mart Posted February 24, 2011 Share Posted February 24, 2011 (edited) I've just bought myself a tiny valve head[i], a Blackstar HT1RH[/i]. It says, as you'd expect, that you should connect a speaker before turning the head on. It also has a headphone socket, and when you plug headphones in, it cuts off the sound to the speaker. Does this mean I can use the head with no speaker attached if I'm using headphones? My understanding is that an amp needs a load, and a valve amp especially needs a load. But if the headphone socket cuts off the signal to the speaker, then surely it's disconnecting the speaker, in which case I don't need it connected in the first place. Am I right? (Edited to insert the name of the amp) Edited February 28, 2011 by mart Quote Link to comment Share on other sites More sharing options...
mep Posted February 24, 2011 Share Posted February 24, 2011 I sometimes do the same with my Trace Series 6 head. I'm pretty sure it is ok from reading my manual. It is quite useful as you can use headphones and / or take a line / DI out for recording or plugging into a PA or something. All without lugging your cab around. Quote Link to comment Share on other sites More sharing options...
lettsguitars Posted February 24, 2011 Share Posted February 24, 2011 you should never run a head without a speaker so i've been told. Quote Link to comment Share on other sites More sharing options...
icastle Posted February 24, 2011 Share Posted February 24, 2011 That depends on what the headphone socket is cutting off. I'd guess that what it's doing is breaking the output from the preamp and leaving the power amp running... Quote Link to comment Share on other sites More sharing options...
mart Posted February 24, 2011 Author Share Posted February 24, 2011 [quote name='icastle' post='1139959' date='Feb 24 2011, 01:46 PM']That depends on what the headphone socket is cutting off. I'd guess that what it's doing is breaking the output from the preamp and leaving the power amp running...[/quote] Ooh, I hadn't thought of that possibility. If it is breaking the output from the pre but leaving the power amp running then presumably it [i]does[/i] need a speaker connected? It would have been so much easier if the manufacturer had just spelt it out in the manual. Or replied to the enquiry I put on their website two weeks ago. Quote Link to comment Share on other sites More sharing options...
icastle Posted February 24, 2011 Share Posted February 24, 2011 [quote name='mart' post='1140004' date='Feb 24 2011, 02:38 PM']Ooh, I hadn't thought of that possibility. If it is breaking the output from the pre but leaving the power amp running then presumably it [i]does[/i] need a speaker connected? It would have been so much easier if the manufacturer had just spelt it out in the manual. Or replied to the enquiry I put on their website two weeks ago. [/quote] Yep. It's certainly not just feeding the amp output into the headphones like the old transistor radios used to - I have a similar socket on one of my heads and 500W into a set of headphones could be a bit uncomfortable. Quote Link to comment Share on other sites More sharing options...
mart Posted February 24, 2011 Author Share Posted February 24, 2011 [quote name='icastle' post='1140055' date='Feb 24 2011, 03:20 PM']Yep. It's certainly not just feeding the amp output into the headphones like the old transistor radios used to - I have a similar socket on one of my heads and 500W into a set of headphones could be a bit uncomfortable. [/quote] Ah, that'll be a design feature so that you can get distortion from the amp itself, or from the speakers, or .... from your eardrums melting. Quote Link to comment Share on other sites More sharing options...
icastle Posted February 24, 2011 Share Posted February 24, 2011 [quote name='mart' post='1140110' date='Feb 24 2011, 04:16 PM']Ah, that'll be a design feature so that you can get distortion from the amp itself, or from the speakers, or .... from your eardrums melting. [/quote] Quote Link to comment Share on other sites More sharing options...
mep Posted February 24, 2011 Share Posted February 24, 2011 (edited) I'm back at home now and have just checked my Trace Manual. It says you can unplug the speaker when using headphones. Of course the amp of the OP is a different make and model so best check with the manufacturer. It also says to use modern headphones of 600ohms not older style of 8ohms. Edited February 24, 2011 by mep Quote Link to comment Share on other sites More sharing options...
mart Posted February 24, 2011 Author Share Posted February 24, 2011 (edited) [quote name='mep' post='1140304' date='Feb 24 2011, 07:20 PM']I'm back at home now and have just checked my Trace Manual. It says you can unplug the speaker when using headphones. Of course the amp of the OP is a different make and model so best check with the manufacturer. It also says to use modern headphones of 600ohms not older style of 8ohms.[/quote] Thanks for checking that. Unfortunately the manual for my amp does not say anything about this (I've read every word - it's not a very long manual!) So I'm inclined to go with icastle's suggestion that the power amp is still on and so needs a load, but is disconnected from the preamp. Which makes me think about constructing a jack to 8ohm resistor lead! I wonder what OBBM would make of such a request Edited February 24, 2011 by mart Quote Link to comment Share on other sites More sharing options...
