Bravo / Indeed Headphone amplifiers

[gomez]

Feb 6, 2010 23:28:41 GMT PinkFloyd said:

Feb 6, 2010 23:21:26 GMT gomez said:

Excellent guide Mike I think I'll leave mine until them new valves your sending arrive not much point trimming my hisser but things are looking very very interesting for next week bit of rolling bit of trimming loads of listening I am so pleased I found this place & you Guys.

Paul.............

Try trimming them Gomez

[/color]

I re trimmed them this morning Mike they were well out 11.5v L / 13.8v R got them reading 16.48 L / 16.48v R that was take after about 40 minutes.
I think the amp sounds more in control, bass has more impact & there is more detail and a real sense of timbre to the instruments really nice improvement. But the HHHHISSSSSSS is still as prominent in the left channel

I'll be over the moon with this thing if the valves Mike is sending sort the hiss out because this bloody thing sounds Jaw droppingly good, something in this price range has no right sounding anywhere near this good. Add a pair of HD681's modded Thanks to Mick & Frans and what you have is Aural Ecstasy for peanuts Something that will embarrass some exotic silly money systems.

Gomez........

[Deleted]

I re trimmed them this morning Mike they were well out 11.5v L / 13.8v R got them reading 16.48 L / 16.48v R that was take after about 40 minutes.

Just trimmed mine out 12.4v L 14.6v R, before biasing.

Followed Mikes procedure got them both to the 16.5 optimum, steady hand required to get it spot on, and that reading is still true after an hour. Will get it connected up and running now to see what the results are, plenty of tissues handy in case of Ear Orgasm, and a roll-up and cup of tea, for the chilling out afterwards syndrome ;D

Just for the time being stuck some rubber feet on mine to stop it sliding around, will get some decent "legs" made up asap.

[gomez]

Will get it connected up and running now to see what the results are, plenty of tissues handy in case of Ear Orgasm, and a roll-up and cup of tea, for the chilling out afterwards syndrome

Just don't peak Too Early Mick

[PinkFloyd]

Feb 7, 2010 15:23:43 GMT gomez said:

I re trimmed them this morning Mike they were well out 11.5v L / 13.8v R got them reading 16.48 L / 16.48v R that was take after about 40 minutes.

Yes, my Bravo was pretty "out" as well Gomez, the indeed was better at 15.4V and 16.1 V. You can see how important it is to set the bias when the amp is FULLY warmed up (and not cold)... there is quite a bit of thermal drift and if you set the bias with a cold amp you can be sure that voltage will change as soon as it heats up. If you let the amp cool right down and measure from cold you will see those 16V measurements have changed..... they will only become 16V again when the amp is fully warm.

This explains WHY valve amps sound better after they have been on for a good hour or so

I'd love to see a little amp like this with the trimpots at the front and a couple of voltage meters fitted.... that way you could adjust the bias (as and when) without having to pop the hood. You can also fine tune the bias (with your headphones on) to get the "tone" you want... a lot of guitarists do this with their amps.....

Pretty cranky little things these amps and if you are an OCD type you'll be constantly adjusting the bias I didn't trust the readings from "one" meter so I checked with "three" just to be absolutely sure I also removed the two 220R resistors (L220 / R220 on the diagram) and fitted two raised resistors in their place so I could clip a pair of test leads onto them..... I can now measure both channels at once (you need two multimeters to do this / £5 a pop meters are more than fine for this job) all good fun!

I think the amp sounds more in control, bass has more impact & there is more detail and a real sense of timbre to the instruments really nice improvement. But the HHHHISSSSSSS is still as prominent in the left channel

Well..... it should sound better with the bias correctly adjusted

I'll be over the moon with this thing if the valves Mike is sending sort the hiss out because this bloody thing sounds Jaw droppingly good, something in this price range has no right sounding anywhere near this good. Add a pair of HD681's modded Thanks to Mick & Frans and what you have is Aural Ecstasy for peanuts Something that will embarrass some exotic silly money systems.

I'm ninety percent sure you have an iffy valve there Gomez.... the fact it is only hissing in one channel suggests it's not the SMPS that's to blame..... I'll post you a couple of valves tomorrow.... try the Russian 6H23N first.

[Deleted]

On my second box of tissues, smoked an ounce of GV and now moved on to the Vodka, staying power or what

And that`s on the standard valve , will try a Russian later, if i can get it in the hole ;D

[gomez]

I'm ninety percent sure you have an iffy valve there Gomez.... the fact it is only hissing in one channel suggests it's not the SMPS that's to blame..... I'll post you a couple of valves tomorrow.... try the Russian 6H23N first.

