes the output somewhere between 10 and 15W depending on the Pr Z of your OT, but the trem is outta sight. It kinda slams you into the middle of next week. (It actually beats the PR trem, and is nicer because the oscillator has that CF stage, plus you get the late 50's tweed rawness when you dime it - not quite at rough as the 5E9A or 5E3, but I reckon the fixed bias combo with LTP and Bias-vary trem works a treat)

If you use 6L6s in there you might lose that mojo (in fact you probably would). AFAICT from my own experiments with swapping Fender fixed bias circuits around in different amps, is that they tend to work optimally with the particular model of amp they were commercially released in. 2CW

I built mine with adjustable bias and am running the bias at about 20-22mA.

I also am running it with a Greenback 12h 20Wer heritage series, and with .047uF coupling caps after the first stage and 2.2uF cathode bypass cap on the first stage. YMMV depending on what speaker you want to run and how big you make the cab.

[azatplayer]

Cheers tubeswell. Looks like i might have a winner here. Certainly a great platform to start with by the looks of it.
Hows the windy city? Was there a few years ago, stayed in the cuba precinct. pretty cool town man. Has some great fish and kumeu chips across from where we stayed too. Brilliant. My folks are in Whangarei, dad just had a sextuple bypass in Auckland last week. Yes sextuple!

Cheers man, must continue to pour over layouts and think some more.

Don

[tubeswell]

Hi Don

Its warming up here lately, so my amp building might get seasonally delayed with the onset of summer.

(I'm doing a little BF PR clone right now - but I had to order a proper kywee-made PT for it from Basil Pagett, because the US-made thing that came with the kit (yes I'm ashamed to say that its a kit this time) apparently has a reputation for not being able to take the heat in 230V-50Hz countries. So we'll see. Unbelieveable that Weber apparently don't understand how to make PTs for 50Hz supplies).

Anyhow already got a couple of end of year party gigs over the next fortnight, so the silly season is beginning. That means amp building with slow down for sure.

The 5G9 is king of all those little trem type tweeds I reckon.

[azatplayer]

Thats a very good point on the 50-60 hertz thing. I was having this discussion with my usual amp parts supplier here in melbourne. I buy direct from heyboer, to a spec im looking for for whatever build. They have been great to work with, but i have to this point only spec'd for 230V, without adding the frequency.
I have a few builds that have used heyboer wreck PT's, tonesluts. One of them is this 5E3x2 i built, and love. Considering its running a quad of 6V6's, mostly now a pair of KT66's, 300ma is more than ample for that load, and considerably overspec'd. But, it does get uncomfortably hot. Hot enough that you can hold it lightly on the trannie after its been running for a couple hours, but squeeze it and you cant stay there for very long at all. None of my other amps that ive built, using locally obtained iron, still US and Canadian made, get anywhere near hot. Most are warm at best.
Will have to bear this in mind next time i buy from heyboer. Also the vibration of the wreck PT's is unlike the other imports ive used. In fact the hammond PT's are rock solid quiet and stay cool.

[tubeswell]

Well the guy I usually get my transformers from is a local winder (in Auckland) and he reckons that 230V-50Hz mains supply PTs need about 20% more iron and windings than the 120V-60Hz counterparts (and he has been winding transformers for NZ conditions 40+ years so he ought to know). The PTs I have had from him are quite a bit larger (and heavier) than US PTs and stay quite cool the whole time.

http://www.smeter.net/daily-facts/4/fact15.php

http://www.epanorama.net/documents/comp ... rmers.html

http://en.wikipedia.org/wiki/Utility_frequency

[VacuumVoodoo]

If you can hold "hot" transformer for a few seconds without getting burned its temperature is ca 60-65 degC which is less than a cup of freshly brewed tea or coffee.
Now, here's the bottom line: we have an international standard for power transformers, it is called IEC/EN 61558-2.
What it says in a nut shell is: allowed temperature rise above ambient (25 deg C) is 45 degC i.e. surface temperature max 70 degC. Allowed winding temperature is 110 degC inside the transformer.
Operating frequency range is 47Hz to 63Hz. It means that all performance parameters must be met across this frequency range under full load conditions.

Transformers made in EU, or imported into EU, must carry a CE mark and a spec sticker that looks like this:
[IMG:530:400]http://i26.photobucket.com/albums/c149/ ... atrafo.jpg[/img]
This particular transformer was manufactured to a tougher (on my request) spec requiring continuous duty operation at ambient temperature of 40 degC since it is sitting inside a tube amp. This is why the quoted norm on the sticker says 61558-2-4

Now you can ask yourselves why certain US manufacturers generally refuse to confirm compliance with IEC/EN 61558 norm.
I have my suspicions...

[azatplayer]

Just heard back from heyboer regards my concerns for the frequency.

They are spec'd as 50 hertz after all. So theres no problem there. And as i just read here from Sweden, 70 degrees is within operating parameters.

It may or may not have gotten that hot, but was certainly hotter than any i have touched after running that long in the past. But works well, sounds great and still works.. all good!

Im really liking the idea of the 5g9. Only thing is i dunno if 15 watts is gonna do it for me.

I guess with an efficient speaker, maybe.

Ive not heard or played an actual tweed 5E3, nor a reissue of other clone, so my only exp is with the double deluxe i built. Ive ran it with 2 tubes pulled and matched the impedance, sounds killer, very different to 4 tubes.
But still dont know if its about how they sound.

As thats my point of reference, with what i did running a pair of KT66's in there and a solid state rec, so about 390V plate, i love it. It has all the 5E3 goodness but with a bigger feel, more air, still not hugely loud in comparison to my other 35 wattish amps, but very sweet.
This has me wondering with the 5G9, if i went that route, adding to it the fixed bias and LTP, with that gorgeous trem, if i would get similar results with KT66's.
I guess im just gonna have to find out..

[tubeswell]

Im really liking the idea of the 5g9. Only thing is i dunno if 15 watts is gonna do it for me.

I guess with an efficient speaker, maybe.

FWIW 15W is loud enough for most small club band situations (the BF Princeton Reverb is only about 10-15W after all - the 5e3 is only about 15-18W). A 97dB+ speaker is ample.

[azatplayer]

There is another new contender, the GA40 Gibbo.
Pretty interesting amp.