paul_5 Posted February 24, 2011 Share Posted February 24, 2011 Didn't we have one of these yesterday? Long story short - a BCer tried running his Orange Terror Bass Head without a cab and turned it into a smoke machine Quote Link to comment Share on other sites More sharing options...
obbm Posted February 24, 2011 Share Posted February 24, 2011 [quote name='mart' post='1139896' date='Feb 24 2011, 01:07 PM']I've just bought myself a tiny valve head.[/quote] It would be really helpful if you could tell us the make and model of this tiny valve head. Quote Link to comment Share on other sites More sharing options...
dincz Posted February 25, 2011 Share Posted February 25, 2011 [quote name='mart' post='1140641' date='Feb 25 2011, 12:21 AM']the power amp is still on and so needs a load, but is disconnected from the preamp[/quote] The power amp needs a load only if it's amplifying a signal. If the headphone jack interrupts signal from preamp to power amp, then you don't need a load - and the unnecessary 8 ohm resistor will be stone cold. The problem running without a load is remembering every time to reconnect the speaker before you pull out the headphone plug. Quote Link to comment Share on other sites More sharing options...
mart Posted February 25, 2011 Author Share Posted February 25, 2011 [quote name='obbm' post='1140655' date='Feb 24 2011, 11:31 PM']It would be really helpful if you could tell us the make and model of this tiny valve head.[/quote] Whoops, yes, I should have mentioned this. It's a Blackstar HT1RH. (Yes, a guitar amp. So I play a bit of guitar. I can handle it. I can stop anytime I want ...) [quote name='dincz' post='1140802' date='Feb 25 2011, 08:14 AM']The power amp needs a load only if it's amplifying a signal. If the headphone jack interrupts signal from preamp to power amp, then you don't need a load - and the unnecessary 8 ohm resistor will be stone cold. The problem running without a load is remembering every time to reconnect the speaker before you pull out the headphone plug.[/quote] So I can run it without a cab? That would be convenient. Quote Link to comment Share on other sites More sharing options...
mart Posted February 25, 2011 Author Share Posted February 25, 2011 [quote name='paul_5' post='1140647' date='Feb 24 2011, 11:25 PM']Didn't we have one of these yesterday? Long story short - a BCer tried running his Orange Terror Bass Head without a cab and turned it into a smoke machine [/quote] There was a similar question yesterday, but that was a general question about running heads without cabs. My question was more specifically about whether headphones change this: on an amp where the headphone socket cuts the speaker output, is a load necessary [i]when using headphones[/i]? Quote Link to comment Share on other sites More sharing options...
obbm Posted February 25, 2011 Share Posted February 25, 2011 [quote name='mart' post='1140917' date='Feb 25 2011, 10:27 AM']There was a similar question yesterday, but that was a general question about running heads without cabs. My question was more specifically about whether headphones change this: on an amp where the headphone socket cuts the speaker output, is a load necessary [i]when using headphones[/i]?[/quote] It's an all-valve amp and therefore should have a speaker load attached at all times. Page 4 of the user Manual - Warning states "before the unit is switched on, the loudspeaker should be connected as describedin the handbook....." Even if plugging in headphones does disable the speaker output, the reflected load of the speker through the output transformer will have an effect on the output valve. The manual is very unclear so I would pick up the phone and ask Blackstar directly. Quote Link to comment Share on other sites More sharing options...
dincz Posted February 25, 2011 Share Posted February 25, 2011 [quote name='mart' post='1140911' date='Feb 25 2011, 11:22 AM']So I can run it without a cab? That would be convenient.[/quote] Yes, as long as you understand the risk involved in forgetting to reconnect the speaker before pulling the headphone plug. Quote Link to comment Share on other sites More sharing options...
dincz Posted February 25, 2011 Share Posted February 25, 2011 [quote name='obbm' post='1140939' date='Feb 25 2011, 11:48 AM']Even if plugging in headphones does disable the speaker output, the reflected load of the speker through the output transformer will have an effect on the output valve.[/quote] There is no reflected load as there's only a small DC current passing through the primary of the output transformer, and therefore absolutely nothing going on in the secondary. Quote Link to comment Share on other sites More sharing options...