Hi Mike
Can't wait Mate even with the hiss it sounds incredible, when the hiss has gone this thing will Sing I take it the Russian 6H23N is a favorite of yours then ?
I actually quite enjoyed the tinkering under the hood today trimming it.

I'm going to build a couple of Cmoy's to make this week My
daughters making one & I'm making the other.
One of them from scratch the other from a kit on ebay 18v Banzai Elna caps the lot for £12 should be fun.

Gomez.....

[PinkFloyd]

Feb 7, 2010 19:53:32 GMT @heliharris said:

On my second box of tissues, smoked an ounce of GV and now moved on to the Vodka, staying power or what

And that`s on the standard valve , will try a Russian later, if i can get it in the hole ;D

It's not at all bad is it Mick? I'm listening to Pink Floyd's "delicate sound of thunder" album and the presentation is BASTARD good (through Senn HD-250 'phones) she's a little gem, no doubt about it

Your 1969 vintage Russians will be in the post tomorrow, please try one in the Bravo (they are VERY nice ) I'll wait until a few more members have joined this thread and then we can have a discussion about which valves / tubes are the best match for the Bravo / Indeed amps.

Very early days but I am particularly impressed with the JAN / Philips 6922.... it seems a lot more open and less rose tinted than the Electro Harmonix..... I will dedicate an entire day / night rolling valves and will present my findings here. I haven't tried one of my "Russians" yet, I'll let you be the first to comment on them

Nice little amp though, great "looks" and superb sonics for £50 GBP.... it just goes to prove you don't need to spend mega bucks to get good sound. Those who have spent mega bucks will refuse to acknowledge this type of amp or will slate it on it's "technical merit" claiming it can't possibly sound good and only "XYZ / £££" can sound good..... bollocks!

I am not stupid, you guys are not stupid.... we all have our own ears and can hear that this little diamond delivers the goods.... we don't need arm chair listeners to tell us what they think.... the proof of the pudding is in the listening.

To really get the audiphools panties into a knot (sorry... "audiophiles") the Bravo / Indeed amps are perfect with the HD-681...... £70 for an amp "and" a pair of headphones? Nope, that cannot possibly sound good can it?

Yes, it CAN! and, IMO, can sound better than quite a lot of expensive amp / headphone combinations.

Get into your favourite position, take a few tokes of your favourite tobacco and let the music do the talking......

Lovely

[PinkFloyd]

Feb 7, 2010 20:09:45 GMT gomez said:

Hi Mike
Can't wait Mate even with the hiss it sounds incredible, when the hiss has gone this thing will Sing I take it the Russian 6H23N is a favorite of yours then ?

Like them so much I bought 2,000 of them

I actually quite enjoyed the tinkering under the hood today trimming it.

Yup, it's great fun.... the feeling that you are squeezing the "max" out of something.... it's what this place is all about man

I'm going to build a couple of Cmoy's to make this week My daughters making one & I'm making the other.
One of them from scratch the other from a kit on ebay 18v Banzai Elna caps the lot for £12 should be fun.

Any problems / questions with the build, you know where to come.

All the best,

Mike.

[gomez]

Any problems / questions with the build, you know where to come.All the best,Mike.

Cheers Mike that's very much appreciated as is all your help

[PinkFloyd]

Feb 7, 2010 20:35:36 GMT gomez said:

Any problems / questions with the build, you know where to come.All the best,Mike.

Cheers Mike that's very much appreciated as is all your help

It's what this place is here for Gomez No agendas, just open HONEST opinions (without fear of reprisal or having to watch your P's and Q's)......

My philosophy has always been "let it rip"... say it as it is and to hell with the naysayers and armchair experts who constantly try to put you off "anything" positive in your life....

Mike.

[Deleted]

Like them so much I bought 2,000 of them

Mike
I imagine that with cheaper land and housing prices up there, (?) that the potential value of your huge collection of valves must be approaching what the value of your house is ?
Alex

[Deleted]

To really get the audiphools panties into a knot (sorry... "audiophiles") the Bravo / Indeed amps are perfect with the HD-681...... £70 for an amp "and" a pair of headphones? Nope, that cannot possibly sound good can it?

Well i`ve "been into" Hi-Fi for longer than i care to remember Mike, been amongst the best names in the business, done the Penta Hi-Fi, show at Heathrow, 3yrs on the trot, had some of the very best gear in my living room, and my main system sounds just how i want it to sound, luckily most of it came considerably discounted through my contacts through the years, but IMHO, this little Bravo system i have running at the moment, is the best "sound per buck" listen, i have come across so far. FANTASTIC.

