Bardwell guitar amp - UK Vintage Radio Repair and Restoration Discussion Forum

Martin Bush · 27th Sep 2020, 9:49 am

Hi all

I have one of those Bardwells amp boards and a 12" 8ohm speaker. I was simply going to use the speaker connected to a guitar amp and build a box to house the speaker, but I was wondering if I could use the amp board to make a combo.

What I want to ask is, can I safely connect one speaker to what is, I believe, a stereo amp?

Second question is what sort of power supply would be best?

Martjn

AC/HL · 27th Sep 2020, 11:48 am

Is this the amplifier, there have been a few threads about it: https://www.vintage-radio.net/forum/...7&postcount=27

Edward Huggins · 27th Sep 2020, 12:55 pm

If you are only going to use one speaker then you must connect a "dummy load" (a resistor) to the unused channell. Even so, you may be dissappointed with the sound.
This little amp will have great difficulty handling the transients of a guitar.

Martin Bush · 27th Sep 2020, 3:03 pm

Thanks chaps. Resistor between o e speaker out and common ground?

My original idea was to make a simple speaker cab to use with a small guitar amp head I have, but that is way too high gain and will be sold soon. It has no clean setting at all! It seems to start at 11!

I will lash up the speaker and amp and see how it sounds. I have no big expectations, but recall that I did manage for a few years in my teens using a Sony midi system.

David G4EBT · 27th Sep 2020, 5:28 pm

As you're using an 8 Ohm speaker, you'd need an 8 Ohm resistor across the unused channel output and ground. As that's not a preferred value, I guess 2 x 15 Ohm in parallel (7.5 Ohms) would suffice. If you use a couple of 5 Watt ceramic ones they would handle 10 Watts between them, so that would easily cope with the output of the unused channel.

EG, order code 924-815 at this link:

https://www.esr.co.uk/components/pro...-resistors.htm

Amazing little amps - virtually indestructible.

Bardwells had boxes full of them in their cellar that never shifted for twenty years till word got out.

This is what they sound like, or should do:

https://www.youtube.com/watch?v=5gZXleVOTIs

Hope that helps.

buggies · 27th Sep 2020, 6:36 pm

Genuine question - if the OP puts a short across the input of the unused channel, is a resistor still necessary?

Martin Bush · 27th Sep 2020, 7:00 pm

Thanks David. We used to play Klaus Wunderlich when I was the Saturday lad at Romers HiFi!

I think I may need to order a few bits for the amp such as new caps perhaps and, given the feedback so far, am also wondering whether to make a box and treat it as a stereo amp instead. I need neither a hifi amp nor a guitar amp as such, but I fancy an easy project with a useful outcome.

Edward Huggins · 28th Sep 2020, 9:25 am

Why not - it makes so much more sense. Ideally a pair of 8" full-range, 8 ohm, 5 Watt speakers. The sound would be fuller and more widely spread.

27th Sep 2020, 9:49 am	#1
Martin Bush Octode Join Date: Jan 2015 Location: Oxfordshire, UK. Posts: 1,910	Bardwell guitar amp Hi all I have one of those Bardwells amp boards and a 12" 8ohm speaker. I was simply going to use the speaker connected to a guitar amp and build a box to house the speaker, but I was wondering if I could use the amp board to make a combo. What I want to ask is, can I safely connect one speaker to what is, I believe, a stereo amp? Second question is what sort of power supply would be best? Martjn __________________ Is it live, or is it... no, it's live actually...

27th Sep 2020, 11:48 am	#2
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Bardwell guitar amp Is this the amplifier, there have been a few threads about it: https://www.vintage-radio.net/forum/...7&postcount=27

27th Sep 2020, 12:55 pm	#3
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: Bardwell guitar amp If you are only going to use one speaker then you must connect a "dummy load" (a resistor) to the unused channell. Even so, you may be dissappointed with the sound. This little amp will have great difficulty handling the transients of a guitar. __________________ Edward.

27th Sep 2020, 3:03 pm	#4
Martin Bush Octode Join Date: Jan 2015 Location: Oxfordshire, UK. Posts: 1,910	Re: Bardwell guitar amp Thanks chaps. Resistor between o e speaker out and common ground? My original idea was to make a simple speaker cab to use with a small guitar amp head I have, but that is way too high gain and will be sold soon. It has no clean setting at all! It seems to start at 11! I will lash up the speaker and amp and see how it sounds. I have no big expectations, but recall that I did manage for a few years in my teens using a Sony midi system. __________________ Is it live, or is it... no, it's live actually...

27th Sep 2020, 5:28 pm	#5
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,761	Re: Bardwell guitar amp As you're using an 8 Ohm speaker, you'd need an 8 Ohm resistor across the unused channel output and ground. As that's not a preferred value, I guess 2 x 15 Ohm in parallel (7.5 Ohms) would suffice. If you use a couple of 5 Watt ceramic ones they would handle 10 Watts between them, so that would easily cope with the output of the unused channel. EG, order code 924-815 at this link: https://www.esr.co.uk/components/pro...-resistors.htm Amazing little amps - virtually indestructible. Bardwells had boxes full of them in their cellar that never shifted for twenty years till word got out. This is what they sound like, or should do: https://www.youtube.com/watch?v=5gZXleVOTIs Hope that helps. __________________ David. BVWS Member. G-QRP Club member 1339.

27th Sep 2020, 6:36 pm	#6
buggies Heptode Join Date: Jan 2009 Location: West Lothian, UK. Posts: 761	Re: Bardwell guitar amp Genuine question - if the OP puts a short across the input of the unused channel, is a resistor still necessary? __________________ George

27th Sep 2020, 7:00 pm	#7
Martin Bush Octode Join Date: Jan 2015 Location: Oxfordshire, UK. Posts: 1,910	Re: Bardwell guitar amp Thanks David. We used to play Klaus Wunderlich when I was the Saturday lad at Romers HiFi! I think I may need to order a few bits for the amp such as new caps perhaps and, given the feedback so far, am also wondering whether to make a box and treat it as a stereo amp instead. I need neither a hifi amp nor a guitar amp as such, but I fancy an easy project with a useful outcome. __________________ Is it live, or is it... no, it's live actually...

28th Sep 2020, 9:25 am	#8
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: Bardwell guitar amp Why not - it makes so much more sense. Ideally a pair of 8" full-range, 8 ohm, 5 Watt speakers. The sound would be fuller and more widely spread. __________________ Edward.