mart Posted February 25, 2011 Author Share Posted February 25, 2011 [quote name='obbm' post='1140939' date='Feb 25 2011, 10:48 AM']It's an all-valve amp and therefore should have a speaker load attached at all times. Page 4 of the user Manual - Warning states "before the unit is switched on, the loudspeaker should be connected as describedin the handbook....." Even if plugging in headphones does disable the speaker output, the reflected load of the speker through the output transformer will have an effect on the output valve.[/quote] Indeed, page 4 warns of the need for a speaker to be connected. And then page 9, referring to the headphone socket, says "when a lead is connected here the combo’s internal speaker is disconnected", suggesting that a speaker isn't needed. (I'm assuming that the amp part of the combo is identical to the head). [quote name='obbm' post='1140939' date='Feb 25 2011, 10:48 AM']The manual is very unclear so I would pick up the phone and ask Blackstar directly.[/quote] I'm glad I'm not the only one who things the manual is not clear enough. I suppose I will have to phone them; I tried contacting them through their website query form and they just ignored it. Quote Link to comment Share on other sites More sharing options...
dincz Posted February 25, 2011 Share Posted February 25, 2011 [quote name='mart' post='1141242' date='Feb 25 2011, 03:12 PM']"when a lead is connected here the combo’s internal speaker is disconnected", suggesting that a speaker isn't needed.[/quote] Not to be taken too literally. What they mean is that no signal is sent to the speaker, almost certainly not that the speaker is physically disconnected. Quote Link to comment Share on other sites More sharing options...
obbm Posted February 25, 2011 Share Posted February 25, 2011 Before going any further I would want to see the wiring schematic of said amplifier. I suspect that getting one is a bit like "blood/stone". Quote Link to comment Share on other sites More sharing options...
dincz Posted February 25, 2011 Share Posted February 25, 2011 (edited) [quote name='obbm' post='1141692' date='Feb 25 2011, 09:23 PM']Before going any further I would want to see the wiring schematic of said amplifier. I suspect that getting one is a bit like "blood/stone". [/quote] I had a poke around and found this: [i]"Thanks for the enquiry. You can use the HT-1 with cabs of a minimum of 4 ohms without causing damage to the head. In other words you can use your cab with the HT-1. Kind regards, Tom Blackstar Customer Services Tel: +44 (0)1604 652844 Email: [email protected]" [/i] .... which makes me wonder if the output stage is actually solid state. Edited February 25, 2011 by dincz Quote Link to comment Share on other sites More sharing options...
mart Posted February 25, 2011 Author Share Posted February 25, 2011 Guitarist magazine had a review of the combo last month and had the following comments about the use of the valves "The single channel runs off a lone ECC83 [i]preamp[/i] valve ..." and then, later, "[i]Power[/i] comes from a not-that-common ECC82 dual triode that's using its two halves to run in class A/B push-pull configuration ..." I can't say that I understand much of that, but I read it as saying that it's using an ECC83 for the preamp and an ECC82 for the power amp, i.e., the output stage is not solid-state. Is that a fair reading? Of course, Guitarist may not know the facts, but that reads like something off a press-release/info pack. Quote Link to comment Share on other sites More sharing options...
dincz Posted February 25, 2011 Share Posted February 25, 2011 [quote name='mart' post='1141895' date='Feb 25 2011, 11:15 PM']Guitarist magazine had a review of the combo last month and had the following comments about the use of the valves "The single channel runs off a lone ECC83 [i]preamp[/i] valve ..." and then, later, "[i]Power[/i] comes from a not-that-common ECC82 dual triode that's using its two halves to run in class A/B push-pull configuration ..." I can't say that I understand much of that, but I read it as saying that it's using an ECC83 for the preamp and an ECC82 for the power amp, i.e., the output stage is not solid-state. Is that a fair reading? Of course, Guitarist may not know the facts, but that reads like something off a press-release/info pack.[/quote] That does seem to be the case. I found a company selling replacement valve sets for it - 1 x ECC83 and 1 x ECC82. I was surprised that Blackstar specify only a minimum load impedance (4 ohms), which is what made me wonder. Quote Link to comment Share on other sites More sharing options...
fretmeister Posted February 26, 2011 Share Posted February 26, 2011 Go on to musicradar and send a message to ecc83. He was involved in the design of some blackstar amps. Some models have protection circuits that stop transformer overload when there is no plug in the speaker out. (the amp still dies if you put a non wired up plug in though). I believe (but don't rely on me) that the ht1 can be run on headphones only as long as there is no jack plug in the speaker out. I have one too. Quote Link to comment Share on other sites More sharing options...
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