[gomez]

Hey Mike
Slightly off topic But a mate of mine phoned rather excitedly the other night he says that Waters is planning another tour apparently he's doing The Wall. Have you heard anything about it ?

[bullpup]

I only seem to be able to find the v2 version with the 12AU7 tube - is this the same thing?

[Deleted]

Feb 7, 2010 21:09:48 GMT @sandyk said:

Like them so much I bought 2,000 of them

Mike
I imagine that with cheaper land and housing prices up there, (?) that the potential value of your huge collection of valves must be approaching what the value of your house is ?
Alex

That's his heating for the winter.

Ian

[Deleted]

Managed to get the Russian in and Bl""dy hell its getting better, and no bias adjustment yet either!!

[gomez]

Feb 7, 2010 21:31:49 GMT @heliharris said:

Managed to get the Russian in and Bl""dy hell its getting better, and no bias adjustment yet either!!

What more tissues, more Gv, more tea, you never said you could go all night.
You got to remeber that, Once a King always a King, But once a Knight is plenty. ;D

[Deleted]

You got to remeber that, Once a King always a King, But once a Knight is plenty.

Once a month would be nice at my age, but like i said before, if the sheets are still dry in the morning, when i get up, and i can still reach my feet to get my socks on, I"M HAPPY!!

[andy]

Just adjusted the bias, was 11.51 in the left and 17.11 in the right!

now 16.49 in each after an hour, and the sound is wonderfull, running it from a portable cd player through a very cheep dac and i love it.

Mike, would you have one of your russian valves that you would prt with, please PM me, thanks.

I have noticed that both the black (large) heatsinks and the small (silver) heatsinks get quite hot, would there be any probelms electronically (shorting and the such) connecting them together onto a larger heatsink? i have a plan i think!

Andy

[PinkFloyd]

Feb 7, 2010 21:49:06 GMT andy said:

Just adjusted the bias, was 11.51 in the left and 17.11 in the right!

Oh well.... they got the right channel almost ok

now 16.49 in each after an hour, and the sound is wonderfull, running it from a portable cd player through a very cheep dac and i love it.

Nice one.

Mike, would you have one of your russian valves that you would part with, please PM me, thanks.

leave it a couple of weeks until you get used to the amp as stock and give me time to try a few of my valves in it to see which is the best bang for the buck.

I have noticed that both the black (large) heatsinks and the small (silver) heatsinks get quite hot, would there be any probelms electronically (shorting and the such) connecting them together onto a larger heatsink? i have a plan i think!

NO! do NOT connect them together!

[Deleted]

I`m now using the Jan Phillips, better still, warm detailed and dynamic, i think this one is staying in, will check bias tomorrow.

[Deleted]

There`s not enough trim to get the bias voltage higher than 15.3L and 15.6R on the Jan Phillips valve ( tried 2) and both much the same. Will that be a problem Mike? gone back to the Russians, plenty of trim available to set 16.5v on those.

[andy]

Thanks for the warning Mike,

will have to rethink my heatsink idea a bit!

And yes it does make sense to get used to the exisiting valve for a while, i have had the amp for 2 months now!

Would replacing the resistors next to the output jack help any as a tweek? looking at the pcb there are not many components to play with on the audio side of things.

Andy

[Deleted]

The Bravo is becoming amazingly good. It's starting to really bloom. Not noticed any major difference following tube and power supply changes until today. (and biasing)

The change of valve and power supply lifted it somewhat but now it's growing in the way it delivers impact and is producing a lovely open sound that doesn't seem trapped in my head at all.

It's powering the K701 with ease and is a rather nice combo. The bass slam is terrific, even on a K701.

I suddenly noticed an improvement listening to some jazz stuff today. Double bass has real presence and there is a beautiful piano tone.

This amp has become a bargain buy for me. I didn't start too well with it, but it seems to be improving with time.

I'm listening to Hiromi's Sonic Bloom on it and it has a real warmth and attack that suits the genre well. Also, I can turn the K701 up with no feeling of edginess that you can get with them. It just gets fuller. It's a nice match actually - seems really silly to be driving a headphone like this with a Bravo.

Ian

[Deleted]

Have a design for 4 extra heat sinks.

4 extra holes in the perspex top cover into which two large black anodised heat sink colomns 20mm dia 30mm high and machined to fit on top of large black originals. and similar, natural finish, 10mm dia 20mm high ones for the smaller front heat sinks.

This design i think would dissipate %25-30 more heat, and give a well balanced look to the original design .