Blackstar HT-5 Tube Swap

Discussion - HT-5 amplifiers.
LonePhantom
Posts: 114
Joined: Tue Apr 20, 2010 12:00 am
Location: Canberra, Australia
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Fri Aug 31, 2012 12:21 am

I've got my V30 in a partially closed box and it sounds fantastic. I wouldn't worry about it. ;)

Guitarist
Posts: 34
Joined: Sat Jun 30, 2012 12:00 am

Fri Aug 31, 2012 7:12 am

Cool... then i'll just swap the speaker for the beggining .

antiq
Posts: 5
Joined: Sun Sep 16, 2012 12:00 am

Sun Sep 16, 2012 6:58 am

I also run a HT-5R through a V30. Earlier I decided to hook the head up to my deadbeat Marshall MG50DFX combo speaker, until I can save up for a decent cab. The Eminence speaker there was either broken or simply the worst sounding speaker imaginable. No wonder both MG and HT-5R sounded like crap. After swapping the speaker for a V30 the Marshall really came to life. The tone is actually very nice, hot and present. However, the improvement with HT-5R was so-so at best. Compared to the MG, HT has a quite dull and distant tone. It's almost like there is a thin drywall between the speaker and the player. No amount of tweaking the EQ and ISF can bring the tone 'up front' - it's muffled all the time. What I've read here, the valve doesn't actually determine the overall tone very much with these amps? If this is the case, then I guess it's not a good idea to go around tweaking inside the amp - it'll only void the warranty (as per Blackstar product info).

EDIT: The line-out is quite bright and thin.

antiq
Posts: 5
Joined: Sun Sep 16, 2012 12:00 am

Sun Sep 16, 2012 10:20 am

I'll just add, that the EQ doesn't do much here: the ISF does function somewhat - the UK side on full sounds like the amp is stuffed inside a wardrobe next door, and the treble goes from 'the wardrobe' (at 0 to about 6) to 'muffled' from 6 to 7.5 all the way to having some presence (full open). The bass and the middle don't really do anything. Gain goes from little crunch to moderate crunch, when treble is NOT open. Saturation occurs only when the treble is on full. Volume changes with the treble a bit too.

The MG has a usable treble control with the exactly same speaker - no discrete jumps or muffling (until the treble is almost fully 'closed').

antiq
Posts: 5
Joined: Sun Sep 16, 2012 12:00 am

Mon Sep 17, 2012 11:10 am

I tested the head at the store through a regular BS 1x12" cab, and it sounds fantastic - no trace of muddiness at all. So it's not the amp, not the speaker, but what? The cab frame? The speaker cable? It's really difficult to grasp the effect either of those has on tone. Apparently the MG is so extremely bright an amp, that the muffled tone my current speaker-cab combination brings about is only taming it down to 'normal'. The HT-5R is fine though, and that's the most important lesson today!

antiq
Posts: 5
Joined: Sun Sep 16, 2012 12:00 am

Wed Oct 03, 2012 2:20 pm

OK I got me a Mesa Stiletto cab, and now the tone is clear and defined. The overdrive is very harsh and gritty though, or at the very clockwise-end of the ISF, boomy and hollow. Where's the distortion? All I get is crunch, really.

Line-out through my computer speakers does have a nice, smooth distortion. Very balanced. Of course the tone is not nearly as powerful as with the cabinet, but the base tone is there. So - is it the power section of the amp that's sucking up the gain and dirt? Boosting the amp with an SD-1 has a negligible effect, it mostly compresses the tone and cuts bass. I swapped the preamp valve to a Tung-Sol, but didn't hear much difference there.

Guitarist
Posts: 34
Joined: Sat Jun 30, 2012 12:00 am

Fri Dec 21, 2012 11:26 pm

So i got some Electro harmonics tubes made in russia.. 12AX7. i have no knowledge about what each tube it can change or improve, but what should i expect if i remove the stock HT-5 tube with that 12AX7 ? more headroom, more open sound, or what else ?

I got Orange PPC 112. with Vintage 30. it really improve the low end, and add some headroom to both, clean and overdrive channel. :mrgreen:

Raoul
Posts: 2
Joined: Sun Jan 27, 2013 5:51 am

Sun Jan 27, 2013 6:03 am

I bought the HT-5RH head. It came stock with an TAD ECC83, and a TAD 12BH7. I replaced the ECC83, which in North America is a 12AX7. I replaced them with a TAD 7025WA and a Electro-Harmonix Gold 12BH7. Each tube was an improvement in the sound. Using the 1 x 12 Blackbird speaker cab (16 ohm). I know the 12BH7 needs biasing so using the pictures in the forum I had a look inside. Bad news, picture does not look at all like my model. There is a bias pot and a balance pot. I turned the balance pot from one side to the other. Made a buzzy noise on each extreme so I turned it so the speaker was the quietest. Although I did fool with the bias pot (and my multimeter looking for the right spot to measure) I left it as best as I could tell where it was.

Now I'm worried I need to see a Tech ASAP to ensure the adjustment is correct...fuse is inside as well, mad I forgot to pop it out and see the value to get a spare.

Guitarist
Posts: 34
Joined: Sat Jun 30, 2012 12:00 am

Sun Jan 27, 2013 8:22 pm

I have just replace the stock Sovtek 12ax7 tube with Tung Sol 12ax7. now i got the question about power tube: which one is good combination with Tung Sol 12ax7 ?

Raoul
Posts: 2
Joined: Sun Jan 27, 2013 5:51 am

Thu Feb 28, 2013 1:07 am

Knocked my HT-5RH head over. Volume was breaking up so I replaced the tubes with balanced Electro-Harmonix 12AX7 (says 110 a side) and a balanced Electro Harmonix 12BH7 (says 65 side). To my surprise these less expensive tubes make my HT-5 sound the best it ever has plus it produces much less heat yet gain and volume are not affected. First tube amp so if someone knows what's going on it would be appreciated! Still have not taken it in for rebiasing ($$$-local shop sends it away for weeks)

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